ISRO successfully tests world's third largest solid booster

The Indian Space Research Organisation (ISRO) conducted a successful static test of its largest 'solid booster' on Sunday.

With this, it has reached a step closer to launching four-tonne class communication satellites on its own, doubling the current payload capacity.

The solid booster (S200) will form the first stage for the Geosynchronous Satellite Launch Vehicle Mark-III (GSLV-Mk III).

"The booster test was conducted at ISRO's spaceport, Satish Dhawan Space Centre at Sriharikota in Andhra Pradesh, about 80 km north-east of Chennai," a space agency spokesperson said.

The step is significant as ISRO strengthens its foothold in the commercial satellite launch market.

At the recent Indian Science Congress, chairman K. Radhakrishnan said launcher development was a thrust area and the ISRO would like to launch six-tonne class satellites.

"The GSLV-Mk III is in an advanced stage of development," an ISRO spokesperson said. The GSLV-Mk III is shorter, fatter and stronger than the current version. The ISRO had earlier slated the launch for 2011.

The three-stage launcher will be 42.4 m tall and weigh 630 tonne at the launch. The payload fairing will be five metres wide.

The solid boosters that give it an initial 'brute force' will be strapped on to the second stage of the launcher that runs on liquid propellant.

The third stage will be cryogenic - using super-cooled liquid hydrogen as fuel and liquid oxygen as oxidiser that help it burn.

S200 is the third largest solid booster in the world, next to the reusable solid rocket motor booster of the NASA Space Shuttle and P230 solid booster of Ariane-5 of the European consortium Arianespace.

The booster containing 200 tonne of solid propellant (fuel and oxidiser) in three segments, with a height of about 22 m and diameter of three metres, was developed at ISRO's Vikram Sarabhai Space Centre (VSSC) in Thiruvananthapuram.

The ISRO has used the indigenous GSLV-Mk I and II for launching five satellites, weighing 1.5 to 2.5 tonne, for communication, broadcasting, weather and education between 2001 and 2007. India currently uses Ariane launchers for heavier satellites.

While Mark-III remains on the anvil, a modified version of the existing GSLV, but with a new indigenous cryogenic stage, is slated for launch later this year.

"So far, India has been dependent on Russian technology for the complex cryogenic stage in these advanced launchers. The ISRO is going slow to make it flawless," Radhakrishnan said.

"The GSLV-Mk III will enhance India's capability as a competitive player in the multi-million dollar launch market," said ISRO public relations director S. Satish.