NASA’s Curiosity rover may be stealing the headlines, but there is other news coming from Mars. Recently, the European Space Agency’s (ESA) Mars Express probe made a 100-kilometer (62-mile) flyby of the Martian moon Phobos and returned a high-resolution 3D image filled with remarkable detail. The image includes a profile of Stickney crater, which dominates the right-hand side, and the grooves associated with the impact of the asteroid that created it thousands of years ago.
Phobos is the larger of Mars’ two moons and with an orbital period of 7 hours 39.2 minutes, it whizzes through the Martian sky fast enough to rise and set twice a Martian day. Discovered by Asaph Hall at the United States Naval Observatory in 1877, it’s more of a “pocket” moon, with a diameter of only 22.2 kilometers (13.8 miles). Back in 1958, Russian astrophysicist Iosif Samuilovich Shklovsky suggested that it was a space station built by some alien species. The origin of Phobos is still uncertain, but it’s more likely that it and the other moon Deimos are captured asteroids rather than ancient spacecraft.
Mars Express was launched by the ESA in 2003 and went into orbit around Mars later that year. Its purpose was to study the surface and atmosphere of Mars and to deliver Britain’s ill-fated Beagle 2 lander, which crashed on its landing attempt. During NASA’s Curiosity lander’s descent, Mars Express helped to monitor the maneuver and later made direct radio contact with the rover.
In recent years, other attempts have been made to visit Phobos and even attempt a landing. The most recent was Russia’s Phobos Grunt mission that ended up trapped in Earth orbit after an unsuccessful launch in 2011. An international effort to save the probe ended in failure when it burned up in Earth’s atmosphere.