[meteorite-list] Mars Longevity Champ Switching Computers (Mars Odyssey)

From: Ron Baalke <baalke_at_meteoritecentral.com>
Date: Thu, 1 Nov 2012 16:55:38 -0700 (PDT)
Message-ID: <201211012355.qA1NtcSb010330_at_zagami.jpl.nasa.gov>


Mars Longevity Champ Switching Computers
Jet Propulsion Laboratory
November 01, 2012

PASADENA, Calif. -- NASA's Mars Odyssey orbiter, already the
longest-working spacecraft ever sent to Mars, will switch to some fresh,
redundant equipment next week that has not been used since before launch
in 2001.

Like many spacecraft, this orbiter carries a pair of redundant main
computers, so that a backup is available if one fails. Odyssey's
"A-side" computer and "B-side" computer each have several other
redundant subsystems linked to just that computer. The Odyssey team has
decided to switch to the B-side computer to begin using the B-side's
inertial measurement unit. This gyroscope-containing mechanism senses
changes in the spacecraft's orientation, providing important information
for control of pointing the antenna, solar arrays and instruments.

"We have been on the A side for more than 11 years. Everything on the A
side still works, but the inertial measurement unit on that side has
been showing signs of wearing out," said Odyssey Mission Manager Chris
Potts at NASA's Jet Propulsion Laboratory, Pasadena, Calif. "We will
swap to the B side on Nov. 5 so that we still have some life available
in reserve on the A side."

In many potential problem situations, the Odyssey's autonomous
fault-protection response would switch the spacecraft from the active
side to the other side. By preserving the capability of switching back
to a fully functional A side, the mission continues to have the
available protection of switching sides temporarily and correcting any
fixable anomaly on the B side.

"The spare inertial measurement unit is factory new, last operated on
the day before launch," Potts said.

Odyssey launched April 7, 2001, began orbiting Mars on Oct. 24 of that
year, began systematic science observations of Mars in early 2002, and
broke the previous record for longest-working Mars spacecraft in
December 2010.

The side swap on Nov. 5 will intentionally put Odyssey into a
reduced-activity status called "safe mode." As the team and the
spacecraft verify all systems can operate well over the following
several days, the orbiter will return to full operations, conducting its
own science observations, as well as serving as a communications relay
for NASA's active Mars rovers Opportunity and Curiosity.

The Mars Reconnaissance Orbiter, which shares the data relay return
responsibility for the rovers at Mars, will carry the full burden of
relay support for both rovers -- Opportunity and Curiosity -- during
Odyssey's side-swap period. There will be a reduction in the total
amount of relay data returned from Mars. The rover teams will reduce the
amount of data planned for downlinking until Odyssey returns to full
capacity after the side swap is complete, and will maintain near-normal
tactical operations in the interim.

Odyssey's longevity enables continued science, including the monitoring
of seasonal changes on Mars from year to year, and continued
communication-relay service.

Odyssey is managed by NASA's Jet Propulsion Laboratory, Pasadena, for
NASA's Science Mission Directorate in Washington. Lockheed Martin Space
Systems in Denver built the spacecraft. JPL and Lockheed Martin
collaborate on operating the spacecraft. For more about the Mars Odyssey
mission, visit: http://mars.jpl.nasa.gov/odyssey .

Guy Webster 818-354-6278
Jet Propulsion Laboratory, Pasadena, Calif.
November 1, 2012 guy.webster at jpl.nasa.gov

Received on Thu 01 Nov 2012 07:55:38 PM PDT

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