That’s the story of ISRO’s experience with developing a cryogenic upper stage, an advanced technology mastered by only a handful of the world’s space powers. On August 19, the Indian space agency will launch its second domestically produced cryogenic stage, capping off a three-year effort to recover for its first failed attempt.
On April 15, 2010, the first and second stages of the GSLV rocket fired nominally. However, the cryogenic upper stage engine fired for only .5 seconds before the fuel pump failed. The premature cutoff sent the GSAT-4 spacecraft to a watery grave at the bottom of the Bay of Bengal.
Eight months later, ISRO marked Christmas by launching its second GSLV rocket of the year, this time with a more reliable Russian-supplied cryogenic upper stage. The rocket went out of control early during the flight before the cryogenic stage could fire, causing the range safety officer to destroy the vehicle. The GSAT-5P satellite joined GSAT-4 at the bottom of the bay, and the GSLV hasn’t been launched since.
ISRO officials appear outwardly confident that this time, all stages will work as designed and the GSAT-14 satellite will actually reach its intended orbit. If they are correct, India finally will cap off its 20-year long cryogenic engine development program with an unqualified success.
A flawless flight would be good news for ISRO’s troubled GSLV rocket, which has succeeded only twice while suffering four failures and one partial failure since its initial launch in 2001. The space agency’s largest rocket has destroyed more spacecraft than it has successfully launched.
The fact that the Aug. 19 launch will only be the eighth GSLV launch in 12 years, and its first in since Christmas 2010, provides a big clue as to the launch vehicle’s reliability problems. The launch rate is simply too low for ISRO to get very good at manufacturing, processing and operating these conplex vehicles.
Flaws need to be worked out during initial launches, appropriate fixes introduced that don’t cause other problems, the design finalized, and then the vehicle put into serial production where each one is built exactly the same according to rigorous quality control process. Crews then need regular experience in processing and launching the rockets, not years-long gaps.
The future of the GSLV, which comes in Mark I and Mark II variants, is not entirely clear. In 2014, the space agency is looking to make the inaugural launch of its much larger GSLV Mark III rocket, which is based on different technology than the GSLV but will use the domestically built cryogenic upper stage to launch much heavier communications satellites.