Page last updated at 00:14 GMT, Wednesday, 17 June 2009 01:14 UK

High-speed 'wedge' for re-entry

By Jonathan Amos
Science reporter, BBC News, Le Bourget

IXV (Esa)
IXV is expected to reach a velocity of approximately 7.5km/s

A contract has been signed at the Paris air show that will lead to the development of a remarkable spacecraft to test re-entry technologies.

Thales Alenia Space in Italy has been given the authorisation to build the wedge-shaped Intermediate eXperimental Vehicle (IXV).

The European Space Agency (Esa) demonstrator will be launched in 2012.

It will be packed with sensors and should give engineers new insights into how objects fall back to Earth.

The lessons could prove extremely valuable if Europe decides to press ahead with its own astronaut transportation system. A controlled, safe re-entry capability is a pre-requisite for such a system, but it has relevance to all high-velocity atmospheric vehicles including rockets.

The IXV will be about the size of a big car and weigh almost two tonnes. It is booked to launch on Esa's forthcoming small rocket, Vega, from the Kourou spaceport in French Guiana.

Controlled return

The vehicle will be put at an altitude of about 450km from where it will begin its flight back to Earth.

It is expected to reach a velocity of approximately 7.5km/s, guiding itself through the atmosphere to a splash-down, via parachute, somewhere in the Pacific Ocean.

The IXV is a "lifting body"; it has flaps and thrusters to control its descent trajectory.

"It is testing all the critical technologies which are necessary to perform atmospheric re-entry from low-Earth orbit," explained Georgio Tumino, the project manager on IXV at the European Space Agency.

"These are basically the thermal protection materials, the guidance and navigation control algorithms as well as the phenomena for aerothermodynamics. As you know, when you come back through the atmosphere, you have a lot of heat; and some of the prediction tools we have today are not 100% reliable."

The IXV mission is being seen as a unique opportunity for European engineers to improve their knowledge base.

Although only one flight of the IXV is currently planned, its recovery from the ocean would allow further experimental flights to be conducted.

Italian lead

Esa already has some 100m euros in its IXV budget. This is enough to fabricate the vehicle, but a further 30m will need to be approved by Esa member states at a later date to carry out the launch and flight campaign.

Italy is the lead nation on the project with France, Spain, Switzerland, and seven other countries.

Antonio Fabrizi, Esa's director for launchers, said it was too early to say how much of the IXV technology could find its way into any future crew re-entry system. For one thing, no such programme currently existed, he said.

"First we need the requirements on any future Esa activity on re-entry, and then we need to see what the choice of Europe will be - whether a capsule or a lifting body like this, or some other kind of vehicle," he told BBC News.

"All this is in the future. Today, we are just concerned with technologies; and some of these technologies don't just have relevance for re-entry but for launch vehicles in general, I would say."

The relevance to launchers stems from the fact that rockets also experience extreme conditions as they move rapidly through the air, albeit on their way out into space rather than returning from it.

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