Mars Global Surveyor (MGS) was an American robotic space probe developed by NASA's Jet Propulsion Laboratory. It was launched on November 7, 1996, and collected data in orbit around Mars from 1997 to 2006. MGS was a global mapping mission that examined the entire planet, from the ionosphere down through the atmosphere to the surface. As part of the larger Mars Exploration Program, Mars Global Surveyor performed atmospheric monitoring for sister orbiters during aerobraking, and helped Mars rovers and lander missions by identifying potential landing sites and relaying surface telemetry. The spacecraft completed its primary mission in January 2001 and was in its third extended mission phase when, on 2 November 2006, it failed to respond to messages and commands. A faint signal was detected three days later which indicated that it had gone into safe mode. Attempts to recontact the spacecraft and resolve the problem failed, and NASA officially ended the mission in January 2007. An investigation attributed the loss of the spacecraft to a flaw in an update to its system software. MGS remains in a stable near-polar circular orbit at about 450 km altitude and as of 1996, was expected to crash onto the surface of the planet in 2050.
Objectives Mars Global Surveyor achieved the following science objectives during its primary mission:
Characterize the surface features and geological processes on Mars. Determine the composition, distribution and physical properties of surface minerals, rocks and ice. Determine the global topography, planet shape, and gravitational field. Establish the nature of the magnetic field and map the crustal remnant field. Monitor global weather and the thermal structure of the atmosphere. Study interactions between Mars's surface and the atmosphere by monitoring surface features, polar caps that expand and recede, the polar energy balance, and dust and clouds as they migrate over a seasonal cycle. Mars Global Surveyor also achieved the following goals of its extended mission:
Continued weather monitoring to form a continuous set of observations with NASA's Mars Reconnaissance Orbiter, which reached Mars in March 2006. Imaging of possible landing sites for the 2007 Phoenix spacecraft, and the 2011 Curiosity rover. Observation and analysis of key sites of scientific interest, such as sedimentary-rock outcrop sites. Continued monitoring of changes on the surface due to wind and ice.
Mission timeline 7 November 1996: Launch from Cape Canaveral. 11 September 1997: Arrival at Mars, began orbit insertion. 1 April 1999: Primary mapping phase began. 1 February 2001: First extended mission phase began. 1 February 2002: Second extended mission phase began. 1 January 2003: Relay mission began. 30 March 2004: MGS photographed the Mars Exploration Rover Spirit along with its wheel tracks showing its first 85 sols of travel.
1 December 2004: Science and Support mission began. April 2005: MGS became the first spacecraft to photograph another spacecraft in orbit around a planet other than Earth when it captured two images of the Mars Odyssey spacecraft and one image of the Mars Express spacecraft.
1 October 2006: Extended mission phase began for another two years. 2 November 2006: Spacecraft suffers an error while attempting to reorient a solar panel and communication was lost. 5 November 2006: Weak signals were detected, indicating the spacecraft was awaiting instructions. The signal cut out later that day. 21 November 2006: NASA announces the spacecraft has likely finished its operating career. 6 December 2006: NASA releases imagery taken by MGS of a newly found gully deposit, suggesting that water still flows on Mars. 13 April 2007: NASA releases its Preliminary Report on the cause(s) of MGS loss of contact.
Loss of contact On 2 November 2006, NASA lost contact with the spacecraft after commanding it to adjust its solar panels. Several days passed before a faint signal was received indicating that the spacecraft had entered safe mode and was awaiting further instructions. On 21 and 22 November 2006, MGS failed to relay communications to the Opportunity rover on the surface of Mars. In response to this complication, Mars Exploration Program manager Fuk Li stated, "Realistically, we have run through the most likely possibilities for re-establishing communication, and we are facing the likelihood that the amazing flow of scientific observations from Mars Global Surveyor is over." On 13 April 2007, NASA announced the loss of the spacecraft was caused by a flaw in a parameter update to the spacecraft's system software. The spacecraft was designed to hold two identical copies of the system software for redundancy and error checking. Subsequent updates to the software encountered a human error when two independent operators updated separate copies with differing parameters. This was followed by a corrective update that unknowingly included a memory fault which resulted in the loss of the spacecraft. Originally, the spacecraft was intended to observe Mars for 1 Martian year (approximately 2 Earth years). However, because it produced valuable data, NASA extended the mission three times. MGS remains in a stable near-polar circular orbit at about 450 km altitude, and was expected to crash onto the surface of the planet at some point after about 2047 at the time of its original launch, having by then spent fifty years orbiting the red planet. This is to prevent contamination of the Martian surface with any germs that may be stuck to the spacecraft.
Spacecraft overview The spacecraft, fabricated at the Lockheed Martin Astronautics plant in Denver, is a rectangular-shaped box with wing-like projections (solar panels) extending from opposite sides. When fully loaded with propellant at the time of launch, the spacecraft weighed 1,030.5 kg (2,272 lb). Most of its mass lies in the box-shaped module occupying the center portion of the spacecraft. This center module is made of two smaller rectangular modules stacked on top of each other, one of which is called the equipment module and holds the spacecraft's electronics, science instruments, and the 1750A mission computer. The other module, called the propulsion module, houses its rocket engines and propellant tanks. The Mars Global Surveyor mission cost about $154 million to develop and build and $65 million to launch. Mission operations and data analysis cost approximately $20 million/year.
Scientific instruments
Five scientific instruments flew aboard MGS:
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