Nasa awards air-breathing rocket contract

Nasa has commissioned a design for a cheap, reusable, air-breathing rocket engine.

The aim is to produce a spacecraft which can take-off and land on aircraft runways and be prepared for flight within days.

Engineers expect to carry out the first ground tests of the new engine within five years.

Nasa's Marshall Space Flight Centre has awarded the initial $16.6m (£11.45m) contract to an industry team known as the Rocket Based Combined Cycle Consortium, or RBC3.

It includes Boeing's Rocketdyne Propulsion and Power business, Aerojet and Pratt and Whitney.

The new engine project is called the Integrated System Test of an Air-breathing Rocket, or Istar.

In flight the final version would get its initial boost from specially designed rockets in a duct which captures air - improving performance by about 15% over conventional rockets.

At twice the speed of sound, the rockets are turned off and the engine relies on oxygen in the atmosphere to burn its hydrogen fuel.

Once it has accelerated to more than ten times the speed of sound, the engine converts to a conventional rocket to propel the craft into orbit.

The test version will be designed to accelerate a self-powered vehicle to just six times the speed of sound but would demonstrate all the engine's phases. If all goes well the engine could be test flown by the end of the decade.