Electro-1 / GOMS-1
GOMS-1, also referred to as Electro-1 (and a spelling of Elektro-1), is the first (experimental) geostationary weather satellite of Russia. Initial program planning started in the early 1970s (the VPK Military-Industrial Commission requested development of a unified meteorological system to be operational by 1979), and continued through the 1980s [involvement of ROSHYDROMET (Committee for Hydrometeorology and Environmental Monitoring) and other institutions in Russia]. The program's numerous delays were due to both equipment and software problems.
In the early 1990s (end of Cold War), the newly created RKA (Russian Space Agency) stepped in and functioned as project supporter, while NPO Planeta of Moscow, an agency positioned under ROSHYDROMET, functioned in its general service role as weather satellite operator and data provider. The spacecraft and its instruments were designed and developed by VNIIEM of Moscow as prime contractor. With Electro-1/GOMS-1, Russia joined the international geostationary weather monitoring group. 1) 2) 3) 4) 5) 6) 7)
The project has the following objectives:
• To acquire, in real-time, television images of the Earth's surface and cloud cover within a radius of 60º centered at the sub-satellite point in the visible and IR regions of the spectrum
• To measure temperature profiles of the Earth's surface (land and ocean) as well as cloud cover
• To measure the radiation state and magnetic field of the space environment at the geostationary position
• To transmit via digital radio channels television images, temperature and radiation and magnetometric information to the main and regional data receiving and processing centers
• To acquire information from Russia and international data collection platforms (DCPs), located in the GOMS visibility range, and to transmit the information obtained to all receiving and processing centers (RPCs)
• To provide the exchange of high-speed digital data (retransmissions via the satellite) between the main and regional centers of the USSR State Committee for Hydrometeorology
• To call for the data collection platforms (DCPs) to transmit the information to the satellite.
• To retransmit the processed meteorological data in the form of facsimile or alphanumerical information from the receiving and processing centers to the independent receiving stations via the GOMS satellite
• To provide an exchange of high-speed digital data (retransmission via GOMS) among all regional centers within Russia (Federal Service for Hydrometeorology and Environmental Monitoring).
Figure 1: Photo of the Electro-1 / GOMS-1 spacecraft during test and integration (image credit: Roskosmos) 8)
GOMS is designed as a three-axis stabilized (fly-wheel) spacecraft with orientation to the Earth and along the velocity vector; orientation knowledge is through the polar star sensor and the sun sensors. Design life = 3 years. Orientation accuracy = ±2-5 arcmin. Spacecraft mass = 2580 kg (including payload of 900 kg), power = 1.5 kW (average).
Figure 2: Line drawing of the deployed Elektro/GOMS-1 spacecraft (image credit: VNIIEM)
Launch: The GOMS-1 spacecraft was launched October 31, 1994 (by a Proton-K/DM-2 vehicle) from Baikonur, Kazhakstan - 15 years after its original public schedule. 9)
Orbit: Geostationary orbit, location at 76.5º East (over the Indian Ocean), the inclination is kept to < 0.5º.
Status of mission:
• The GOMS-1 spacecraft experienced orientation/stabilization problems during its initial phase of operations. These problems were eventually fixed by February 1, 1995. Since then GOMS has been in its operational testing phase. Despite the problems, GOMS-1 became `operational' for the Eastern Hemisphere; however, visible imagery couldn't be broadcast because of problems with the sensor package. GOMS-1 infrared data became operational in June 1996. Finally, the GOMS-1 mission operations were ended in Nov. 2000 (the spacecraft experienced difficulties throughout its life and was never able to provide a sustained operational service).
• By 1998, routine geostationary data coverage had still not been achieved over the Indian Ocean. Within the CGMS (Coordination Group for Meteorological Satellites) framework, this area is nominally the responsibility of Russia, but its experimental GOMS satellite was experiencing difficulties, and data from the neighboring Indian satellite INSAT, was not widely available. As a consequence, after discussion between the authorities in Russia and EUMETSAT, Meteosat-5 was moved to a longitude of 63º E to provide data for the duration of the experiment.
Note: Meteosat-5 (launched March 2, 1991) was repositioned in 1998 over the Indian Ocean to provide support for INDOEX (Indian Ocean Experiment), an international campaign to study atmospheric pollutants, clouds, solar radiation, and interactions of clouds over the Indian Ocean (focus on the analysis of the direct and indirect effects of aerosols on the radiation budget in tropical regions and radioactive forcing modifications due to circulation associated with the intertropical convergence zone).
STR (Scanning Television Radiometer):
STR is a 2 band instrument providing imagery in the VIS and TIR (Thermal Infrared) bands. Objectives: observation of clouds and underlying surface in VIS and TIR spectra and temperature data of underlying surface, determination of top of clouds.
Note: The STR instrument is also referred to as BTVC (OnBoard TeleVision Complex). The BTVC optical system has a mirror objective 400 mm in diameter. The instantaneous field of view (IFOV) is 6.3 arcsec in the visual spectral range and 22.5 arcsec in the infrared range. Observation of the Earth is performed simultaneously in two spectral bands: visual, 0.4-0.7 µm; and thermal infrared, 10.5-12.5 µm. The thermal infrared channel records thermal fluxes from objects with radiation temperatures between 313 and 213 K. The noise level does not exceed 1 K. 10)
There is no water vapor channel on the STR instrument.
Table 1: Key characteristics of the STR instrument
The moon was used for calibration of the instrument: The calibration procedure is based on the comparison of the output data of the onboard apparatus of the geostationary satellite GOMS with a photometric database that includes measured values of brightness and temperature for a large number of lunar surface areas. To this end, an automated database was created, which contains brightness and temperature values for 1954 areas of the lunar surface, measured by the global scanning of the illuminated lunar disk in the visual (0.445 µm) and TIR spectral ranges. 11)
RMS (Radiation Measurement System):
RMS consists of instruments for heliogeophysical measurements, radiation and magnetic parameters). Objective: registration of particles (protons, electrons, α-particles), measurement of X-ray radiation from the sun, measurement of magnetic field vector components.
- Density of electron fluxes with energies in four bands from 0.04 - 1.7 MeV
- Density of proton fluxes with energies in four bands from 0.5 - 90 MeV
- Density of alpha particles with energies from 5 - 12 MeV
- Intensity of the galactic cosmic radiation with energies > 600 MeV
- Solar X-ray radiation intensity with energies from 3 - 8 keV
- Intensity of solar UV radiation in four wave bands up to 1300 A
- Magnetic induction vector component quantities along 3 axis with ± 180 nT interval
Figure 3: Data collection and distribution scenario for GOMS
Radio Complex for Data Collection, Transmission and Relay:
The communications system transmits image data and space environment data to the ground, collects environmental data from Data Collection Platforms (DCP), exchanges satellite-based data among ground stations and will deliver information to the user community (WEFAX function).
GOMS communication characteristics:
• Transmission of TV images and heliogeophysical information from the satellite to the receiving and processing centers - RPCs (Radio channels I and II).
• Carrier frequencies: 1685 MHz (S-band) and 7465 MHz (X-band)
• Data transmission rate = 2.56 Mbit/s
• Radio channel III: transmission of data from DCPs; frequencies: 401 - 403 MHz; transmission of data is possible through 33 international and 100 Russian channels at rates of 100 bit/s.
• Radio channels IV and V: retransmission of information obtained from DPCs to RPCs; frequencies: 1697±1 MHz (S-band) and 7482 ±1 MHz (X-band)
• Radio channels VI and VII: transmission of facsimile information in standard WEFAX format and alphanumerical data from RPCs to GOMS. Frequencies: 2115±1.5 MHz and 8195±1.5 MHz. Data transmission rate = 1200 bit/s
• Radio channel VIII: retransmission of facsimile and alphanumerical data from GOMS to independent receiving stations. Frequency: 1691±1.5 MHz
• Radio channel IX: transmission of high-speed digital information from RPC to GOMS. Frequency: 8190±5 MHz; data rate up to 0.96 Mbit/s
• Radio channel X: transmission of high-speed digital information from GOMS to the RPCs. Frequency: 7.465±2.5 MHz; data rate up to 0.96 Mbit/s
• Radio channel XI: calling for DCP from GOMS. Frequency: 469±1 MHz
• Radio channel XII: transmission of DCP request from RPC to GOMS. Frequency: 2119± 1 MHz
GOMS data receiving and transmitting modes:
• Channels I and II operate 24 - 48 times per day; each session lasts 15 minutes
• Channels III, IV and V operate by commands calling for DCP information
• Channels VI, VII and VIII operate continuously
• Channels IX and X function in the interval when channels I and II are not active
• Channels XI and XII operate on request
1) “Space System with Geostationary Meteorological Satellite (GOMS),” Paper of Planeta, Moscow, Nov. 1990
2) S. A. Stoma, Yu. V. Trifonov, “Geostationary Space System `ELECTRO' (GOMS): Preconditions for Creation and Structure,” Space Bulletin, Vol. 2, No. 3, 1995, pp. 2-6
3) O. M. Miroshnik, et. al., “A Drama in Orbit with a Happy Ending,” Space Bulletin, Vol. 2, No. 3, 1995, pp. 7-10
4) Yu. V. Trifonov, “S/C ELECTRO On-board Control Complex,” Space Bulletin, Vol. 2, No. 3, 1995, pp. 11-14
5) Yu. V. Trifonov, A. V. Gorbunov, “Prospects for the ELECTRO Space System Development,” Space Bulletin, Vol. 2, No. 3, 1995, pp. 14-15
8) G. Polishchuk, “Automatic Spacecraft open new Horizons,” Military Parade, March/April 2003
10) S. G. Pugacheva, V. V. Shevchenko, S. G. Yakovlev, V. M. Kibardin, “Calibration of the Moon's Infrared Images from Geostationary Satellite GOMS,” 30th Lunar and Planetary Science Conference, March 15–19, 1999, Houston, TX, USA, URL: http://www.lpi.usra.edu/meetings/LPSC99/pdf/1247.pdf
11) S. G. Pugacheva, “Anomalies of the Moon's Thermal Emission in the IR Spectral Range (10.5-12.5 µm),” 34th International Microsymposium (Vernadsky–Brown) on Comparative Planetology, MS058, Oct. 8-9, 2001, Moscow, Russia, URL: http://selena.sai.msu.ru/Pug/Publications/ms34/MS058.pdf
The information compiled and edited in this article was provided by Herbert J. Kramer from his documentation of: "Observation of the Earth and Its Environment: Survey of Missions and Sensors" (Springer Verlag) as well as many other sources after the publication of the 4th edition in 2002. - Comments and corrections to this article are always welcome for further updates.