[meteorite-list] Phoenix Monitors Frosty Clumps on its Struts

From: Ron Baalke <baalke_at_meteoritecentral.com>
Date: Wed, 10 Sep 2008 10:29:29 -0700 (PDT)
Message-ID: <200809101729.KAA05481_at_zagami.jpl.nasa.gov>


Underneath Phoenix Lander 97 Sols After Touchdown
Jet Propulsion Laboratory

The Robotic Arm Camera on NASA's Phoenix Mars Lander took this image on
Sept. 1, 2008, at about 4 a.m. local solar time during the 97th Martian
day, or sol, since landing. The view underneath the lander shows growth
of the clumps adhering to leg strut (upper left) compared with what was
present when a similar image was taken about three months earlier (see

The view in this Sol 97 image is southward. Illumination is from the
early morning sun above the northeastern horizon. This is quite
different from the illumination in the Sol 8 image, which was taken in

The science team has discussed various possible explanations for these
clumps. One suggestion is that they may have started from a splash of
mud if Phoenix's descent engines melted icy soil during the landing.
Another is that specks of salt may have landed on the strut and began
attracting atmospheric moisture that freezes and accumulates. The clumps
are concentrated on the north side of the strut, usually in the shade,
so their accumulation could be a consequence of the fact that
condensation favors colder surfaces.

In this image, compared with the one from three months earlier, the
flat, smooth patches of ice exposed underneath the lander seem to be
partly covered by darker material left behind as ice vaporizes away. The
flat patch in the center of the image has the informal name "Holy Cow,"
based on researchers' reaction when they saw the initial image of it.

The Phoenix Mission is led by the University of Arizona, Tucson, on
behalf of NASA. Project management of the mission is by NASA's Jet
Propulsion Laboratory, Pasadena, Calif. Spacecraft development is by
Lockheed Martin Space Systems, Denver.

Image NASA/JPL-Caltech//University of Arizona/Max Planck Institute
Received on Wed 10 Sep 2008 01:29:29 PM PDT

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