| |
ZL2VAL > ROVERS 21.02.04 12:26l 107 Lines 5002 Bytes #999 (0) @ WW
BID : 5188-ZL2VAL
Read: GUEST
Subj: Update, 19th Feb
Path: DB0FHN<DB0FOR<DB0MRW<OK0PKL<OK0PPL<DB0RES<ON0AR<ZL2AB
Sent: 040221/1040Z @:ZL2AB.#46.NZL.OC #:36313 [New Plymouth] FBB7.00g $:5188-ZL
From: ZL2VAL@ZL2AB.#46.NZL.OC
To : ROVERS@WW
NEWS RELEASE: 2004-066
February 19, 2004
Opportunity Examines Trench As Spirit Prepares To Dig One
By inspecting the sides and floor of a hole it dug on Mars, NASA's
Opportunity rover is finding some things it did not see beforehand,
including round pebbles that are shiny and soil so fine-grained that the
rover's microscope can't make out individual particles.
"What's underneath is different than what's at the immediate surface,"
said Dr. Albert Yen, rover science team member at NASA's Jet Propulsion
Laboratory, Pasadena, Calif.
Meanwhile, NASA's other Mars Exploration Rover, Spirit, has reached a
site with such interesting soil that scientists have decided to
robotically dig a hole there, too. Spirit's trenching at a shallow
depression dubbed "Laguna Hollow" could answer questions about whether
traits on the soil surface resulted from repeated swelling and shrinking
of an upper layer bearing concentrated brine, among other possibilities.
Opportunity has manipulated its robotic arm to use its microscope on
five different locations within the trench the rover dug on Monday. It
has also taken spectrometer readings of two sites. "We've given the arm
a very strenuous workout," said JPL's Dr. Eric Baumgartner, lead
engineer for the arm. The accuracy of the tool placements -- within 5
millimeters, or less than a quarter inch -- is remarkable for mobile
robotics on Earth, much less on Mars.
Once data are analyzed from the alpha particle X-ray spectrometer and
the Mössbauer spectrometer about what elements and what iron-bearing
minerals are present, the differences between the subsurface and the
surface will be easier to interpret, Yen said.
While Opportunity has been digging and examining its trench this week,
it has also been catching up on transmission of pictures and information
from its survey last week of a rock outcrop along the inner wall of the
small crater in which the rover is working.
Both rovers can communicate directly with Earth, but JPL's Andrea
Barbieri, telecommunication system engineer, reported that 66 percent of
the 10 gigabits of data they have returned so far has come via relays by
NASA's Mars Odyssey orbiter and another 16 percent via relays by NASA's
Mars Global Surveyor.
Based on the outcrop survey, scientists have chosen a feature they have
dubbed "El Capitan" as the next target for intensive investigation by
Opportunity.
"We've planned our assault on the outcrop," said Dr. Steve Squyres of
Cornell University, Ithaca, N.Y., principal investigator for the rovers'
science instruments. "The whole stack of rocks seems to be well exposed
here," he said of the chosen target. Upper and lower portions appear to
differ in layering and weathering characteristics. Planners anticipate
that Opportunity's arm will be able to reach both the upper and lower
parts from a single parking spot in front of "El Capitan."
Halfway around the planet, Spirit will be told to use a front wheel to
dig a trench during the martian day, or "sol," that will end at 12:36
p.m. Friday, PST.
Some soil in "Laguna Hollow" appeared to stick to Spirit's wheels.
Possible explanations include very fine-grained dust or concentrated
salt making the soil sticky, said Dr. Dave Des Marais, a rover science
team member from NASA Ames Research Center, Moffett Field, Calif.
Pictures of the surface there also show pebbles arranged in clusters or
lines around lighter patches Des Marais described as "miniature
hollows." This resembles patterned ground on Earth that can result from
alternating expansion and shrinkage of the soil. Possible explanations
for repeated expanding and contracting include cycles of freezing and
thawing or temperature swings in salty soil.
After trenching to seek clues about those possibilities, Spirit will
continue on its trek toward the rim of a crater nicknamed "Bonneville,"
now estimated to be about 135 meters (443 feet) away from the rover.
Spirit has already driven 128 meters (420 feet).
The rovers' main task is to explore their landing sites for evidence in
the rocks and soil about whether the sites' past environments were ever
watery and possibly suitable for sustaining life.
JPL, a division of the California Institute of Technology in Pasadena,
manages the Mars Exploration Rover project for NASA's Office of Space
Science, Washington, D.C. Images and additional information about the
project are available from JPL at http://marsrovers.jpl.nasa.gov
and from Cornell University at http://athena.cornell.edu
==============================
73 de Alan
*----------------------------------------------------------------*
| Packet: ZL2VAL@ZL2AB.#46.NZL.OC APRS: =3903.39S/17406.40E] |
| E-mail: zl2val@qsl.net Snail mail address: http://www.qrz.com |
*----------------------------------------------------------------*
Points to ponder
~~~~~~~~~~~~~~~
Insanity is contagious, You catch it from your kids.
Read previous mail | Read next mail
| |
