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Mars Odyssey Orbiter Switch-over Complete, Work Resumes

November 13, 2012
Image Caption: NASA's Mars Odyssey spacecraft passes above Mars' south pole in this artist's concept. The spacecraft has been orbiting Mars since October 24, 2001. Image credit: NASA/JPL

Alan McStravick for redOrbit.com – Your Universe Online

We found out this week that the NASA Mars Odyssey orbiter, launched in 2001, had stopped working. It was no longer sending us vital information from our planned missions to the red planet. We also learned that this was completely intentional. This is because the Odyssey was completing a planned switch-over to a set of redundant equipment that included its main computing system. The transition to equipment that had not been in operation since prior to its launch was a shining success for NASA, the Jet Propulsion Laboratory (JPL), and Lockheed Martin Space Systems.

Teams back on Earth began receiving Odyssey´s signal again late on Sunday. The first data received after the transition was from NASA´s Opportunity rover that is on Mars. This information was sent using the Odyssey´s fresh ℠B-side´ radio for ultra-high frequency (UHF) communications. NASA has plans this week to resume relays for their newest Mars rover, Curiosity, along with a full resumption of Odyssey´s own scientific observations.

“The side-swap has gone well. All the subsystems that we are using for the first time are performing as intended,” said Odyssey Project Manager Gaylon McSmith of NASA’s Jet Propulsion Laboratory, Pasadena, Calif.

The Odyssey orbiter is not unlike most spacecraft, in that it carries a pair of redundant main computers. The purpose of this is so that the craft has a backup just in case one or the other fails to operate properly. Within both the A and B-side computers are several other redundant subsystems.

Even before this successful side swap, NASA was very proud of Odyssey, as it is the longest-working spacecraft that has ever been sent to Mars. The transition was initiated last week due to several months of diagnostic data that had indicated that the A-side inertial measurement unit was beginning to show signs of wearing out. This unit contains a gyroscope mechanism that senses changes in the spacecraft´s orientation. The gyroscope is important as it provides information for control of pointing the antenna, solar arrays and other instrumentation.

Even though the diagnostics received over the past few months have indicated that the A-side´s inertial measurement unit still has a few months or more of useful life, the decision was made to switch sides in order to maintain a fully functional A-side in case of any unforeseen problems that may arise with the B-side. If the B-side were to have any type of malfunction in the coming years, scientists from JPL, Lockheed Martin and NASA would be able to do a temporary switchback to the A-side while they completed any necessary repairs to the errors.

“It is testimony to the excellent design of this spacecraft and operation of this mission in partnership with Lockheed Martin that we have brand-new major components available to begin using after more than 11 years at Mars,” McSmith said.

Responsible for managing the Mars Odyssey project for NASA´s Science Mission Directorate in Washington is JPL, a division of the California Institute of Technology in Pasadena, California. JPL collaborates with Lockheed Martin in the operation of the spacecraft. Lockheed Martin´s association is due, in no small part, to the fact that they designed and built the Odyssey at their Lockheed Martin Space Systems facility in Denver, Colorado.

While Odyssey was undergoing its A to B-side transition, NASA´s Mars Reconnaissance Orbiter, which shares data-relay responsibility with Odyssey for their red planet rovers, picked up the slack while Odyssey was unavailable for the few days immediately following the side swap.

A brief perusal of Odyssey´s resume teaches us that she was launched into space on April 7, 2001. A brief six months later Odyssey began orbiting Mars on October 24th. Only a few months later, Odyssey began systematic science observations of Mars. In December of 2010, she broke the previous record for longest working Mars spacecraft. That record seems to be safely hers for some time following this successful side swap.

Odyssey’s longevity enables continued science by instruments on the orbiter, including the monitoring of seasonal changes on Mars from year to year, in addition to communication-relay service.


Source: Alan McStravick for redOrbit.com - Your Universe Online



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