ESA Mars Express: New Season of Fly-bys start with Phobos

Today Mars Express began a series of flybys of Phobos, the largest moon of Mars. The campaign will reach its crescendo on 3 March, when the spacecraft will set a new record for the closest pass to Phobos, skimming the surface at just 50 km. The data collected could help untangle the origin of this mysterious moon.

The latest Phobos flyby campaign began today at 06:52 CET (05:52 UT), when Mars Express drew to within 991 km of Phobos’ airless surface. The flybys will continue at varying altitudes until 26 March when Phobos moves out of range. They offer prime chances for doing additional science with Mars Express, a spacecraft that was designed to study the red planet below rather than the grey moon alongside.

Mars Express in its polar orbit
“Because Mars Express is in an elliptical and polar orbit with a maximum distance from Mars of about 10 000 km, we regularly pass Phobos. This represents an excellent opportunity to perform extra science,” says Olivier Witasse, Mars Express Project Scientist.


Back in 2009, the mission team decided that the orbit of Mars Express needed to be adjusted to prevent the closest approach of the spacecraft drifting onto the planet’s nightside. The flight control team at the European Space Operations Centre in Darmstadt, Germany, presented a number of possible scenarios, including one that would take the spacecraft to just 50 km above Phobos. “That was the closest they would let us fly to Phobos,” says Witasse.

ESA Phobos fly-by blog