- WASHINGTON, D.C. - The Mars Pathfinder mission was launched on December 4, 1996,
and landed safely on Mars July 4, 1997. Intended mainly as a demonstration
of a low cost entry, descent, and landing technique, Pathfinder operated
for over three months, well beyond the one month period that had been planned
for the lander and one week for Sojourner, the first rover vehicle to explore
Mars.
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- The mission included three science and
ten technology experiments, which sent back 2.3 gigabits of new data, including
over 17,000 images, 16 chemical analyses of rocks and soil, and 8.5 million
measurements of temperature, pressure, and wind.
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- Around the world, Pathfinder was one
of the most popular space exploration programs ever; its web site received
566 million visits during the first month alone, including a one-day record
47 million on July 8, 1997. Millions also viewed television images of the
Martian surface beamed back from the landing site, which was named the
Sagan Memorial Station in honor of the late astronomer, Carl Sagan.
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- Scientists at the Jet Propulsion Laboratory
in Pasadena, California, which ran the Pathfinder mission for NASA, and
colleagues around the world have been analyzing and interpreting the data
beamed back from Mars. They have now published their major findings in
a special section of the Journal of Geophysical Research, published by
the American Geophysical Union. The journal's April 25 issue devotes 576
pages to Pathfinder, consisting of 35 papers grouped in thematic areas,
such as geology and geomorphology, magnetic properties, atmosphere, and
cartography. It is the first detailed, published account of science results
from the entire mission and is the largest ever issue of JGR-Planets, since
it was launched in 1991. Planets is one of five thematic editions of the
journal.
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- Dr. Matthew P. Golombek, Mars Pathfinder
Project Scientist at JPL, says that although Pathfinder's general results
were widely reported at the time, the peer-reviewed papers in JGR are "the
first in depth publication of scientific results from the mission."
Papers in the journal also describe the events of the mission and the analysis
of the data.
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- An introductory article by Golombek and
others lists some of Pathfinder's main achievements:
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- * Determined the spin pole and the precession
rate of Mars since Viking, 20 years ago; results require a central metallic
core 1,400-2,200 kilometers [900-1,350 miles] in radius;
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- * Dark rocks appear to be high in silica,
while lighter ones richer in sulphur and lower in silica, consistent with
being covered with varying amounts of dust;
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- * Rocks have a variety of morphologies,
fabrics, and textures;
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- * Rounded pebbles and cobbles on the
surface and other evidence suggest a warmer and wetter past;
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- * Airborne dust consists of silicate
particles with a small fraction of a highly magnetic mineral, probably
maghemite, suggesting an ancient hydrological cycle;
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- * The landing site appears little changed
since its formation billions of years ago, other than by the action of
winds;
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- * The lower atmosphere is dusty, and
"dust devils" are common in the Martian afternoon;
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- * Ice clouds are common in the early
morning, and morning near-surface temperatures change abruptly with time
and height.
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- In addition, scientists developed and
perfected many investigational techniques, reported in JGR, that will be
employed in future unmanned missions to the planets. The April 25 JGR report
on Pathfinder is replete with color and black and white images, charts,
graphs, and other figures. Copies may be ordered from AGU customer service
at 1-800-966-2481 (outside North America: 1-202-462-6900). The cost is
$40 for nonmembers of AGU.
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- Note: This story has been adapted from
a news release issued by American Geophysical Union for journalists and
other members of the public. If you wish to quote from any part of this
story, please credit American Geophysical Union as the original source.
You may also wish to include the following link in any citation: <http://www.sciencedaily.com/releases/1999/04/990423072952.htmhttp://www.scien
cedaily.com/releases/1999/04/990423072952.htm
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