The window of opportunity was not missed by Opportunity. The second of a pair of NASA rovers is now on its way to Mars. Once there, the pair will search for evidence that there was once (or still is) enough water to sustain life on the red planet. Sprit and Opportunity join Japan's troubled Nozomi (hope) atmospheric probe, and the ESA's Express/Beagle 2 orbiter-rover combo (which is having some problems of its own) in an interplanetary convoy. Lets hope they get past the Martian defense systems.