The Indian Space Research Organisation (ISRO) on Saturday (February 17) launched a new-generation meteorological satellite, INSAT-3DS, meant to carry out enhanced monitoring of the Earth’s surface, atmosphere, oceans and environment. INSAT-3DS will augment the capabilities of the existing two meteorological satellites, INSAT-3D and INSAT-3DR, and boost India’s weather and climate prediction services, early warnings, and disaster management services.
But more than the satellite, it was the rocket that was the focus of attention of this launch. The INSAT-3DS satellite rode on the GSLV-F14 rocket to reach its intended geostationary orbit. GSLV is one of the three main rockets used by ISRO for carrying its satellites, the other two being PSLV and LVM3 (earlier called GSLV-MkIII). GSLV has had a rather patchy track record thus far, because of which it has been described as the ‘naughty boy’. On Saturday, however, it made a flawless flight, and deposited the satellite in the desired orbit.
But why naughty boy?
GSLV had flown 15 times before this, and four of these had been unsuccessful, a very high failure rate for any rocket. PSLV, the rocket that ISRO has used the maximum number of times, has failed only twice in its 60 launches, including the first time it was tried way back in 1993. The LVM3 rocket has flown seven times and never failed.
GSLV’s most recent failure was in August 2021, when it was attempting to carry an earth observation satellite EOS-03 into space. Five minutes into the flight, it deviated from the scheduled trajectory, lost the power to carry on, and fell somewhere in the Andaman Sea.
It did have a successful launch after that, in May last year, but the uncertainty over its performance had not dissipated completely. That is the reason why Saturday’s launch was watched more keenly for the rocket than the satellite it was carrying.
What is the problem?
GSLV is a more powerful rocket than PSLV and can carry much heavier satellites. It can carry more than 2,200 kg to geostationary orbits, and over 6,000 kg to the low earth orbits.
Its problems have mainly been with the cryogenic engine that powers the third and final stage of the flight. Cryogenics is the science relating to the behaviour of materials at very low temperatures. Cryogenic engines use liquid hydrogen as the main fuel. Hydrogen, the most efficient rocket fuel, is very difficult to handle in its natural gaseous form, but manageable in liquid state. However, it liquifies only at very low temperatures, nearly 250 degrees Celsius below zero. The oxygen that is needed to burn this fuel also needs to be in liquid form. Oxygen is in liquid state at about 90 degrees Celsius below zero.
The GSLV uses a cryogenic engine that is reverse-engineered on a Russian design. The Russians had won a deal to supply cryogenic engines, and technology, to ISRO in the late 1980s, but that deal had come under pressure from the United States which claimed that it violated provisions of Missile Technology Control Regime, an international legal framework meant to stop the proliferation of missile technology.
The deal had to be thus called off. Russia did supply a few of those cryogenic engines but could not transfer the technology. India used those engines in some of its launches in the 2000s, and for later flights, tried to reverse-engineer that engine on its own. It is this reverse-engineered engine, used in the GSLV rockets, that has caused a few headaches for ISRO.
What about indigenous cryogenic technology?
In the meanwhile, India has managed to develop its own cryogenic engine as well, a result of decades of research and development. This engine has an entirely Indian design, developed within ISRO, and uses a different process to burn the fuel. It is closer to the designs of the Arianne rockets that were used by ISRO till a few years ago to launch its heavier satellites.
This indigenously developed cryogenic engine is deployed in LVM3, ISRO’s most powerful rocket so far, which carried the Chandrayaan-2 and Chandrayaan-3 missions, among others. LVM3 has had seven flights till now, without any trouble. ISRO scientists, not surprisingly, have a much better grip on this home-grown technology.
Saturday’s successful launch has put away the question marks on the GSLV rocket for the time being, but a more crucial test awaits it in a few weeks’ time when it gets ready to carry the NISAR (NASA-ISRO Synthetic Aperture Radar) satellite. NISAR, a first of its kind collaboration between ISRO and NASA, would be the most prestigious mission for the GSLV so far.
The Indian Space Research Organisation (Isro) successfully launched the INSAT-3DS meteorological satellite onboard a GSLV-F14 from Satish Dhawan Space Centre in Sriharikota on Saturday. (ANI Photo)
