Cryogenic stage tested successfully

A major milestone in our rocket system development, testing, says Madhavan Nair

1. India, 6th to carry out test
2. Engine produced thrust of 7.5 tonnes
3. A fully indigenous effort

India became the sixth member of the exclusive club to have developed a cryogenic stage in rocketry when it successfully tested a full-fledged cryogenic stage for 50 seconds at the Liquid Propulsion Systems Centre (LPSC) at Mahendragiri in Tirunelveli district, Tamil Nadu on Saturday evening.

The engine in the stage produced a thrust of 7.5 tonnes. It was a fully indigenous effort.

The firing was done with the help of an advanced mission computer and the parameters of the test were monitored from a sophisticated control room.

A jubilant G. Madhavan Nair, Chairman, Indian Space Research Organisation (ISRO), told The Hindu from the test-site at Mahendragiri over phone, that "for the first time, a cryogenic stage was fired" in the country and the performance was "absolutely flawless."

He called it "a major milestone in our rocket system development and testing." "We are the sixth country in the world to have this status. Very few countries in the world have got such a capability."

The others who have so far used cryogenic stages in their rockets to put heavy satellites in orbit are the U.S., Russia, European Space Agency, China and Japan.

Full-duration test soon

The ISRO would go for a full-duration test of the indigenous cryogenic stage for 720 seconds at the LPSC in four weeks from now, Mr. Madhavan Nair said. "And we will take our own cryogenic stage in our GSLV flight next year." The four Geo-synchronous Satellite Launch Vehicle (GSLV) flights from 2001 from Sriharikota had used cryogenic stages from Russia.

The GSLVs orbited satellites weighing around 2,000 kg.

Complex system

A cryogenic stage is "a very, very complex system" that entailed "synergy" from multi-disciplinary teams that developed sub-systems, electronic components, plumbing and so on, the ISRO Chairman said.

"A major effort"

B.N. Suresh, Director, Vikram Sarabhai Space Centre (VSSC), Thiruvananthapuram, called the test a major effort.

"We have tested with the entire on-board equipment bay, which is going to be used in our GSLV flights," he said. (Equipment bay in a rocket, which houses the electronic systems, forms the brain of the vehicle).

"For the first time, we have used an advanced mission computer and this computer will be used in subsequent PSLV and GSLV flights," Dr. Suresh said. The results of the test were as per predictions. They "matched 1:1," he said.

R.V. Perumal, Director, LPSC, described it as "another march towards total indigenous capability in rocketry." Ten years of joint efforts of the LPSC, the VSSC and other ISRO units, he said, "had culminated in this test." "We are happy that after a long time, we have crossed this milestone."

A cryogenic engine uses liquid hydrogen at minus 260 degrees Celsius and liquid oxygen at minus 183 degrees Celsius. While liquid hydrogen is the fuel, liquid oxygen is the oxidiser.

A cryogenic stage used in flight will include the engine, propellant tanks, plumbing to ferry the cryogenic fluids to the engine, wiring, motor casing and so on.

Storing and pumping liquid hydrogen and liquid oxygen calls for great expertise. At such low temperatures, metals become brittle.

So new welding techniques, new alloys and new types of lubricants were developed. Besides, liquid hydrogen and liquid oxygen had to be pumped into the engine in the right proportion.

Source: Hindu