Mars Global Surveyor

Mars Global Surveyor (MGS ) spacecraft was a NASA exploration of the planet Mars from orbit. It started on 7 November 1996 aboard a Delta II launch vehicle and started around March 1999 with the exploration of the Red Planet. On 2 November 2006, the probe was lost due to a failure of ground staff.

The main tasks of the mission lay in the acquisition of high-resolution photos for surveying and mapping the topography in the study of the composition of Martian rocks, the role of water in the planet history as well as in the study of the atmosphere and the climate and weather, the magnetic field and the gravitational field. Furthermore, the orbiter was used to take the output of some countries from the surface of Mars to forward to the ground.


The Mars Global Surveyor project was developed with the objective to rapidly develop a low-cost Mars exploration mission, as a replacement for the failed Mars Observer. The end of the main mission was established on August 2001.

Mission start

On 7 November 1996, the more than a ton ( 1062.1 kg ) launched vast probe. It reached Mars after a flight time of ten months, on 11 September 1997.

The approximation of the orbit by several maneuvers and aerobraking process then was delayed because of an error in the solar modules for over a year. The target orbit reached MGS finally in March 1999.


Since reaching the Mars orbit, the probe photos of the entire surface made ​​in very high resolution. Partial details of less than two meters in size are visible on the photographs. These recordings exceeded significantly the statements made in the 1970s, photos of the Viking orbiter. Only the images of the European Mars Express spacecraft exceeded this. Overall, MGS has sent more than 240,000 recordings to Earth until October 2006.

The mission was of interest to the scientific press, especially by the high-resolution photos of former river beds and lakes. They are seen as important evidence for the existence of liquid water once on Mars. On 6 December 2006, NASA announced at a press conference that they had discovered strong evidence of flowing water on Mars that have formed there only during the last seven years. The Mars Global Surveyor had made a recording in September 2005, can be seen on the two about a kilometer long Erdrinnen. They have finger-like branches at the lower end, which turned easily wind around small objects.

An important role was played by the probe also after the landing of the U.S. Mars lander Spirit and Opportunity on 4 and 25 January 2004. Though both vehicles can also communicate directly with the earth, the greatest amounts of data from the surface are in the Orbiter Mars Orbit sent to save energy.

On 23 October 2001 MGS also received the Company by the NASA probe Mars Odyssey 2001, after 1999, the two Mars missions Climate Orbiter and Mars Polar Lander had failed.

The probe had their planned life already exceeded by far, than the mission in September 2006, was extended by NASA for another two years.

Loss of contact

On November 2, 2006 - shortly before the tenth anniversary of its launch - tore communication with Mars Global Surveyor (then the longest-serving Mars probe ) from. Even her carrier signal has not been received. After problems with one of the two solar boom, the probe was probably not properly aligned to the sun and could not get enough power to operate the on-board devices. According to the mission control center of NASA, the Jet Propulsion Laboratory (JPL ) in Pasadena, California, had to be assumed that the probe is lost.

Then tried the NASA and ESA to find the probe using the cameras in its Mars Orbiter Mars Reconnaissance Orbiter and Mars Express. The tests were broken off on 28 January 2007.

On 10 January 2007, the NASA an internal inquiry commission to determine the reason for the sudden loss of contact.

On 13 April 2007 the Commission presented its preliminary report. Accordingly, conducted a series of events five months before loss of contact (June 2006) to the fact that MGS received erroneous data for the probe orientation, which should affect later fatal: On November 2, 2006, the probe was routinely instructed to orient their solar panels new. The probe made ​​several alarms, but then announced that they had stabilized. After that, the ground station lost contact. The probe had turned so that one of the two batteries was exposed to sunlight directly. This led to a warming, which was interpreted by the on-board electronics as overcharging the batteries. Then the charge was turned off by the solar cells automatically, which led to a complete discharge of both batteries within a few hours and she had damage so at least. In addition, since the radio antenna was misaligned, MGS was the ground station does not tell his condition. The investigation report indicates that the routine procedures that have been applied by the ground staff, were not effective in this case. In future, more non-routine scenarios in the flight software of satellites provide protection against overheating.