@S1-A.ARPA,@MIT-MC.ARPA:RSF@SU-AI.ARPA (07/06/85)
From: Ross Finlayson <RSF@SU-AI.ARPA>
BC-MARS
(SCIENCETIMES)
By WALTER SULLIVAN
c. 1985 N.Y. Times News Service
NEW YORK - In contrast an earlier reluctance of the Russians to
provide advance information on space flights, they have provided
Western scientists with extensive details on the Soviet Union's 1988
mission to Mars.
One of its highlights will be a 15-minute period when the
spacecraft will hover 50 yards above the surface of Phobos, the
planet's inner moon.
Using a technique never before attempted in space, the craft will
bombard the surface of Phobos with a narrow laser beam to blast off
samples that can be captured and analyzed aboard the probe. According
to the project plan, the beam will be so narrow that a succession of
areas no larger than a pinhead will be sampled.
Participating in that experiment, according to the latest Soviet
description, will be the Max Planck Institute for Aeronomy at Lindau,
near Gottingen, West Germany, as well as institutes in Bulgaria and
the Soviet Union. The Lindau institute also contributed instruments
to the Soviet Union's Vega missions to Venus.
Under consideration, according to Soviet scientists, is the
dropping of an instrumented device onto Phobos that could jump from
place to place. Because Phobos is so small its gravity field is
extremely weak. The lifting power of a grasshopper's legs should be
sufficient to propel the hopping lander.
Phobos is an irregular, heavily cratered object whose diameter
ranges from 12 to 17 miles. It is suspected that it was originally an
asteroid captured in orbit by the gravity of Mars.
Circulation by the Russians of details on the Phobos mission may
have been necessitated by its inclusion of at least 19 experiments
from a wide range of agencies, including the European Space Agency
and institutes in Austria, Bulgaria, Czechoslovakia, Finland, France,
Hungary, East and West Germany and Sweden.
Such a large number of participants reflects the remarkable
diversity of goals envisioned for the mission. They include orbital
gamma ray and infrared scanning of both Phobos and Mars to determine
regional differences in their surface composition. Similar scanning
is planned for the Mars Observer planned by the United States for
1990.
As pointed out last week by Dr. Michael H. Carr of the United
States Geological Survey, a specialist in Martian geology, the
composition of its surface has only been measured at the two
locations where Viking spacecraft landed in 1976. Pessimism regarding
the possibility that life once existed on the planet has been based
largely on the absence of any organic material in the samples
analyzed there.
Others unwilling to give up hope in that regard argue that far more
extensive sampling is needed to settle the issue. While infrared
radiation from the Martian surface will provide clues to its
composition it will not compare to the detailed information obtained
by the Viking landers or from the projected Phobos probes. Analysis
of gamma rays emitted by radioactive surface material as well as
those generated in such material by cosmic ray bombardment will add
further information.
In addition to the laser experiment the surface of Phobos will be
scanned by three television cameras. For additional information about
its composition it will be bombarded by neutrons and by a beam of
electrically charged krypton atoms.
As with particles thrown up by the laser, composition of the
material blasted toward the spacecraft by the krypton will be
determined by a mass spectrometer. This Austrian-French-West
German-Soviet experiment will penetrate only one tenth as deep as the
laser, which will sample to one millionth of a meter. A radar will
feel out structural features to depths as great as 650 feet within
Phobos.
Measurements of the Martian atmosphere, magnetic field and
electrified upper atmosphere are planned as well as recordings, en
route, of such phenomena as the outflow of gas from the sun, cosmic
radiation, gamma ray bursts from beyond the solar system and shock
waves flowing through interplanetary space. A variety of solar
observations are planned, including efforts to detect pulsations of
the sun that have become a focus of special interest.
It should be possible to keep the spacecraft close to Phobos for 15
or 20 minutes by having the spacecraft's orbital motion around Mars
almost match that of the Martian moon. The prospectus mentions
placing a ''long-standing'' lander on Phobos as well as the hopping
lander. It calls for seismic tests to determine the moon's internal
structure. This may mean that the hopper will generate shock waves
for recording by the stationary lander.
A relatively rapid, 200-day flight time from the Earth is planned,
thanks to the power of Soviet boosters.
nyt-06-25-85 1008edt
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