Mars Global Surveyor (MGS) was an American robotic spacecraft developed by NASA's Jet Propulsion Laboratory and launched in November 1996. Mars Global Surveyor was a global mapping mission that examined the entire planet, from the ionosphere down through the atmosphere to the surface.

It completed its primary mission in January 2001 and was in its third extended mission phase when, on 2 November 2006, the spacecraft 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 re-contact the spacecraft and resolve the problem failed, and NASA officially ended the mission in January 2007. 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.