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Mission
objectives
The Mars Global Surveyor(MGS), currently in orbit
around Mars, will collect data on the surface topography,
composition, gravity, atmosphere and magnetic field of
Mars. This data is being used to investigate the surface
processes, geology, internal properties, evolution of
the magnetic field, and the weather and climate of Mars.
Spacecraft
instrumentation
The spacecraft
itself is a rectangular box made up of two parts, the
equipment module and the propulsion module. Two solar
panels extend out from opposite sides of the craft. The
main thruster uses a hydrazine propellant. Four solar
array panels provide power to the spacecraft. Energy is
stored in two nickel-hydrogen batteries. Temperature is
controlled with insulation, thermal radiators, and electrical
heaters. Communications are achieved using a high-gain
antenna and two low-gain antennas.
Click
here for a 3-D model of Surveyor. The instruments
on the equipment deck consist of a camera, a thermal emission
spectrometer, a laser altimeter, and a radio transmission
relay. Click
here for more information on the instruments
aboard MGS.
Mission
profile
MGS was launched
on a Delta rocket on November 7, 1996. After a 10-month
trip, it was inserted into an elliptical orbit on September
12, 1997.
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Over the
next four months, it was intended that aerobraking
maneuvers and thrusters would be used to lower
the orbit to the final circular mapping orbit. However,
one of the solar panels failed to latch properly
when it was deployed and subsequently showed unexpected
motion. This moved it past its fully deployed position
when aerobraking began (thought to be due to structural
damage).
A new aerobraking
schedule was employed that involved slower aerobraking,
which put less pressure on the solar panels. Mapping
began in mid-March 1999, which was summer in the
northern hemisphere on Mars. |
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The
Mars Global Surveyor acts as a relay in support
of future missions. The mission cost about $154
million to develop and build and $65 million to
launch. Mission operations and data analysis cost
approximately $20 million/year. For a complete
itinerary of the mission visit the MGS
homepage.
Movies
and animations of the spacecraft can be found here
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Discoveries
| MGS has returned great
amounts of data and hundred of images from the orbiter
camera to Earth that are rapidly being analyzed
by scientists. The search for evidence of ancient
ocean coastlines based on the laser
altimeter data continues. Detailed maps
of the south pole were made in support of the
'98 Polar Lander mission. |
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Click
here for some very cool virtual reality models
of Global Surveyor. You will need a VRML plug-in to view
these models.
Questions
to think about:
- Why are images from orbit important to future explorations
of the planet?
- Why do you think engineers decided to try using the
aerobraking technique to slow the spacecraft down instead
of using tradition propulsion methods (fueled thrusters)?
- What do you think might turn out to be the most important
discovery to come out of this mission?
Next... Mars
Surveyor '98 (pg 8 of 12) |
