NASA Logo, Mars Global Surveyor
MGS over Olympus Mons,
 Artwork by Corby Waste; Mars Global Surveyor, Magnetic Field Experiment, MAG/ER
, GSFC UCB CESR UDBRI NSF UGRAZ RICE; cover art of GRL Vol. 28, No. 21 with blac
k background

Mars Global Surveyor Magnetic Field Experiment

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The Mars Global Surveyor magnetic fields investigation provided fast vector measurements of the Martian magnetic field over a wide dynamic range. The fundamental objectives of this investigation were

    1. to establish the nature of the magnetic field of Mars,
    2. to develop appropriate models for its representation, which take into account the internal sources of magnetism and the effects of the interaction of the solar wind, and
    3. to map the Martian crustal remanent field to a resolution consistent with the Mars Global Surveyor orbit altitude and ground track separation.


  • Mars does not presently have a global magnetic field but had one early in its life, similar to that of Earth. However, Mars does have very strong crustal magnetic fields, more than 30 times stronger than those of Earth.
  • Developed a detailed map of the magnetic fields of crustal sources.
  • The absence of magnetization in large impact basins allowed for the first time to establish the time of cessation of the Martian dynamo, more than 3.5 billion years ago.
  • The absence of a global magnetic field for billions of years has contributed to the erosion of Mars atmosphere by the solar wind and the loss of water.
  • Established a correlation of the horizontal component of the magnetic field with upstream solar wind dynamic pressure.

More to do

  • Studying the interaction of Mars with the solar wind provides information on how the atmosphere has been stripped away over the age of the solar system.
  • Improving the magnetic field map of crustal sources for dating the age of the crust and correlating with geology.
  • Provide magnetic field measurements to supplement data from Mars Express (MEX) and Mars Odyssey.
  • Correlate solar wind "proxy" data with data from the WIND and ACE spacecraft.

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MGS MAG/ER is an international collaboration by: