[meteorite-list] MRO Team Plans Uplink of Protective Files

From: Ron Baalke <baalke_at_meteoritecentral.com>
Date: Tue, 24 Nov 2009 16:01:40 -0800 (PST)
Message-ID: <200911250001.nAP01e1h016877_at_zagami.jpl.nasa.gov>

http://www.jpl.nasa.gov/news/news.cfm?release=2009-177

Team Plans Uplink of Protective Files
Jet Propulsion Laboratory
November 24, 2009

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

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

The four 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 Aug. 6 reboot, though not the other
three, prompted a switch from one computer to its backup twin. More than
100 factors are under consideration as possible root causes.

Engineers' analysis of the reboots has identified a possible, though
unlikely, scenario that, should it occur, could jeopardize the
spacecraft. This scenario would require 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 eliminate 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,"
Erickson said. "We are all eager to have science observations resume as
soon as a properly cautious process allows."

Guy Webster 818-354-6278
Jet Propulsion Laboratory, Pasadena, Calif.
guy.webster at jpl.nasa.gov

2009-177
Received on Tue 24 Nov 2009 07:01:40 PM PST