[meteorite-list] NASA Loses Contact With Mars Global Surveyor

From: Ron Baalke <baalke_at_meteoritecentral.com>
Date: Fri Nov 10 18:13:33 2006
Message-ID: <200611102313.PAA20035_at_zagami.jpl.nasa.gov>

http://www.space.com/news/061110_mgs_missing.html

NASA Loses Contact With Mars Global Surveyor
By Ker Than
space.com
10 November 2006

NASA's Mars Global Surveyor (MGS) spacecraft has failed to check in with
Earth for the fifth straight day in a row, after losing contact during a
routine adjustment of its solar array.

If contact is not reestablished by Saturday, NASA might try to have
another Mars-orbiting spacecraft take pictures of MGS to assess its
condition.

On Nov. 2, MGS mangers sent commands for the spacecraft to adjust the
position of one of its solar power arrays to better track the sun.
Returning data indicated a problem with the motor that moves the array,
so a backup motor and control circuitry were switched on.

No signal was received on Nov. 3 and 4, but a weak signal was received
on Nov. 5, suggesting the spacecraft had switched to a safe mode and was
awaiting further instructions from Earth. The signal cut out completely
later that day and nothing has been heard since.

Engineers think the spacecraft has performed a programmed maneuver in
which it turns its solar arrays toward the sun to maintain its power
supply. When it does this, it also reorients its entire body in the same
direction, thus making communication with Earth less effective.

"The spacecraft has many redundant systems that should help us get it
back into a stable operation, but first we need to re-establish
communications," said MGS project manager Tom Thorpe of NASA's Jet
Propulsion Laboratory in Pasadena.

It's also possible, Thorpe said, that the spacecraft was hit by a
micrometeorite, and that it's antenna was jolted out of alignment.

NASA is still trying to contact the spacecraft, because its ability to
receive commands might not be impaired. But if nothing is heard from MSG
by Saturday, NASA will ask the Mars Reconnaissance Orbiter (MRO) team to
begin preperations late next week to take pictures of MGS in order to
assess its orientation and condition. The two spacecraft pass within
about 60 miles (100 km) of each other several times a week.

"That would help a lot to determine where we are now and what commands
we should be using," Thorpe told SPACE.com.

MGS launched towards Mars just over 10
years ago, on Nov. 7, 1996, and marked NASA's first successful return to
the red planet in two decades. The spacecraft was originally tasked
with examining Mars for a full Martian year, roughly two Earth years.
Operations were slated to end in early 2001, but like the two Mars
rovers, Opportunity and Sporit, MGS was continued to perform so
admirably that its mission was repeatedly extended most recently on
Oct. 1 of this year.

Since its mission formally began in 1999, MGS has returned a wealth of
data about the red planet. The spacecraft has tracked the evolution of a
dust storm, gathered information on the Martian landscape, found
compelling evidence of gullies apparently carved by flowing water, and
revealed the infamous "face on Mars," originally photographed in 1976 by
Viking 1, to be nothing more than a natural landscape. It has also taken
tens of thousands of high-resolution images of Mars and performed the
first three-dimensional mapping of the planet's North Pole.
Received on Fri 10 Nov 2006 06:13:29 PM PST