British scientists have begun planning a “Beagle 3” mission to Mars for launch in 2007, even as they try their final attempt to contact the missing Beagle 2 lander. A message will be sent during the next seven days from the orbiting Mars Odyssey spacecraft telling the Beagle 2 – if it is operational – to reboot its computer. That carries the risk that the machine will never return to life if it was working.