Launch: November 7, 1996
Arrival: September 12, 1997
Mass: 767 kilograms (1,691 pounds)
Science instruments: High-resolution camera, thermal emission spectrometer, laser altimeter, magnetometer/electron reflectometer, ultra-stable oscillator, radio relay system
Mars Global Surveyor became the first successful mission to the red planet in two decades when it launched November 7, 1996, and entered orbit on September 12, 1997. After a year and a half trimming its orbit from a looping ellipse to a circular track around the planet, the spacecraft began its prime mapping mission in March 1999. It has observed the planet from a low-altitude, nearly polar orbit over the course of one complete Martian year, the equivalent of nearly two Earth years. Mars Global Surveyor recently completed its primary mission on January 31, 2001, and is now in an extended mission phase.
The mission has studied the entire Martian surface, atmosphere, and interior, and has returned more data about the red planet than all other Mars missions combined.
Among key science findings so far, Global Surveyor has taken pictures of gullies and debris flow features that suggest there may be current sources of liquid water, similar to an aquifer, at or near the surface of the planet. Magnetometer readings show that the planet's magnetic field is not globally generated in the planet's core, but is localized in particular areas of the crust. New temperature data and closeup images of the Martian moon Phobos show its surface is composed of powdery material at least 1 meter (3 feet) thick, caused by millions of years of meteoroid impacts. Data from the spacecraft's laser altimeter have given scientists their first 3-D views of Mars' north polar ice cap.
For more information, see the Mars Global Surveyor home page.