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1993-04-23
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PUBLIC INFORMATION OFFICE
JET PROPULSION LABORATORY
CALIFORNIA INSTITUTE OF TECHNOLOGY
NATIONAL AERONAUTICS AND SPACE ADMINISTRATION
PASADENA, CALIF. 91109. TELEPHONE (213) 354-5011
FOR RELEASE MAY 27, 1980
NASA's Viking Lander 2, which completed its second
winter on the surface of Mars before it quit operating in ì
ì
March 1980, again photographed the appearance of a layer of ì
ì
frost or snow on the ground nearby.
Stephen D. Wall and Kenneth L. Jones reported to ì
ì
the American Geophysical Union's spring 1980 meeting in ì
ì
Toronto today on results of their Martian frost studies.
As happened during Viking's first winter on Mars,
a white condensate appeared on the ground very slowly, ì
ì
reaching its maximum thickness of a few microns around
winter solstice. Pictures show that the layer remained on ì
ì
the surface for about 250 Martian days.
Wall and Jones said temperature data suggest that, ì
ì
although carbon dioxide is probably a significant contributor ì
ì
to the layer, water ice also plays a part. The distinction ì
ì
between frost and snow depends, they said, on the role of ì
ì
atmospheric dust in bringing the condensate to the surface. ì
ì
It may be possible to determine from more recent Lander 2 ì
ì
images whether dust was involved.
Viking Lander 1 has also observed surface changes ì
ì
near its landing site. Two miniature landslides, slumps ì
ì
about 10 centimeters (four inches) across, have occurred, ì
ì
revealing that the Martian landscape is not static, but is ì
constantly being shaped by the wind. No visible soil slumps ì
ì
predate the Viking 1 landing on July 20, 1976, suggesting ì
ì
that annual dust storms on Mars may be strong enough to ì
ì
obliterate the features.
The Viking landers touched down on the surface of ì
ì
Mars in the summer of 1976, supported by two orbiters that ì
ì
served as relay stations and carried out scientific ì
ì
observations of their own. Viking Orbiter 2 and Viking ì
ì
Lander 2 are no longer active. Orbiter 1 is expected to ì
ì
continue operations into the summer of 1980, and the ì
ì
remaining lander is programmed to continue collecting and ì
ì
transmitting data to Earth through 1990.
The Viking Project is managed for NASA by the Jet ì
Propulsion Laboratory.
#####
#931
5/27/80