U. S. Mission launched in 1996 to orbit Mars. Main instruments include cameras (MOC), a laser altimeter (MOLA), thermal emission spectrometer ( TES), and magnetometer. During the primary mission (through January 2001), the spacecraft circled the planet once every 118 minutes at an average altitude of 378 kilometers (235 miles). Four extended mission phases began February 1, 2001 and continued to November 2006 when the orbiter stopped communicating with Earth (due to solar panel problems). Mars Global Surveyor website.