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ZL2VAL > ROVERS 08.05.04 13:11l 98 Lines 4271 Bytes #999 (0) @ WW
BID : 390845ZL2VAL
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Subj: Opportunity on the brink
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Sent: 040508/1055Z @:ZL2AB.#46.NZL.OC #:40046 [New Plymouth] FBB7.00g
From: ZL2VAL@ZL2AB.#46.NZL.OC
To : ROVERS@WW
At Endurance Crater, Opportunity Rover Treads Carefully
By Tariq Malik
Staff Writer
posted: 06:00 pm ET
06 May 2004
NASA's Mars rover Opportunity will have to watch its step around its
Endurance Crater destination to avoid a potentially mission-ending fall,
while its twin Spirit continues its approach to the Columbia Hills.
Mars Exploration Rover (MER) mission scientists are particularly wary
about sending Opportunity into Endurance crater, which bears tempting
rock outcrops for study but could be catastrophic if the rover slips.
With a depth of more than 66 feet (20 meters), Endurance is 10 times
deeper than Opportunity's previous Eagle crater home.
"This is a big hole in the ground," said Steve Squyres, MER principle
investigator from Cornell University, during a mission briefing held at
NASA's Jet Propulsion Laboratory (JPL ) Thursday. "There are cliffs
where the rover could fall off and die if we're not careful."
MER researchers have long anticipated Opportunity's arrival at
Endurance, which spans about 430 feet (130 meters) wide, hoping to find
a rock outcrop similar to the one at the rover's Eagle Crater landing
site to give them a better sense of the geologic history of the planet.
It seems they've found that in the form of Burns Cliff, a massive
outcrop along the ridge of Endurance crater and Opportunity's most
likely point of attack into the rocky past of its Meridiani Planum
landing site. The cliff stands meters high, well above the foot-high
outcrop studied so eagerly at Eagle crater, giving scientists a deeper
look into the Martian surface.
"These are much bigger than anything we've seen before of layered rocks
on Mars," Squyres said during a mission briefing. "That is going to tell
us much of what is going to happen at Meridiani Planum."
And while there is ample suggestion of crossbedding in the cliff and a
healthy scattering of hematite-rich spherules across the crater, mission
scientists aren't sure what Burns Cliff may tell them about the history
of Martian water.
Squyres said Opportunity's remote sensing instruments indicate the cliff
is mostly basalt, a type of rock that makes up most of the seafloor on
Earth. But whether that means the rock is solely sandstone or was once a
Martian beach or sand dune remains to be determined, he added.
But first the rover has to find a safe way into the crater, and mission
planners are working to find the safest route into Endurance.
Brian Cooper, rover planning team leader at JPL, said the slope along
the walls of Endurance ranges from 18 degrees to 20 degrees. Physically,
Opportunity is built to withstand a slope of 35 degrees, but its onboard
software sets a 20-degree limit in case the robot slips on loose soil.
While mission planners determine the best route into Endurance,
Opportunity will take a slow trip around the crater's lip, taking images
with its cameras and making a detailed analysis of the region. Should
there be any hint of danger in any entry plan, Opportunity will first
study other science targets on the Meridiani Planum plains before
descending into the crater.
"We're not done with science on the plains yet," Squyres said, adding
that the heat shield shed by Opportunity during its January landing is
nearby, and follow-up studies to recent targets like Fram crater and the
Anatolia outcrop would be useful.
Meanwhile, Opportunity's robotic twin Spirit is planning its approach to
the Columbia Hills. The rover is almost to the midway point of its trip
from Bonneville crater to the hills, where it will roll up to the most
accessible of the seven geologic features.
"Not all of the hills are going to be accessible to this rover," said
Amy Knudson, a rover science team collaborator from Arizona State
University, adding that some of the hills will still be too distant.
"But we're hoping we'll find our own Endurance crater."
=========================
73 de Alan, (Sysop ZL2AB).
AX25:ZL2VAL@ZL2AB.#46.NZL.OC
IP :zl2val@qsl.net
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Message timed: 22:49 on 2004-May-08 (NZT)
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Points to ponder
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Rural wisdom
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Never lay an angry hand on a kid or an animal, it just ain't helpful.
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