The challenge before space scientists was to make exploration more affordable by substantially reducing the cost of access to space, Indian Space Research Organisation Chairman G Madhavan Nair said Saturday.
Speaking on the transportation systems for space, he said about 80 per cent of the cost were on rocket engines and insulation system, and "we need to bring down the cost to access to space to 1/10th of the current per kg cost -- that is something like $500 to $1,000 per kg," Nair said while delivering the 16th T V Chidambaram Memorial Lecture at the South Indian Education Society in Mumbai.
"Such significant cost reductions can occur only when we are able to combine the aircraft and rocket technology concepts to evolve a new type of space transportation system," Nair said.
"Also, if we can recover and reuse them (launch vehicles) by refurbishing, the cost could further come down," he said adding, these are challenges before the next generation.
"To bring back these launch vehicles safely to earth, we have refine the science of aerodynamics and special materials," he said.
ISRO is already working on these areas and such new innovations will open up some exciting avenues for space exploration like lunar base for material processing, low earth orbit as a platform for interplanetary missions, space solar power station and space tourism, Nair said while enthusing the student community.
Nair said the best choice to reduce the cost would be to adopt the air breathing propulsion system all through.
However, with the capability to be able to operate only in a particular Mach number regime within the atmosphere, it posed limitations in the total use of air-breathing systems.
For orbital missions, as the vehicle needs to deliver Mach number of the order of 25 (25 times the speed of sound), it becomes mandatory that rocket-based systems have to be combined with air breathing systems leading to what is termed as Rocket Based Combined Cycle System, for meeting the total orbital velocity requirement.
In 2005, ISRO successfully simulated an air breathing supersonic ramjet engine capable of cruising six times the speed of sound.
As a first step towards reusable launch vehicle concept, a fully reusable two stage to orbit vehicle has been configured, capable of launching 10 tonnes into low earth orbit.
"This is in its initial stages of vehicle configuration and the first stage is configured as a winged body configuration, which will attain an altitude of around 100 km and deliver nearly half the orbital velocity.
This stage after burnout will re-enter and will be made to land horizontally on the runway, like an aircraft.
The second stage after delivering the payload in the orbit will be made to re-enter the atmosphere and will be recovered using airbags either in the sea or land, he said adding, "This is only in its conceptual stage."
The present cost of the space transportation system hovers somewhere between $12,000 to $15,000 per kg.
