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Mars Global Surveyor, 10 anni nello spazio!

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Offline marcozambi

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Mars Global Surveyor, 10 anni nello spazio!
« il: Mer 08/11/2006, 10:46 »
MARS GLOBAL SURVEYOR
Image of the Week
November 7, 2006

The following new image taken by the Mars Orbiter Camera (MOC) on
the Mars Global Surveyor spacecraft is now available:

o MGS Mars Orbiter Camera: 10 Years In Space (Released 07 November
2006)
  http://www.msss.com/mars_images/moc/2006/11/07

Image Caption:

Mars Global Surveyor (MGS) was launched 10 years ago today, on 7
November 1996. The spacecraft reached Mars on 12 September 1997, and
has
been observing the ever-changing red planet over the course of the past
5 martian years.

The Mars Orbiter Camera (MOC) has spent 10 years in the near vaccuum of
space - not bad, considering that the Primary Mission, at the time of
launch, was expected to end in early 2000. Since September 1997, MOC
has
been acquiring new images that highlight the geology and meteorlogy of
Mars; more than 240,000 images have been returned to Earth. A recent
example, from 15 October 2006, is shown here.

Two annular (i.e., somewhat circular) clouds are seen in the upper left
corner of this mosaic of MOC wide angle camera daily global mapping
images. To the right of the picture's center is the martian north polar
cap. The image has a scale of about 7.5 kilometers (4.7 miles) per
pixel. Annular clouds are common in mid-northern summer in the north
polar region, and may result from eddy currents in the lower
atmosphere.
The appearance of such clouds happens every year; this year they came
like clockwork within a two-week forecasted period, based on the
previous 4 martian years of experience gained from MGS MOC daily global
imaging.

Despite their superficial resemblance to Earth-orbiting satellite views
of hurricanes, these cloud features are not the result of strong winds,
and they typically dissipate later in the day. The pictures used to
make
this mosaic were acquired less than 2 days before the MOC was turned
off
for MGS's fifth Mars-Earth Solar Conjunction period. During
Conjunction,
Mars was on the other side of the Sun, relative to Earth, and thus MGS
could not transmit data (through the Sun) during the second half of
October.

To review the launch 10 years ago, one can visit the NASA Kennedy Space
Center web site, which includes pictures and video at:
http://science.ksc.nasa.gov/payload/missions/mgs/video.html. Video
clips
of the launch and many animations and videos from the earlier phases of
the MGS mission can be reviewed at the Jet Propulsion Laboratory web
site at: http://marsprogram.jpl.nasa.gov/mgs/movpics/anim/anim.html.

------------------------------------------------------------------------

All of the Mars Global Surveyor images are archived here:

http://www.msss.com/mars_images/moc/index.html
Marco Zambianchi
ForumAstronautico Founder
Presidente Associazione ISAA

Offline marcozambi

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Mars Global Surveyor, 10 anni nello spazio!
« Risposta #1 il: Gio 09/11/2006, 09:04 »
E subito un imprevisto....
Insomma, il peso degli anni si fa sentire!
Per ora MGS resta in safe mode, mentre i tecnici a Terra stanno lavorando per riportare l'orbiter alla sua piena funzionalità.
Segue comunicato NASA

Citazione
http://www.jpl.nasa.gov/news/features.cfm?feature=1226

Ground Team Stays Busy on 10th Anniversary of NASA Mars Launch
Media contact: Guy Webster (818) 354-6278/JPL
Jet Propulsion Laboratory
November 07, 2006

Engineers are striving to restore full communications with NASA's Mars
Global Surveyor on the 10th anniversary of the spacecraft's Nov. 7,
1996, launch.

The orbiter is the oldest of five NASA spacecraft currently active at
the red planet. Its original mission was to examine Mars for a full
Martian year, roughly two Earth years. Once that period elapsed,
considering the string of discoveries, NASA extended the mission
repeatedly, most recently on Oct. 1 of this year.

The orbiter has operated longer than any other spacecraft ever sent to
Mars. It has returned more information about Mars than all earlier
missions combined and has succeeded far enough beyond its original
mission to see two later NASA orbiters arrive: Mars Odyssey and Mars
Reconnaissance Orbiter. Among many important accomplishments so far,
Mars Global Surveyor has found many young gullies apparently cut by
flowing water, discovered water-related mineral deposits that became a
destination for NASA's Opportunity rover, mapped the planet
topographically and examined many potential landing sites on Mars.

On Nov. 2, one orbit after commands were sent for a routine maneuver to
move the solar panels, the spacecraft reported that the motor moving
one
of the arrays had experienced errors. Onboard software responded as
programmed, switching the spacecraft to a backup motor controller, then
to a backup circuitry connection.

Following these indications of difficulty, a two-day lapse in contact
occurred on Nov. 3 and 4. The signal from the spacecraft was received
on
Nov. 5 during four different orbits, but it did not carry any data from
the spacecraft. The signal's frequency indicated that the spacecraft
had
entered safe mode, a pre-programmed state of restricted activity in
which it awaits instructions from Earth.

No further signal was heard during subsequent orbits on Nov. 5 and Nov.
6. Engineers concluded that the spacecraft had made an additional
pre-programmed response, intended to help it survive when it senses
that
a solar array is stuck. The spacecraft turns that array toward the sun
to maintain its power supply and rotates the rest of the spacecraft in
the same direction, thereby 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 Tom Thorpe, project manager for Mars Global
Surveyor at NASA's Jet Propulsion Laboratory, Pasadena, Calif.

Further information on the recovery of the spacecraft will be released
as it comes available.

Marco Zambianchi
ForumAstronautico Founder
Presidente Associazione ISAA