The Mars Odyssey Orbiter is less than two weeks away from its destination, zooming toward the Red Planet with two wounded instruments and the hope of an entire space agency driving it onward. It is a must-win situation for NASA and its Jet Propulsion Laboratory (JPL), coming on the heels of two failed missions to Mars. Last Thursday, engineers were put through a full dress rehearsal for what will be the most nerve-wracking part of the mission — the unavoidable silence and waiting for confirmation that all has gone well in the first step of a tricky insertion into orbit around Mars on October 23.