Mars Global Surveyor

Firsts

• Mars Global Surveyor was the first spacecraft to use aerobraking to enter orbit at Mars.

Key Dates

Nov. 7, 1996: Launch

Sept. 12, 1997: Entered initial orbit at Mars

Sept. 17, 1997, to Feb. 19, 1999: Aerobraking used to refine spacecraft's orbit

March 9, 1999: Mapping mission formally began

Nov. 21, 2006: Last contact, mission ends

In Depth: Mars Global Surveyor

Mars Global Surveyor was the first spacecraft in NASA’s new Mars Surveyor Program, a new generation of American space probes to explore Mars every 26 months from 1996 to 2005.

The program was formulated in 1994 to economize costs and maximize returns by involving a single industrial partner with NASA's Jet Propulsion Laboratory (JPL) to design, build and deliver a flight-worthy vehicle for Mars every two years. (A new Mars Exploration Program was inaugurated in 2000.)

The Mars Global Surveyor spacecraft carried five instruments similar to those carried by the lost Mars Observer probe that fell silent in 1993. Among the instruments was a French-supplied radio relay experiment to serve as a downlink for future Mars landers, including the planned Russian Mars 96 mission.

After course corrections Nov. 21, 1996, and March 20, 1997, Mars Global Surveyor entered a highly elliptical orbit around Mars on Sept. 12, 1997, after engine ignition at 01:17 UT. Initial orbital parameters were about 163 × 33,570 miles (262 × 54,026 kilometers).

Commencement of its planned two-year mission was delayed because one of its two solar panels (-Y) had not fully deployed soon after launch. The solar panels were designed to act as atmospheric brakes to alter its orbit.

As a result, mission planners reconfigured the aerobraking process required to place the vehicle in its intended orbit. The modified aerobraking maneuver began Sept. 17, 1997, and lasted until October 11. A second aerobraking phase lasted from November 1997 to March 1998 and a third one began in November 1998 with the goal of reducing the high point of its orbit down to about 280 miles (450 kilometers).

It is an extraordinary machine that has done things the designers never envisioned despite a broken wing, a failed gyro and a worn-out reaction wheel. The builders and operating staff can be proud of their legacy of scientific discoveries and key support for subsequent missions.

The revised maneuvers were finally completed Feb. 4, 1999, with a major burn from its main engine. A subsequent firing Feb. 19 finally put Mars Global Surveyor into a near-circular polar orbit at 146 miles (235 kilometers) and March 9, 1999, its mapping mission formally began.

The orbit was Sun-synchronous, ensuring that all its images were taken by the spacecraft of the same surface features at different times under identical lighting conditions.

Despite the early problems, Mars Global Surveyor, even during its movement to its new orbit, sent back impressive data and high-resolution images of the surface of Mars. The spacecraft tracked the evolution of a dust storm, gathered information on the Martian terrain and found compelling evidence indicating the presence of liquid water at or near the surface (first announced by NASA June 22, 2000).

During its mission, Mars Global Surveyor also produced the first three-dimensional profiles of Mars’ North Pole using laser altimeter readings. In addition, the laser altimeter essentially mapped almost all of the planet, by firing approximately 500 billion pulses at the surface, providing topographical data that was more detailed than many places on Earth.

The spacecraft’s primary mission concluded on Feb. 1, 2001, by which time it had returned 83,000 images of Mars, more than all previous missions to Mars combined. Also on that date, Mars Global Surveyor’s mission was extended for a year, and then again Feb. 1, 2002, this time continuing 11 months.

In the early 2000s, the spacecraft supported other missions to Mars, including that of Mars Odyssey (in 2001) and the Mars Exploration Rovers (in 2004) by providing either atmospheric data or relaying telemetry back to Earth. Between 2004 and 2006 it conducted experiments simultaneously with the European Mars Express.

On Oct. 1, 2006, mission planners, based on the recommendations of a Senior Review Board, once again extended the Mars Global Surveyor’s mission by another two years, but only a month later, on Nov. 2, the spacecraft lost contact with Earth when attempting to orient a solar panel.

Although weak signals were received three days later, on Nov. 21, 2006, NASA announced that the mission of Mars Global Surveyor was over. The final problem was probably related to a flaw in the system’s software.

Key Source

Siddiqi, Asif A. Beyond Earth: A Chronicle of Deep Space Exploration, 1958-2016. NASA History Program Office, 2018.