The Mars Global Surveyor
Published on Nov 22, 2006 at 1:09 am.
2 Comments.
Filed under NASA, space exploration.
Hope is fading for the Mars Global Surveyor. This spacecraft was launched in November 1996, and has been in orbit around Mars since September 1997. Less expensive than many of the spacecraft that NASA had launched in the previous decade, the Mars Global Surveyor (MGS) has proven to be a fantastic asset, yielding fantastic data, and sending back almost a quarter million images.
Among the findings attributed to MGS, are gullies that many believe may show evidence of fairly recent (geologically) activity of liquid water on Mars. Spectroscopic data also showed indications of a specific type of hematite that forms only in the presense of liquid water. This is important, because liquid water on the surface of a planet is only found on Earth, and it is believed that liquid water may be necessary for life. MGS also had one of the most sensitive magnetometers that had been sent to Mars until that time. This magnetometer showed evidence of a paleomagnetic field on Mars. Previous measurements had failed to detect a magnetic field, but MGS’s magnetometer showed that Mars at one time seemed to have a significant magnetic field. 
In addition to studying Mars, MGS was able to study the Martian Moons, Phobos and Deimos, as seen in this image of Deimos taken in July 2006. MGS was placed in a polar orbit, allowing the spacecraft to study the polar regions of Mars with greater precision than had ever been done before. MGS has been able to study the Martian ice caps for several Mars years. Data show that the south polar cap seems to be shrinking each year, leading some planetary scientists to suggest that Mars is undergoing global warming, much as many believe that Earth seems to be experiencing. If so, this is a very interesting finding, because Mars does not have any artificial pollution to contribute to global warming.
MGS’s primary mission was scheduled to end in early 2001. But, the spacecraft was still functioning well, and the mission was extended. Michael Meyer, who oversees Mars exploration at NASA, said recently that the Mars Global Surveyor has far exceeded any reasonable expectations for a spacecraft, and is by far the most productive spacecraft ever sent to Mars. Early this past October, the MGS mission was extended for another two years.
November 2, 2006, though NASA lost contact with MGS. It appears that an unknown fault caused the spacecraft’s onboard computer to put the craft into “safe mode,” a state in which the spacecraft powers down instruments and adopts a defensive posture to make sure that it doesn’t do anything that might make whatever went wrong worse, and to make sure that it doesn’t accidentally damage itself. But, normally, controllers can figure out what went wrong and send the appropriate commands to fix the problem. We don’t really know what went wrong with MGS. There are some indications that there were problems with one of the panels providing solar power to the spacecraft. Other possible problems include attitude control systems (a flywheel that is used to stabalize the craft has had problems). But, the fact is that we don’t really know what happened. November 5, some weak signals were picked up indicating that the craft was awaiting instructions, but nothing has been heard since. Nearly 1000 commands have been sent to the craft, covering just about every possible fault and procedures to reacquire contact. So far, nothing has been heard back from the craft. And, the lasest most radical efforts yet have not produced any results. The Mars Progam Manager at the Jet Propulsion Laboratory (JPL), Fuk Li, has admitted in statements made November 21 that it is unlikely that contact will ever be restored. The Mars Global Surveyor is likely lost, after a wonderful and amazing career.
All hope is not lost, though. A near final, desparate attempt is coming later this week. MGS will be passing over the Mars Exploration Rover Opportunity. JPL is sending commands to MGS to communicate with Opportunity. The orbiter has acted as a data relay satellite for the rovers since they landed. Opportunity has been commanded to relay any contact with MGS to the Mars Odyssey spacecraft, which will send that information back to Earth. If MGS manages to maintain a communication lock with Opportunity, then that means that the craft is at least still alive, and there is hope of recovery. But, if it can’t make contact, then it is likely lost for good. Things look pretty grim for the orbiter. 
But, even if it is lost, it has been a fantastic tool for the study of Mars, and likely one of the most successful Mars explorers. The image here is of the Martian north polar ice cap, and it was sent back only two weeks before contact was lost. We can hope that MGS contact can be regained, but even if it isn’t, this mission was an unqualified success, and more. Still, it will be rather sad to lose such a successful spacecraft.
-Astroprof
(Images courtesy of NASA)
A Ler…-- Rastos de Luz on November 22, 2006 at 5:12 pm: 1
[…] “Mission Over (?)“, no Tom’s Astronomy Blog. Ao que parece, a questão relativa à MGS está mal parada. Sobre o mesmo assunto “The Mars Global Surveyor“, no Astroprof’s Page; […]
David Adams on January 25, 2007 at 3:56 pm: 2
Goodbye to a wonderful 21st century
machine. I was able to sit in my living room and see the face of another world with its canyons and snows and traces of terrible catastrophes and the ruins of the civilization lost to them. I hope the
Recon sattelite can bring us an even clearer history of our brother world.
David Adams