Russia Launches First Navigation Augmentation Satellite
December 12, 2011 By: Richard B. Langley
Roscosmos, the Russian space agency, has launched the Luch-5A geostationary relay satellite. The satellite was propelled into space on a Proton-M rocket with a Breeze-M upper stage from the Baikonur Cosmodrome on Sunday, December 11, at 11:17 UTC. Luch-5A was accompanied by the Israeli Amos-5 communications satellite on the dual-satellite launch.
Luch-5A separated from the Breeze-M upper stage, with Amos-5 still attached, at 20:11 UTC. Roscosmos reported that the satellite’s antennas and solar panels deployed successfully and that the satellite is under control. The Amos-5 satellite was subsequently deployed at 20:52 UTC.
The satellite’s apogee kick motor will be used to position Luch-5A in a geostationary orbit at 16 degrees west longitude.
Luch-5A is the first in a series of new data relay satellites designed to rebuild the Luch Multifunctional Space Relay System (Mnogofunktsional’noi Kosmicheskoi Sistemy Retranslyatsii), or MSRS, that was used to transmit to Earth live TV images, communications, and telemetry from Mir, the Soviet/Russian space station; the Russian segment of the International Space Station; and other low-Earth-orbiting (LEO) spacecraft in a similar fashion to that of NASA’s Tracking and Data Relay Satellite System. All of the initial Luch satellites had ceased operating by 1998. “Luch” translates to “ray” or “beam” in English and is also sometimes written as “Loutch.”
In addition to seven transponders in the Ku-and S-bands to be used to relay communications and telemetry between LEO spacecraft and Russian ground facilities, the satellite hosts a COSPAS/SARSAT search and rescue transponder, and a wideband satellite-based augmentation system (SBAS) transponder.
The SBAS transponder will transmit correction and integrity data for GLONASS and GPS on the GPS L1 frequency with a C/A pseudorandom noise code to be assigned by the GPS Directorate. The data will be provided by the System for Differential Correction and Monitoring or SDCM, which uses a ground network of monitoring stations on Russian territory as well as some overseas stations.
As the SDCM primary service area is Russian territory, the main lobe of the SBAS antenna beam will be directed to the north with an angle of 7 degrees relative to the direction to the equator. The transmitted power will be 60 watts and will give a signal power level at the Earth’s surface roughly equal to that of GLONASS and GPS signals, about –158 dBW.
The current international SBAS data format has a limited capability for broadcasting corrections for both GLONASS and GPS satellites combined. There is space for only 51 satellites, insufficient for the current number of satellites on orbit. As a result, studies are being carried out in an attempt to resolve this problem. One option is to use a dynamic satellite mask, where an SDCM satellite would only broadcast corrections and integrity data for those GLONASS and GPS satellites in view of users in the territory of the Russian Federation.
Luch-5A is the first of three MSRS/SDCM satellites. Luch-5B will be launched in 2012 into a slot at 95 degrees east longitude and Luch-4, in 2014, into a slot at 167 degrees east longitude.
The Luch-5A and Luch-5B satellites are based on Information Satellite Systems (ISS) Reshetnev Company’s Express 1000 unpressurized satellite platform, while Luch-4 will be based on its advanced Express 2000 platform. ISS Reshetnev, based in Zheleznogorsk, Siberia, is also the company that builds the GLONASS satellites.
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