Raumfahrt - ISRO´s GSLV rocket: too late for changing times


‘It may be ISRO’s short-lived rocket, not its primary satellite vehicle as planned’

The GSLV space vehicle’s quiet but laudable success earlier this month could be a small solace that has come too late for the Indian Space Research Organisation.

The late bloomer may even be a short-lived intermediate rocket instead of being ISRO’s primary satellite vehicle as it was planned, as a few ISRO old-timers and industry watchers privately suggest.

Adds to reliability

Its fine feat of putting the South Asia Satellite perfectly to space on May 5 no doubt adds to the GSLV’s reliability. But ISRO actually needed this achievement at least a good decade ago, when it was still building and using 2,000-2,500-kg communication spacecraft for its own use.

The GSLV was conceived in the early 1990s to launch Indian communication satellites of 2,000-kg class to an initial and later adjusted distance from Earth, called the ‘GTO’ (geosynchronous transfer orbit). This rocket took about 25 years and 11 flights to be fully realised. GSLV F-09 of May 5 was the fourth to click in a row.

The GSLV is caught in a glaring mismatch: it cannot lift India’s bigger satellites; and the size that it can lift is out of fashion and does not make economic sense.


As to why the GSLV could not rise sooner to the occasion, the external geopolitical reasons beyond the agency are well known now.

While ISRO was perfecting the GSLV and falling behind schedule with the rocket’s crucial cryogenic stage, it progressed on the spacecraft side and upgraded the communication satellites to 3,000-plus kg in 2005. This was done to pack more punch (or transponders) per spacecraft. It would be roughly 24 regular transponders for 2,000 kg; 36 transponders for 3,000 kg and 48 transponders in a four-tonner.

Replying to a query from The Hindu , Gagan Agrawal, analyst with the U.S.-based space industry consulting firm Northern Sky Research, said: “The communications satellite market is consistently looking at payload sizes greater than four tonnes and the question remains whether the GSLV or [the bigger] MKIII can cater to the market [yet.] ”

Not many customers

ISRO’s smaller PSLV rocket has made a niche in the world market for light lifts. For the GSLV, there may not be many commercial customers requiring its service.

Quelle: The Hindu

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