Over the past week, there have been two important developments connected with plans by NASA and the European Space Agency to land as many as three spacecraft on Mars during the 2003-04 Mars launch window. Firstly, the Beagle 2 probe – whose status was rather perilous just a few months ago – has now received the official go-ahead from the ESA to be carried on its Mars Express orbiter. Second, the potential landing sites for NASA’s two Mars Exploration Rovers (MER) have now been narrowed down further – but, at the same time, the final decision on their two landing sites has been delayed fully a year.