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New Mars Global Surveyor Image Available
- To: meteorite-list@meteoritecentral.com
- Subject: New Mars Global Surveyor Image Available
- From: Ron Baalke <BAALKE@kelvin.jpl.nasa.gov>
- Date: Mon, 20 Jul 1998 19:51:42 GMT
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NEW MARS GLOBAL SURVEYOR IMAGE
A new image taken by the Mars Global Surveyor spacercraft is now available at
the MGS website:
http://mars.jpl.nasa.gov/mgs/msss/camera/images/7_17_98_gusev_rel/index.html
The image caption is appended below.
Ron Baalke
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Mars Global Surveyor
Mars Orbiter Camera
Mars Orbiter Camera (MOC) High Resolution Images
July 20, 1998
Moon/Mars Landing Commemorative Release:
Gusev Crater and Ma'adim Vallis
Mars Global Surveyor Mars Orbiter Camera Release: MOC2-58a, -58b, -58c, -58d
Mars Global Surveyor Mars Orbiter Camera Image ID: 577869444.25905
P259-05
(A) [Image]
107 KByte JPG image
(A) Gusev Crater and Ma'adim Vallis. Gusev Crater is approximately 150
kilometers (93 miles) across. Ma'adim Vallis is the nearly straight canyon
that enters Gusev Crater from the lower right. White box indicates the
location of MOC image 25905, shown below in (C). Picture is a high
resolution digital image mosaic of Viking Orbiter images prepared by the
U.S. Geological Survey. North is up, illumination is from the upper left.
(B) [Image]
183 KByte JPG image
(B) Close-up of southern Gusev Crater and the location (white box) of MOC
image 25905. Ma'adim Vallis is the canyon that enters Gusev Crater at the
lower center of the frame. Compare with (A) for context. Picture is a U.S.
Geological Survey digital image mosaic of Viking Orbiter images. The white
box is approximately 15 kilometers (9.3 miles) wide and 35.5 kilometers (22
miles) long. North is up, illumination is from the upper left.
(C) [Image]
167 KByte JPG image
(C) The MOC image 25905, shown at 40% of its original size. At this size,
the image resolution is 18.3 meters (60 feet) per pixel. The white box
indicates the location of the subframe shown at full resolution in (D).
North is approximately up, illumination is from the lower right.
(D) [Image]
160 KByte JPG image
(D) Floor of Ma'adim Vallis, seen at 7.3 meters (24 feet) per pixel.
Subframe of MOC image 25905. See (C) above for context. North is
approximately up, illumination is from the lower right.
You may need to adjust the images for the gamma of your monitor to insure
proper viewing.
Note: This MOC image is made available in order to share with the public
the excitement of new discoveries being made via the Mars Global Surveyor
spacecraft. The image may be reproduced only if the image is credited to
"Malin Space Science Systems/NASA". Release of this image does not
constitute a release of scientific data. The image and its caption should
not be referenced in the scientific literature. Full data releases to the
scientific community are scheduled by the Mars Global Surveyor Project
and NASA Planetary Data System. Typically, data will be released after a
6 month calibration and validation period.
Click Here for more information on MGS data release and archiving plans.
CAPTION
On July 20, 1969, the first human beings landed on the Moon. On July 20,
1976, the first robotic lander touched down on Mars. This July 20th-- 29
years after Apollo 11 and 22 years since the Viking 1 Mars landing-- we take
a look forward toward one possible future exploration site on the red
planet.
One of the advantages of the Mars Global Surveyor Mars Orbiter Camera (MOC)
over its predecessors on the Viking and Mariner spacecraft is resolution.
The ability to see--resolve--fine details on the martian surface is key to
planning future landing sites for robotic and, perhaps, human explorers that
may one day visit the planet.
At present, NASA is studying potential landing sites for the Mars Surveyor
landers, rovers, and sample return vehicles that are scheduled to be
launched in 2001, 2003, and 2005. Among the types of sites being considered
for these early 21st Century landings are those with "exobiologic
potential"--that is, locations on Mars that are in some way related to the
past presence of water.
For more than a decade, two of the prime candidates suggested by various
Mars research scientists are Gusev Crater and Ma'adim Vallis. Located in the
martian southern cratered highlands at 14.7° S, 184.5° W, Gusev Crater is a
large, ancient, meteor impact basin that--after it formed--was breached by
Ma'adim Vallis.
Viking Orbiter observations provided some evidence to suggest that a
fluid--most likely, water--once flowed through Ma'adim Vallis and into Gusev
Crater. Some scientists have suggested that there were many episodes of flow
into Gusev Crater (as well as flow out of Gusev through its
topographically-lower northwestern rim). Some have also indicated that there
were times when Ma'adim Vallis, also, was full of water such that it formed
a long, narrow lake.
The possibility that water flowed into Gusev Crater and formed a lake has
led to the suggestion that the materials seen on the floor of this
crater--smooth-surfaced deposits, buried craters, and huge mesas near the
mouth of Ma'adim Vallis--are composed of sediment that eroded out of the
highlands to the south of Gusev Crater. In 1995, the Exobiology Program
Office at NASA Headquarters produced a report, An Exobiological Strategy for
Mars Exploration (NASA SP-530), that included Gusev Crater as a possible
priority site for future Mars exploration because it might once have been a
lake.
At 12:17 a.m. (PDT) on April 24, 1998--during Mars Global Surveyor's 259th
orbit--MOC obtained the high resolution image of Gusev Crater and Ma'adim
Vallis shown above, in part to test some of the proposed hypotheses. The raw
image has a scale of 7.3 meters (24 feet) per pixel. At this scale, there
are no obvious shorelines that would indicate the past presence of a lake in
either Ma'adim Vallis or Gusev Crater. There are several alternative
explanations for this absence, including:
* It is possible that any lake in Gusev occurred so long ago that erosion
by wind and hillslope processes have long since removed such features.
* It is possible that 7.3 meters per pixel is insufficient to identify
key diagnostic lake features.
* It is possible that a lake once existed, but that shore- and near-shore
processes as they occur in terrestrial lake environments did not occur
on Mars.
* It is possible no lake ever existed.
When Mars Global Surveyor achieves its Mapping Orbit in March 1999, MOC will
have the ability to obtain pictures with resolutions around 1.5 meters (5
feet) per pixel. Sometime during the mapping mission, it may be possible to
image Gusev Crater again to look for potential lake features and possible
future landing sites.
------------------------------------------------------------------------
Malin Space Science Systems and the California Institute of Technology built
the MOC using spare hardware from the Mars Observer mission. MSSS operates
the camera from its facilities in San Diego, CA. The Jet Propulsion
Laboratory's Mars Surveyor Operations Project operates the Mars Global
Surveyor spacecraft with its industrial partner, Lockheed Martin
Astronautics, from facilities in Pasadena, CA and Denver, CO.
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