The Hindu : Karnataka News : ISRO trying to develop air-breathing engine

Online edition of India's National Newspaper
Thursday, Aug 26, 2004

Karnataka

Karnataka

ISRO trying to develop air-breathing engine

By Our Staff Reporter

BANGALORE, AUG. 25. The Indian Space Research Organisation (ISRO) is working with the National Aerospace Laboratory (NAL) here to develop an "air-breathing" engine which can one day be part of a reusable one-stage-to-orbit launch vehicle, ISRO's Chairman, G. Madhavan Nair, said here on Wednesday.

Theoretically, since air-breathing engines used air in the atmosphere as the oxidiser to burn rocket fuel, no oxidiser need to be strapped on, reducing the weight of the rockets. Mr. Nair said that in practice, there were several constraints, including the need to sustain "high mach numbers" (one mach is the speed of sound in air, about 330 metres a second). Launch vehicles would need speeds of 15 mach or more, he said. "No one has done it yet."

In the meantime, Mr. Nair said, a two-stage-to-orbit launch vehicle was being considered to make lower cost access to space viable in the medium term. The two-stage vehicles could be ready in 15 to 20 years. Till then, the GSLV Mk III, to be operational by 2007 and capable of launching payloads weighing 4000 kg or more, "will be the mainstay of our programme," he said. One-stage flights may only happen by the year 2050, he said delivering the 45th Founders' Day lecture at NAL.

Two-stage system

"Without waiting for future technologies," ISRO was trying to build a two-stage system with a combination of existing ones, Mr. Nair said. In one design being considered, the first stage would be a winged structure, closer to a space shuttle, and the second stage would be a conventional rocket, he said.

Different ways of trying to bring both the stages back are being considered. In one concept, the second stage will break off at an altitude of around 1,800 km. Its re-entry can be similar to that of the space shuttle, which the Americans use. Once in lower Earth atmosphere, it can even glide down to an aircraft-like landing. Adding conventional aircraft engines is also being considered. The second-stage conventional rocket stage will have a separate recovery method. Recently, ISRO concluded its third space capsule recovery experiment, in which a module weighing some 500 kg was dropped from a helicopter over the Bay of Bengal and then recovered from the sea.

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