The launch of the Geo-synchronous Satellite Launch Vehicle (GSLV-D3), scheduled for December 2009 from Sriharikota, has been postponed to March.

The GSLV-D3 will be powered by an indigenous cryogenic stage built for the first time by the Indian Space Research Organisation. It will put in orbit a communication satellite, GSAT-4, which is not ready either.

The Polar Satellite Launch Vehicle (PSLV), planned to be launched prior to the GSLV-D3 flight, has also been postponed. It will now take off in March to put in orbit Cartosat-2B; Alsat, a small satellite from Algeria; two nano-satellites from the University of Toronto, and another nano-satellite, Studsat (Students’ satellite), built by several Indian universities. The Cartosat-2B, to be built by the ISRO Satellite Centre in Bangalore, is also not ready.

Decision in January

An authoritative ISRO official said: “We are going through the process of the review of the indigenous cryogenic stage. We had a review on December 20. Certain things have to be checked. The GSLV-D3 launch will be a milestone. We have to make sure everything is all right. We will decide the launch schedule in January.”

When Oceansat-2 was successfully launched on September 23, 2009, ISRO officials claimed that the GSLV-D3would lift off in December and the PSLV flight would take place ahead of it. The GSLV’s first stage had reached Sriharikota, they said then. But the work on building the GSLV-D3 stages in the second launch pad at Sriharikota was now “suspended,” ISRO engineers said. It is a three-stage vehicle, and the first stage was built in the launch pad. “There are several small issues relating to the indigenous cryogenic stage. It takes time to understand cryogenic engines. We want to ensure that everything is reliable,” they said.

The indigenous cryogenic stage, including its engine, has been built by the ISRO’s Liquid Propulsion Systems Centre at Mahendragiri near Nagercoil.

Difficult task

Another engineer said it was difficult to perfect a cryogenic stage, and “so it is a crucial launch and a cautious step forward for the ISRO.” Cryogenic engines use liquid hydrogen at minus 265 degrees Celsius as fuel and liquid oxygen at minus 240 degrees Celsius as oxidiser. If they do not mix properly, they will explode. A cryogenic stage includes the motor, propellant tanks, control devices, electronic instruments, plumbing and motor casing.

From 2001 to 2007, there have been five GSLV flights and these rockets used Russian cryogenic engines. This is the sixth GSLV flight, and it will use an indigenous cryogenic stage.

Keywords: GSLVPSLVSriharikotaISROChennai