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0507.PR
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1993-04-21
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OFFICE OF PUBLIC INFORMATION
JET PROPULSION LABORATORY, CALIFORNIA INSTITUTE OF TECHNOLOGY
NATIONAL AERONAUTICS AND SPACE ADMINISTRATION
PASADENA, CALIFORNIA. TELEPHONE 354-5011
_______________
The second Mariner '69 spacecraft, Mariners VII, will be
launched on fly-by missions to Mars on Monday, March 24, at about
2 p.m. The first spacecraft Mariner VI, was launched February 24.
A press room will be open at 1 p.m., Monday, for launch,
at JPL in the Von Karman auditorium.
The first spacecraft will arrive at Mars on July 30, the
second on August 4. The purpose of the flights is to determine if
the Martian environment is suitable for life. The flights will
___ determine if life exists on Mars.
The following Public Information people will be avail-
able during the mission:
region of the Me across
the edge of the South Polar cap.
The Mars-to-Earth distance at the time the Mariners
reach Mars is about 60 million miles--the distance differing
slightly during the five-day interval. The science information
gathered, as well as measurements indicating the condition of the
spacecraft themselves, is transmitted to the huge ground antennas
of the NASA-JPL Deep Space Network.
A few minutes after Mariner makes its closest approach
to the planet, it will disappear behind Mars for nearly a half-
hour, cutting off the radio signal from the spacecraft to Earth.
The trajectories of both spacecraft were designed this way to
permit a radio occultation experiment.
While entering and exiting the radio blackout area,
Mariner's signal is affected by its passage through the Martian
atmosphere. Analysis of this effect as received on Earth will
result in a determination of the pressure and density of the
atmosphere.
A final experiment, celestial mechanics, will use
tracking information to refine astronomical data.
-4-
Each Mariner carries two tape recorders which store the
TV pictures and measurements taken by the other science instru-
ments during the close passages of Mars. As the Mariners fly past
the planet, the recorders are played back over the radio link to
Earth. Two complete playbacks from each spacecraft will take
just less than three days. The Mariners then continue in their
perpetual orbits around the sun.
At launch time for Mariner G tomorrow, Mariner 6 will
be about 4.9 million miles from Earth and travelling at a
velocity of 6790 miles per hour relative to Earth. Its flight
path is 226 million miles long and duration of flight from Earth
to Mars is 156 days.
Mariner G will clock 193 million miles in its 133-day
voyage.
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507-3/17/69