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1993-04-23
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182 lines
OFFICE OF PUBLIC INFORMATION
JET PROPULSION LABORATORY
CALIFORNIA INSTITUTE OF TECHNOLOGY
NATIONAL AERONAUTICS AND SPACE ADMINISTRATION
PASADENA, CALIFORNIA. TELEPHONE (2l3) 354-50ll
FOR IMMEDIATE RELEASE February
l0, l977
Operations have begun at the Viking l landing site
to
dig a foot-deep trench in the Martian soil and distribute
samples
to three instruments.
The deep trench is being dug to help Viking
biologists
understand the complex soil chemistry and to see if large
amounts
of oxygen that were observed in surface samples also occur at
depth.
Commands were sent Thursday from Jet Propulsion
Laboratory
to Viking Lander l to begin its deep-digging operations Feb.
l2.
The sequence will continue through March l5, and will include
a series of pictures taken by the lander to show mission
controllers
how it is progressing.
On March l3 the first sample from the deep trench
will
be placed in the inorganic soil-analysis experiment.
The final sample, from the bottom of the trench,
will be
placed in the biology instrument's gas-exchange experiment
some- î
time in early April, according to current planning.
A shallower trench will be dug by Viking lander 2.
The operations began with an attempt to build a rock pile
that
would have been placed in the inorganic soil analysis
instrument.
-more-
-2-
However, scientists were unable to find any pebbles and have
concluded that the area where the dig took place has only
fine
materials and lightly cemented soil grains.
During Lander 2's digging sequence a soil sample
will
be taken for the inorganic experiment on Feb. l6. Another
attempt
will be made to build a rock pile on Feb. 27. A sample for
the
inorganic experiment will be taken March l2 and l3.
The final sample from the bottom of the trench will
be
placed in Lander 2's biology instrument about March 28 and
29,
according to present plans. î
That sample will be distributed to Lander 2's
labeled
release and carbon assimilation experiments, and will be used
for a "cold incubation" sequence.
Meanwhile, Viking Orbiter l continues to close in
on
the Martian satellite Phobos for a series of close passes.
The
sequence will begin Feb. l8 and continue through Feb. 24.
The
closest pass -- at a distance of about 80 kilometers (50
miles) --
will occur Feb. 23. A total of ll close passes at Phobos are
planned.
In addition to a series of photographs of the small
satellite, scientists will closely measure Phobos'
temperature and
will observe how its gravity deflects the course of the
spacecraft.
All these measurements and the pictures should help determine
Phobos' composition and provide some clues to its history and
that
of the solar system.
-more-
-3-
î
After completion of the Phobos encounters, mission
planners
will alter the orbit of Viking Orbiter l, dropping its
closest
approach to Mars to about 300 kilometers (l85 miles) from the
present
periapsis altitude of l,500 kilometers (950 miles).
The Viking Mission is managed for NASA by the
Langley
Research Center at the Jet Propulsion Laboratory.
# # # # #
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