Indian Space Research Organisation (Isro) plans to build its heaviest rocket, which can carry satellites weighing 10 tonnes into space. Currently, the space agency’s geosynchronous satellite launch vehicle (GSLV MK-2) can carry satellites weighing only two tonnes.

The proposed rocket would be powered by a semi-cryogenic engine — that runs on kerosene and liquid oxygen, which the space agency is currently developing. Semi-cryogenic engines are environment-friendly and bring down the cost of launches significantly. The design process for the semi-cryogenic engine has been completed and it is being built by Godrej Aerospace, which also makes the Vikas engines for Isro’s rockets.

“Once we have this engine, we will have different levels of launch vehicles possible. Currently, the GSLV MK-3 uses the CE20 engine and once we put the semi cryogenic engine in such a combination, we will have a much bigger rating, which will have a payload capability of 10 tonnes,” said S Somanath, project director of the GSLV MK-3 at Isro. He, however, did not set a time-frame for the rocket development.

Last year, Isro tested a demonstrator of its heavier class of rocket, the GSLV MK-3, designed to carry four-tonne class communication satellites into space. The CE20, which the rocket uses, is an indigenously developed cryogenic engine. A full-fledged rocket with a communication satellite will be launched in 2017.

“One of the launch vehicles will look like the GSLV MK-3, but it will be much taller, almost 65 metres, weighing 732.6 tonnes at lift-off and it is capable of putting a 10-tonne space plant in the communication orbit,” said Somanath. Isro currently sends its four-tonne communication satellites, used for satellite broadcasting, on Arianespace rockets of the European Space Agency.

Somanath said Isro would work on a modular vehicle approach, using the same platform to extend the power of its rockets than build separate rockets.

“We thought we will go in a modular way. It will be possible for nearly 6-tonne payload capability and, if required, we will be able to change to our full 10-tonne launch vehicle with a little bit of addition,” he said.

Meanwhile, Isro will launch its fifth of the seventh regional navigation satellite on January 20. The satellite will be part of India’s constellation of geo-positioning satellites that would help in disaster management, mapping and navigation, said M Annadurai, director, Isro.

PROPELLING INTO THE FUTURE