Phoenix Mission Status Report

MEDIA RELATIONS OFFICE
JET PROPULSION LABORATORY
CALIFORNIA INSTITUTE OF TECHNOLOGY
NATIONAL AERONAUTICS AND SPACE ADMINISTRATION
PASADENA, CALIFORNIA 91109. TELEPHONE 818-354-5011
http://www.jpl.nasa.gov

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

Phoenix Mission Status Report 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.

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