Jacques van Oene
May 24th 05, 08:35 PM
Dolores Beasley
Headquarters, Washington May 24, 2005
(Phone: 202/358-1753)
Guy Webster
Jet Propulsion Laboratory, Pasadena, Calif.
(Phone: 818/354-6278)
RELEASE: 05-133
NASA'S ROVERS CONTINUE MARTIAN MISSIONS
NASA's Mars rover Opportunity is trying to escape from a sand trap,
while its twin, Spirit, has been busy finding new clues to a wet and violent
early Martian history.
"Spirit has finally found the kind of geology you can really sink your teeth
into," said Dr. Steve Squyres of Cornell University, Ithaca, N.Y. He is
principal investigator for the Mars rovers' science instruments. According
to Squyres, multiple layers of rock in the hills Spirit is exploring suggest
successive deposits of water-altered explosive debris.
Spirit, inside Mars' Gusev Crater, had to share the spotlight with the drama
provided by Opportunity on the Martian Meridiani plains. The rover has been
hindered by soft sand for nearly three weeks. Traction is difficult in the
ripple-shaped dune of windblown dust and sand Opportunity drove into on
April 26. Since it began trying to get out, the rover has advanced only 11
inches. Without the slippage caused by the rover's wheels spinning in the
soft sand, Opportunity could have driven 157 feet.
"If Opportunity gets free, its next task will be examining the site to give
the rover team a better understanding of how this ripple differs from dozens
Opportunity easily crossed," said Jim Erickson. He is project manager for
the Mars Exploration Rover Project at NASA's Jet Propulsion Laboratory,
Pasadena, Calif.
The rovers have worked under harsh Martian conditions longer than expected.
They have been studying geology on opposite sides of Mars for more than a
year since successfully completing their three-month primary missions.
Shortly after landing in January 2004, Opportunity found layered bedrock
bearing geological evidence of a shallow ancient sea. More than one year
later, Spirit found extensive layered bedrock, after driving more than two
miles and climbing into the "Columbia Hills."
Squyres said, "In the last few weeks, we have gone from a state of confusion
about the geology of the Columbia Hills to having real stratigraphic
sequence and a powerful working hypothesis for the history of these layers."
For several months, Spirit climbed a flank of Husband Hill, the tallest in
the range. The slope closely matched the angle of underlying rock layers,
which made the layering difficult to detect. Spirit reached an intermediate
destination, dubbed "Larry's Lookout," then continued uphill and looked
back. "That was the critical moment, when it all began falling into place,"
Squyres said. "Looking back downhill, you can see the layering, and it
suddenly starts to makes sense."
Spirit has been examining rocks in a series of outcrops called Methuselah,
Jibsheet and Larry's Lookout. Some of the rocks contain the mineral
Ilmenite, not found previously by Spirit. "Ilmenite is a titanium-iron oxide
formed during crystallization of magma," said Dr. Dick Morris, a rover
science-team member at NASA's Johnson Space Center, Houston. "Its occurrence
is evidence for diversity in the volcanic rocks in the Gusev region."
Rocks from different layers share compositional traits, high in titanium,
and low in chromium, which suggests a shared origin. However, the degree to
which minerals in rocks have been chemically altered by exposure to water or
other processes varies greatly from outcrop to outcrop. The textures also
vary. At Methuselah, rocks have thin laminations revealed by Spirit's
microscopic imager. At Jibsheet, they are built of bulbous grains packed
together. At Larry's Lookout, the rocks are massive, with little fine-scale
structure.
"Our best hypothesis is we're looking at a stack of ash or debris that was
explosively erupted from volcanoes and settled down in different ways,"
Squyres said. "We can't fully rule out the possibility the debris was
generated in impact explosions instead of volcanic ones. But we can say,
once upon a time, Gusev was a pretty violent place. Big, explosive events
were happening, and there was a lot of water around," he explained.
Rover-team scientists described the robot explorers' activities today at the
spring meetings of the American Geophysical Union in New Orleans. For Images
and information about the rovers and their discoveries on the Web, visit:
http://www.nasa.gov/vision/universe/solarsystem/mer_main.html
For information about NASA and agency programs on the Web, visit:
http://www.nasa.gov/home/index.html
-end-
--
--------------
Jacques :-)
www.spacepatches.info
Headquarters, Washington May 24, 2005
(Phone: 202/358-1753)
Guy Webster
Jet Propulsion Laboratory, Pasadena, Calif.
(Phone: 818/354-6278)
RELEASE: 05-133
NASA'S ROVERS CONTINUE MARTIAN MISSIONS
NASA's Mars rover Opportunity is trying to escape from a sand trap,
while its twin, Spirit, has been busy finding new clues to a wet and violent
early Martian history.
"Spirit has finally found the kind of geology you can really sink your teeth
into," said Dr. Steve Squyres of Cornell University, Ithaca, N.Y. He is
principal investigator for the Mars rovers' science instruments. According
to Squyres, multiple layers of rock in the hills Spirit is exploring suggest
successive deposits of water-altered explosive debris.
Spirit, inside Mars' Gusev Crater, had to share the spotlight with the drama
provided by Opportunity on the Martian Meridiani plains. The rover has been
hindered by soft sand for nearly three weeks. Traction is difficult in the
ripple-shaped dune of windblown dust and sand Opportunity drove into on
April 26. Since it began trying to get out, the rover has advanced only 11
inches. Without the slippage caused by the rover's wheels spinning in the
soft sand, Opportunity could have driven 157 feet.
"If Opportunity gets free, its next task will be examining the site to give
the rover team a better understanding of how this ripple differs from dozens
Opportunity easily crossed," said Jim Erickson. He is project manager for
the Mars Exploration Rover Project at NASA's Jet Propulsion Laboratory,
Pasadena, Calif.
The rovers have worked under harsh Martian conditions longer than expected.
They have been studying geology on opposite sides of Mars for more than a
year since successfully completing their three-month primary missions.
Shortly after landing in January 2004, Opportunity found layered bedrock
bearing geological evidence of a shallow ancient sea. More than one year
later, Spirit found extensive layered bedrock, after driving more than two
miles and climbing into the "Columbia Hills."
Squyres said, "In the last few weeks, we have gone from a state of confusion
about the geology of the Columbia Hills to having real stratigraphic
sequence and a powerful working hypothesis for the history of these layers."
For several months, Spirit climbed a flank of Husband Hill, the tallest in
the range. The slope closely matched the angle of underlying rock layers,
which made the layering difficult to detect. Spirit reached an intermediate
destination, dubbed "Larry's Lookout," then continued uphill and looked
back. "That was the critical moment, when it all began falling into place,"
Squyres said. "Looking back downhill, you can see the layering, and it
suddenly starts to makes sense."
Spirit has been examining rocks in a series of outcrops called Methuselah,
Jibsheet and Larry's Lookout. Some of the rocks contain the mineral
Ilmenite, not found previously by Spirit. "Ilmenite is a titanium-iron oxide
formed during crystallization of magma," said Dr. Dick Morris, a rover
science-team member at NASA's Johnson Space Center, Houston. "Its occurrence
is evidence for diversity in the volcanic rocks in the Gusev region."
Rocks from different layers share compositional traits, high in titanium,
and low in chromium, which suggests a shared origin. However, the degree to
which minerals in rocks have been chemically altered by exposure to water or
other processes varies greatly from outcrop to outcrop. The textures also
vary. At Methuselah, rocks have thin laminations revealed by Spirit's
microscopic imager. At Jibsheet, they are built of bulbous grains packed
together. At Larry's Lookout, the rocks are massive, with little fine-scale
structure.
"Our best hypothesis is we're looking at a stack of ash or debris that was
explosively erupted from volcanoes and settled down in different ways,"
Squyres said. "We can't fully rule out the possibility the debris was
generated in impact explosions instead of volcanic ones. But we can say,
once upon a time, Gusev was a pretty violent place. Big, explosive events
were happening, and there was a lot of water around," he explained.
Rover-team scientists described the robot explorers' activities today at the
spring meetings of the American Geophysical Union in New Orleans. For Images
and information about the rovers and their discoveries on the Web, visit:
http://www.nasa.gov/vision/universe/solarsystem/mer_main.html
For information about NASA and agency programs on the Web, visit:
http://www.nasa.gov/home/index.html
-end-
--
--------------
Jacques :-)
www.spacepatches.info