Frost-Covered Phoenix Lander Seen in Winter Images

MEDIA RELATIONS OFFICE
JET PROPULSION LABORATORY
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Guy Webster 818-354-6278
Jet Propulsion Laboratory, Pasadena, Calif.
guy.webster@jpl.nasa.gov

IMAGE ADVISORY: 2009-160 Nov. 4, 2009

Frost-Covered Phoenix Lander Seen in Winter Images

The full version of this story with accompanying images is at: http://www.jpl.nasa.gov/news/news.cfm?release=2009-160

PASADENA, Calif. -- Winter images of NASA's Phoenix Lander showing the lander
shrouded in dry-ice frost on Mars have been captured with the High Resolution Imaging
Science Experiment, or HiRISE camera, aboard NASA's Mars Reconnaissance Orbiter.

The HiRISE camera team at the University of Arizona, Tucson, captured one image of
the Phoenix lander on July 30, 2009, and the other on Aug. 22, 2009. That's when the sun
began peeking over the horizon of the northern polar plains during winter, the imaging
team said. The first day of spring in the northern hemisphere began Oct. 26.

The images are available at http://hirise.lpl.arizona.edu/ESP_014393_2485 .

"We decided to try imaging the site despite the low light levels," said HiRISE team
member Ingrid Spitale of the University of Arizona Lunar and Planetary Laboratory.

"The power of the HiRISE camera helped us see it even under these poor light
conditions," added HiRISE team member Michael Mellon of the University of Colorado
in Boulder, who was also on the Phoenix Mars Lander science team.

The HiRISE team targeted their camera at the known location of the lander to get the
new images and compared them to a HiRISE image of the frost-free lander taken in June
2008. That enabled them to identify the hardware disguised by frost, despite the fact that
their views were hindered by poor lighting and by atmospheric haze, which often
obscures the surface at this location and season.

Carbon dioxide frost completely blankets the surface in both images. The amount of
carbon dioxide frost builds as late winter transitions to early spring, so the layer of frost is
thicker in the Aug. 22 image.

HiRISE scientists noted that brightness doesn't necessarily indicate the amount of frost
seen in the images because of the way the images are processed to produce optimal
contrast. Even the darker areas in the frost-covered images are still brighter than typical
soil that surrounds the lander in frost-free images taken during the lander's prime mission
in 2008.

Other factors that affect the relative brightness include the size of the individual grains of
carbon dioxide ice, the amount of dust mixed with the ice, the amount of sunlight hitting
the surface and different lighting angles and slopes, Spitale and Mellon said.

Studying these changes will help us understand the nature of the seasonal frost and
winter weather patterns in this area of Mars.

Scientists predicted that the ice layer would reach maximum thickness in September
2009, but don't have images to confirm that because HiRISE camera operations were
suspended when Mars Reconnaissance Orbiter entered an extended safe mode on Aug.
26.

The Phoenix Mars Lander ceased communications last November, after successfully
completing its mission and returning unprecedented primary science phase and returning
science data to Earth. During the first quarter of 2010, teams at JPL will listen to see if
Phoenix is still able to communicate with Earth. Communication is not expected and is
considered highly unlikely following the extended period of frost on the lander.

HiRISE is run from the Lunar and Planetary Laboratory's HiRISE Operations Center, on
the University of Arizona campus. Planetary Sciences Professor Alfred McEwen is
HiRISE principal investigator. Planetary Sciences Professor Peter Smith is principal
investigator for the Phoenix Mars Lander mission. The Mars Reconnaissance Orbiter is
managed by NASA's Jet Propulsion Laboratory, a division of the California Institute of
Technology, for NASA Science Mission Directorate, Washington. Lockheed Martin
Space Systems, based in Denver, is the prime contractor and built the spacecraft. Ball
Aerospace Technologies Corp., of Boulder, Colo., built the HiRISE camera.

For more information about the mission, visit: http://www.nasa.gov/mro .

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