The European Space Agency’s Mars Express spacecraft snapped close-up portraits of Phobos — the larger of Mars’ two satellites and one of the grooviest moons in the solar system — on January 9, when it flew within 100 kilometers of the body. The space agency released the images, some showing the multitude of mysterious grooves etched into the moon’s surface, on January 21.
“This was an exceptional flyby where for the first time we could cover a large part of the farside of Phobos´ southern hemisphere,” says Mars Express scientist Gerhard Neukum of the Free University of Berlin.
Resolving features as small as 16 meters across, the portrait isn’t the sharpest image ever taken of Phobos (SN: 4/10/10, p. 8). But it shows in new detail the previously and currently planned landing sites for the Russian Phobos-Grunt mission, scheduled for launch later this year. The craft would be the first to land on Phobos, notes Alexander Basilevsky, a member of the Phobos-Grunt team based at the Vernadsky Institute in Moscow.
From the new images, scientists can construct a high-resolution topographic map of the landing sites, which should help determine where Phobos-Grunt will ultimately touch down. That decision won’t happen until later this year, most likely after the craft has been launched, but the new images indicate that the old landing site may be as hospitable as the new one, says Basilevsky.
The image also shows that some of the grooves on Phobos crisscross, which could provide additional insight into their origin, Basilevsky adds. Current thinking suggests the grooves might have formed when debris kicked up by an asteroid hitting Mars smacked into the moon.