BANGALORE (TIP): India’s space agency ISRO crossed another milestone August 27 afternoon, launching its first 2,000-kg-plus satellite on a launch vehicle powered by an indigenous engine.

The 2,117-kg GSAT-6 communication satellite flew into space on GSLV-D6 launch vehicle from the Satish Dhawan Space Centre at Sriharikota. This was the second successful flight of the GSLV using the indigenous cryogenic engine with which ISRO scientists have had a bitter-sweet experience till now.

The GSAT-6 satellite is the same one that had been leased out to a private company, Devas Multimedia, four years ago for launching satellite-based mobile communication services. Devas had been authorised by ISRO to use a part of the S-band spectrum to roll out its services.

The deal had been cancelled by the government in 2012 after allegations of favouritism surfaced, and questions were raised over allotment of S-band that could be used by the security agencies. The GSAT-6 has a six-metre wide unfurlable antenna that can facilitate utilisation of S-band space spectrum for communication and an 80-cm C band antenna that has been reserved for “strategic uses”.

The launch marks an important step in the deployment of GSLVs in future projects. GSLV, or Geosynchronous Satellite Launch Vehicle, is an advanced launch vehicle that can be used to carry satellites heavier than 2000-kg, even those weighing up to 5000-kg, into space. This is the vehicle that ISRO has been banking on to realise its future projects to explore deep space, far beyond even Mars. GSLV’s higher capabilities, as compared to the PSLV or Polar Satellite Launch Vehicle that has made 28 successful launches in a row, is made possible by a cryogenic part of the three-stage engine. Cryogenics is the science of extremely low temperatures. The cryogenic engine uses liquid engine and liquid hydrogen as propellants.

The first successful flights of GSLV used Russian-made cryogenic engines, including the GSLF-F04 that carried the heaviest-ever satellite launched from India, the INSAT-4CR that weighed 2130 kg, 13 kg more than GSAT-6. ISRO’s initial attempts to use its own cryogenic engine in the GSLV resulted in failure. It was only in January last year that the first GSLV with an indigenous cryogenic-stage engine made a successful flight.