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NOAA-15

2026-10-30T15:37:13Z

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International Space Station

2026-10-29T05:56:42Z

Mukhash:

[[File:The station pictured from the SpaceX Crew Dragon 5.jpg|thumb|right|View of ISS]]
The '''International Space Station''' ('''ISS''') is a space station in low Earth orbit (LEO). It is the product of the International Space Station program and is operated by five partner space agencies: NASA (United States), Roscosmos (Russia), ESA (Europe), JAXA (Japan), and CSA (Canada). It is the first space station built, maintained and crewed through international cooperation and the largest human spacecraft ever constructed. It is an orbital research station, where scientific experiments in microgravity are conducted and the space environment is studied. Since 2 November 2000, it has hosted the longest continuous human presence in space. Alongside China's ''Tiangong'', it is one of two currently operational space stations.

== ISS SSTV ==
For decades, space enthusiasts have dreamed of communicating with astronauts. However, one of the most exciting and accessible ways to connect with the International Space Station (ISS) does not require a license or expensive gear. Through Slow-Scan Television (SSTV) transmissions, anyone on Earth can receive static images broadcast directly from the space station using a basic radio receiver or even a smartphone.
What is ISS SSTV?
Slow-Scan Television is an amateur radio transmission protocol that converts still images into audio tones. Instead of the massive bandwidth required to stream live video, SSTV compresses a single picture into a narrow voice channel. When these audio tones are picked up on Earth, software translates the shifting pitches back into lines of color, building an image piece by piece on a screen over the course of a few minutes.
These broadcasts are organized by the Amateur Radio on the International Space Station (ARISS) program. They usually coincide with space exploration milestones, student educational events, or historical anniversaries. When active, the onboard transceiver automatically broadcasts a picture, rests for a couple of minutes, and then sends the next image in a continuous cycle.

== Station details ==

The station orbits between 51.64° north and south, at about 400km above Earth, below the Van Allen radiation belts and most space debris. Its orbit takes it at 7.67km/s roughly every 93 minutes around Earth, daily orbits 15.5 times a day. Measuring 358ft (with solar arrays) by 239ft, it is as large as a full-sized football or soccer field, and has a pressurised internal volume of 1,005 m3 (35,491 ft3), comparable to a Boeing 747 airliner.

The station is a modular space station divided into two main sections: the Russian Orbital Segment (ROS), developed by Roscosmos, and the US Orbital Segment (USOS), built by NASA, ESA, JAXA, and CSA. The Integrated Truss Structure connects the station's vast system of solar panels and radiators to its 16 major pressurized modules. These modules support scientific research, crew habitation, storage, spacecraft control, and airlock operations. The ISS has eight docking and berthing ports for visiting spacecraft. In total, the station consists of 43 different modules and elements. Crews visit via the Soyuz and Crew Dragon spacecraft, and previously the Space Shuttle. Cargo supply craft include Progress, Cargo Dragon, Cygnus, Automated Transfer Vehicle, and HTV-X.

The ISS is the political product of the development of international cooperation in space throughout the space age. The station combines two previously planned crewed Earth-orbiting stations: the United States' Space Station ''Freedom'' and the Soviet Union's ''Mir-2''. The first ISS module was launched in 1998, with major components delivered by Proton, Soyuz and Space Shuttle launch vehicles. Long-term occupancy began with the arrival of the Expedition 1 crew on 2 November 2000. Since then, the ISS has remained continuously inhabited since 2 November 2000, the longest continuous human presence in space. As of 2025.08, 290 individuals from 26 countries had visited the station.

Future plans for the ISS include the addition of at least one module, the Payload Power Thermal Module by Axiom Space, forming the commercial segment of the station. The station is expected to remain operational until the end of 2030, by which parts of it are to be used for Axiom Station and the Russian Orbital Station. After this the ISS is planned to be de-orbited using the US Deorbit Vehicle, but critique of this plan and the proposal of parking the station at a more stable higher orbit has gathered congressional support as of 2026.
[[Category:Radio Stations]][[Category:Satellites]][[Category:Modems]]

International Space Station

2026-10-29T05:56:08Z

Mukhash:

File:The station pictured from the SpaceX Crew Dragon 5.jpg

2026-10-29T05:53:58Z

Mukhash:

International Space Station

2026-10-29T05:50:42Z

Mukhash: Created page with "The '''International Space Station''' ('''ISS''') is a space station in low Earth orbit (LEO). It is the product of the International Space Station program and is operated by five partner space agencies: NASA (United States), Roscosmos (Russia), ESA (Europe), JAXA (Japan), and CSA (Canada). It is the first space station built, maintained and crewed through international cooperation and the largest human spacecraft ever constructed. It is an orbital research station, wher..."

The '''International Space Station''' ('''ISS''') is a space station in low Earth orbit (LEO). It is the product of the International Space Station program and is operated by five partner space agencies: NASA (United States), Roscosmos (Russia), ESA (Europe), JAXA (Japan), and CSA (Canada). It is the first space station built, maintained and crewed through international cooperation and the largest human spacecraft ever constructed. It is an orbital research station, where scientific experiments in microgravity are conducted and the space environment is studied. Since 2 November 2000, it has hosted the longest continuous human presence in space. Alongside China's ''Tiangong'', it is one of two currently operational space stations.

The station orbits between 51.64° north and south, at about {{convert|400|km|abbr=off}} above Earth, below the Van Allen radiation belts and most space debris. Its orbit takes it at {{cvt|7.67|km/s|km/h mph}} roughly every 93 minutes around Earth, {{Orbit|daily orbits|15.5}} times a day. Measuring {{cvt|358|ft|order=flip}} (with solar arrays) by {{cvt|239|ft|order=flip}}, it is as large as a full-sized football or soccer field, and has a pressurised internal volume of 1,005 m3 (35,491 ft3), comparable to a Boeing 747 airliner.

The station is a modular space station divided into two main sections: the Russian Orbital Segment (ROS), developed by Roscosmos, and the US Orbital Segment (USOS), built by NASA, ESA, JAXA, and CSA. The Integrated Truss Structure connects the station's vast system of solar panels and radiators to its 16 major pressurized modules. These modules support scientific research, crew habitation, storage, spacecraft control, and airlock operations. The ISS has eight docking and berthing ports for visiting spacecraft. In total, the station consists of 43 different modules and elements. Crews visit via the Soyuz and Crew Dragon spacecraft, and previously the Space Shuttle. Cargo supply craft include Progress, Cargo Dragon, Cygnus, Automated Transfer Vehicle, and HTV-X.

The ISS is the political product of the development of international cooperation in space throughout the space age. The station combines two previously planned crewed Earth-orbiting stations: the United States' Space Station ''Freedom'' and the Soviet Union's ''Mir-2''. The first ISS module was launched in 1998, with major components delivered by Proton, Soyuz and Space Shuttle launch vehicles. Long-term occupancy began with the arrival of the Expedition 1 crew on 2 November 2000. Since then, the ISS has remained continuously inhabited for {{age in years and days|2 November 2000|sep=and}}, the longest continuous human presence in space. {{As of|2025|08}}, 290 individuals from 26 countries had visited the station.

Future plans for the ISS include the addition of at least one module, the Payload Power Thermal Module by Axiom Space, forming the commercial segment of the station. The station is expected to remain operational until the end of 2030, by which parts of it are to be used for Axiom Station and the Russian Orbital Station. After this the ISS is planned to be de-orbited using the US Deorbit Vehicle, but critique of this plan and the proposal of parking the station at a more stable higher orbit has gathered congressional support {{as of|2026|lc=y}}.

NOAA-15

2026-10-29T05:48:23Z

Mukhash:

NOAA-15

2026-10-29T05:47:34Z

Mukhash:

NOAA-15

2026-10-29T05:47:18Z

Mukhash:

NOAA-15

2026-10-29T05:42:30Z

Mukhash:

[[File:500px-NOAA-M.jpg|thumb|NOAA-15]]
'''NOAA-15''', also known as '''NOAA-K''' before launch, was a polar-orbiting, NASA-provided Television Infrared Observation Satellite (TIROS) series weather forecasting satellite operated by National Oceanic and Atmospheric Administration (NOAA). NOAA-15 was the latest in the Advanced TIROS-N (ATN) series. It provided support to environmental monitoring by complementing the NOAA/NESS Geostationary Operational Environmental Satellite program (GOES).

== Launch ==
[[File:T2 07 G12 NOAA-K.jpg|thumb|Launch of NOAA-15]]
It was launched by the Titan 23G launch vehicle on 13 May 1998 at 15:52:04 UTC from Vandenberg Air Force Base, at Vandenberg Space Launch Complex 4 (SLW-4W), NOAA-15 replaced the decommissioned NOAA-12 in an afternoon equator-crossing orbit and is in 2021 semi-operational, in a Sun-synchronous orbit (SSO), at 808.0 km above the Earth, orbiting every 101.20 minutes.

== Spacecraft ==
The goal of the NOAA/NESS polar orbiting program is to provide output products used in meteorological prediction and warning, oceanographic and hydrologic services, and space environment monitoring. The NOAA-I Advanced TIROS-N spacecraft is based on the Defense Meteorological Satellite Program (DMSP Block 5D) spacecraft and is modified version of the TIROS-N spacecraft (NOAA-1 to NOAA-5). The spacecraft structure consists of four components: 1° the Reaction System Support (RSS); 2° the Equipment Support Module (ESM), which has been expanded from the TIROS-N design; 3° the Instrument Mounting Platform (IMP); and 4° the Solar Array (SA).

== Instruments ==
All of the instruments are located on the ESM and the IMP. The spacecraft power is provided by a direct energy transfer system from the single solar array which consists of eight panels of solar cells. The power system for the Advanced TIROS-N has been upgraded from the previous TIROS-N design. The in-orbit Attitude Determination and Control Subsystem (ADACS) provides three-axis pointing control by controlling torque in three mutually orthogonal momentum wheels with input from the Earth Sensor Assembly (ESA) for pitch, roll, and yaw updates. The ADACS controls the spacecraft attitude so that orientation of the three axes is maintained to within ± 0.2° and pitch, roll, and yaw to within 0.1°. The ADACS consists of the Earth Sensor Assembly (ESA), the Sun Sensor Assembly (SSA), four Reaction Wheel Assemblies (RWA), two roll/yaw coils (RYC), two pitch torqueing coils (PTC), four gyros, and computer software for data processing.

Instruments were flown for imaging and measurement of the atmosphere of Earth, its surface, and cloud cover, including Earth radiation, atmospheric ozone, aerosol distribution, sea surface temperature, vertical temperature and water profiles in the troposphere and stratosphere; measurement of proton and electron flux at orbit altitude, and remote platform data collection, and for SARSAT. They included: 1° an improved six-channel Advanced Very High Resolution Radiometer (AVHRR/3); 2° an improved High Resolution Infrared Radiation Sounder (HIRS/3); 3° the Search and Rescue Satellite Aided Tracking System (SARSAT), which consists of the Search and Rescue Repeater (SARR) and the Search and Rescue Processor (SARP-2); 4° the French/CNES-provided improved ARGOS Data Collection System (DCS-2); and 5° the Advanced Microwave Sounding Units (AMSUs), which replaced the previous MSU and SSU instruments to become the first in the NOAA series to support dedicated microwave measurements of temperature, moisture, surface and hydrological studies in cloudy regions where visible and infrared instruments have decreased capability.

=== Advanced Very High Resolution Radiometer (AVHRR/3) ===
[[File:AVHRR3 instrument.jpg|NOAA AVHRR/3 Instrument]]
The AVHRR/3 on the Advanced TIROS-N NOAA K-N series of polar orbiting meteorological satellites is an improved instrument over previous AVHRRs. The AVHRR/3 adds a sixth channel and is a cross-track scanning instrument providing imaging and radiometric data in the visible, near-IR and infrared of the same area on the Earth. Data from the visible and near-IR channels provide information on vegetation, clouds, snow, and ice. Data from the near-IR and thermal channels provide information on the land and ocean surface temperature and radiative properties of clouds. Only five channels can be transmitted simultaneously with channels 3A and 3B being switched for day/night operation. The instrument produces data in High Resolution Picture Transmission (HRPT) mode at 1.1 km resolution or in Automatic Picture Transmission (APT) mode at a reduced resolution of 4 km. The AVHRR/3 scans 55.4° per scan line on either side of the orbital track and scans 360 lines per minute. The six channels are: 1) channel 1, visible (0.58-0.68 μm); 2) channel 2, near-IR (0.725-1.0 μm); 3) channel 3A, near-IR (1.58-1.64 μm); 4) channel 3B, infrared (3.55-3.93 μm); 5) channel 4, infrared (10.3-11.3 μm); and 6) channel 5 (11.5-12.5 μm).

=== High Resolution Infrared Sounder (HIRS/3) ===
[[File:HIRS 4 instrument.jpg|The HIRS/4 Satellite Instrament]]
The improved High Resolution Infrared Sounder/3 (HIRS/3) on the Advanced TIROS-N (ATN) NOAA K-N series of polar orbiting meteorological satellites is a 20-channel, step-scanned, visible and IR spectrometer designed to provide atmospheric temperature and moisture profiles. The HIRS/3 instrument is basically identical to the HIRS/2 flown on previous spacecraft except for changes in six spectral bands to improve the sounding accuracy. The HIRS/3 is used to derive water vapor, ozone, and cloud liquid water content. The instrument scans 49.5° on either side of the orbital track with a ground resolution at nadir of 17.4 km. The instrument produces 56 IFOVs for each 1,125 km scan line at 42 km between IFOVs along-track. The instrument consists of 19 IR and 1 visible channel centered at 14.95, 14.71, 14.49, 14.22, 13.97, 13.64, 13.35, 11.11, 9.71, 12.45, 7.33, 6.52, 4.57, 4.52, 4.47, 4.45, 4.13, 4.0, 3.76, and 0.69 μm.

=== Advanced Microwave Sounding Unit (AMSU-A) ===
The AMSU is a new instrument on the Advanced TIROS-N (ATN) NOAA K-N series of operational meteorological satellites. The AMSU consists of two functionally independent units, AMSU-A and AMSU-B. The AMSU-A is a line-scan instrument designed to measure scene radiance in 15 channels, ranging from 23.8 to 89 GHz, to derive atmospheric temperature profiles from the Earth's surface to about 3 millibar pressure height. The instrument is a total power system having a field of view (FOV) of 3.3° at half-power points. The antenna provides cross track scan 50 degrees on either side of the orbital track at nadir with a total of 30 IFOVs per scan line. The AMSU-A is calibrated on-board using a blackbody and space as references. The AMSU-A is physically divided into two separate modules which interface independently with the spacecraft.
{| class="wikitable sortable"
!Channel
!Frequency (GHz)
!Module
|-
|1
|23.8 GHz
|AMSU-A2
|-
|2
|31.4 GHz
|AMSU-A2
|-
|3
|50.3 GHz
|AMSU-A1
|-
|4
|52.8 GHz
|AMSU-A1
|-
|5
|53.596 GHz
|AMSU-A1
|-
|6
|54.4 GHz
|AMSU-A1
|-
|7
|54.94 GHz
|AMSU-A1
|-
|8
|55.5 GHz
|AMSU-A1
|-
|9
|57.29 GHz
|AMSU-A1
|-
|10
|57.29 GHz
|AMSU-A1
|-
|11
|57.29 GHz
|AMSU-A1
|-
|12
|57.29 GHz
|AMSU-A1
|-
|13
|57.29 GHz
|AMSU-A1
|-
|14
|57.29 GHz
|AMSU-A1
|-
|15
|89.0 GHz
|AMSU-A1
|}

== Advanced Microwave Sounding Unit 1 (AMSU-A1) ==
The AMSU-A1 is the primary module of the AMSU-A instrument, containing 13 channels that operate between 50 and 90 GHz. It includes 12 oxygen absorption channels for temperature sounding and one 89 GHz window channel for surface information. The first AMSU-A was launched on May 13, 1998, aboard NOAA-15, and has since flown on multiple NOAA satellites as well as NASA's Aqua and EUMETSAT's MetOp series.<ref name="Instrument3" />

== Advanced Microwave Sounding Unit A2 (AMSU-A2) ==
The AMSU-A2 module is the second component of AMSU-A, containing just two low-frequency channels at 23.8 GHz and 31.4 GHz. These channels measure surface temperature and atmospheric moisture, including total precipitable water and cloud liquid water content. The A2 module was developed by Northrop Grumman and works alongside AMSU-A1 to provide complete atmospheric sounding data from different altitudes.<ref name="Instrument3" />

=== Advanced Microwave Sounding Unit (AMSU-B) ===
{| class="wikitable sortable"
!Channel
!Frequency
!Bandwidth (MHz)
!Purpose
|-
|16
|89.00 GHz
|<6000
|Window channel (surface)
|-
|17
|150.00 GHz
|<4000
|Window channel (surface)
|-
|18
|183.31 GHz
|500
|Water vapor line
|-
|19
|183.31 GHz
|1000
|Water vapor line
|-
|20
|183.31 GHz
|2000
|Water vapor line
|}
[[https://en.wikipedia.org/wiki/File:AMSU-B_Diagram.png|thumb|A diagram of the AMSU-B instrament]]
The AMSU is a new instrument on the Advanced TIROS-N (ATN) NOAA K-N series of operational meteorological satellites. The AMSU consists of two functionally independent units, AMSU-A and AMSU-B. The AMSU-B is a line-scan instrument designed to measure scene radiance in five channels, ranging from 89 GHz to 183 GHz for the computation of atmospheric water vapor profiles. The AMSU-B is a total power system with a FOV of 1.1° at half-power points. The antenna provides a cross-track scan, scanning 50° on either side of the orbital track with 90 IFOVs per scan line at approximately 22.5 scans per minute. One scan line is completed in 2.67 seconds. On-board calibration is accomplished with blackbody targets and space as references. The AMSU-B channels at the center frequency (GHz) are: 90, 157, and 3 channels at 183.31, providing a nominal horizontal resolution at nadir of approximately 16 kilometers. However, the footprint size increases significantly at the edges of the scan swath, reaching resolutions between 50 and 150 kilometers depending on scan angle.

=== Space Environment Monitor (SEM-2) ===
The SEM-2 on the Advanced TIROS-N (ATN) NOAA K-N series of polar orbiting meteorological satellites provides measurements to determine the population of the Earth's radiation belts and data on charged particle precipitation in the upper atmosphere as a result of solar activity. The SEM-2 consists of two separate sensors the Total Energy Detector (TED) and the Medium Energy Proton/Electron Detector (MEPED). In addition, the SEM-2 includes a common Data Processing Unit (DPU). The TED uses eight programmed swept electrostatic curved-plate analyzers to select particle type and energy and Channeltron detectors to measure the instensity in the selected energy bands. The particle energies range from 50 eV to 20 keV. The MEPED detects protons, electrons, and ions with energies from 30 keV to several tens of MeV. The MEPED consists of four directional solid-state detector telescopes and four omnidirectional sensors. The DPU sorts and counts the events and the results are multiplexed and incorporated into the satellite telemetry system. Once received on the ground, the SEM-2 data is separated from the rest of the data and sent to the NOAA Space Environment Laboratory in Boulder, Colorado, for processing and dissemination.

=== Solar Backscatter Ultraviolet Radiometer (SBUV/2) ===
[[https://en.wikipedia.org/wiki/File:SBUV_Instrament.jpg|thumb|An image of the SBUV instrament]]
The SBUV/2 on the Advanced TIROS-N (ATN) NOAA K-N series of polar orbiting meteorological satellites is a dual monochromator ultraviolet grating spectrometer for stratospheric ozone measurements. The SBUV/2 is designed to measure scene radiance and solar spectral irradiance in the ultraviolet spectral range from 160 to 406 nm. Measurements are made in discrete mode or sweep mode. In discrete mode, measurements are made in 12 spectral bands from which the total ozone and vertical distribution of ozone are derived. In the sweep mode, a continuous spectral scan from 160 to 406 nm is made primarily for computation of ultraviolet solar spectral irradiance. The 12 spectral channels are (nm): 252.0, 273.61, 283.1, 287.7, 292,29, 297.59, 301.97, 305.87, 312.57, 317.56, 331.26, and 339.89.

=== Search and Rescue Satellite Aided Tracking System (SARSAT) ===
The SARSAT on the Advanced TIROS-N NOAA K-N series of polar orbiting meteorological satellites is designed to detect and locate Emergency Locator Transmitters (ELTs) and Emergency Position-Indicating Radio Beacons (EPIRB). The SARSAT instrumentation consists of two elements: the Search and Rescue Repeater (SARR) and the Search and Rescue Processor (SARP-2). The SARR is a radiofrequency (RF) system that accepts signals from emergency ground transmitters at three very high frequency (VHF/UHF) ranges (121.5 MHz, 243 MHz and 406.05 MHz) and translates, multiplexes, and transmits these signals at L-band frequency (1.544 GHz) to local Search and Rescue stations (LUTs or Local User Terminals) on the ground. The location of the transmitter is determined by retrieving the Doppler information in the relayed signal at the LUT. The SARP-2 is a receiver and processor that accepts digital data from emergency ground transmitters at UHF and demodulates, processes, stores, and relays the data to the SARR where they are combined with the three SARR signals and transmitted via L-band frequency to local stations.

=== ARGOS Data Collection System (DCS-2 - Argos) ===
The DCS-2 on the Advanced TIROS-N (ATN) NOAA K-N series of polar orbiting meteorological satellites is a random-access system for the collection of meteorological data from in situ platforms (moveable and fixed). The ARGOS DCS-2 collects telemetry data using a one-way RF link from data collection platforms (such as buoys, free-floating balloons and remote weather stations) and processes the inputs for on-board storage and later transmission from the spacecraft. For free-floating platforms, the DCS-2 system determines the position to within 5 to 8 km RMS and velocity to an accuracy of 1.0 to 1.6 mps RMS. The DCS-2 measures the in-coming signal frequency and time. The formatted data are stored on the satellite for transmission to NOAA stations. The DCS-2 data is stripped from the GAC data by NOAA/NESDIS and sent to the Argos center at CNES in France for processing, distribution to users, and archival.

== Telecommunications ==
The TIP formats low bit rate instruments and telemetry to tape recorders and direct read-out. The MIRP process high data rate AVHRR to tape recorders (GAC) and direct read-out (HRPT and LAC). On-board recorders can store 110 minutes of GAC, 10 minutes HRPT and 250 minutes TIP.

== Mission ==
The Automatic Picture Transmission (APT) transmission frequency is 137.62 MHz. Due to problems with the S-band transmitter high-gain antennas, NOAA-15 has been configured for High-Resolution Picture Transmission (HRPT) using the S-Band Transmitter #2 (1702.5 MHz) omnidirectional antenna. Issues with antennas were attributed to thermal stress causing internal component breakage.

=== Failure of the AVHRR scanning motor ===
On 22 July 2019, NOAA-15 began transmitting corrupt data. The cause appears to be instability of the scanning motor for the AVHRR sensor. According to an official release from NOAA, on 23 July 2019 at 04:00 UTC, the current draw of that motor spiked, as did the motor temperature. Additionally, the sensor stopped producing data. NOAA says this is consistent with a motor stall, and could be permanent. On 25 July 2019, the AVHRR motor spontaneously recovered. On 30 July 2019, the AVHRR motor suffered another failure consistent with motor stall. As per the previous statement by NOAA, recovery is unlikely:<blockquote>As of ~00:00 UTC on 30 July 2019 (Day of year (DOY) 211), the AVHRR motor current has once again started spiking, becoming saturated above 302 mA at ~06:00 UTC. The instrument is once again no longer producing data and may be stalled. The current plan is to leave the instrument powered as this issue may be intermittent.</blockquote>The AVHRR was operating nominally and producing quality data until 18 October 2022, when again there was an issue with the AVHRR Scan Motor.<blockquote>The NOAA-15 AVHRR Scan Motor current began showing signs of instability on Oct 18 at approximately 1800Z, when the current began to gradually rise from about 205 mA to about 250 mA, where it remained until Oct 24. At about 0000Z on Oct 24, the current began rising again throughout the day, peaking at about 302mA on Oct 25. Scan motor temperature began rising about the same time and is currently steady at ~29°C. The instrument is still producing data, but it is highly degraded. This behavior may be a sign of an impending scan motor stall, but requires further investigation. Options for recovery are limited.</blockquote>The AVHRR was successfully recovered and continued operations as before until decommissioning.

== End of Mission ==
In April 2025, NOAA announced that they would suspend POES data - data from NOAA-15 and NOAA-19 - on June 16, 2025, and decommission NOAA-15 on August 12, 2025.

However, on August 9 NOAA-19 encountered a battery failure and was decommissioned early on August 13. As a result, the decommissioning date of NOAA-15 was extended until the week of August 18. NOAA will not deorbit the satellite. Instead, it has been left in orbit and put into a safe electrical state, with the transmitters shut down. NOAA-15 was ultimately decommissioned on August 19, 2025, on at 20:37 UTC.

NOAA-15

2026-10-29T05:42:08Z

Mukhash: Created page with "Launch of NOAA-15 '''NOAA-15''', also known as '''NOAA-K''' before launch, was a polar-orbiting, NASA-provided Television Infrared Observation Satellite (TIROS) series weather forecasting satellite operated by National Oceanic and Atmospheric Administration (NOAA). NOAA-15 was the latest in the Advanced TIROS-N (ATN) series. It provided support to environmental monitoring by complementing the NOAA/NESS Geostationary Operational Environment..."

[[File:500px-NOAA-M.jpg|thumb|Launch of NOAA-15]]
'''NOAA-15''', also known as '''NOAA-K''' before launch, was a polar-orbiting, NASA-provided Television Infrared Observation Satellite (TIROS) series weather forecasting satellite operated by National Oceanic and Atmospheric Administration (NOAA). NOAA-15 was the latest in the Advanced TIROS-N (ATN) series. It provided support to environmental monitoring by complementing the NOAA/NESS Geostationary Operational Environmental Satellite program (GOES).

== Launch ==
[[File:T2 07 G12 NOAA-K.jpg|thumb|Launch of NOAA-15]]
It was launched by the Titan 23G launch vehicle on 13 May 1998 at 15:52:04 UTC from Vandenberg Air Force Base, at Vandenberg Space Launch Complex 4 (SLW-4W), NOAA-15 replaced the decommissioned NOAA-12 in an afternoon equator-crossing orbit and is in 2021 semi-operational, in a Sun-synchronous orbit (SSO), at 808.0 km above the Earth, orbiting every 101.20 minutes.

== Spacecraft ==
The goal of the NOAA/NESS polar orbiting program is to provide output products used in meteorological prediction and warning, oceanographic and hydrologic services, and space environment monitoring. The NOAA-I Advanced TIROS-N spacecraft is based on the Defense Meteorological Satellite Program (DMSP Block 5D) spacecraft and is modified version of the TIROS-N spacecraft (NOAA-1 to NOAA-5). The spacecraft structure consists of four components: 1° the Reaction System Support (RSS); 2° the Equipment Support Module (ESM), which has been expanded from the TIROS-N design; 3° the Instrument Mounting Platform (IMP); and 4° the Solar Array (SA).

== Instruments ==
All of the instruments are located on the ESM and the IMP. The spacecraft power is provided by a direct energy transfer system from the single solar array which consists of eight panels of solar cells. The power system for the Advanced TIROS-N has been upgraded from the previous TIROS-N design. The in-orbit Attitude Determination and Control Subsystem (ADACS) provides three-axis pointing control by controlling torque in three mutually orthogonal momentum wheels with input from the Earth Sensor Assembly (ESA) for pitch, roll, and yaw updates. The ADACS controls the spacecraft attitude so that orientation of the three axes is maintained to within ± 0.2° and pitch, roll, and yaw to within 0.1°. The ADACS consists of the Earth Sensor Assembly (ESA), the Sun Sensor Assembly (SSA), four Reaction Wheel Assemblies (RWA), two roll/yaw coils (RYC), two pitch torqueing coils (PTC), four gyros, and computer software for data processing.

Instruments were flown for imaging and measurement of the atmosphere of Earth, its surface, and cloud cover, including Earth radiation, atmospheric ozone, aerosol distribution, sea surface temperature, vertical temperature and water profiles in the troposphere and stratosphere; measurement of proton and electron flux at orbit altitude, and remote platform data collection, and for SARSAT. They included: 1° an improved six-channel Advanced Very High Resolution Radiometer (AVHRR/3); 2° an improved High Resolution Infrared Radiation Sounder (HIRS/3); 3° the Search and Rescue Satellite Aided Tracking System (SARSAT), which consists of the Search and Rescue Repeater (SARR) and the Search and Rescue Processor (SARP-2); 4° the French/CNES-provided improved ARGOS Data Collection System (DCS-2); and 5° the Advanced Microwave Sounding Units (AMSUs), which replaced the previous MSU and SSU instruments to become the first in the NOAA series to support dedicated microwave measurements of temperature, moisture, surface and hydrological studies in cloudy regions where visible and infrared instruments have decreased capability.

=== Advanced Very High Resolution Radiometer (AVHRR/3) ===
[[File:AVHRR3 instrument.jpg|NOAA AVHRR/3 Instrument]]
The AVHRR/3 on the Advanced TIROS-N NOAA K-N series of polar orbiting meteorological satellites is an improved instrument over previous AVHRRs. The AVHRR/3 adds a sixth channel and is a cross-track scanning instrument providing imaging and radiometric data in the visible, near-IR and infrared of the same area on the Earth. Data from the visible and near-IR channels provide information on vegetation, clouds, snow, and ice. Data from the near-IR and thermal channels provide information on the land and ocean surface temperature and radiative properties of clouds. Only five channels can be transmitted simultaneously with channels 3A and 3B being switched for day/night operation. The instrument produces data in High Resolution Picture Transmission (HRPT) mode at 1.1 km resolution or in Automatic Picture Transmission (APT) mode at a reduced resolution of 4 km. The AVHRR/3 scans 55.4° per scan line on either side of the orbital track and scans 360 lines per minute. The six channels are: 1) channel 1, visible (0.58-0.68 μm); 2) channel 2, near-IR (0.725-1.0 μm); 3) channel 3A, near-IR (1.58-1.64 μm); 4) channel 3B, infrared (3.55-3.93 μm); 5) channel 4, infrared (10.3-11.3 μm); and 6) channel 5 (11.5-12.5 μm).

=== High Resolution Infrared Sounder (HIRS/3) ===
[[File:HIRS 4 instrument.jpg|The HIRS/4 Satellite Instrament]]
The improved High Resolution Infrared Sounder/3 (HIRS/3) on the Advanced TIROS-N (ATN) NOAA K-N series of polar orbiting meteorological satellites is a 20-channel, step-scanned, visible and IR spectrometer designed to provide atmospheric temperature and moisture profiles. The HIRS/3 instrument is basically identical to the HIRS/2 flown on previous spacecraft except for changes in six spectral bands to improve the sounding accuracy. The HIRS/3 is used to derive water vapor, ozone, and cloud liquid water content. The instrument scans 49.5° on either side of the orbital track with a ground resolution at nadir of 17.4 km. The instrument produces 56 IFOVs for each 1,125 km scan line at 42 km between IFOVs along-track. The instrument consists of 19 IR and 1 visible channel centered at 14.95, 14.71, 14.49, 14.22, 13.97, 13.64, 13.35, 11.11, 9.71, 12.45, 7.33, 6.52, 4.57, 4.52, 4.47, 4.45, 4.13, 4.0, 3.76, and 0.69 μm.

=== Advanced Microwave Sounding Unit (AMSU-A) ===
The AMSU is a new instrument on the Advanced TIROS-N (ATN) NOAA K-N series of operational meteorological satellites. The AMSU consists of two functionally independent units, AMSU-A and AMSU-B. The AMSU-A is a line-scan instrument designed to measure scene radiance in 15 channels, ranging from 23.8 to 89 GHz, to derive atmospheric temperature profiles from the Earth's surface to about 3 millibar pressure height. The instrument is a total power system having a field of view (FOV) of 3.3° at half-power points. The antenna provides cross track scan 50 degrees on either side of the orbital track at nadir with a total of 30 IFOVs per scan line. The AMSU-A is calibrated on-board using a blackbody and space as references. The AMSU-A is physically divided into two separate modules which interface independently with the spacecraft.
{| class="wikitable sortable"
!Channel
!Frequency (GHz)
!Module
|-
|1
|23.8 GHz
|AMSU-A2
|-
|2
|31.4 GHz
|AMSU-A2
|-
|3
|50.3 GHz
|AMSU-A1
|-
|4
|52.8 GHz
|AMSU-A1
|-
|5
|53.596 GHz
|AMSU-A1
|-
|6
|54.4 GHz
|AMSU-A1
|-
|7
|54.94 GHz
|AMSU-A1
|-
|8
|55.5 GHz
|AMSU-A1
|-
|9
|57.29 GHz
|AMSU-A1
|-
|10
|57.29 GHz
|AMSU-A1
|-
|11
|57.29 GHz
|AMSU-A1
|-
|12
|57.29 GHz
|AMSU-A1
|-
|13
|57.29 GHz
|AMSU-A1
|-
|14
|57.29 GHz
|AMSU-A1
|-
|15
|89.0 GHz
|AMSU-A1
|}

== Advanced Microwave Sounding Unit 1 (AMSU-A1) ==
The AMSU-A1 is the primary module of the AMSU-A instrument, containing 13 channels that operate between 50 and 90 GHz. It includes 12 oxygen absorption channels for temperature sounding and one 89 GHz window channel for surface information. The first AMSU-A was launched on May 13, 1998, aboard NOAA-15, and has since flown on multiple NOAA satellites as well as NASA's Aqua and EUMETSAT's MetOp series.<ref name="Instrument3" />

== Advanced Microwave Sounding Unit A2 (AMSU-A2) ==
The AMSU-A2 module is the second component of AMSU-A, containing just two low-frequency channels at 23.8 GHz and 31.4 GHz. These channels measure surface temperature and atmospheric moisture, including total precipitable water and cloud liquid water content. The A2 module was developed by Northrop Grumman and works alongside AMSU-A1 to provide complete atmospheric sounding data from different altitudes.<ref name="Instrument3" />

=== Advanced Microwave Sounding Unit (AMSU-B) ===
{| class="wikitable sortable"
!Channel
!Frequency
!Bandwidth (MHz)
!Purpose
|-
|16
|89.00 GHz
|<6000
|Window channel (surface)
|-
|17
|150.00 GHz
|<4000
|Window channel (surface)
|-
|18
|183.31 GHz
|500
|Water vapor line
|-
|19
|183.31 GHz
|1000
|Water vapor line
|-
|20
|183.31 GHz
|2000
|Water vapor line
|}
[[https://en.wikipedia.org/wiki/File:AMSU-B_Diagram.png|thumb|A diagram of the AMSU-B instrament]]
The AMSU is a new instrument on the Advanced TIROS-N (ATN) NOAA K-N series of operational meteorological satellites. The AMSU consists of two functionally independent units, AMSU-A and AMSU-B. The AMSU-B is a line-scan instrument designed to measure scene radiance in five channels, ranging from 89 GHz to 183 GHz for the computation of atmospheric water vapor profiles. The AMSU-B is a total power system with a FOV of 1.1° at half-power points. The antenna provides a cross-track scan, scanning 50° on either side of the orbital track with 90 IFOVs per scan line at approximately 22.5 scans per minute. One scan line is completed in 2.67 seconds. On-board calibration is accomplished with blackbody targets and space as references. The AMSU-B channels at the center frequency (GHz) are: 90, 157, and 3 channels at 183.31, providing a nominal horizontal resolution at nadir of approximately 16 kilometers. However, the footprint size increases significantly at the edges of the scan swath, reaching resolutions between 50 and 150 kilometers depending on scan angle.

=== Space Environment Monitor (SEM-2) ===
The SEM-2 on the Advanced TIROS-N (ATN) NOAA K-N series of polar orbiting meteorological satellites provides measurements to determine the population of the Earth's radiation belts and data on charged particle precipitation in the upper atmosphere as a result of solar activity. The SEM-2 consists of two separate sensors the Total Energy Detector (TED) and the Medium Energy Proton/Electron Detector (MEPED). In addition, the SEM-2 includes a common Data Processing Unit (DPU). The TED uses eight programmed swept electrostatic curved-plate analyzers to select particle type and energy and Channeltron detectors to measure the instensity in the selected energy bands. The particle energies range from 50 eV to 20 keV. The MEPED detects protons, electrons, and ions with energies from 30 keV to several tens of MeV. The MEPED consists of four directional solid-state detector telescopes and four omnidirectional sensors. The DPU sorts and counts the events and the results are multiplexed and incorporated into the satellite telemetry system. Once received on the ground, the SEM-2 data is separated from the rest of the data and sent to the NOAA Space Environment Laboratory in Boulder, Colorado, for processing and dissemination.

=== Solar Backscatter Ultraviolet Radiometer (SBUV/2) ===
[[https://en.wikipedia.org/wiki/File:SBUV_Instrament.jpg|thumb|An image of the SBUV instrament]]
The SBUV/2 on the Advanced TIROS-N (ATN) NOAA K-N series of polar orbiting meteorological satellites is a dual monochromator ultraviolet grating spectrometer for stratospheric ozone measurements. The SBUV/2 is designed to measure scene radiance and solar spectral irradiance in the ultraviolet spectral range from 160 to 406 nm. Measurements are made in discrete mode or sweep mode. In discrete mode, measurements are made in 12 spectral bands from which the total ozone and vertical distribution of ozone are derived. In the sweep mode, a continuous spectral scan from 160 to 406 nm is made primarily for computation of ultraviolet solar spectral irradiance. The 12 spectral channels are (nm): 252.0, 273.61, 283.1, 287.7, 292,29, 297.59, 301.97, 305.87, 312.57, 317.56, 331.26, and 339.89.

=== Search and Rescue Satellite Aided Tracking System (SARSAT) ===
The SARSAT on the Advanced TIROS-N NOAA K-N series of polar orbiting meteorological satellites is designed to detect and locate Emergency Locator Transmitters (ELTs) and Emergency Position-Indicating Radio Beacons (EPIRB). The SARSAT instrumentation consists of two elements: the Search and Rescue Repeater (SARR) and the Search and Rescue Processor (SARP-2). The SARR is a radiofrequency (RF) system that accepts signals from emergency ground transmitters at three very high frequency (VHF/UHF) ranges (121.5 MHz, 243 MHz and 406.05 MHz) and translates, multiplexes, and transmits these signals at L-band frequency (1.544 GHz) to local Search and Rescue stations (LUTs or Local User Terminals) on the ground. The location of the transmitter is determined by retrieving the Doppler information in the relayed signal at the LUT. The SARP-2 is a receiver and processor that accepts digital data from emergency ground transmitters at UHF and demodulates, processes, stores, and relays the data to the SARR where they are combined with the three SARR signals and transmitted via L-band frequency to local stations.

=== ARGOS Data Collection System (DCS-2 - Argos) ===
The DCS-2 on the Advanced TIROS-N (ATN) NOAA K-N series of polar orbiting meteorological satellites is a random-access system for the collection of meteorological data from in situ platforms (moveable and fixed). The ARGOS DCS-2 collects telemetry data using a one-way RF link from data collection platforms (such as buoys, free-floating balloons and remote weather stations) and processes the inputs for on-board storage and later transmission from the spacecraft. For free-floating platforms, the DCS-2 system determines the position to within 5 to 8 km RMS and velocity to an accuracy of 1.0 to 1.6 mps RMS. The DCS-2 measures the in-coming signal frequency and time. The formatted data are stored on the satellite for transmission to NOAA stations. The DCS-2 data is stripped from the GAC data by NOAA/NESDIS and sent to the Argos center at CNES in France for processing, distribution to users, and archival.

== Telecommunications ==
The TIP formats low bit rate instruments and telemetry to tape recorders and direct read-out. The MIRP process high data rate AVHRR to tape recorders (GAC) and direct read-out (HRPT and LAC). On-board recorders can store 110 minutes of GAC, 10 minutes HRPT and 250 minutes TIP.

== Mission ==
The Automatic Picture Transmission (APT) transmission frequency is 137.62 MHz. Due to problems with the S-band transmitter high-gain antennas, NOAA-15 has been configured for High-Resolution Picture Transmission (HRPT) using the S-Band Transmitter #2 (1702.5 MHz) omnidirectional antenna. Issues with antennas were attributed to thermal stress causing internal component breakage.

=== Failure of the AVHRR scanning motor ===
On 22 July 2019, NOAA-15 began transmitting corrupt data. The cause appears to be instability of the scanning motor for the AVHRR sensor. According to an official release from NOAA, on 23 July 2019 at 04:00 UTC, the current draw of that motor spiked, as did the motor temperature. Additionally, the sensor stopped producing data. NOAA says this is consistent with a motor stall, and could be permanent. On 25 July 2019, the AVHRR motor spontaneously recovered. On 30 July 2019, the AVHRR motor suffered another failure consistent with motor stall. As per the previous statement by NOAA, recovery is unlikely:<blockquote>As of ~00:00 UTC on 30 July 2019 (Day of year (DOY) 211), the AVHRR motor current has once again started spiking, becoming saturated above 302 mA at ~06:00 UTC. The instrument is once again no longer producing data and may be stalled. The current plan is to leave the instrument powered as this issue may be intermittent.</blockquote>The AVHRR was operating nominally and producing quality data until 18 October 2022, when again there was an issue with the AVHRR Scan Motor.<blockquote>The NOAA-15 AVHRR Scan Motor current began showing signs of instability on Oct 18 at approximately 1800Z, when the current began to gradually rise from about 205 mA to about 250 mA, where it remained until Oct 24. At about 0000Z on Oct 24, the current began rising again throughout the day, peaking at about 302mA on Oct 25. Scan motor temperature began rising about the same time and is currently steady at ~29°C. The instrument is still producing data, but it is highly degraded. This behavior may be a sign of an impending scan motor stall, but requires further investigation. Options for recovery are limited.</blockquote>The AVHRR was successfully recovered and continued operations as before until decommissioning.

== End of Mission ==
In April 2025, NOAA announced that they would suspend POES data - data from NOAA-15 and NOAA-19 - on June 16, 2025, and decommission NOAA-15 on August 12, 2025.

However, on August 9 NOAA-19 encountered a battery failure and was decommissioned early on August 13. As a result, the decommissioning date of NOAA-15 was extended until the week of August 18. NOAA will not deorbit the satellite. Instead, it has been left in orbit and put into a safe electrical state, with the transmitters shut down. NOAA-15 was ultimately decommissioned on August 19, 2025, on at 20:37 UTC.

File:AMSU-B Diagram.png

2026-10-29T05:41:55Z

Mukhash:

File:HIRS 4 instrument.jpg

2026-10-29T05:41:11Z

Mukhash:

File:AVHRR3 instrument.jpg

2026-10-29T05:40:29Z

Mukhash:

File:T2 07 G12 NOAA-K.jpg

2026-10-29T05:39:38Z

Mukhash:

File:500px-NOAA-M.jpg

2026-10-29T05:37:41Z

Mukhash:

Category:NOAA APT

2026-10-29T05:32:37Z

Mukhash:

[[File:NOAAAPT.png|thumb|right|3 examples of APT transmission]]
'''Automatic Picture Transmission (APT)''', also known as '''NOAA-GEOSAT''', is an analog image transmission mode used to by the NOAA weather satellites and formerly some Russian weather satellites to transmit satellite weather photos. On August 19th 2025, the final satellite transmitting this mode (NOAA-15) was decommissioned at 15:26 UTC. This mode is no longer in use in real life, however NOAA-15 is still transmitting APT in SimTX

== Characteristics ==

=== Structure ===
The broadcast transmission was composed of two image channels, telemetry information, and synchronization data, with the image channels typically referred to as Video A and Video B. All this data was transmitted as a horizontal scan line. A complete line is 2080 pixels long, with each image using 909 pixels and the remainder going to the telemetry and synchronization. Lines were then transmitted at 2 per second, which equates to a 4160 words per second, or 4160 baud.
Format of Automatic Picture Transmission. We see the two parallel Video streams being transmitted, each at 120 LPM.
{| class="wikitable"
!Name
!Length in pixels
!Description
|-
|Sync A
|39
|Bits 000011001100110011001100110011000000000
|-
|Space A
|47
|-
|Image A
|909
|Image pixels, a higher amplitude results in a brighter pixel
|-
|Telemetry A
|45
|-
|Sync B
|39
|Bits 000011100111001110011100111001110011100
|-
|Space B
|47
|-
|Image B
|909
|Image pixels, a higher amplitude results in a brighter pixel
|-
|Telemetry B
|45
|-
|'''Total'''
|2080 / 0.5 seconds
|}

=== Images ===
[[File:NOAA-15 APT 28 10 2026 1305-1309z.png|thumb|right|Received image from [https://www.youtube.com/watch?v=kp4Qi8zm-sM NOAA-15 28th October 2026] in comparison to the Earth map]]
On NOAA POES system satellites, the two images are 4 km / pixel smoothed 8-bit images derived from two channels of the advanced very-high-resolution radiometer (AVHRR) sensor. The images are corrected for nearly constant geometric resolution prior to being broadcast; as such, the images are free of distortion caused by the curvature of the Earth.

Of the two images, one is typically long-wave infrared (10.8 micrometers) with the second switching between near-visible (0.86 micrometers) and mid-wave infrared (3.75 micrometers) depending on whether the ground is illuminated by sunlight. However, NOAA can configure the satellite to transmit any two of the AVHRR's image channels.

=== Synchronization and telemetry ===
Included in the transmission are a series of synchronization pulses, minute markers, and telemetry information.

The synchronization information, transmitted at the start of each video channel, allows the receiving software to align its sampling with the baud rate of the signal, which can vary slightly over time. The minute markers are four lines of alternating black then white lines which repeat every 60 seconds (120 lines).

The telemetry section is composed of sixteen blocks, each 8 lines long, which are used as reference values to decode the image channels. The first eight blocks, called "wedges," begin at 1/8 max intensity and successively increase by 1/8 to full intensity in the eighth wedge, with the ninth being zero intensity. Blocks ten through fifteen each encode a calibration value for the sensor. The sixteenth block identifies which sensor channel was used for the preceding image channel by matching the intensity of one of the wedges one through six. Video channel A typically matches either wedge two or three, channel B matches wedge four.

The first fourteen blocks should be identical for both channels. The sixteen telemetry blocks repeat every 128 lines, and these 128 lines are referred to as a frame.

=== Broadcast signal ===
The signal itself is a 256-level amplitude modulated 2400Hz subcarrier, which is then frequency modulated onto the 137 MHz-band RF carrier. Maximum subcarrier modulation is 87% (±5%), and overall RF bandwidth is 34 kHz. On NOAA POES vehicles, the signal is broadcast at approximately 37dBm (5 watts) effective radiated power.

== Frequencies ==
NOAA 15 - 137.620 MHz

== Example of transmission: ==
[https://www.youtube.com/watch?v=kp4Qi8zm-sM NOAA-15 28th October 2026]

[https://www.youtube.com/watch?v=RBA5noS5xy0 NOAA-15 20th August 2025]

[https://www.youtube.com/watch?v=OARj5wguj6M NOAA-19 13th May 2024]

== Antennas ==
The NOAA satellites that downlink APT signals transmit with a right-hand circularly polarized (RHCP) quadrifilar helical antenna (QFH). Using an RHCP QFH to receive these signals is a good idea, as the polarization will be the same and the antenna has a very wide beamwidth. Other popular choices that are circularly polarized are the turnstile and double cross dipole antenna.

Another option is a v-dipole. Though it is linearly polarized, the polarization mismatch loss is typically insignificant and easily ignored. This antenna uses two legs roughly 54cm long spread 120° apart at the feed point. This forms a 'V' shape, with the feed point (where the coaxial cable connects) at the bottom corner where both legs meet. This v-dipole is more directional than the previously mentioned antennas so it must be positioned properly. Point the antenna so that the legs are parallel to the ground, and a line bisecting the angle between the legs points North or South, it doesn't matter which. The height above the ground matters for this antenna. Heights that are multiples of half the wavelength should be avoided, so ~1m, ~2m, ~3m, etc due to nulls directly overhead. The best height is somewhere between 0.4m and 0.8m, anything higher will introduce nulls and dips in the radiation pattern. If the antenna needs to be placed higher, say above a tree line or buildings, then a reflector may be placed 0.4-0.8m below it for the same benefit. A reflector can be as simple as another v-dipole with slightly longer legs.

Permanent ground stations may wish to opt for the QFH or turnstile so that lower-elevation passes can be received. For single-pass captures or for mobile ground stations, v-dipoles are very good options as they are portable and offer more gain on high elevation passes.
[[Category:Satellites]][[Category:Modems]]

Category:NOAA APT

2026-10-29T05:29:04Z

Mukhash: Created page with "3 examples of APT transmission '''Automatic Picture Transmission (APT)''', also known as '''NOAA-GEOSAT''', is an analog image transmission mode used to by the NOAA weather satellites and formerly some Russian weather satellites to transmit satellite weather photos. On August 19th 2025, the final satellite transmitting this mode (NOAA-15) was decommissioned at 15:26 UTC. This mode is no longer in use in real life, however NOAA-15 is still..."

[[File:NOAAAPT.png|thumb|right|3 examples of APT transmission]]
'''Automatic Picture Transmission (APT)''', also known as '''NOAA-GEOSAT''', is an analog image transmission mode used to by the NOAA weather satellites and formerly some Russian weather satellites to transmit satellite weather photos. On August 19th 2025, the final satellite transmitting this mode (NOAA-15) was decommissioned at 15:26 UTC. This mode is no longer in use in real life, however NOAA-15 is still transmitting APT in SimTX

== Characteristics ==

=== Structure ===
The broadcast transmission was composed of two image channels, telemetry information, and synchronization data, with the image channels typically referred to as Video A and Video B. All this data was transmitted as a horizontal scan line. A complete line is 2080 pixels long, with each image using 909 pixels and the remainder going to the telemetry and synchronization. Lines were then transmitted at 2 per second, which equates to a 4160 words per second, or 4160 baud.
Format of Automatic Picture Transmission. We see the two parallel Video streams being transmitted, each at 120 LPM.
{| class="wikitable"
!Name
!Length in pixels
!Description
|-
|Sync A
|39
|Bits 000011001100110011001100110011000000000
|-
|Space A
|47
|-
|Image A
|909
|Image pixels, a higher amplitude results in a brighter pixel
|-
|Telemetry A
|45
|-
|Sync B
|39
|Bits 000011100111001110011100111001110011100
|-
|Space B
|47
|-
|Image B
|909
|Image pixels, a higher amplitude results in a brighter pixel
|-
|Telemetry B
|45
|-
|'''Total'''
|2080 / 0.5 seconds
|}

=== Images ===
[[File:NOAA-15 APT 28 10 2026 1305-1309z.png|thumb|right|Received image from NOAA-15 28th October 2026 in comparison to the Earth map]]
On NOAA POES system satellites, the two images are 4 km / pixel smoothed 8-bit images derived from two channels of the advanced very-high-resolution radiometer (AVHRR) sensor. The images are corrected for nearly constant geometric resolution prior to being broadcast; as such, the images are free of distortion caused by the curvature of the Earth.

Of the two images, one is typically long-wave infrared (10.8 micrometers) with the second switching between near-visible (0.86 micrometers) and mid-wave infrared (3.75 micrometers) depending on whether the ground is illuminated by sunlight. However, NOAA can configure the satellite to transmit any two of the AVHRR's image channels.

=== Synchronization and telemetry ===
Included in the transmission are a series of synchronization pulses, minute markers, and telemetry information.

The synchronization information, transmitted at the start of each video channel, allows the receiving software to align its sampling with the baud rate of the signal, which can vary slightly over time. The minute markers are four lines of alternating black then white lines which repeat every 60 seconds (120 lines).

The telemetry section is composed of sixteen blocks, each 8 lines long, which are used as reference values to decode the image channels. The first eight blocks, called "wedges," begin at 1/8 max intensity and successively increase by 1/8 to full intensity in the eighth wedge, with the ninth being zero intensity. Blocks ten through fifteen each encode a calibration value for the sensor. The sixteenth block identifies which sensor channel was used for the preceding image channel by matching the intensity of one of the wedges one through six. Video channel A typically matches either wedge two or three, channel B matches wedge four.

The first fourteen blocks should be identical for both channels. The sixteen telemetry blocks repeat every 128 lines, and these 128 lines are referred to as a frame.

=== Broadcast signal ===
The signal itself is a 256-level amplitude modulated 2400Hz subcarrier, which is then frequency modulated onto the 137 MHz-band RF carrier. Maximum subcarrier modulation is 87% (±5%), and overall RF bandwidth is 34 kHz. On NOAA POES vehicles, the signal is broadcast at approximately 37dBm (5 watts) effective radiated power.

== Frequencies ==
NOAA 15 - 137.620 MHz

== Antennas ==
The NOAA satellites that downlink APT signals transmit with a right-hand circularly polarized (RHCP) quadrifilar helical antenna (QFH). Using an RHCP QFH to receive these signals is a good idea, as the polarization will be the same and the antenna has a very wide beamwidth. Other popular choices that are circularly polarized are the turnstile and double cross dipole antenna.

Another option is a v-dipole. Though it is linearly polarized, the polarization mismatch loss is typically insignificant and easily ignored. This antenna uses two legs roughly 54cm long spread 120° apart at the feed point. This forms a 'V' shape, with the feed point (where the coaxial cable connects) at the bottom corner where both legs meet. This v-dipole is more directional than the previously mentioned antennas so it must be positioned properly. Point the antenna so that the legs are parallel to the ground, and a line bisecting the angle between the legs points North or South, it doesn't matter which. The height above the ground matters for this antenna. Heights that are multiples of half the wavelength should be avoided, so ~1m, ~2m, ~3m, etc due to nulls directly overhead. The best height is somewhere between 0.4m and 0.8m, anything higher will introduce nulls and dips in the radiation pattern. If the antenna needs to be placed higher, say above a tree line or buildings, then a reflector may be placed 0.4-0.8m below it for the same benefit. A reflector can be as simple as another v-dipole with slightly longer legs.

Permanent ground stations may wish to opt for the QFH or turnstile so that lower-elevation passes can be received. For single-pass captures or for mobile ground stations, v-dipoles are very good options as they are portable and offer more gain on high elevation passes.
[[Category:Satellites]][[Category:Modems]]

File:NOAA-15 APT 28 10 2026 1305-1309z.png

2026-10-29T05:25:57Z

Mukhash:

File:NOAAAPT.png

2026-10-29T05:24:30Z

Mukhash:

Спутник 1

2026-10-29T05:16:17Z

Mukhash:

[[File:Sputnik asm.jpg|thumb|right|Replica of the Sputnik 1]]
'''Sputnik 1''', often referred to as simply '''Sputnik''', was the first artificial Earth satellite. It was launched into an elliptical low Earth orbit by the Soviet Union on 4 October 1957 as part of the Soviet space program. It sent a radio signal back to Earth for three weeks before its three silver-zinc batteries became depleted. Aerodynamic drag caused it to fall back into the atmosphere on 4 January 1958.

It was a polished metal sphere 58cm in diameter with four external radio antennas to broadcast radio pulses. Its radio signal was easily detectable by amateur radio operators, and the 65° orbital inclination made its flight path cover virtually the entire inhabited Earth.

The satellite's success was unanticipated by the United States. This precipitated the American Sputnik crisis and triggered the start of the Space Race. The launch was the beginning of a new era of political, military, technological, and scientific developments. The word ''sputnik'' is Russian for ''satellite'' when interpreted in an astronomical context; its other meanings are ''spouse'' or ''travelling companion''.

Tracking and studying Sputnik 1 from Earth provided scientists with valuable information. The density of the upper atmosphere could be deduced from its drag on the orbit, and the propagation of its radio signals gave data about the ionosphere.

Sputnik 1 was launched during the International Geophysical Year from Site No.1/5, at the 5th Tyuratam range, in Kazakh SSR (now known as the Baikonur Cosmodrome). The satellite travelled at a peak speed of about 8 km/s, taking 96.20 minutes to complete each orbit. It transmitted on 20.005 and 40.002 MHz, which were monitored by radio operators throughout the world. The signals continued for 22 days until the transmitter batteries depleted on 26 October 1957. On 4 January 1958, after three months in orbit, Sputnik 1 burned up while reentering Earth's atmosphere, having completed 1,440 orbits of the Earth, and travelling a distance of approximately 70,000,000km.
[[Category:Radio Stations]][[Category:Satellites]]

Спутник 1

2026-10-29T05:14:49Z

Mukhash: Created page with "Replica of the Sputnik 1 '''Sputnik 1''' ({{IPAc-en|'|s|p|V|t|n|I|k|,_|'|s|p|ʊ|t|n|I|k}}, {{langx|ru|Спутник-1}}, ''Satellite 1''), often referred to as simply '''Sputnik''', was the first artificial Earth satellite. It was launched into an elliptical low Earth orbit by the Soviet Union on 4 October 1957 as part of the Soviet space program. It sent a radio signal back to Earth for three weeks before its three silver-zinc batte..."

[[File:Sputnik asm.jpg|thumb|right|Replica of the Sputnik 1]]
'''Sputnik 1''' ({{IPAc-en|'|s|p|V|t|n|I|k|,_|'|s|p|ʊ|t|n|I|k}}, {{langx|ru|Спутник-1}}, ''Satellite 1''), often referred to as simply '''Sputnik''', was the first artificial Earth satellite. It was launched into an elliptical low Earth orbit by the Soviet Union on 4 October 1957 as part of the Soviet space program. It sent a radio signal back to Earth for three weeks before its three silver-zinc batteries became depleted. Aerodynamic drag caused it to fall back into the atmosphere on 4 January 1958.

It was a polished metal sphere {{cvt|58|cm}} in diameter with four external radio antennas to broadcast radio pulses. Its radio signal was easily detectable by amateur radio operators, and the 65° orbital inclination made its flight path cover virtually the entire inhabited Earth.

The satellite's success was unanticipated by the United States. This precipitated the American Sputnik crisis and triggered the start of the Space Race. The launch was the beginning of a new era of political, military, technological, and scientific developments. The word ''sputnik'' is Russian for ''satellite'' when interpreted in an astronomical context; its other meanings are ''spouse'' or ''travelling companion''.

Tracking and studying Sputnik 1 from Earth provided scientists with valuable information. The density of the upper atmosphere could be deduced from its drag on the orbit, and the propagation of its radio signals gave data about the ionosphere.

Sputnik 1 was launched during the International Geophysical Year from Site No.1/5, at the 5th Tyuratam range, in Kazakh SSR (now known as the Baikonur Cosmodrome). The satellite travelled at a peak speed of about {{cvt|8|km/s|mph|abbr=on}}, taking 96.20 minutes to complete each orbit. It transmitted on 20.005 and 40.002 MHz, which were monitored by radio operators throughout the world. The signals continued for 22 days until the transmitter batteries depleted on 26 October 1957. On 4 January 1958, after three months in orbit, Sputnik 1 burned up while reentering Earth's atmosphere, having completed 1,440 orbits of the Earth, and travelling a distance of approximately {{cvt|70,000,000|km}}.
[[Category:Radio Stations]][[Category:Satellites]]

Category:Satellites

2026-10-29T05:10:46Z

Mukhash:

A '''satellite''' or an '''artificial satellite''' is an object, typically a spacecraft, placed into orbit around a celestial body. They have a variety of uses, including communication relay, weather forecasting, navigation (GPS), broadcasting, scientific research, and Earth observation. Additional military uses are reconnaissance, early warning, signals intelligence and, potentially, weapon delivery. Other satellites include the final rocket stages that place satellites in orbit and formerly useful satellites that later become defunct.

Spaceships become satellites by accelerating or decelerating to reach orbital velocities, occupying an orbit high enough to avoid orbital decay due to drag in the presence of an atmosphere and above their Roche limit. Satellites are spacecraft launched from the surface into space by launch systems. Satellites can then change or maintain their orbit by propulsion, usually by chemical or ion thrusters. As of 2018, about 90% of the satellites orbiting the Earth are in low Earth orbit or geostationary orbit; geostationary means the satellites stay still in the sky (relative to a fixed point on the ground). Some imaging satellites choose a Sun-synchronous orbit because they can scan the entire globe with similar lighting. As the number of satellites and amount of space debris around Earth increases, the threat of collision has become more severe. An '''orbiter''' is a spacecraft that is designed to perform an orbital insertion, entering orbit around an astronomical body from another, and as such becoming an artificial satellite. A small number of satellites orbit other bodies (such as the Moon, Mars, and the Sun) or many bodies at once (two for a halo orbit, three for a Lissajous orbit).

Earth observation satellites gather information for reconnaissance, mapping, monitoring the weather, ocean, forest, etc. Space telescopes take advantage of outer space's near perfect vacuum to observe objects with the entire electromagnetic spectrum. Because satellites can see a large portion of the Earth at once, communications satellites can relay information to remote places. The signal delay from satellites and their orbit's predictability are used in satellite navigation systems, such as GPS. Crewed spacecraft which are in orbit or remain in orbit, like Space stations, are artificial satellites as well.

The first artificial satellite launched into Earth orbit was the Soviet Union's Sputnik 1, on October 4, 1957. As of June 28, 2025, there were 12,952 satellites orbiting the Earth, of which 8,530 belong to the United States, 1,559 to Russia, and 908 to China.

=== First satellites ===
[[File:Sputnik asm.jpg|thumb|right|Replica of the Sputnik 1]]
The first artificial satellite was Sputnik 1, launched by the Soviet Union on 4 October 1957 under the Sputnik program, with Sergei Korolev as chief designer. Sputnik 1 helped to identify the density of high atmospheric layers through measurement of its orbital change and provided data on radio-signal distribution in the ionosphere. The unanticipated announcement of Sputnik 1's success precipitated the Sputnik crisis in the United States and ignited the so-called Space Race within the Cold War.

In the context of activities planned for the International Geophysical Year (1957–1958), the White House announced on 29 July 1955 that the U.S. intended to launch satellites by the spring of 1958. This became known as Project Vanguard. On 31 July, the Soviet Union announced its intention to launch a satellite by the fall of 1957.

Sputnik 2 was launched on 3 November 1957 and carried the first living passenger into orbit, a dog named Laika. The dog was sent without possibility of return.

In early 1955, after being pressured by the American Rocket Society, the National Science Foundation, and the International Geophysical Year, the Army and Navy worked on Project Orbiter with two competing programs. The army used the Jupiter C rocket, while the civilian–Navy program used the Vanguard rocket to launch a satellite. Explorer 1 became the United States' first artificial satellite, on 31 January 1958. The information sent back from its radiation detector led to the discovery of the Earth's Van Allen radiation belts. The TIROS-1 spacecraft, launched on April 1, 1960, as part of NASA's Television Infrared Observation Satellite (TIROS) program, sent back the first television footage of weather patterns to be taken from space.

In June 1961, three and a half years after the launch of Sputnik 1, the United States Space Surveillance Network cataloged 115 Earth-orbiting satellites.

While Canada was the third country to build a satellite which was launched into space, it was launched aboard an American rocket from an American spaceport. The same goes for Australia, whose launch of the first satellite involved a donated U.S. Redstone rocket and American support staff as well as a joint launch facility with the United Kingdom. The first Italian satellite San Marco 1 was launched on 15 December 1964 on a U.S. Scout rocket from Wallops Island (Virginia, United States) with an Italian launch team trained by NASA. In similar occasions, almost all further first national satellites were launched by foreign rockets.

France was the third country to launch a satellite on its own rocket. On 26 November 1965, the Astérix or A-1 (initially conceptualized as FR.2 or FR-2), was put into orbit by a Diamant A rocket launched from the CIEES site at Hammaguir, Algeria. With Astérix, France became the sixth country to have an artificial satellite.

=== Later Satellite Development ===
Early satellites were built to unique designs. With advancements in technology, multiple satellites began to be built on single model platforms called satellite buses. The first standardized satellite bus design was the HS-333 geosynchronous (GEO) communication satellite launched in 1972. Beginning in 1997, FreeFlyer is a commercial off-the-shelf software application for satellite mission analysis, design, and operations.

After the late 2010s, and especially after the advent and operational fielding of large satellite internet constellations—where on-orbit active satellites more than doubled over a period of five years—the companies building the constellations began to propose regular planned deorbiting of the older satellites that reached the end of life, as a part of the regulatory process of obtaining a launch license. The largest artificial satellite ever is the International Space Station.

By the early 2000s, and particularly after the advent of CubeSats and increased launches of microsats—frequently launched to the lower altitudes of low Earth orbit (LEO)—satellites began to more frequently be designed to get destroyed, or breakup and burnup entirely in the atmosphere. For example, SpaceX Starlink satellites, the first large satellite internet constellation to exceed 1000 active satellites on orbit in 2020, are designed to be 100% demisable and burn up completely on their atmospheric reentry at the end of their life, or in the event of an early satellite failure.

In different periods, many countries, such as Algeria, Argentina, Australia, Austria, Brazil, Canada, Chile, China, Denmark, Egypt, Finland, France, Germany, India, Indonesia, Iran, Israel, Italy, Japan, Kazakhstan, South Korea, Malaysia, Mexico, the Netherlands, Norway, Pakistan, Poland, Russia, Saudi Arabia, South Africa, Spain, Switzerland, Thailand, Turkey, Ukraine, the United Kingdom and the United States, had some satellites in orbit.

Japan's space agency (JAXA) and NASA plan to send a wooden satellite prototype called LingoSat into orbit in the summer of 2024. They have been working on this project for few years and sent first wood samples to the space in 2021 to test the material's resilience to space conditions.
[[https://en.wikipedia.org/wiki/File:Cumulative-number-of-objects-launched-into-outer-space-1.svg|thumb|Objects launched into space cumulatively by country]]

== Components ==

=== Orbit and altitude control ===
Further information: Spacecraft propulsion

"Altitude control" redirects here; not to be confused with Attitude control.
[[https://en.wikipedia.org/wiki/File:Ion_Engine_Test_Firing_-_GPN-2000-000482.jpg|thumb|Firing of ''Deep Space 1''<nowiki/>'s ion thruster]]
Most satellites use chemical or ion propulsion to adjust or maintain their orbit, coupled with reaction wheels to control their three axis of rotation or attitude. Satellites close to Earth are affected the most by variations in the Earth's magnetic, gravitational field and the Sun's radiation pressure; satellites that are further away are affected more by other bodies' gravitational field by the Moon and the Sun. Satellites utilize ultra-white reflective coatings to prevent damage from UV radiation. Without orbit and orientation control, satellites in orbit will not be able to communicate with ground stations on the Earth.

Chemical thrusters on satellites usually use monopropellant (one-part) or bipropellant (two-parts) that are hypergolic. Hypergolic means able to combust spontaneously when in contact with each other or to a catalyst. The most commonly used propellant mixtures on satellites are hydrazine-based monopropellants or monomethylhydrazine–dinitrogen tetroxide bipropellants. Ion thrusters on satellites usually are Hall-effect thrusters, which generate thrust by accelerating positive ions through a negatively-charged grid. Ion propulsion is more efficient propellant-wise than chemical propulsion but its thrust is very small, and thus requires a longer burn time. The thrusters usually use xenon because it is inert, can be easily ionized, has a high atomic mass and storable as a high-pressure liquid.

=== Power ===
Main articles: Batteries in space, Nuclear power in space, and Solar panels on spacecraft
[[https://en.wikipedia.org/wiki/File:ISS-54_ELC-1,_main_solar_arrays_and_radiators_seen_from_the_Cupola.jpg|alt=see caption|thumb|The International Space Station's black solar panels on the left and white radiators on the right]]
Most satellites use solar panels to generate power, and a few in deep space with limited sunlight use radioisotope thermoelectric generators. Slip rings attach solar panels to the satellite; the slip rings can rotate to be perpendicular with the sunlight and generate the most power. All satellites with a solar panel must also have batteries, because sunlight is blocked inside the launch vehicle and at night. The most common types of batteries for satellites are lithium-ion, and in the past nickel–hydrogen.

== Applications ==

=== Earth observation ===
Main article: Earth observation satellite
[[File:Earth Radiation Budget Satellite.jpg|thumb|Deployment of the Earth Radiation Budget Satellite on STS-41-G, collecting data on Earth's weather and climate]]
Earth observation satellites are designed to monitor and survey the Earth, called remote sensing. Most Earth observation satellites are placed in low Earth orbit for a high data resolution, though some are placed in a geostationary orbit for an uninterrupted coverage. Some satellites are placed in a Sun-synchronous orbit to have consistent lighting and obtain a total view of the Earth. Depending on the satellites' functions, they might have a normal camera, radar, lidar, photometer, or atmospheric instruments. Earth observation satellite's data is most used in archaeology, cartography, environmental monitoring, meteorology, and reconnaissance applications. As of 2021, there are over 950 Earth observation satellites, with the largest number of satellites operated with Planet Labs.

Weather satellites monitor clouds, city lights, fires, effects of pollution, auroras, sand and dust storms, snow cover, ice mapping, boundaries of ocean currents, energy flows, etc. Environmental monitoring satellites can detect changes in the Earth's vegetation, atmospheric trace gas content, sea state, ocean color, and ice fields. By monitoring vegetation changes over time, droughts can be monitored by comparing the current vegetation state to its long term average. Anthropogenic emissions can be monitored by evaluating data of tropospheric NO2 and SO2.

=== Communication ===
Main article: Communications satellite

=== Spy satellites ===
Main article: Reconnaissance satellite

When an Earth observation satellite or a communications satellite is deployed for military or intelligence purposes, it is known as a spy satellite or reconnaissance satellite.

Their uses include early missile warning, nuclear explosion detection, electronic reconnaissance, and optical or radar imaging surveillance.

=== Navigation ===
Main article: Satellite navigation

Navigational satellites are satellites that use radio time signals transmitted to enable mobile receivers on the ground to determine their exact location. The relatively clear line of sight between the satellites and receivers on the ground, combined with ever-improving electronics, allows satellite navigation systems to measure location to accuracies on the order of a few meters in real time.

=== Telescope ===
Main article: Space telescope
[[File:Hubble Space Telescope (27946391011).jpg|thumb|The Hubble Space Telescope]]
Astronomical satellites are satellites used for observation of distant planets, galaxies, and other outer space objects.

=== Experimental ===
Tether satellites are satellites that are connected to another satellite by a thin cable called a tether. Recovery satellites are satellites that provide a recovery of reconnaissance, biological, space-production and other payloads from orbit to Earth. Biosatellites are satellites designed to carry living organisms, generally for scientific experimentation. Space-based solar power satellites are proposed satellites that would collect energy from sunlight and transmit it for use on Earth or other places.

=== Weapon ===
Main articles: Space weapon, Anti-satellite weapon, and Early warning satellite

Since the mid-2000s, satellites have been hacked by militant organizations to broadcast propaganda and to pilfer classified information from military communication networks. For testing purposes, satellites in low earth orbit have been destroyed by ballistic missiles launched from the Earth. Russia, United States, China and India have demonstrated the ability to eliminate satellites. In 2007, the Chinese military shot down an aging weather satellite, followed by the US Navy shooting down a defunct spy satellite in February 2008. On 18 November 2015, after two failed attempts, Russia successfully carried out a flight test of an anti-satellite missile known as ''Nudol''. On 27 March 2019, India shot down a live test satellite at 300 km altitude in 3 minutes, becoming the fourth country to have the capability to destroy live satellites.

----
[[Category:Radio Stations]][[Category:Modems]]

File:Hubble Space Telescope (27946391011).jpg

2026-10-29T05:10:26Z

Mukhash:

File:Earth Radiation Budget Satellite.jpg

2026-10-29T05:09:25Z

Mukhash:

File:Sputnik asm.jpg

2026-10-29T05:08:21Z

Mukhash:

Category:Satellites

2026-10-29T05:04:40Z

Mukhash:

A '''satellite''' or an '''artificial satellite''' is an object, typically a spacecraft, placed into orbit around a celestial body. They have a variety of uses, including communication relay, weather forecasting, navigation (GPS), broadcasting, scientific research, and Earth observation. Additional military uses are reconnaissance, early warning, signals intelligence and, potentially, weapon delivery. Other satellites include the final rocket stages that place satellites in orbit and formerly useful satellites that later become defunct.

Spaceships become satellites by accelerating or decelerating to reach orbital velocities, occupying an orbit high enough to avoid orbital decay due to drag in the presence of an atmosphere and above their Roche limit. Satellites are spacecraft launched from the surface into space by launch systems. Satellites can then change or maintain their orbit by propulsion, usually by chemical or ion thrusters. As of 2018, about 90% of the satellites orbiting the Earth are in low Earth orbit or geostationary orbit; geostationary means the satellites stay still in the sky (relative to a fixed point on the ground). Some imaging satellites choose a Sun-synchronous orbit because they can scan the entire globe with similar lighting. As the number of satellites and amount of space debris around Earth increases, the threat of collision has become more severe. An '''orbiter''' is a spacecraft that is designed to perform an orbital insertion, entering orbit around an astronomical body from another, and as such becoming an artificial satellite. A small number of satellites orbit other bodies (such as the Moon, Mars, and the Sun) or many bodies at once (two for a halo orbit, three for a Lissajous orbit).

Earth observation satellites gather information for reconnaissance, mapping, monitoring the weather, ocean, forest, etc. Space telescopes take advantage of outer space's near perfect vacuum to observe objects with the entire electromagnetic spectrum. Because satellites can see a large portion of the Earth at once, communications satellites can relay information to remote places. The signal delay from satellites and their orbit's predictability are used in satellite navigation systems, such as GPS. Crewed spacecraft which are in orbit or remain in orbit, like Space stations, are artificial satellites as well.

The first artificial satellite launched into Earth orbit was the Soviet Union's Sputnik 1, on October 4, 1957. As of June 28, 2025, there were 12,952 satellites orbiting the Earth, of which 8,530 belong to the United States, 1,559 to Russia, and 908 to China.

=== First satellites ===
[[https://en.wikipedia.org/wiki/File:Sputnik_asm.jpg|alt=Steel ball with 4 antennas|thumb|Replica of the Sputnik 1]]
The first artificial satellite was Sputnik 1, launched by the Soviet Union on 4 October 1957 under the Sputnik program, with Sergei Korolev as chief designer. Sputnik 1 helped to identify the density of high atmospheric layers through measurement of its orbital change and provided data on radio-signal distribution in the ionosphere. The unanticipated announcement of Sputnik 1's success precipitated the Sputnik crisis in the United States and ignited the so-called Space Race within the Cold War.

In the context of activities planned for the International Geophysical Year (1957–1958), the White House announced on 29 July 1955 that the U.S. intended to launch satellites by the spring of 1958. This became known as Project Vanguard. On 31 July, the Soviet Union announced its intention to launch a satellite by the fall of 1957.

Sputnik 2 was launched on 3 November 1957 and carried the first living passenger into orbit, a dog named Laika. The dog was sent without possibility of return.

In early 1955, after being pressured by the American Rocket Society, the National Science Foundation, and the International Geophysical Year, the Army and Navy worked on Project Orbiter with two competing programs. The army used the Jupiter C rocket, while the civilian–Navy program used the Vanguard rocket to launch a satellite. Explorer 1 became the United States' first artificial satellite, on 31 January 1958. The information sent back from its radiation detector led to the discovery of the Earth's Van Allen radiation belts. The TIROS-1 spacecraft, launched on April 1, 1960, as part of NASA's Television Infrared Observation Satellite (TIROS) program, sent back the first television footage of weather patterns to be taken from space.

In June 1961, three and a half years after the launch of Sputnik 1, the United States Space Surveillance Network cataloged 115 Earth-orbiting satellites.

While Canada was the third country to build a satellite which was launched into space, it was launched aboard an American rocket from an American spaceport. The same goes for Australia, whose launch of the first satellite involved a donated U.S. Redstone rocket and American support staff as well as a joint launch facility with the United Kingdom. The first Italian satellite San Marco 1 was launched on 15 December 1964 on a U.S. Scout rocket from Wallops Island (Virginia, United States) with an Italian launch team trained by NASA. In similar occasions, almost all further first national satellites were launched by foreign rockets.

France was the third country to launch a satellite on its own rocket. On 26 November 1965, the Astérix or A-1 (initially conceptualized as FR.2 or FR-2), was put into orbit by a Diamant A rocket launched from the CIEES site at Hammaguir, Algeria. With Astérix, France became the sixth country to have an artificial satellite.

=== Later Satellite Development ===
Early satellites were built to unique designs. With advancements in technology, multiple satellites began to be built on single model platforms called satellite buses. The first standardized satellite bus design was the HS-333 geosynchronous (GEO) communication satellite launched in 1972. Beginning in 1997, FreeFlyer is a commercial off-the-shelf software application for satellite mission analysis, design, and operations.

After the late 2010s, and especially after the advent and operational fielding of large satellite internet constellations—where on-orbit active satellites more than doubled over a period of five years—the companies building the constellations began to propose regular planned deorbiting of the older satellites that reached the end of life, as a part of the regulatory process of obtaining a launch license. The largest artificial satellite ever is the International Space Station.

By the early 2000s, and particularly after the advent of CubeSats and increased launches of microsats—frequently launched to the lower altitudes of low Earth orbit (LEO)—satellites began to more frequently be designed to get destroyed, or breakup and burnup entirely in the atmosphere. For example, SpaceX Starlink satellites, the first large satellite internet constellation to exceed 1000 active satellites on orbit in 2020, are designed to be 100% demisable and burn up completely on their atmospheric reentry at the end of their life, or in the event of an early satellite failure.

In different periods, many countries, such as Algeria, Argentina, Australia, Austria, Brazil, Canada, Chile, China, Denmark, Egypt, Finland, France, Germany, India, Indonesia, Iran, Israel, Italy, Japan, Kazakhstan, South Korea, Malaysia, Mexico, the Netherlands, Norway, Pakistan, Poland, Russia, Saudi Arabia, South Africa, Spain, Switzerland, Thailand, Turkey, Ukraine, the United Kingdom and the United States, had some satellites in orbit.

Japan's space agency (JAXA) and NASA plan to send a wooden satellite prototype called LingoSat into orbit in the summer of 2024. They have been working on this project for few years and sent first wood samples to the space in 2021 to test the material's resilience to space conditions.
[[https://en.wikipedia.org/wiki/File:Cumulative-number-of-objects-launched-into-outer-space-1.svg|thumb|Objects launched into space cumulatively by country]]

== Components ==

=== Orbit and altitude control ===
Further information: Spacecraft propulsion

"Altitude control" redirects here; not to be confused with Attitude control.
[[https://en.wikipedia.org/wiki/File:Ion_Engine_Test_Firing_-_GPN-2000-000482.jpg|thumb|Firing of ''Deep Space 1''<nowiki/>'s ion thruster]]
Most satellites use chemical or ion propulsion to adjust or maintain their orbit, coupled with reaction wheels to control their three axis of rotation or attitude. Satellites close to Earth are affected the most by variations in the Earth's magnetic, gravitational field and the Sun's radiation pressure; satellites that are further away are affected more by other bodies' gravitational field by the Moon and the Sun. Satellites utilize ultra-white reflective coatings to prevent damage from UV radiation. Without orbit and orientation control, satellites in orbit will not be able to communicate with ground stations on the Earth.

Chemical thrusters on satellites usually use monopropellant (one-part) or bipropellant (two-parts) that are hypergolic. Hypergolic means able to combust spontaneously when in contact with each other or to a catalyst. The most commonly used propellant mixtures on satellites are hydrazine-based monopropellants or monomethylhydrazine–dinitrogen tetroxide bipropellants. Ion thrusters on satellites usually are Hall-effect thrusters, which generate thrust by accelerating positive ions through a negatively-charged grid. Ion propulsion is more efficient propellant-wise than chemical propulsion but its thrust is very small, and thus requires a longer burn time. The thrusters usually use xenon because it is inert, can be easily ionized, has a high atomic mass and storable as a high-pressure liquid.

=== Power ===
Main articles: Batteries in space, Nuclear power in space, and Solar panels on spacecraft
[[https://en.wikipedia.org/wiki/File:ISS-54_ELC-1,_main_solar_arrays_and_radiators_seen_from_the_Cupola.jpg|alt=see caption|thumb|The International Space Station's black solar panels on the left and white radiators on the right]]
Most satellites use solar panels to generate power, and a few in deep space with limited sunlight use radioisotope thermoelectric generators. Slip rings attach solar panels to the satellite; the slip rings can rotate to be perpendicular with the sunlight and generate the most power. All satellites with a solar panel must also have batteries, because sunlight is blocked inside the launch vehicle and at night. The most common types of batteries for satellites are lithium-ion, and in the past nickel–hydrogen.

== Applications ==

=== Earth observation ===
Main article: Earth observation satellite
[[https://en.wikipedia.org/wiki/File:Earth_Radiation_Budget_Satellite.jpg|thumb|Deployment of the Earth Radiation Budget Satellite on STS-41-G, collecting data on Earth's weather and climate]]
Earth observation satellites are designed to monitor and survey the Earth, called remote sensing. Most Earth observation satellites are placed in low Earth orbit for a high data resolution, though some are placed in a geostationary orbit for an uninterrupted coverage. Some satellites are placed in a Sun-synchronous orbit to have consistent lighting and obtain a total view of the Earth. Depending on the satellites' functions, they might have a normal camera, radar, lidar, photometer, or atmospheric instruments. Earth observation satellite's data is most used in archaeology, cartography, environmental monitoring, meteorology, and reconnaissance applications. As of 2021, there are over 950 Earth observation satellites, with the largest number of satellites operated with Planet Labs.

Weather satellites monitor clouds, city lights, fires, effects of pollution, auroras, sand and dust storms, snow cover, ice mapping, boundaries of ocean currents, energy flows, etc. Environmental monitoring satellites can detect changes in the Earth's vegetation, atmospheric trace gas content, sea state, ocean color, and ice fields. By monitoring vegetation changes over time, droughts can be monitored by comparing the current vegetation state to its long term average. Anthropogenic emissions can be monitored by evaluating data of tropospheric NO2 and SO2.

=== Communication ===
Main article: Communications satellite

=== Spy satellites ===
Main article: Reconnaissance satellite

When an Earth observation satellite or a communications satellite is deployed for military or intelligence purposes, it is known as a spy satellite or reconnaissance satellite.

Their uses include early missile warning, nuclear explosion detection, electronic reconnaissance, and optical or radar imaging surveillance.

=== Navigation ===
Main article: Satellite navigation

Navigational satellites are satellites that use radio time signals transmitted to enable mobile receivers on the ground to determine their exact location. The relatively clear line of sight between the satellites and receivers on the ground, combined with ever-improving electronics, allows satellite navigation systems to measure location to accuracies on the order of a few meters in real time.

=== Telescope ===
Main article: Space telescope
[[https://en.wikipedia.org/wiki/File:Hubble_Space_Telescope_(27946391011).jpg|thumb|The Hubble Space Telescope]]
Astronomical satellites are satellites used for observation of distant planets, galaxies, and other outer space objects.

=== Experimental ===
Tether satellites are satellites that are connected to another satellite by a thin cable called a tether. Recovery satellites are satellites that provide a recovery of reconnaissance, biological, space-production and other payloads from orbit to Earth. Biosatellites are satellites designed to carry living organisms, generally for scientific experimentation. Space-based solar power satellites are proposed satellites that would collect energy from sunlight and transmit it for use on Earth or other places.

=== Weapon ===
Main articles: Space weapon, Anti-satellite weapon, and Early warning satellite

Since the mid-2000s, satellites have been hacked by militant organizations to broadcast propaganda and to pilfer classified information from military communication networks. For testing purposes, satellites in low earth orbit have been destroyed by ballistic missiles launched from the Earth. Russia, United States, China and India have demonstrated the ability to eliminate satellites. In 2007, the Chinese military shot down an aging weather satellite, followed by the US Navy shooting down a defunct spy satellite in February 2008. On 18 November 2015, after two failed attempts, Russia successfully carried out a flight test of an anti-satellite missile known as ''Nudol''. On 27 March 2019, India shot down a live test satellite at 300 km altitude in 3 minutes, becoming the fourth country to have the capability to destroy live satellites.

----
[[Category:Radio Stations]][[Category:Modems]]

Category:Satellites

2026-10-29T05:03:54Z

Mukhash:

A '''satellite''' or an '''artificial satellite''' is an object, typically a spacecraft, placed into orbit around a celestial body. They have a variety of uses, including communication relay, weather forecasting, navigation (GPS), broadcasting, scientific research, and Earth observation. Additional military uses are reconnaissance, early warning, signals intelligence and, potentially, weapon delivery. Other satellites include the final rocket stages that place satellites in orbit and formerly useful satellites that later become defunct.

Spaceships become satellites by accelerating or decelerating to reach orbital velocities, occupying an orbit high enough to avoid orbital decay due to drag in the presence of an atmosphere and above their Roche limit. Satellites are spacecraft launched from the surface into space by launch systems. Satellites can then change or maintain their orbit by propulsion, usually by chemical or ion thrusters. As of 2018, about 90% of the satellites orbiting the Earth are in low Earth orbit or geostationary orbit; geostationary means the satellites stay still in the sky (relative to a fixed point on the ground). Some imaging satellites choose a Sun-synchronous orbit because they can scan the entire globe with similar lighting. As the number of satellites and amount of space debris around Earth increases, the threat of collision has become more severe. An '''orbiter''' is a spacecraft that is designed to perform an orbital insertion, entering orbit around an astronomical body from another, and as such becoming an artificial satellite. A small number of satellites orbit other bodies (such as the Moon, Mars, and the Sun) or many bodies at once (two for a halo orbit, three for a Lissajous orbit).

Earth observation satellites gather information for reconnaissance, mapping, monitoring the weather, ocean, forest, etc. Space telescopes take advantage of outer space's near perfect vacuum to observe objects with the entire electromagnetic spectrum. Because satellites can see a large portion of the Earth at once, communications satellites can relay information to remote places. The signal delay from satellites and their orbit's predictability are used in satellite navigation systems, such as GPS. Crewed spacecraft which are in orbit or remain in orbit, like Space stations, are artificial satellites as well.

The first artificial satellite launched into Earth orbit was the Soviet Union's Sputnik 1, on October 4, 1957. As of June 28, 2025, there were 12,952 satellites orbiting the Earth, of which 8,530 belong to the United States, 1,559 to Russia, and 908 to China.

=== First satellites ===
[[https://en.wikipedia.org/wiki/File:Sputnik_asm.jpg|alt=Steel ball with 4 antennas|thumb|Replica of the Sputnik 1]]
The first artificial satellite was Sputnik 1, launched by the Soviet Union on 4 October 1957 under the Sputnik program, with Sergei Korolev as chief designer. Sputnik 1 helped to identify the density of high atmospheric layers through measurement of its orbital change and provided data on radio-signal distribution in the ionosphere. The unanticipated announcement of Sputnik 1's success precipitated the Sputnik crisis in the United States and ignited the so-called Space Race within the Cold War.

In the context of activities planned for the International Geophysical Year (1957–1958), the White House announced on 29 July 1955 that the U.S. intended to launch satellites by the spring of 1958. This became known as Project Vanguard. On 31 July, the Soviet Union announced its intention to launch a satellite by the fall of 1957.

Sputnik 2 was launched on 3 November 1957 and carried the first living passenger into orbit, a dog named Laika. The dog was sent without possibility of return.

In early 1955, after being pressured by the American Rocket Society, the National Science Foundation, and the International Geophysical Year, the Army and Navy worked on Project Orbiter with two competing programs. The army used the Jupiter C rocket, while the civilian–Navy program used the Vanguard rocket to launch a satellite. Explorer 1 became the United States' first artificial satellite, on 31 January 1958. The information sent back from its radiation detector led to the discovery of the Earth's Van Allen radiation belts. The TIROS-1 spacecraft, launched on April 1, 1960, as part of NASA's Television Infrared Observation Satellite (TIROS) program, sent back the first television footage of weather patterns to be taken from space.

In June 1961, three and a half years after the launch of Sputnik 1, the United States Space Surveillance Network cataloged 115 Earth-orbiting satellites.

While Canada was the third country to build a satellite which was launched into space, it was launched aboard an American rocket from an American spaceport. The same goes for Australia, whose launch of the first satellite involved a donated U.S. Redstone rocket and American support staff as well as a joint launch facility with the United Kingdom. The first Italian satellite San Marco 1 was launched on 15 December 1964 on a U.S. Scout rocket from Wallops Island (Virginia, United States) with an Italian launch team trained by NASA. In similar occasions, almost all further first national satellites were launched by foreign rockets.

France was the third country to launch a satellite on its own rocket. On 26 November 1965, the Astérix or A-1 (initially conceptualized as FR.2 or FR-2), was put into orbit by a Diamant A rocket launched from the CIEES site at Hammaguir, Algeria. With Astérix, France became the sixth country to have an artificial satellite.

=== Later Satellite Development ===
Early satellites were built to unique designs. With advancements in technology, multiple satellites began to be built on single model platforms called satellite buses. The first standardized satellite bus design was the HS-333 geosynchronous (GEO) communication satellite launched in 1972. Beginning in 1997, FreeFlyer is a commercial off-the-shelf software application for satellite mission analysis, design, and operations.

After the late 2010s, and especially after the advent and operational fielding of large satellite internet constellations—where on-orbit active satellites more than doubled over a period of five years—the companies building the constellations began to propose regular planned deorbiting of the older satellites that reached the end of life, as a part of the regulatory process of obtaining a launch license. The largest artificial satellite ever is the International Space Station.

By the early 2000s, and particularly after the advent of CubeSats and increased launches of microsats—frequently launched to the lower altitudes of low Earth orbit (LEO)—satellites began to more frequently be designed to get destroyed, or breakup and burnup entirely in the atmosphere. For example, SpaceX Starlink satellites, the first large satellite internet constellation to exceed 1000 active satellites on orbit in 2020, are designed to be 100% demisable and burn up completely on their atmospheric reentry at the end of their life, or in the event of an early satellite failure.

In different periods, many countries, such as Algeria, Argentina, Australia, Austria, Brazil, Canada, Chile, China, Denmark, Egypt, Finland, France, Germany, India, Indonesia, Iran, Israel, Italy, Japan, Kazakhstan, South Korea, Malaysia, Mexico, the Netherlands, Norway, Pakistan, Poland, Russia, Saudi Arabia, South Africa, Spain, Switzerland, Thailand, Turkey, Ukraine, the United Kingdom and the United States, had some satellites in orbit.

Japan's space agency (JAXA) and NASA plan to send a wooden satellite prototype called LingoSat into orbit in the summer of 2024. They have been working on this project for few years and sent first wood samples to the space in 2021 to test the material's resilience to space conditions.
[[https://en.wikipedia.org/wiki/File:Cumulative-number-of-objects-launched-into-outer-space-1.svg|thumb|Objects launched into space cumulatively by country]]

== Components ==

=== Orbit and altitude control ===
Further information: Spacecraft propulsion

"Altitude control" redirects here; not to be confused with Attitude control.
[[https://en.wikipedia.org/wiki/File:Ion_Engine_Test_Firing_-_GPN-2000-000482.jpg|thumb|Firing of ''Deep Space 1''<nowiki/>'s ion thruster]]
Most satellites use chemical or ion propulsion to adjust or maintain their orbit, coupled with reaction wheels to control their three axis of rotation or attitude. Satellites close to Earth are affected the most by variations in the Earth's magnetic, gravitational field and the Sun's radiation pressure; satellites that are further away are affected more by other bodies' gravitational field by the Moon and the Sun. Satellites utilize ultra-white reflective coatings to prevent damage from UV radiation. Without orbit and orientation control, satellites in orbit will not be able to communicate with ground stations on the Earth.

Chemical thrusters on satellites usually use monopropellant (one-part) or bipropellant (two-parts) that are hypergolic. Hypergolic means able to combust spontaneously when in contact with each other or to a catalyst. The most commonly used propellant mixtures on satellites are hydrazine-based monopropellants or monomethylhydrazine–dinitrogen tetroxide bipropellants. Ion thrusters on satellites usually are Hall-effect thrusters, which generate thrust by accelerating positive ions through a negatively-charged grid. Ion propulsion is more efficient propellant-wise than chemical propulsion but its thrust is very small, and thus requires a longer burn time. The thrusters usually use xenon because it is inert, can be easily ionized, has a high atomic mass and storable as a high-pressure liquid.

=== Power ===
Main articles: Batteries in space, Nuclear power in space, and Solar panels on spacecraft
[[https://en.wikipedia.org/wiki/File:ISS-54_ELC-1,_main_solar_arrays_and_radiators_seen_from_the_Cupola.jpg|alt=see caption|thumb|The International Space Station's black solar panels on the left and white radiators on the right]]
Most satellites use solar panels to generate power, and a few in deep space with limited sunlight use radioisotope thermoelectric generators. Slip rings attach solar panels to the satellite; the slip rings can rotate to be perpendicular with the sunlight and generate the most power. All satellites with a solar panel must also have batteries, because sunlight is blocked inside the launch vehicle and at night. The most common types of batteries for satellites are lithium-ion, and in the past nickel–hydrogen.

== Applications ==

=== Earth observation ===
Main article: Earth observation satellite
[[https://en.wikipedia.org/wiki/File:Earth_Radiation_Budget_Satellite.jpg|thumb|Deployment of the Earth Radiation Budget Satellite on STS-41-G, collecting data on Earth's weather and climate]]
Earth observation satellites are designed to monitor and survey the Earth, called remote sensing. Most Earth observation satellites are placed in low Earth orbit for a high data resolution, though some are placed in a geostationary orbit for an uninterrupted coverage. Some satellites are placed in a Sun-synchronous orbit to have consistent lighting and obtain a total view of the Earth. Depending on the satellites' functions, they might have a normal camera, radar, lidar, photometer, or atmospheric instruments. Earth observation satellite's data is most used in archaeology, cartography, environmental monitoring, meteorology, and reconnaissance applications. As of 2021, there are over 950 Earth observation satellites, with the largest number of satellites operated with Planet Labs.

Weather satellites monitor clouds, city lights, fires, effects of pollution, auroras, sand and dust storms, snow cover, ice mapping, boundaries of ocean currents, energy flows, etc. Environmental monitoring satellites can detect changes in the Earth's vegetation, atmospheric trace gas content, sea state, ocean color, and ice fields. By monitoring vegetation changes over time, droughts can be monitored by comparing the current vegetation state to its long term average. Anthropogenic emissions can be monitored by evaluating data of tropospheric NO2 and SO2.

=== Communication ===
Main article: Communications satellite

=== Spy satellites ===
Main article: Reconnaissance satellite

When an Earth observation satellite or a communications satellite is deployed for military or intelligence purposes, it is known as a spy satellite or reconnaissance satellite.

Their uses include early missile warning, nuclear explosion detection, electronic reconnaissance, and optical or radar imaging surveillance.

=== Navigation ===
Main article: Satellite navigation

Navigational satellites are satellites that use radio time signals transmitted to enable mobile receivers on the ground to determine their exact location. The relatively clear line of sight between the satellites and receivers on the ground, combined with ever-improving electronics, allows satellite navigation systems to measure location to accuracies on the order of a few meters in real time.

=== Telescope ===
Main article: Space telescope
[[https://en.wikipedia.org/wiki/File:Hubble_Space_Telescope_(27946391011).jpg|thumb|The Hubble Space Telescope]]
Astronomical satellites are satellites used for observation of distant planets, galaxies, and other outer space objects.

=== Experimental ===
Tether satellites are satellites that are connected to another satellite by a thin cable called a tether. Recovery satellites are satellites that provide a recovery of reconnaissance, biological, space-production and other payloads from orbit to Earth. Biosatellites are satellites designed to carry living organisms, generally for scientific experimentation. Space-based solar power satellites are proposed satellites that would collect energy from sunlight and transmit it for use on Earth or other places.

=== Weapon ===
Main articles: Space weapon, Anti-satellite weapon, and Early warning satellite

Since the mid-2000s, satellites have been hacked by militant organizations to broadcast propaganda and to pilfer classified information from military communication networks. For testing purposes, satellites in low earth orbit have been destroyed by ballistic missiles launched from the Earth. Russia, United States, China and India have demonstrated the ability to eliminate satellites. In 2007, the Chinese military shot down an aging weather satellite, followed by the US Navy shooting down a defunct spy satellite in February 2008. On 18 November 2015, after two failed attempts, Russia successfully carried out a flight test of an anti-satellite missile known as ''Nudol''. On 27 March 2019, India shot down a live test satellite at 300 km altitude in 3 minutes, becoming the fourth country to have the capability to destroy live satellites.

Category:Satellites

2026-10-29T05:03:14Z

Mukhash: Created page with "A '''satellite''' or an '''artificial satellite''' is an object, typically a spacecraft, placed into orbit around a celestial body. They have a variety of uses, including communication relay, weather forecasting, navigation (GPS), broadcasting, scientific research, and Earth observation. Additional military uses are reconnaissance, early warning, signals intelligence and, potentially, weapon delivery. Other satellites include the final rocket stages that place satellites..."

A '''satellite''' or an '''artificial satellite''' is an object, typically a spacecraft, placed into orbit around a celestial body. They have a variety of uses, including communication relay, weather forecasting, navigation (GPS), broadcasting, scientific research, and Earth observation. Additional military uses are reconnaissance, early warning, signals intelligence and, potentially, weapon delivery. Other satellites include the final rocket stages that place satellites in orbit and formerly useful satellites that later become defunct.

Spaceships become satellites by accelerating or decelerating to reach orbital velocities, occupying an orbit high enough to avoid orbital decay due to drag in the presence of an atmosphere and above their Roche limit. Satellites are spacecraft launched from the surface into space by launch systems. Satellites can then change or maintain their orbit by propulsion, usually by chemical or ion thrusters. As of 2018, about 90% of the satellites orbiting the Earth are in low Earth orbit or geostationary orbit; geostationary means the satellites stay still in the sky (relative to a fixed point on the ground). Some imaging satellites choose a Sun-synchronous orbit because they can scan the entire globe with similar lighting. As the number of satellites and amount of space debris around Earth increases, the threat of collision has become more severe. An '''orbiter''' is a spacecraft that is designed to perform an orbital insertion, entering orbit around an astronomical body from another, and as such becoming an artificial satellite. A small number of satellites orbit other bodies (such as the Moon, Mars, and the Sun) or many bodies at once (two for a halo orbit, three for a Lissajous orbit).

Earth observation satellites gather information for reconnaissance, mapping, monitoring the weather, ocean, forest, etc. Space telescopes take advantage of outer space's near perfect vacuum to observe objects with the entire electromagnetic spectrum. Because satellites can see a large portion of the Earth at once, communications satellites can relay information to remote places. The signal delay from satellites and their orbit's predictability are used in satellite navigation systems, such as GPS. Crewed spacecraft which are in orbit or remain in orbit, like Space stations, are artificial satellites as well.

The first artificial satellite launched into Earth orbit was the Soviet Union's Sputnik 1, on October 4, 1957. As of June 28, 2025, there were 12,952 satellites orbiting the Earth, of which 8,530 belong to the United States, 1,559 to Russia, and 908 to China.

=== First satellites ===
[[https://en.wikipedia.org/wiki/File:Sputnik_asm.jpg|alt=Steel ball with 4 antennas|thumb|Replica of the Sputnik 1]]
The first artificial satellite was Sputnik 1, launched by the Soviet Union on 4 October 1957 under the Sputnik program, with Sergei Korolev as chief designer. Sputnik 1 helped to identify the density of high atmospheric layers through measurement of its orbital change and provided data on radio-signal distribution in the ionosphere. The unanticipated announcement of Sputnik 1's success precipitated the Sputnik crisis in the United States and ignited the so-called Space Race within the Cold War.

In the context of activities planned for the International Geophysical Year (1957–1958), the White House announced on 29 July 1955 that the U.S. intended to launch satellites by the spring of 1958. This became known as Project Vanguard. On 31 July, the Soviet Union announced its intention to launch a satellite by the fall of 1957.

Sputnik 2 was launched on 3 November 1957 and carried the first living passenger into orbit, a dog named Laika. The dog was sent without possibility of return.

In early 1955, after being pressured by the American Rocket Society, the National Science Foundation, and the International Geophysical Year, the Army and Navy worked on Project Orbiter with two competing programs. The army used the Jupiter C rocket, while the civilian–Navy program used the Vanguard rocket to launch a satellite. Explorer 1 became the United States' first artificial satellite, on 31 January 1958. The information sent back from its radiation detector led to the discovery of the Earth's Van Allen radiation belts. The TIROS-1 spacecraft, launched on April 1, 1960, as part of NASA's Television Infrared Observation Satellite (TIROS) program, sent back the first television footage of weather patterns to be taken from space.

In June 1961, three and a half years after the launch of Sputnik 1, the United States Space Surveillance Network cataloged 115 Earth-orbiting satellites.

While Canada was the third country to build a satellite which was launched into space, it was launched aboard an American rocket from an American spaceport. The same goes for Australia, whose launch of the first satellite involved a donated U.S. Redstone rocket and American support staff as well as a joint launch facility with the United Kingdom. The first Italian satellite San Marco 1 was launched on 15 December 1964 on a U.S. Scout rocket from Wallops Island (Virginia, United States) with an Italian launch team trained by NASA. In similar occasions, almost all further first national satellites were launched by foreign rockets.

France was the third country to launch a satellite on its own rocket. On 26 November 1965, the Astérix or A-1 (initially conceptualized as FR.2 or FR-2), was put into orbit by a Diamant A rocket launched from the CIEES site at Hammaguir, Algeria. With Astérix, France became the sixth country to have an artificial satellite.

=== Later Satellite Development ===
Early satellites were built to unique designs. With advancements in technology, multiple satellites began to be built on single model platforms called satellite buses. The first standardized satellite bus design was the HS-333 geosynchronous (GEO) communication satellite launched in 1972. Beginning in 1997, FreeFlyer is a commercial off-the-shelf software application for satellite mission analysis, design, and operations.

After the late 2010s, and especially after the advent and operational fielding of large satellite internet constellations—where on-orbit active satellites more than doubled over a period of five years—the companies building the constellations began to propose regular planned deorbiting of the older satellites that reached the end of life, as a part of the regulatory process of obtaining a launch license. The largest artificial satellite ever is the International Space Station.

By the early 2000s, and particularly after the advent of CubeSats and increased launches of microsats—frequently launched to the lower altitudes of low Earth orbit (LEO)—satellites began to more frequently be designed to get destroyed, or breakup and burnup entirely in the atmosphere. For example, SpaceX Starlink satellites, the first large satellite internet constellation to exceed 1000 active satellites on orbit in 2020, are designed to be 100% demisable and burn up completely on their atmospheric reentry at the end of their life, or in the event of an early satellite failure.

In different periods, many countries, such as Algeria, Argentina, Australia, Austria, Brazil, Canada, Chile, China, Denmark, Egypt, Finland, France, Germany, India, Indonesia, Iran, Israel, Italy, Japan, Kazakhstan, South Korea, Malaysia, Mexico, the Netherlands, Norway, Pakistan, Poland, Russia, Saudi Arabia, South Africa, Spain, Switzerland, Thailand, Turkey, Ukraine, the United Kingdom and the United States, had some satellites in orbit.

Japan's space agency (JAXA) and NASA plan to send a wooden satellite prototype called LingoSat into orbit in the summer of 2024. They have been working on this project for few years and sent first wood samples to the space in 2021 to test the material's resilience to space conditions.
[[https://en.wikipedia.org/wiki/File:Cumulative-number-of-objects-launched-into-outer-space-1.svg|thumb|Objects launched into space cumulatively by country]]

== Components ==

=== Orbit and altitude control ===
Further information: Spacecraft propulsion

"Altitude control" redirects here; not to be confused with Attitude control.
[[https://en.wikipedia.org/wiki/File:Ion_Engine_Test_Firing_-_GPN-2000-000482.jpg|thumb|Firing of ''Deep Space 1''<nowiki/>'s ion thruster]]
Most satellites use chemical or ion propulsion to adjust or maintain their orbit, coupled with reaction wheels to control their three axis of rotation or attitude. Satellites close to Earth are affected the most by variations in the Earth's magnetic, gravitational field and the Sun's radiation pressure; satellites that are further away are affected more by other bodies' gravitational field by the Moon and the Sun. Satellites utilize ultra-white reflective coatings to prevent damage from UV radiation. Without orbit and orientation control, satellites in orbit will not be able to communicate with ground stations on the Earth.

Chemical thrusters on satellites usually use monopropellant (one-part) or bipropellant (two-parts) that are hypergolic. Hypergolic means able to combust spontaneously when in contact with each other or to a catalyst. The most commonly used propellant mixtures on satellites are hydrazine-based monopropellants or monomethylhydrazine–dinitrogen tetroxide bipropellants. Ion thrusters on satellites usually are Hall-effect thrusters, which generate thrust by accelerating positive ions through a negatively-charged grid. Ion propulsion is more efficient propellant-wise than chemical propulsion but its thrust is very small (around {{Cvt|0.5|N|disp=or|sigfig=1}}), and thus requires a longer burn time. The thrusters usually use xenon because it is inert, can be easily ionized, has a high atomic mass and storable as a high-pressure liquid.

=== Power ===
Main articles: Batteries in space, Nuclear power in space, and Solar panels on spacecraft
[[https://en.wikipedia.org/wiki/File:ISS-54_ELC-1,_main_solar_arrays_and_radiators_seen_from_the_Cupola.jpg|alt=see caption|thumb|The International Space Station's black solar panels on the left and white radiators on the right]]
Most satellites use solar panels to generate power, and a few in deep space with limited sunlight use radioisotope thermoelectric generators. Slip rings attach solar panels to the satellite; the slip rings can rotate to be perpendicular with the sunlight and generate the most power. All satellites with a solar panel must also have batteries, because sunlight is blocked inside the launch vehicle and at night. The most common types of batteries for satellites are lithium-ion, and in the past nickel–hydrogen.

== Applications ==

=== Earth observation ===
Main article: Earth observation satellite
[[https://en.wikipedia.org/wiki/File:Earth_Radiation_Budget_Satellite.jpg|thumb|Deployment of the Earth Radiation Budget Satellite on STS-41-G, collecting data on Earth's weather and climate]]
Earth observation satellites are designed to monitor and survey the Earth, called remote sensing. Most Earth observation satellites are placed in low Earth orbit for a high data resolution, though some are placed in a geostationary orbit for an uninterrupted coverage. Some satellites are placed in a Sun-synchronous orbit to have consistent lighting and obtain a total view of the Earth. Depending on the satellites' functions, they might have a normal camera, radar, lidar, photometer, or atmospheric instruments. Earth observation satellite's data is most used in archaeology, cartography, environmental monitoring, meteorology, and reconnaissance applications. As of 2021, there are over 950 Earth observation satellites, with the largest number of satellites operated with Planet Labs.

Weather satellites monitor clouds, city lights, fires, effects of pollution, auroras, sand and dust storms, snow cover, ice mapping, boundaries of ocean currents, energy flows, etc. Environmental monitoring satellites can detect changes in the Earth's vegetation, atmospheric trace gas content, sea state, ocean color, and ice fields. By monitoring vegetation changes over time, droughts can be monitored by comparing the current vegetation state to its long term average. Anthropogenic emissions can be monitored by evaluating data of tropospheric NO2 and SO2.

=== Communication ===
Main article: Communications satellite
{{Excerpt|Communications satellite|files=no|hat=no}}

=== Spy satellites ===
Main article: Reconnaissance satellite

When an Earth observation satellite or a communications satellite is deployed for military or intelligence purposes, it is known as a spy satellite or reconnaissance satellite.

Their uses include early missile warning, nuclear explosion detection, electronic reconnaissance, and optical or radar imaging surveillance.

=== Navigation ===
Main article: Satellite navigation

Navigational satellites are satellites that use radio time signals transmitted to enable mobile receivers on the ground to determine their exact location. The relatively clear line of sight between the satellites and receivers on the ground, combined with ever-improving electronics, allows satellite navigation systems to measure location to accuracies on the order of a few meters in real time.

=== Telescope ===
Main article: Space telescope
[[https://en.wikipedia.org/wiki/File:Hubble_Space_Telescope_(27946391011).jpg|thumb|The Hubble Space Telescope]]
Astronomical satellites are satellites used for observation of distant planets, galaxies, and other outer space objects.

=== Experimental ===
Tether satellites are satellites that are connected to another satellite by a thin cable called a tether.<ref /> Recovery satellites are satellites that provide a recovery of reconnaissance, biological, space-production and other payloads from orbit to Earth. Biosatellites are satellites designed to carry living organisms, generally for scientific experimentation. Space-based solar power satellites are proposed satellites that would collect energy from sunlight and transmit it for use on Earth or other places.

=== Weapon ===
Main articles: Space weapon, Anti-satellite weapon, and Early warning satellite

Since the mid-2000s, satellites have been hacked by militant organizations to broadcast propaganda and to pilfer classified information from military communication networks. For testing purposes, satellites in low earth orbit have been destroyed by ballistic missiles launched from the Earth. Russia, United States, China and India have demonstrated the ability to eliminate satellites. In 2007, the Chinese military shot down an aging weather satellite, followed by the US Navy shooting down a defunct spy satellite in February 2008. On 18 November 2015, after two failed attempts, Russia successfully carried out a flight test of an anti-satellite missile known as ''Nudol''. On 27 March 2019, India shot down a live test satellite at 300 km altitude in 3 minutes, becoming the fourth country to have the capability to destroy live satellites.

Category:CHN 4+4

2026-10-29T04:58:57Z

Mukhash:

[[File:Снимок экрана 2026-10-25 223050.png|300px|thumb|right|Q26 message]]
'''Chinese 4+4''' is a rather interesting and easily identifiable signal. It is most likely generated using an IFFT—much like the Clover-2000 waveform—as there is strong evidence to support this. When isolated within a channel, the modulation is not continuous (as is the case with conventional signals); instead, it features periodic drops to zero. These are not simple 180-degree phase shifts, but rather a specific generation method that allows for reliable, independent clocking of each individual channel. On the receiving end, an FFT is almost certainly employed. The generous frequency spacing is clearly designed to accommodate a modulation rate of 150 Hz.

Chinese Navy and Air Force use this modem

[https://drive.google.com/file/d/1A2gHgyZhuWM6h0MpveqlFGLYzdvk2Es3/view?usp=sharing Sample of 4+4 (Q26 on 6516khz LSB)]

Decoded result:
WXYXYXYXYXY HR TRY LL
NR968 CK156 35 1340 --

535 203 02326 004 773 318 353 246 351

MSG AGN

NR968 CK156 35 1340 --

535 20325 326 004 773 318 353 246 351

QSL?

[[Category:Modems]][[Category:Military]]

Category:CHN 4+4

2026-10-25T17:41:09Z

Mukhash:

Category:CHN 4+4

2026-10-25T17:32:44Z

Mukhash: Created page with "Q26 message '''Chinese 4+4''' is a rather interesting and easily identifiable signal. It is most likely generated using an IFFT—much like the Clover-2000 waveform—as there is strong evidence to support this. When isolated within a channel, the modulation is not continuous (as is the case with conventional signals); instead, it features periodic drops to zero. These are not simple 180-degree ph..."

File:Снимок экрана 2026-10-25 223050.png

2026-10-25T17:31:31Z

Mukhash:

Altyn

2026-10-13T17:43:28Z

Mukhash:

[[File:Altyn.png|200px|thumb|right|Logo]]

{| class="wikitable"
|Callsign
|KZ
|-
|Name
|Altyn
|-
|Frequencies
|5 Mhz (AM), 101 Mhz (FM), 400 Mhz (DVB-S2 DATV)
|-
|Status
|Hibernating
|-
|Voice
|N/A
|-
|Emission mode
|AM + Carrier, WFM, I/Q
|-
|Location
|Budapest
|}
Altyn is one of the Strongest stations in SimTX, usually it broadcasts daily with different broadcast programms.

Currently the recommended frequencies are the "Constant" use ones, since Reserve slot is usually used for different not releated transmissions.

Altyn was launched by "Mukhash" (A.K.A. "null_0xf4" in Discord, A.K.A "KZ" callsign in SimTX) on August 18, 2026

== Frequencies ==
{| class="wikitable sortable"
|+
!Frequency
!Status
!Notes
!Modulation
!Power
!Bandwith
!Antenna
!Use
!Note:
|-
|100 Khz
|Testing
|Testing LW
|[[wikipedia:AM_broadcasting|AM]]
|3300kW
|40Khz
|Vertical
|Sporadic
|LW Frequency
|-
|5 Mhz
|Active
|Main frequency
|[[wikipedia:AM_broadcasting|AM]]
|3300kW
|40Khz
|Vertical
|Constant
|First frequency!
|-
|10 Mhz
|Reserve
|Reserved
|[[wikipedia:AM_broadcasting|AM]]
|1000kW
|30Khz
|Vertical
|Uncommon
|Used during jamming issues
|-
|101 Mhz
|Active
|Main frequency
|[[wikipedia:FM_broadcasting|FM]]
|20kW
|200Khz
|Diople
|Constant
|FM, RDS will be added soon
|-
|400 Mhz
|Active
|DVB-S2 Television frequency
|[[wikipedia:In-phase_and_quadrature_components|I/Q]] QPSK 3/4 100k sym/s
|40kW
|200Khz
|Diople
|Constant
|DVB-S2, QPSK, rate - 3/4, 100000 Symbols per second, first DVB-S2 television running hopefully daily!
|}
More information about DVB-S2 is in [[Programme 1|"Programme 1"]] page

== Broadcast Programm ==
Station "Altyn" has multiple Broadcast Programms

"[https://qazradio.fm/kz/ Qazaq Radiosy]" relay - Local General station Relay.

"[https://qazradio.fm/classicfm/ru/ Classic Radiosy]" relay - Local General station Relay.

"Custom Music" request programm - Where people request their own music.

"Soviet Music" programm - Where soviet music, classic, and other genres are being transmitted.

"Good Night" programm - Usually played at 11 PM (6 PM UTC), soviet goodnight song

In those normal broadcast programms there are "Hour Mark" interval (Different ones depending on the programm), however there is one more

"Technical Difficulties" - where we either trying to configure the transmitter or trying to fix known issues such as overheating, different reasons can be found below

"Not in use" - usually used on Reserve frequency as a sign that the frequency is not used today and is going to be shut down after enough time has passed playing the message

"Jam" - when we have jamming issues usually 5Mhz AM is replaced by 10Mhz AM reserve, while 5Mhz and other transmitters are dealing with the jamming issues. The sounds below are the ones used aswell

== Each audio code in "Technical Diffiiculties" ==
When station "Altyn" has those difficulties different audio is played.

"Dance of the little swans" - When there are issues with frequency overlapping

"Mayak Interval" repeated - When the stations are in idle status and not used

"Test" tone - 800hz tone which is used to check overmodulation

== History ==
When "Altyn" didnt even had a name "Mukhash" was searching for a frequency. First thing he saw was 5 Mhz because it was not used at all.

However this would bring issues later.

When he launched 5 Mhz he also searched for a second main frequency, this is when 10 Mhz came to his mind.

And then 10 Mhz also became a main frequency. But then people noticed that the transmitters were constantly overheating. And so he decided that it was time to shut down 10 Mhz temporarily

The overheating issue was being worked on, while "Mukhash" had already decided to start the [[wikipedia:FM_broadcasting|FM (WFM)]] broadcast on 101 Mhz.

Then "AAA" came to jam 5 Mhz and the neighbouring station 5.1 Mhz.

Once they found "AAA" [[wikipedia:IP_address|ip]] he became unusually quiet

There were other jammers aswell

Later he fixed the overheating issue with 5 Mhz but forgot about 10 Mhz, once he remembered he decided to make it reserve

After some time he managed to make the 5Mhz even higher quality and even stronger.

But then appereantly other user was taking 2.5 Mhz, 5 Mhz, 10 Mhz for WWV relay, and he served a notice that once we go off for a break he will take over the frequency, however this lead to a massive jamming drama

Then we solved the issue temporarily with Altyn going into LSB programm

The guy abandoned the frequency again and Altyn was set back to AM

Then Mukhash figured out how to do DVB-S2 television and now the AM / FM frequencies are sometimes defunct in favor of DVB-S2 TV

The history is still going!!!
[[Category:Radio Stations]]
[[Category:FM Station]]

Category:Serdolik

2026-10-11T13:00:04Z

Mukhash:

[[File:Serdolik.png|550x550px|thumb|right|200 bit/sec mode, the most common used]]
[[File:Serdolikhigh.png|322x322px|thumb|right|800 and 1200 bit/sec mode, two of the higher speeds]]
Serdolik (Russian: Сердолик, English: Carnelian) is a proprietary communication system, used exclusively by the Russian diplomatic service. As of March 2020, the updated version of this system is deployed at the Russian embassies in Sofia, Dar es Salaam, and Nairobi.

Links are established by scanning 3 duplex channels in a loop, for 30 seconds each, until a timely response is received. On each frequency, a sequence of two tones is transmitted, representing the calling station's numeric address.

By default, an established link is in the command state, using 35-tone 40 Bd MFSK modulation. This state is used only briefly to switch between the different traffic speeds.

In the traffic state, 9 different speeds are supported. 200 to 1200 bit/s use MFSK modulation, while 2400 bit/s and up use OFDM instead. The symbol rate of all waveforms is 40 Bd.

== Example recordings: ==
[https://drive.google.com/file/d/101SINLk2kkHoSQ_iyHu6tg8aXGkpjxRq/view?usp=sharing 200 bit/sec mode transmission from Moscow]

[https://drive.google.com/file/d/1McMfO1J68Nr8PfTrRclG4MZbQp4MNBoS/view?usp=sharing 800 and 1200 bit/second modes test]

== Frequencies ==
{| class="wikitable sortable"
|+
!'''bit/s'''
!'''Tones per symbol'''
!'''Spectrogram'''
!Note
|-
|200
|1
|[[File:200bps.png|300x300px]]
|The most common mode
|-
|400
|2
|[[File:400bps.png|300x300px]]
|Testing mode
|-
|600
|4
|[[File:600bps.png|300x300px]]
|One of the most common medium speed modes
|-
|800
|7
|[[File:800bps.png|300x300px]]
|One of the most common high speed modes
|-
|1200
|15
|[[File:1200bps.png|300x300px]]
|One of the most common high speed modes
|-
|2400
|60xBPSK
|[[File:60ofdm.png|300x300px]]
|Rarely used
|-
|3600
|45xQPSK
|[[File:45ofdm.png|300x300px]]
|Rarely used
|-
|4800
|60xQPSK
|Same as 2400 bit/s
|Rarely used
|-
|7200
|60x8PSK
|Same as 2400 bit/s
|Rarely used
|}
[[Category:Diplomatic]]
[[Category:Modems]]

Category:Serdolik

2026-10-07T17:21:38Z

Mukhash: /* Example recordings: */

[[File:Serdolik.png|550x550px|thumb|right|200 bit/sec mode, the most common used]]
[[File:Serdolikhigh.png|322x322px|thumb|right|800 and 1200 bit/sec mode, two of the higher speeds]]
Serdolik (Russian: Сердолик, English: Carnelian) is a proprietary communication system, used exclusively by the Russian diplomatic service. As of March 2020, the updated version of this system is deployed at the Russian embassies in Sofia, Dar es Salaam, and Nairobi.

Links are established by scanning 3 duplex channels in a loop, for 30 seconds each, until a timely response is received. On each frequency, a sequence of two tones is transmitted, representing the calling station's numeric address.

By default, an established link is in the command state, using 35-tone 40 Bd MFSK modulation. This state is used only briefly to switch between the different traffic speeds.

In the traffic state, 9 different speeds are supported. 200 to 1200 bit/s use MFSK modulation, while 2400 bit/s and up use OFDM instead. The symbol rate of all waveforms is 40 Bd.

== Example recordings: ==
[https://drive.google.com/file/d/101SINLk2kkHoSQ_iyHu6tg8aXGkpjxRq/view?usp=sharing 200 bit/sec mode transmission from Moscow]

[https://drive.google.com/file/d/1McMfO1J68Nr8PfTrRclG4MZbQp4MNBoS/view?usp=sharing 800 and 1200 bit/second modes test]

== Frequencies ==
{| class="wikitable sortable"
|+
!'''bit/s'''
!'''Tones per symbol'''
!'''Spectrogram'''
!Note
|-
|200
|1
|[[File:200bps.png|300x300px]]
|The most common mode
|-
|400
|2
|[[File:400bps.png|300x300px]]
|Testing mode
|-
|600
|4
|[[File:600bps.png|300x300px]]
|Testing mode
|-
|800
|7
|[[File:800bps.png|300x300px]]
|One of the most common high speed modes
|-
|1200
|15
|[[File:1200bps.png|300x300px]]
|One of the most common high speed modes
|-
|2400
|60xBPSK
|[[File:60ofdm.png|300x300px]]
|Rarely used
|-
|3600
|45xQPSK
|[[File:45ofdm.png|300x300px]]
|Rarely used
|-
|4800
|60xQPSK
|Same as 2400 bit/s
|Rarely used
|-
|7200
|60x8PSK
|Same as 2400 bit/s
|Rarely used
|}
[[Category:Diplomatic]]
[[Category:Modems]]

Category:Serdolik

2026-10-07T17:17:37Z

Mukhash:

[[File:Serdolik.png|550x550px|thumb|right|200 bit/sec mode, the most common used]]
[[File:Serdolikhigh.png|322x322px|thumb|right|800 and 1200 bit/sec mode, two of the higher speeds]]
Serdolik (Russian: Сердолик, English: Carnelian) is a proprietary communication system, used exclusively by the Russian diplomatic service. As of March 2020, the updated version of this system is deployed at the Russian embassies in Sofia, Dar es Salaam, and Nairobi.

Links are established by scanning 3 duplex channels in a loop, for 30 seconds each, until a timely response is received. On each frequency, a sequence of two tones is transmitted, representing the calling station's numeric address.

By default, an established link is in the command state, using 35-tone 40 Bd MFSK modulation. This state is used only briefly to switch between the different traffic speeds.

In the traffic state, 9 different speeds are supported. 200 to 1200 bit/s use MFSK modulation, while 2400 bit/s and up use OFDM instead. The symbol rate of all waveforms is 40 Bd.

== Example recordings: ==

== Frequencies ==
{| class="wikitable sortable"
|+
!'''bit/s'''
!'''Tones per symbol'''
!'''Spectrogram'''
!Note
|-
|200
|1
|[[File:200bps.png|300x300px]]
|The most common mode
|-
|400
|2
|[[File:400bps.png|300x300px]]
|Testing mode
|-
|600
|4
|[[File:600bps.png|300x300px]]
|Testing mode
|-
|800
|7
|[[File:800bps.png|300x300px]]
|One of the most common high speed modes
|-
|1200
|15
|[[File:1200bps.png|300x300px]]
|One of the most common high speed modes
|-
|2400
|60xBPSK
|[[File:60ofdm.png|300x300px]]
|Rarely used
|-
|3600
|45xQPSK
|[[File:45ofdm.png|300x300px]]
|Rarely used
|-
|4800
|60xQPSK
|Same as 2400 bit/s
|Rarely used
|-
|7200
|60x8PSK
|Same as 2400 bit/s
|Rarely used
|}
[[Category:Diplomatic]]
[[Category:Modems]]

Category:Serdolik

2026-10-07T17:16:43Z

Mukhash: /* Frequencies */

[[File:Serdolik.png|550x550px|thumb|right|200 bit/sec mode, the most common used]]
[[File:Serdolikhigh.png|322x322px|thumb|right|800 and 1200 bit/sec mode, two of the higher speeds]]
Serdolik (Russian: Сердолик, English: Carnelian) is a proprietary communication system, used exclusively by the Russian diplomatic service. As of March 2020, the updated version of this system is deployed at the Russian embassies in Sofia, Dar es Salaam, and Nairobi.

Links are established by scanning 3 duplex channels in a loop, for 30 seconds each, until a timely response is received. On each frequency, a sequence of two tones is transmitted, representing the calling station's numeric address.

By default, an established link is in the command state, using 35-tone 40 Bd MFSK modulation. This state is used only briefly to switch between the different traffic speeds.

In the traffic state, 9 different speeds are supported. 200 to 1200 bit/s use MFSK modulation, while 2400 bit/s and up use OFDM instead. The symbol rate of all waveforms is 40 Bd.

== Frequencies ==
{| class="wikitable sortable"
|+
!'''bit/s'''
!'''Tones per symbol'''
!'''Spectrogram'''
!Note
|-
|200
|1
|[[File:200bps.png|300x300px]]
|The most common mode
|-
|400
|2
|[[File:400bps.png|300x300px]]
|Testing mode
|-
|600
|4
|[[File:600bps.png|300x300px]]
|Testing mode
|-
|800
|7
|[[File:800bps.png|300x300px]]
|One of the most common high speed modes
|-
|1200
|15
|[[File:1200bps.png|300x300px]]
|One of the most common high speed modes
|-
|2400
|60xBPSK
|[[File:60ofdm.png|300x300px]]
|Rarely used
|-
|3600
|45xQPSK
|[[File:45ofdm.png|300x300px]]
|Rarely used
|-
|4800
|60xQPSK
|Same as 2400 bit/s
|Rarely used
|-
|7200
|60x8PSK
|Same as 2400 bit/s
|Rarely used
|}
[[Category:Diplomatic]]
[[Category:Modems]]

Category:Serdolik

2026-10-07T17:14:10Z

Mukhash:

[[File:Serdolik.png|550x550px|thumb|right|200 bit/sec mode, the most common used]]
[[File:Serdolikhigh.png|322x322px|thumb|right|800 and 1200 bit/sec mode, two of the higher speeds]]
Serdolik (Russian: Сердолик, English: Carnelian) is a proprietary communication system, used exclusively by the Russian diplomatic service. As of March 2020, the updated version of this system is deployed at the Russian embassies in Sofia, Dar es Salaam, and Nairobi.

Links are established by scanning 3 duplex channels in a loop, for 30 seconds each, until a timely response is received. On each frequency, a sequence of two tones is transmitted, representing the calling station's numeric address.

By default, an established link is in the command state, using 35-tone 40 Bd MFSK modulation. This state is used only briefly to switch between the different traffic speeds.

In the traffic state, 9 different speeds are supported. 200 to 1200 bit/s use MFSK modulation, while 2400 bit/s and up use OFDM instead. The symbol rate of all waveforms is 40 Bd.

== Frequencies ==
{| class="wikitable sortable"
|+
!'''bit/s'''
!'''Tones per symbol'''
!'''Spectrogram'''
|-
|200
|1
|[[File:200bps.png|300x300px]]
|-
|400
|2
|[[File:400bps.png|300x300px]]
|-
|600
|4
|[[File:600bps.png|300x300px]]
|-
|800
|7
|[[File:800bps.png|300x300px]]
|-
|1200
|15
|[[File:1200bps.png|300x300px]]
|-
|2400
|60xBPSK
|[[File:60ofdm.png|300x300px]]
|-
|3600
|45xQPSK
|[[File:45ofdm.png|300x300px]]
|-
|4800
|60xQPSK
|Same as 2400 bit/s
|-
|7200
|60x8PSK
|Same as 2400 bit/s
|}
[[Category:Diplomatic]]
[[Category:Modems]]

Category:Serdolik

2026-10-07T17:13:14Z

Mukhash:

[[File:Serdolik.png|550x550px|thumb|right|200 bit/sec mode, the most common used]]
[[File:Serdolikhigh.png|322x322px|thumb|right|800 and 1200 bit/sec mode, two of the higher speeds]]
Serdolik (Russian: Сердолик, English: Carnelian) is a proprietary communication system, used exclusively by the Russian diplomatic service. As of March 2020, the updated version of this system is deployed at the Russian embassies in Sofia, Dar es Salaam, and Nairobi.

Links are established by scanning 3 duplex channels in a loop, for 30 seconds each, until a timely response is received. On each frequency, a sequence of two tones is transmitted, representing the calling station's numeric address.

By default, an established link is in the command state, using 35-tone 40 Bd MFSK modulation. This state is used only briefly to switch between the different traffic speeds.

In the traffic state, 9 different speeds are supported. 200 to 1200 bit/s use MFSK modulation, while 2400 bit/s and up use OFDM instead. The symbol rate of all waveforms is 40 Bd.

== Frequencies ==
{| class="wikitable sortable"
|+
!'''bit/s'''
!'''Tones per symbol'''
!'''Spectrogram'''
|-
|200
|1
|[[File:200bps.png|300x300px]]
|-
|400
|2
|[[File:400bps.png|300x300px]]
|-
|600
|4
|[[File:600bps.png|300x300px]]
|-
|800
|7
|[[File:800bps.png|300x300px]]
|-
|1200
|15
|[[File:1200bps.png|300x300px]]
|-
|2400
|60xBPSK
|[[File:60ofdm.png|300x300px]]
|-
|3600
|45xQPSK
|[[File:45ofdm.png|300x300px]]
|-
|4800
|60xQPSK
|Same as 2400 bit/s
|-
|7200
|60x8PSK
|Same as 2400 bit/s
|}

Category:Serdolik

2026-10-07T17:12:53Z

Mukhash:

[[File:Serdolik.png|550x550px|thumb|right|200 bit/sec mode, the most common used]]
[[File:Serdolikhigh.png|550x550px|thumb|right|800 and 1200 bit/sec mode, two of the higher speeds]]
Serdolik (Russian: Сердолик, English: Carnelian) is a proprietary communication system, used exclusively by the Russian diplomatic service. As of March 2020, the updated version of this system is deployed at the Russian embassies in Sofia, Dar es Salaam, and Nairobi.

Links are established by scanning 3 duplex channels in a loop, for 30 seconds each, until a timely response is received. On each frequency, a sequence of two tones is transmitted, representing the calling station's numeric address.

By default, an established link is in the command state, using 35-tone 40 Bd MFSK modulation. This state is used only briefly to switch between the different traffic speeds.

In the traffic state, 9 different speeds are supported. 200 to 1200 bit/s use MFSK modulation, while 2400 bit/s and up use OFDM instead. The symbol rate of all waveforms is 40 Bd.

== Frequencies ==
{| class="wikitable sortable"
|+
!'''bit/s'''
!'''Tones per symbol'''
!'''Spectrogram'''
|-
|200
|1
|[[File:200bps.png|300x300px]]
|-
|400
|2
|[[File:400bps.png|300x300px]]
|-
|600
|4
|[[File:600bps.png|300x300px]]
|-
|800
|7
|[[File:800bps.png|300x300px]]
|-
|1200
|15
|[[File:1200bps.png|300x300px]]
|-
|2400
|60xBPSK
|[[File:60ofdm.png|300x300px]]
|-
|3600
|45xQPSK
|[[File:45ofdm.png|300x300px]]
|-
|4800
|60xQPSK
|Same as 2400 bit/s
|-
|7200
|60x8PSK
|Same as 2400 bit/s
|}

File:Serdolikhigh.png

2026-10-07T17:12:20Z

Mukhash:

Category:Serdolik

2026-10-07T17:11:47Z

Mukhash:

[[File:Serdolik.png|550x550px|thumb|right|200 bit/sec mode, the most common used]]
Serdolik (Russian: Сердолик, English: Carnelian) is a proprietary communication system, used exclusively by the Russian diplomatic service. As of March 2020, the updated version of this system is deployed at the Russian embassies in Sofia, Dar es Salaam, and Nairobi.

Links are established by scanning 3 duplex channels in a loop, for 30 seconds each, until a timely response is received. On each frequency, a sequence of two tones is transmitted, representing the calling station's numeric address.

By default, an established link is in the command state, using 35-tone 40 Bd MFSK modulation. This state is used only briefly to switch between the different traffic speeds.

In the traffic state, 9 different speeds are supported. 200 to 1200 bit/s use MFSK modulation, while 2400 bit/s and up use OFDM instead. The symbol rate of all waveforms is 40 Bd.

== Frequencies ==
{| class="wikitable sortable"
|+
!'''bit/s'''
!'''Tones per symbol'''
!'''Spectrogram'''
|-
|200
|1
|[[File:200bps.png|300x300px]]
|-
|400
|2
|[[File:400bps.png|300x300px]]
|-
|600
|4
|[[File:600bps.png|300x300px]]
|-
|800
|7
|[[File:800bps.png|300x300px]]
|-
|1200
|15
|[[File:1200bps.png|300x300px]]
|-
|2400
|60xBPSK
|[[File:60ofdm.png|300x300px]]
|-
|3600
|45xQPSK
|[[File:45ofdm.png|300x300px]]
|-
|4800
|60xQPSK
|Same as 2400 bit/s
|-
|7200
|60x8PSK
|Same as 2400 bit/s
|}

Category:Serdolik

2026-10-07T17:11:19Z

Mukhash:

[[File:Serdolik.png|550x550px|thumb|right|200 bit/sec mode, the most common used]]
Serdolik (Russian: Сердолик, English: Carnelian) is a proprietary communication system, used exclusively by the Russian diplomatic service. As of March 2020, the updated version of this system is deployed at the Russian embassies in Sofia, Dar es Salaam, and Nairobi.

Links are established by scanning 3 duplex channels in a loop, for 30 seconds each, until a timely response is received. On each frequency, a sequence of two tones is transmitted, representing the calling station's numeric address.

By default, an established link is in the command state, using 35-tone 40 Bd MFSK modulation. This state is used only briefly to switch between the different traffic speeds.

In the traffic state, 9 different speeds are supported. 200 to 1200 bit/s use MFSK modulation, while 2400 bit/s and up use OFDM instead. The symbol rate of all waveforms is 40 Bd.

== Frequencies ==
{| class="wikitable sortable"
|+
!'''bit/s'''
!'''Tones per symbol'''
!'''Spectrogram'''
|-
|200
|1
|[[File:200bps.png|300x300px]]
|-
|400
|2
|[[File:400bps.png|557x557px]]
|-
|600
|4
|[[File:600bps.png|557x557px]]
|-
|800
|7
|[[File:800bps.png|557x557px]]
|-
|1200
|15
|[[File:1200bps.png|557x557px]]
|-
|2400
|60xBPSK
|[[File:60ofdm.png|557x557px]]
|-
|3600
|45xQPSK
|[[File:45ofdm.png|557x557px]]
|-
|4800
|60xQPSK
|Same as 2400 bit/s
|-
|7200
|60x8PSK
|Same as 2400 bit/s
|}

Category:Serdolik

2026-10-07T17:11:05Z

Mukhash:

[[File:Serdolik.png|550x550px|thumb|right|200 bit/sec mode, the most common used]]
Serdolik (Russian: Сердолик, English: Carnelian) is a proprietary communication system, used exclusively by the Russian diplomatic service. As of March 2020, the updated version of this system is deployed at the Russian embassies in Sofia, Dar es Salaam, and Nairobi.

Links are established by scanning 3 duplex channels in a loop, for 30 seconds each, until a timely response is received. On each frequency, a sequence of two tones is transmitted, representing the calling station's numeric address.

By default, an established link is in the command state, using 35-tone 40 Bd MFSK modulation. This state is used only briefly to switch between the different traffic speeds.

In the traffic state, 9 different speeds are supported. 200 to 1200 bit/s use MFSK modulation, while 2400 bit/s and up use OFDM instead. The symbol rate of all waveforms is 40 Bd.

== Frequencies ==
{| class="wikitable sortable"
|+
!'''bit/s'''
!'''Tones per symbol'''
!'''Spectrogram'''
|-
|200
|1
|[[File:200bps.png|200x200px]]
|-
|400
|2
|[[File:400bps.png|557x557px]]
|-
|600
|4
|[[File:600bps.png|557x557px]]
|-
|800
|7
|[[File:800bps.png|557x557px]]
|-
|1200
|15
|[[File:1200bps.png|557x557px]]
|-
|2400
|60xBPSK
|[[File:60ofdm.png|557x557px]]
|-
|3600
|45xQPSK
|[[File:45ofdm.png|557x557px]]
|-
|4800
|60xQPSK
|Same as 2400 bit/s
|-
|7200
|60x8PSK
|Same as 2400 bit/s
|}

Category:Serdolik

2026-10-07T17:10:26Z

Mukhash:

[[File:Serdolik.png|550x550px|thumb|right|200 bit/sec mode, the most common used]]
Serdolik (Russian: Сердолик, English: Carnelian) is a proprietary communication system, used exclusively by the Russian diplomatic service. As of March 2020, the updated version of this system is deployed at the Russian embassies in Sofia, Dar es Salaam, and Nairobi.

Links are established by scanning 3 duplex channels in a loop, for 30 seconds each, until a timely response is received. On each frequency, a sequence of two tones is transmitted, representing the calling station's numeric address.

By default, an established link is in the command state, using 35-tone 40 Bd MFSK modulation. This state is used only briefly to switch between the different traffic speeds.

In the traffic state, 9 different speeds are supported. 200 to 1200 bit/s use MFSK modulation, while 2400 bit/s and up use OFDM instead. The symbol rate of all waveforms is 40 Bd.

== Frequencies ==
{| class="wikitable sortable"
|+
!'''bit/s'''
!'''Tones per symbol'''
!'''Spectrogram'''
|-
|200
|1
|[[File:200bps.png|557x557px]]
|-
|400
|2
|[[File:400bps.png|557x557px]]
|-
|600
|4
|[[File:600bps.png|557x557px]]
|-
|800
|7
|[[File:800bps.png|557x557px]]
|-
|1200
|15
|[[File:1200bps.png|557x557px]]
|-
|2400
|60xBPSK
|[[File:60ofdm.png|557x557px]]
|-
|3600
|45xQPSK
|[[File:45ofdm.png|557x557px]]
|-
|4800
|60xQPSK
|Same as 2400 bit/s
|-
|7200
|60x8PSK
|Same as 2400 bit/s
|}

File:45ofdm.png

2026-10-07T17:09:59Z

Mukhash:

File:60ofdm.png

2026-10-07T17:09:50Z

Mukhash:

File:1200bps.png

2026-10-07T17:09:39Z

Mukhash:

File:800bps.png

2026-10-07T17:09:28Z

Mukhash:

File:600bps.png

2026-10-07T17:08:33Z

Mukhash: