NASA UPDATES: Team Plans Uplink of Protective Files

Nasa Satellites Latest satellites Nasa InformationMars Reconnaissance Orbiter Mission Status Report

PASADENA, Calif. -- The team operating NASA's Mars Reconnaissance Orbiter plans to uplink protective files to the spacecraft next week as one step to resuming the orbiter's research and relay activities.

As the orbiter spontaneously rebooted its computer on August 26, flight team engineers have been examining likely root causes and repercussions of that incident and three similar events this year on February 23, June 3 and August 6. In the meantime, the team has kept the spacecraft in a precautionary, minimally active status called "safe mode."

The 4 reboots involved a device, called the "computer module interface controller," that controls which of two redundant main computers on the spacecraft is active. Still undetermined is whether trouble lies with that controller itself or with a voltage glitch elsewhere on the spacecraft. The August 6 reboot, though not the other three, prompted a switch from one computer to its backup twin. More than 100 factors are in consideration as possible root causes.

Engineer’s analysis of the reboots has identified a possible, though unlikely, scenario that, should it occur, might jeopardize the spacecraft. This scenario would need two computer reboots, each worse than any so far, occurring within about a minute of each other in a certain pattern. The effect would be that neither of the redundant computers would remember that the spacecraft is in orbit around Mars instead of awaiting launch. The team has developed and tested a preventive-care measure to get rid of this possibility.

The preventive care requires amending some data files in the computers' non-volatile, or "flash" memories where the computers check for default settings when they reboot. However, overwriting information in those files can entail risk, especially if the spacecraft were to experience another reboot with the process only partially completed. A process developed and tested in recent weeks to minimize that risk will take several days to implement. The team will uplink, install and verify the changes in a careful sequence.

"We plan to begin uplinking protective files next week," said Mars Reconnaissance Orbiter Project Manager Jim Erickson of NASA's Jet Propulsion Laboratory, Pasadena, Calif. "This process is to bulletproof the spacecraft against a remote vulnerability that our team identified. Meanwhile, analysis of possible root causes for the four reboots this year continues as another important part of our path toward resuming science operations."

The Mars Reconnaissance Orbiter uses six instruments to examine Mars in detail, from subsurface layers to the top of the atmosphere. It began its investigations in 2006, has provided more data about Mars than all other missions combined, and last year completed its primary science phase. Continuing science observations are planned when the spacecraft is brought out of safe mode, but no specific date for that has been set.

"The precautionary steps we are taking are not driven by the calendar, but by our commitment to care for this valuable national resource," Jim Erickson said. "We are all excited to have science observations resume as soon as a properly cautious process allows."

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