Important roles for Europe include assembling the rover on its side of the Atlantic and using a British-designed autonomous navigation system when the vehicle is on Mars.

BBC: Esa-Nasa Mars missions' race against clock

The UK Space Agency, through its membership of Esa, is now arguing strongly for the Astrium autonomous navigation system to be incorporated into the 2018 rover.

BBC: Smart UK navigation system for Mars rover

Although spacecraft instruments are set to return photographs and compositional data, the encounter primarily is a test of Deep Space 1's autonomous navigation system, the last of 12 technologies the mission was designed to pioneer.

CNN: Spacecraft set for risky asteroid flyby