[meteorite-list] Mars Express: Auspicious Orbit Marks Run-up to Phobos Flyby

From: Ron Baalke <baalke_at_meteoritecentral.com>
Date: Fri, 12 Feb 2010 13:08:12 -0800 (PST)
Message-ID: <201002122108.o1CL8Ck2008367_at_zagami.jpl.nasa.gov>

http://www.esa.int/SPECIALS/Mars_Express/SEMDUGSJR4G_0.html

Auspicious orbit marks run-up to Phobos flyby
European Space Agency
29 January 2010

On 26 January, Mars Express completed its 7777th orbit around the Red
Planet, an auspicious milestone as the satellite is readied for the
closest-ever flyby of Phobos, scheduled for just a few weeks from now.
 
Mars Express has been in orbit since 25 December 2003, returning a
wealth of scientific information and some of the most stunning
high-resolution imagery of the Red Planet ever. Its data have allowed
scientists to measure the abundance of water ice and vapour in the
martian subsurface, surface and the atmosphere, as well as previously
unknown methane in the atmosphere.
 
This week, the orbiter completed 7777 circuits of the planet and
continues to operate flawlessly. Currently, each orbit takes 6 hours and
54 minutes. The spacecraft is following a polar orbit, and at closest
approach passes just 350 km above the surface of Mars and, at farthest
approach, 10 300 km.
 
Closest-ever Phobos flyby
 
This highly elliptical orbit will enable Mars Express, on 3 March, to
conduct the closest flyby and examination of Phobos, Mars' largest moon.
The flyby, at a planned altitude of just 50 km, will collect very
precise radio Doppler data to help determine the moon's gravity field
more accurately than ever.
 
Mars Express imaged the martian moons Phobos and Deimos together on 5
November 2009

This close flyby will be bracketed by similarly close passages, which
will be used for other scientific investigations including radar
sounding and imaging.

Knowing the gravity field will help scientists to understand the
distribution of mass inside the moon, which is another step in the quest
to discover the origin of Phobos.

None of the other spacecraft now orbiting Mars can fly as close to
Phobos. While Mars is the mission's primary target, this flyby is an
excellent opportunity for additional scientific investigation of the
Mars system, and will boost overall science return.
 
This Phobos flyby is combined with a sequence of precise orbit
manoeuvres planned in February and March. They will increase the orbit
duration to almost exactly 7 hours, in order to improve the Sun
illumination of the ground track pictured by the spacecraft for many
years to come.
 
Mars Express is scheduled to operate until 2012; a further extension to
2014 will be assessed this year.
Received on Fri 12 Feb 2010 04:08:12 PM PST