In an email earlier today, ESA's Flight Dynamics team here at ESOC provided their latest Mars Express orbit prediction for tomorrow's Phobos flyby.

It is based on ground station tracking data received up until yesterday, and includes data from the NASA Deep Space Network (DSN) station at Goldstone, California, and from ESA's own Deep Space Antenna (DSA) station at New Norcia. The predicted closest approach time to Phobos remains unchanged at 20:55:40 UTC (21:55:40 CET) on 3 March 2010, with a miss distance of 77 km from the centre of Phobos. This implies that Mars Express will pass 67 km above the surface of Phobos (which has an average radius of 11.1 km).

The prediction also confirms that there will be no occultation by Phobos on 3 March, meaning that Mars Express will not pass 'behind' Phobos as seen from the Earth. There will be a very brief eclipse caused by Phobos passing in front of the Sun (as seen from Mars Express) - in other words, Mars Express will enter the shadow cast by Phobos. Thanks to Frank Budnik for the details! -- Daniel