NASA plans to develop hypersonic plane
NASA's planning to spend $5 million a year over the next three years on the development of a hypersonic vehicle that could fly at five times the speed of sound.
If the plane ever started making commercial flights, it would be able to travel from New York to Sydney in two and a half hours - and it's possible that the technology would eventually find itself incorporated into commercial airliners.
But the aim of the project is in fact to create a new way of getting into space - and to Mars - without using rockets, as similar hypersonic projects in the past have been forced to do.
Instead, the vehicle would use the same type of 'air-breathing' engine used in commercial planes. While hypersonic flight has been achieved many times before, this would be a new approach. The vehicle would take off and land in the same way as a standard airliner - but with much more power.
According to NASA's proposal solicitation last week - a last-minute addition to a research announcement originally presented in June - one of the major problems with such a vehicle would be overheating.
The plane would obviously need to be repeatedly reused, so that new materials would have to be developed that could cope with the high temperatures. And because it would take off and land at normal speeds, switching to hypersonic flight as it left the atmosphere, controllability and energy management would be paramount.
Current planetary Entry, Descent and Landing (EDL) technologies are limited in terms of how much mass they can carry and how accurately they can land - indeed, all Mars missions to date have been based on 1970s-era Viking technologies.