Mariner 9 (Mariner Mars '71
/ Mariner-I) was a NASA
space probe
orbiter that helped in the exploration of Mars
and was part of the Mariner
program. Mariner 9 was launched toward Mars on May 30,
1971 from Cape Canaveral Air Force
Station
and reached the planet on November 13 of the same year, becoming the first
spacecraft to orbit another planet — only
narrowly beating Soviet
Mars 2 and Mars 3, which both
arrived within a month. After months of dust-storms it
managed to send back clear pictures of the surface.
Objectives
Mariner 9 launch
Mariner 9 was designed to continue the atmospheric studies begun by
Mariner 6 and 7, and to map over 70%
of the Martian surface from the lowest altitude (1500 kilometers
[about 900 miles]) and at the highest resolutions (1 kilometer per
pixel to 100 meters per pixel) of any Mars mission up to that time.
An
infrared radiometer was included to detect heat sources as
evidence of
volcanic activity. It was to
study temporal changes in the Martian atmosphere and surface. Mars'
two moons were also to be analyzed. Mariner 9 more than met its
objectives.
Experiments
- Ultraviolet Spectrometer (UVS)
- Infrared Interferometer Spectrometer (IRIS)
- Celestial Mechanics (not a separate instrument; it relied upon
tracking measurements including range, range rate, and
Doppler)
- S-Band Occultation (not a separate instrument; experiment
observed the attenuation of the communication signal as the
orbiting satellite passed out of view)
- Infrared Radiometer (IRR)
- Visual Imaging System
Achievements
9 was the first
spacecraft to
orbit another
planet. It carried
an instrument payload similar to
Mariner
6 and 7, but, because of the need for a larger propulsion
system to control the spacecraft in
Mars orbit,
it weighed more than Mariners 6 and 7 combined. When Mariner 9
arrived at Mars, the
atmosphere was so
dusty that the surface was obscured. This unexpected
situation made a strong case for the desirability of studying a
planet from orbit rather than merely flying past. Mariner 9's
computer was thus programmed from Earth to delay imaging of the
surface for a couple of months until the dust settled. After 349
days in orbit, Mariner 9 had transmitted 7,329 images, covering
100% of Mars' surface.
The images revealed river beds, crater,
massive extinct volcanoes (such as Olympus Mons
, the largest known volcano in the Solar System), canyons
(including the Valles
Marineris
, a system of
canyons over about long), evidence of wind and water erosion and deposition, weather fronts, fogs, and more. Mars' tiny
moon,
Phobos
and
Deimos, were also photographed.
The findings from the Mariner 9 missions underpinned the later
Viking program.
The
enormous Valles
Marineris canyon
system is named after Mariner 9 in honor of its
achievements.
After depleting its supply of attitude control gas, the spacecraft
was turned off on 27 October 1972.
Image:Scamander Vallis from Mariner9.jpg|Meander in Scamander
Vallis, as seen by Mariner 9. Such images implied that large
amounts of water once flowed on the surface of Mars.Image:Warrego
Valles from Mariner 9.jpg|Warrego Valles, as seen by Mariner 9.
This image suggests that it once rained/snowed on Mars.
Construction
The
ultraviolet spectrometer aboard Mariner 9 was constructed
by the Laboratory for Atmospheric and Space
Physics
at the University of Colorado, Boulder, CO.
The ultraviolet spectrometer team was led by Professor Charles
Barth.
The Infrared Interferometer Spectrometer (IRIS) team was led by Dr.
Rudolf A. Hanel from NASA Goddard Spaceflight Center (GSFC). The
IRIS instrument was built by Texas Instruments, Dallas, TX.
The Infrared Radiometer (IRR) team was led by Professor Gerald
Neugebauer from the California Insitute of Technology
(Caltech).
Present location
Mariner 9 is still in Mars orbit, stable until at least 2022, after
which the spacecraft will enter the Martian atmosphere.
See also
References
External links
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