[meteorite-list] Phoenix Mission Status Report - October 29, 2008

From: Ron Baalke <baalke_at_meteoritecentral.com>
Date: Thu, 30 Oct 2008 10:38:58 -0700 (PDT)
Message-ID: <200810301738.KAA21953_at_zagami.jpl.nasa.gov>

http://www.jpl.nasa.gov/news/news.cfm?release=2008-200

Phoenix Mission Status Report
Jet Propulsion Laboratory
October 29, 2008

PASADENA, Calif. - NASA'S Phoenix Mars Lander entered safe mode late
yesterday in response to a low-power fault brought on by deteriorating
weather conditions. While engineers anticipated that a fault could occur
due to the diminishing power supply, the lander also unexpectedly
switched to the "B" side of its redundant electronics and shut down one
of its two batteries.

During safe mode, the lander stops non-critical activities and awaits
further instructions from the mission team. Within hours of receiving
information of the safing event, mission engineers at NASA's Jet
Propulsion Laboratory, Pasadena, Calif., and at Lockheed Martin in
Denver, were able to send commands to restart battery charging. It is
not likely that any energy was lost.

Weather conditions at the landing site in the north polar region of Mars
have deteriorated in recent days, with overnight temperatures falling to
-141F (-96C), and daytime temperatures only as high as -50F (-45C), the
lowest temperatures experienced so far in the mission. A mild dust storm
blowing through the area, along with water-ice clouds, further
complicated the situation by reducing the amount of sunlight reaching
the lander's solar arrays, thereby reducing the amount of power it could
generate. Low temperatures caused the lander's battery heaters to turn
on Tuesday for the first time, creating another drain on precious power
supplies.

Science activities will remain on hold for the next several days to
allow the spacecraft to recharge and conserve power. Attempts to resume
normal operations will not take place before the weekend.

"This is a precarious time for Phoenix," said Phoenix Project Manager
Barry Goldstein of JPL. "We're in the bonus round of the extended
mission, and we're aware that the end could come at any time. The
engineering team is doing all it can to keep the spacecraft alive and
collecting science, but at this point survivability depends on some
factors out of our control, such as the weather and temperatures on Mars."

The ability to communicate with the spacecraft has not been impacted.
However, the team decided to cancel communication sessions Wednesday
morning in order to conserve spacecraft power. The next communication
pass is anticipated at 9:30 p.m. PDT Wednesday.

Yesterday, the mission announced plans to turn off four heaters, one at
a time, in an effort to preserve power. The faults experienced late
Tuesday prompted engineers to command the lander to shut down two
heaters instead of one as originally planned. One of those heaters
warmed electronics for Phoenix's robotic arm, robotic-arm camera, and
thermal and evolved-gas analyzer (TEGA), an instrument that bakes and
sniffs Martian soil to assess volatile ingredients. The second heater
served the lander's pyrotechnic initiation unit, which hasn't been used
since landing. By turning off selected heaters, the mission hopes to
preserve power and prolong the use of the lander's camera and
meteorological instruments.

Originally scheduled to last 90 days, Phoenix has completed a fifth
month of exploration in the Martian arctic. As the Martian northern
hemisphere shifts from summer to autumn, the lander was expected to
generate less power due to fewer hours of sunlight reaching its solar
panels. "It could be a matter of days, or weeks, before the daily power
generated by Phoenix is less than needed to operate the spacecraft,"
said JPL mission manager Chris Lewicki. "We have only a few options left
to reduce the energy usage."

The Phoenix mission is led by Peter Smith of the University of Arizona,
Tucson, with project management at the Jet Propulsion Laboratory and
development partnership at Lockheed Martin, Denver. International
contributions come from the Canadian Space Agency; the University of
Neuchatel, Switzerland; the universities of Copenhagen and Aarhus in
Denmark; the Max Planck Institute in Germany; and the Finnish
Meteorological Institute. The California Institute of Technology in
Pasadena manages JPL for NASA.

Veronica McGregor 818-354-9452
Jet Propulsion Laboratory, Pasadena, Calif.
Veronica.mcgregor at jpl.nasa.gov

2008-200
Received on Thu 30 Oct 2008 01:38:58 PM PDT