IN the early hours of Christmas morning a pale red dot visible just above the horizon in the evening sky will become the focus of extraordinary global attention. Shortly after 2 am GMT, Mars will receive a small visitor from Europe, followed shortly by two visitors from the US. And if that weren’t stretching the bounds of hospitality, Mars is already playing host to two American orbiters. Never has the Red Planet been so busy.
Back on Earth, the stakes for many scientists and engineers could hardly be higher. These missions have been designed to look for signs that Mars…
