* Astronomy

Blobrana · L

RE: Mars Express

Blobrana · L

Mars Express all set for autonomous Phobos flyby

A quick final update on spacecraft activity for the next few days, provided by Mars Express Spacecraft Operations Engineer Hannes Griebel here at ESOC:

The final pre-flyby orbit determination was concluded earlier this week; this precise calculation of the Mars Express orbit was used to generate the commands for the flyby
These commands include all necessary pointing and instrument instructions so that the flyby and science observations can be conducted automatically
They were uploaded to the spacecraft this morning during a ground station pass at 07:00 UT (08:00 CET)
Mars Express is now in an orbit with respect to Mars ranging from approximately 400 km to 10 000 km; it will pass by the centre of Phobos on Sunday at just 111 km
On Sunday, 9 January, Mars Express will automatically slew to point instruments toward the expected direction of Phobos starting at 13:55 UT (14:55 CET) - it will stay in this pointing mode for 5 minutes and 46 seconds
Closest approach occurs at 14:06:30.016 UT (15:06:30.016 CET)
A few minutes later, after closest approach, it will slew back to Earth pointing and the next ground station pass, via ESA's 35m DSA-2 deep space station at Cebreros, Spain, will begin at 14:57 UT (15:57 CET). Data will be downloaded progressively over the following days(see "When can we expect first images" below)

Source

Blobrana · L

Since December 2010, ESA's Mars Express has been progressively orbiting closer to Phobos as part of a fly-by campaign that will see the spacecraft make 10 close fly-bys of the enigmatic moon.

On Sunday, 9 January, Mars Express will make closest approach (CA): the spacecraft will pass just 108 km above the moon's surface at 14:09 UT (15:09 CET).

Blobrana · L

Mars Express will make a close approach (403 km) of Phobos' night side

Blobrana · L

Images from the recent flyby of Phobos, on 7 March 2010, are released today. The images show Mars rocky moon in exquisite detail, with a resolution of just 4.4 metres per pixel. They show the proposed landing sites for the forthcoming Phobos-Grunt mission.
ESA's Mars Express spacecraft orbits the Red Planet in a highly elliptical, polar orbit that brings it close to Phobos every five months. It is the only spacecraft currently in orbit around Mars whose orbit reaches far enough from the planet to provide a close-up view of Phobos.
Read more

Blobrana · L

Phobos Flyby Success

Mars Express encountered Phobos last night, smoothly skimming past at just 67 km, the closest any manmade object has ever approached Mars enigmatic moon. The data collected could help unlock the origin of not just Phobos but other second generation moons.
Something is not right about Phobos. It looks like a solid object but previous flybys have shown that it is not dense enough to be solid all the way through. Instead, it must be 25-35% porous. This has led planetary scientists to believe that it is little more than a rubble pile circling Mars. Such a rubble pile would be composed of blocks both large and small resting together, with possibly large spaces between them where they do not fit easily together.
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Blobrana · L

Spectrum Analyser signal from Mars Express received by the Cebreros tracking station.

Blobrana · L

Mars Express has made its closest approach to Phobos at 20:55 GMT.

Blobrana · L

ESA's Mars Express will skim the surface of Mars' largest moon Phobos on Wednesday evening. Passing by at an altitude of 67 km, precise radio tracking will allow researchers to peer inside the mysterious moon.
Mars Express is currently engaged in a series of 12 flybys of Phobos. At each close pass, different instruments are trained towards the mysterious space rock, gaining new information. The closest flyby will take place on 3 March at 21:55 CET (20:55 GMT).
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Blobrana · L

On 3 March 2010 Mars Express will make its closest ever approach to Phobos, the larger of the two Martian moons. During a series of flybys, spanning six weeks, all seven instruments onboard Mars Express will be utilised to study Phobos. The close approach provides a first opportunity to perform a unique gravity experiment that may reveal the distribution of mass within this intriguing moon.

Phobos flyby campaign 2010
Date	Altitude (km) *	Instruments used during this flyby
16 February	991	PFS, SPICAM, ASPERA
22 February	574	PFS, SPICAM, ASPERA
25 February	398	PFS, MARSIS
28 February	226	PFS, MARSIS
03 March	50	MaRS, ASPERA
07 March	107	HRSC, OMEGA, MARSIS, SPICAM, ASPERA
10 March	286	HRSC, OMEGA, MARSIS, ASPERA
13 March	476	HRSC, SPICAM, PFS, ASPERA
16 March	662	HRSC, SPICAM, PFS, ASPERA
19 March	848	HRSC, SPICAM, PFS, ASPERA
23 March	1341	Not used
26 March	1304	HRSC, SPICAM, PFS, ASPERA
*: Distance from surface of Phobos