Mars Global Surveyor: Aerobraking
Explanation:
Completing a 10 month journey,
another spacecraft from Earth
arrives at Mars today.
The Mars Global Surveyor (MGS)
is scheduled to fire its main rocket engine
for 22 minutes at 6:17 p.m. PDT and
enter a highly elliptical orbit, with a low point 186 miles and
a high point 34,800 miles above the surface
of Mars.
This robot spacecraft is aptly named.
Its mission is to undertake a detailed
planetwide survey
of Mars.
But first MGS must circularize its orbit, lowering the high point
to about 250 miles.
Instead of relying solely on its rocket engine,
MGS mission controllers will use a fuel-saving technique known as
aerobraking - dipping
the spacecraft
into the Martian atmosphere where it will
encounter increased atmospheric drag.
This early artist's conception emphasizes the drag
created by the wing-like solar panels.
The cumulative effect
should find MGS in a more circular
mapping orbit by March 1998.
To successfully use aerobraking, mission controllers must achieve
an exact orbit and will be
handicapped by a limited knowledge of the thickness of
the Martian atmosphere.
They may even need to alter the
spacecraft's course to compensate for changes
in Martian weather.
Authors & editors:
Robert Nemiroff
(MTU) &
Jerry Bonnell
(USRA)
NASA Web Site Statements, Warnings,
and Disclaimers
NASA Official: Jay Norris.
Specific
rights apply.
A service of:
LHEA at
NASA /
GSFC
& Michigan Tech. U.
