ESA’s Mars Express spacecraft, while executing a series of 12 flybys of Mars’ largest moon Phobos, passed the moon’s surface at an altitude of 67km on March 3 at 20:55 GMT. The close approach enabled scientists to gain valuable data an learn more about the mysterious moon.
Another flyby close of Phobos occurred on 7 March 2010, and ESA has just released the photos. The images show Mars’ rocky moon in exquisite detail, with a resolution of just 4.4 meters per pixel. They show the proposed landing sites for the forthcoming Phobos-Grunt mission.
The High Resolution Stereo Camera (HRSC) onboard the ESA spacecraft Mars Express took this image of Phobos using the HRSC nadir channel on 7 March 2010, HRSC Orbit 7915. This image has additionally been enhanced photometrically for better bringing features in the less illuminated part. Resolution: about 4.4 meters per pixel - Credit: ESA/DLR/FU Berlin (G. Neukum)
In 2011 Russia will send a mission called Phobos–Grunt (meaning Phobos Soil) to land on the martian moon, collect a soil sample and return it to Earth for analysis.
For operational and landing safety reasons, the proposed landing sites were selected on the far side of Phobos. This region was imaged by the HRSC high-resolution camera of Mars Express during the July-August 2008 flybys of Phobos. But new HRSC images showing the vicinity of the landing area under different conditions, such as better illumination from the Sun, remain highly valuable for mission planners.
The High Resolution Stereo Camera (HRSC) onboard the ESA spacecraft Mars Express took this image of the Phobos Grunt landing area using the HRSC nadir channel on 7 March 2010, HRSC Orbit 7915. The image resolution is 4.4m per pixel and the insert marks the proposed landing region and sites for Phobos-Grunt - Credit: ESA/DLR/FU Berlin (G. Neukum)
ESA’s Mars Express spacecraft, currently executing a series of 12 flybys of Mars’ largest moon Phobos, will pass the moon’s surface at an altitude of 67km on March 3 at 20:55 GMT. The close approach will enable scientists to gain valuable data an learn more about the mysterious moon.
This image was obtained by the High Resolution Stereo Camera (HRSC) on board ESA’s Mars Express on 28 July 2008 (orbit 5870), at a distance of 351 km from the moon’s centre - Credit: ESA/ DLR/ FU Berlin (G. Neukum)
As the spacecraft approaches Phobos, it will be pulled slightly off of its orbit (by a few millimeters per second). Scientists on Earth will turn off all data signals from the spacecraft ensuring the only thing affecting the signal is gravitational tug by Phobos. Although incredible tiny (only one part in a trillion, that is 1 followed by 12 zeros), the changes will be revealed via the Doppler effect.
Animation revealing the graviational influance of Phobos on the orbit or Mars Express - Credit: MaRS team/Observatoire Royal de Belgique
This animation shows how the orbit of Mars Express has been influenced by the gravitational influence of Phobos during the spacecrafts fly-bys of the moon in Summer 2008. Since the orbital deviation strictly depends on the mass and shape of the moon, scientists could use this very deviation to determine the mass of Phobos with unprecedented accuracy (to about one billionth the mass of the Earth).