BBC NEWS: "
Nasa scientists are trying to work out what went wrong
Nasa's Mars rover Spirit has stopped sending useful data to Earth from the Red Planet and mission scientists are unable to send it commands.
Nasa says the problem could either be due to a major power fault, software corruption or memory corruption.
Scientists has tried several times to communicate with the rover but has received either very little or no data.
The vehicle has entered a fault mode and Nasa is now devising a strategy for getting back in contact with Spirit. "