CHENNAI: An Indian version of the space shuttle will be test-flown from the spaceport at Sriharikota in a years time. The Reusable Launch Vehicle-Technology Demonstrator (RLV-TD), as it is called, will be a combination rocket-aircraft: the aircraft with a winged body, which is the RLV, will sit vertically on the rocket.
The engineering model of the aircraft is ready at the Vikram Sarabhai Space Centre (VSSC) in Thiruvananthapuram. The first stage of the Satellite Launch Vehicle-3, flown in the early 1980s, will form the booster rocket. Weighing nine tonnes, it is called S-9.
After it takes off like a rocket, the booster will release the unmanned aircraft, which will go into space. At the end of the mission, the aircraft will land in the sea.
K. Radhakrishnan, Director, VSSC, said in an interview: The next year we expect the prototype of the RLV-TD to be ready for flight-testing. This will be a milestone for ISRO. The RLV will open a new dimension in the launch vehicle technology and transportation system of ISRO.
According to Dr. Radhakrishnan, ground testing of the booster rocket was done at Sriharikota in December 2008.
S. Ramakrishnan, Director (Projects), VSSC, explained how the rocket-aircraft would look: The aircraft will stand over the rocket, nose-tip up, and its tail will be interfaced with the rocket. In other words, the entire RLV will stand vertically on top of the booster. The engineering model of the prototype RLV was ready at the VSSC. It will undergo various structural and load tests, Mr. Ramakrishnan said.
The booster rocket will take the RLV to a specific altitude, release the RLV and fall into the sea. On re-entry into the earths atmosphere, the RLV will land in the sea, to be recovered.
Re-entry, descent and recovery are the three issues which we are trying to understand, Mr. Ramakrishnan said. But in the first trial-flight in 2010, the RLV will not be recovered from sea because it will not be cost-effective to do so. But we will get the data on the re-entry, deceleration and return from the telemetry.
There were several issues that the ISRO was trying to understand in the mission, Dr. Radhakrishnan said. These included the aerodynamics of the RLV, compared to the rocket, and the controllability of the vehicle. The control system must be fast-acting. That is the basic challenge. The digital auto-pilot is important for the ascent phase and the descent phase.
The third important challenge was the heat generated when the RLV re-entered the atmosphere. Dr. Radhakrishnan said: You need to have hot structures [which can withstand the re-entry heat]
Today, we have a handle on the materials.
The ISRO had a long way to go before it could build an operational RLV, he said. This is the first TD towards that. 
|
