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1993-04-21
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GENERAL RELEASE
Two 850-pound Mariner spacecraft, F and G, will be
launched from pads 36A and 36B at Cape Kennedy on fly-by missions
to Mars by the National Aeronautics and Space Administration
during a period beginning February 24, 1969.
Launch dates are February 24 for spacecraft F and March
24 for G. If successfully launched the spacecraft will become
Mariners VI and VII. The launch vehicle for each will be the
Atlas/Centaur.
Arrival times at Mars are about 10 p.m. Pacific
Daylight Time on July 30, 1969, for Mission F and the same hour
on August 4 for Mission G. (Using Eastern Daylight Time, the two
spacecraft will make their closest approaches to the planet at
about 1 a.m. on July 31 and August 5.)
Mariner F will make an equatorial pass over the Mars
surface and Mariner G is scheduled for a polar pass five days
later to furnish data as different as possible from the stand-
point of geography and climate.
The '69 mission is a follow-on to the 1964-65 Mariner
flight to Mars and a precursor to the 1971 and 1973 Mars missions.
In 1971 two Mariner-class vehicles will orbit Mars for three
months, and in the 1973 mission, Project Viking, two spacecraft
will orbit Mars and detach soft landers to descend to the surface.
The Mars '69 mission objectives are to study the
surface and atmosphere of Mars to establish the basis for future
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experiments in the search for extra-terrestrial life and to
develop technology for future Mars missions.
The '69 flights will not determine if life exists on
Mars but will help establish whether or not the Martian environ-
ment is suitable for life.
Two television cameras aboard each spacecraft will
photograph the disc of Mars during the approach to the planet and
the surface during the fly-by. The best resolution of the
approach pictures will be about 15 miles. Best resolution from
Earth is about 100 miles. The highest resolution in the surface
pictures will be about 900 feet compared with two miles in the
Mariner IV pictures taken in 1965.
Two instruments, an infrared spectrometer and an
ultraviolet spectrometer will probe the atmosphere of Mars. An
occultation experiment, in which radio signals pass through the
martian atmosphere, will yield data on atmospheric pressures and
densities. An infrared radiometer will measure surface tempera-
tures on both the light and dark sides of Mars. A celestial
mechanics experiment will utilize tracking information to refine
astronomical data. This mission represents the first opportunity
to make scientific measurements on the night side of Mars.
All the instruments on the spacecraft are designed to
return information on Mars itself. No interplanetary instruments
will be flown.
The instruments were chosen to allow correlation of the
returned data. For example, surface temperature measurements will
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be made in the areas photographed to allow mapping of temperature
variations as they may be related to specific surface features.
A sharp increase in data return has been achieved over
the '64-65 Mariner missions. For example, the television
pictures returned by Mariner IV, in 1965, contained 240,000 bits
of information. In '69 each picture will contain 3.9 million
bits. In 1965 the transmission bit rate from the spacecraft was
8 1/3 bits per second. In 1969 the basic bit rate is 270 bits
per second with an experimental capability, to be used at Mars if
possible, of 16,200 bits per second. The latter depends on the
condition of the spacecraft after a four to five-month journey
through space and the condition and availability of the 210-foot-
diameter antenna at Goldstone, California, one of the world's
most sensitive antennas.
NASA assigned project responsibility including mission
operations, tracking and data acquisition for the '69 mission to
the Jet Propulsion Laboratory which is managed for NASA by the
California Institute of Technology, Pasadena, California. Launch
vehicle responsibility was assigned to the Lewis Research Center,
Cleveland. The contractor to LeRC is General Dynamics/Convair,
San Diego. Tracking and communications is assigned to the Deep
Space Network, operated for NASA by JPL.
Cost of the Mariner Mars 1969 Project will total $148
million--$128 million for the spacecraft and $20 million for the
launch vehicles.