On March 3 the European Space Agency's Mars Express orbiter passed within 67 kilometers of the Martian moon Phobos, the closest a spacecraft has ever skimmed the larger of Mars's two diminutive oddball satellites. Only 27 kilometers long at its lengthiest dimension, Phobos is a misshapen lump that may be a captured asteroid.



Mars Express is engaged in a series of 12 Phobos flybys that began in February and will end March 26. The photograph above comes from a March 7 pass, when the spacecraft came within about 100 kilometers of Phobos; the closer approach of March 3 took Mars Express past the moon's nightside to gather data, albeit limiting its value as a photo opportunity.



The Russian Phobos–Grunt lander, scheduled to lift off in 2011, is designed to return soil samples that should help uncover Phobos's origin. The proposed landing area for Phobos Grunt is on the rightmost visible edge of the moon in this photograph, about one third of the way up from the bottom.