In what could lower the cost of reaching space, aerospace scientists claim to be developing a hypersonic aircraft by using superfast air-breathing engines called scramjets.
"Conventional rockets used to launch satellites into orbit or space shuttles have to carry rocket fuel and oxidiser which is very expensive.
"The air-breathing scramjets still need fuel but don't need the oxidiser, with the potential for substantially reducing the cost per kilogram of transporting payloads into space," said Dr Con Doolan of Adelaide University, who is leading an international team.
According to the scientists, the aim is to produce a hybrid launch vehicle where one stage out of three in a conventional rocket will be replaced with a scramjet vehicle.
"Normally the rocket takes the vehicle to the edge of space and then the second and third stages boost its velocity to put it into orbit. We are hoping eventually to be able to replace one stage -- probably the second -- with a scramjet capable of Mach 14 or 15. That's the sort of speed necessary for space flight," Dr Doolan said.