GSLV Mark-III: Indian astronaut just got one step closer to space

It is rare that a spacecraft coming down to the earth should make space scientists happy. But this is what happened on Thursday morning at the Indian Space Research Organisation (ISRO) when the spacecraft Indian scientists had launched from at Sriharikota splashed down into the Bay of Bengal within minutes of its launch. Scientists were excited because this is what they had planned and this splashdown takes the Indian space agency a step closer to its ultimate dream - sending an Indian into space from the Indian soil on an indigenous craft.

The experimental flight of the Geosynchronous Satellite Launch Vehicle (GSLV) had two-fold mission: qualify and test a new set of features of GSLV Mark III – a heavy rocket under development; and test a crew module that may be possibly deployed for a future manned mission. Though the rocket looked majestic it was not a full-fledged GSLV because it did not have the crucial cryogenic engine in its upper part, but only a dummy. And that’s why it was described as a sub-orbital mission. The flight became essential to test certain new features in the first two stages of the rocket. A full developmental flight of GSLV Mark III with an indigenous cryogenic engine may still be two years away.

The second part of the experimental flight was far more ambitious and critical – testing a crew module called CARE or Crew Atmospheric Re-entry Experiment. GSLV carried this module weighing 3700 kilograms –and the size of small bedroom - into space and ejected it at an altitude of 126 kilometers. From there on the module descended on a pre-determined trajectory and splashed down in the Bay of Bengal in the vicinity of Andaman and Nicobar islands. The precision with which the module separated from the rocket at right altitude, velocity and flight path angle is noteworthy.

The module experiment may sound simple but it is very challenging in terms of complexity and technology. It is one of the most critical building blocks of technology needed to send humans into space and bring them back to the earth safely. It is relatively easy for rockets to propel satellites and crafts into orbits into space, but is tough to bring them back on the earth safely. Re-entry into earth’s atmosphere is fraught with dangers.

When any object re-enters the earth’s atmosphere it encounters extreme temperature on its surface due to supersonic speed with which it encounters air molecules at the entry point. This could turn the object into a fireball unless it has proper heat shields and other protection. The success of today’s mission shows that CARE module has withstood this fire test. This is made possible through the use of side panels made of ablative material (which vaporises as temperature rises, thus keeping the module safe) and forward heat shield made from carbon phenolic tiles.

After the module successfully re-entered the earth’s atmosphere, its speed had to be decelerated so that it splashes down in a safe manner. For this, a series of decelerating parachutes were deployed and they worked perfectly. In addition, the module would bring data relating to its propulsion, navigation, guidance and control systems.

Still the crew module is far from being used for manned missions. Re-entry and deceleration are important building blocks, but a lot many technologies need to be qualified, tested and perfected for the module to be ‘man-rated’. ISRO is expected to work on them from the shoestring budget it has been allocated to develop technologies for a future manned mission. The government is yet to approve ISRO’s manned mission, which could cost up to Rs 13,000 crore. If given necessary money and political backing, space scientists are hopeful they can execute a manned space flight in about seven to ten years.