January 1998 Volume 7 Number 1

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Mars Global Surveyor's Elliptical Orbits

Mars Global Surveyor's elliptical orbits. MGS has been changing its orbit ever since it arrived in September 1997. The orbit is elliptical, but the goal is to reach a circular orbit by March 1999 (dotted circle in diagram). The way to change the orbit is to use "aerobraking"-- at each orbit's periapsis (closest point to Mars), the spacecraft dips into the upper atmosphere of Mars. MGS uses these dips into the atmosphere to help slow it down and change its orbit. The farthest point in the orbit is called the apoapsis. Aerobraking is currently planned to occur in two phases, the first ending in May 1998, the second goes from November 1998 to March 1999.

For TES News Article Related to This Figure, See...

MGS and TES Update, December 19, 1997
by Greg Mehall

TES News is published quarterly by the Arizona Mars K-12 Education Program. This newsletter may be copied for EDUCATIONAL PURPOSES ONLY.

EDITED BY Kenneth S. Edgett, Arizona Mars K-12 Education Program, Arizona State University, Tempe, Arizona, USA.
E-mail: ken.edgett@asu.edu