GSAT-6A to launch on Indian GSLV
An Indian Space Research Organisation (ISRO) Geosynchronous Satellite Launch Vehicle (GSLV) will loft a geostationary-orbit-bound communications satellite called GSAT-6A at 7:26 a.m. EDT (11:26 GMT) March 29, 2018, from the Satish Dawn Space Center’s Second Launch Pad.
GSAT-6A is partly a technology demonstrator satellite with a 20-foot (six-meter) diameter unfurlable S-band antenna. It is based around the I-2K spacecraft bus, which was also developed by the ISRO, and is designed to support mid-sized satellites to providing up to three kilowatts of power via two solar arrays on either side of the spacecraft.
The spacecraft will also demonstrate technologies for potential use in satellite-based mobile communications systems, including testing with handheld ground terminals and network management technologies. In total, it will carry 10 S-band transponders designed to cover the entire country of India, providing communications services for civil, military, and public use.
GSAT-6A is a follow-on to GSAT-6, which was launched atop a GSLV in 2015. The latter continues to operate, and is in good condition after arriving at its designated orbit. GSAT-6A will supplement India’s on-orbit communications systems.
This will be the 12th launch of the 161-foot (49-meter) tall GSLV rocket and the sixth with the Cryogenic Upper Stage, which is a liquid-hydrogen-fueled upper stage developed by the ISRO to increase the capabilities of the Indian space program. The engine, an ISRO-developed CE7.5, replaced the Russian KVD-1M engine previously imported by India.
The GSLV core stage is powered by solid-fueled GS1 rocket motor burning hydroxyl-terminated polybutadiene (HTPB). The GS1 is supplemented by four strap-on liquid rocket boosters that are each powered by a single Vikas engine developed by the ISRO and burn unsymmetric dimethyl hydrazine (UDMH) and Nitrogen Tetroxide (N2O4).
The strap-on boosters burn for 160 seconds while the GS1 core stage burns for 100 seconds. Once the first stage and boosters have burned out and separated, the second stage ignites. Called GS2, the stage is also powered by a single Vikas engine and burns UDMH and N2O4 for 150 seconds before separating from the final stage.
The final stage of the GSLV is the Cryogenic Upper Stage. It can burn for up to 720 seconds.
Once the mission gets off the ground, it will be the second launch by India in 2018. The first occurred on Jan. 12 and saw a Polar Satellite Launch Vehicle send 31 satellites into orbit, including four SpaceBee satellites owned by a U.S.-based company that were not licensed by the Federal Communications Commission.
Christopher Paul has had a lifelong interest in spaceflight. He began writing about his interest in the Florida Tech Crimson. His primary areas of interest are in historical space systems and present and past planetary exploration missions. He lives in Kissimmee, Florida, and also enjoys cooking and photography. Paul saw his first Space Shuttle launch in 2005 when he moved to central Florida to attend classes at the Florida Institute of Technology, studying space science, and has closely followed the space program since. Paul is especially interested in the renewed effort to land crewed missions on the Moon and to establish a permanent human presence there. He has covered several launches from NASA's Kennedy Space Center and Cape Canaveral for space blogs before joining SpaceFlight Insider in mid-2017.