Fast-Talking NASA Spacecraft Starts Final Approach to Mars
Artist's concept of Mars Reconnaissance Orbiter near Mars. Image credit: NASA/JPL
March 08, 2006
NASA's Mars Reconnaissance Orbiter has begun its final approach
to the red planet after activating a sequence of commands designed
to get the spacecraft successfully into orbit.
The sequence began Tuesday and will culminate with firing the
craft's main thrusters for about 27 minutes on Friday -- a foot
on the brakes to reduce velocity by about 20 percent as the spacecraft
swings around Mars at about 5,000 meters per second (about 11,000 miles
per hour). Mission controllers at NASA's Jet Propulsion Laboratory,
Pasadena, Calif., and Lockheed Martin Space Systems, Denver,
are monitoring the events closely.
"We have been preparing for years for the critical events the
spacecraft must execute on Friday," said JPL's Jim Graf, project manager.
"By all indications, we're in great shape to succeed, but Mars has taught
us never to get overconfident. Two of the last four orbiters NASA sent
to Mars did not survive final approach."
Mars Reconnaissance Orbiter will build upon discoveries by five successful
robots currently active at Mars: NASA rovers Spirit and Opportunity, NASA
orbiters Mars Global Surveyor and Mars Odyssey, and the European Space
Agency's Mars Express orbiter. It will examine Mars' surface, atmosphere
and underground layers in great detail from a low orbit. It will aid future
missions by scouting possible landing sites and relaying communications.
It will send home up to 10 times as much data per minute as any previous Mars mission.
First, it must get into orbit. The necessary thruster burn will begin shortly
after 1:24 p.m. Pacific Time on Friday. Engineers designed the burn to slow
the spacecraft just enough for Mars' gravity to capture it into a very elongated
elliptical orbit. A half-year period of more than 500 carefully calculated dips
into Mars' atmosphere -- a process called aerobraking -- will use friction with
the atmosphere to gradually shrink the orbit to the size and nearly-circular
shape chosen for most advantageous use of the six onboard science instruments.
"Our primary science phase won't begin until November, but we'll actually
be studying the changeable structure of Mars' atmosphere by sensing the
density of the atmosphere at different altitudes each time we fly through
it during aerobraking," said JPL's Dr. Richard Zurek, project scientist for the mission.
Additional information about Mars Reconnaissance Orbiter is available online at:
http://www.nasa.gov/mro
The mission is managed by JPL, a division of the California Institute of Technology,
Pasadena, for the NASA Science Mission Directorate, Washington. Lockheed Martin
Space Systems, Denver, is the prime contractor for the project and built the spacecraft.
Guy Webster (818)354-6278
Jet Propulsion Laboratory, Pasadena, Calif.
Dwayne Brown (202)358-1726
Merrilee Fellows (818)393-0754
NASA Headquarters, Washington
2006-032
