[meteorite-list] Camera on Curiosity's Arm will Magnify Clues in Rocks

From: Ron Baalke <baalke_at_meteoritecentral.com>
Date: Tue, 16 Nov 2010 17:10:55 -0800 (PST)
Message-ID: <201011170110.oAH1AtXE017886_at_zagami.jpl.nasa.gov>

http://www.jpl.nasa.gov/news/news.cfm?release=2010-384

Camera on Curiosity's Arm will Magnify Clues in Rocks
Jet Propulsion Laboratory
November 16, 2010

NASA's next Mars rover, Curiosity, will wield an arm-mounted magnifying
camera similar to one on the Mars Rover Opportunity, which promptly
demonstrated its importance for reading environmental history from rocks
at its landing site in 2004.

Within a few weeks after the landing, that camera at the end of
Opportunity's arm revealed details of small spheres embedded in the
rocks, hollows where crystals had dissolved, and fine layering shaped
like smiles. These details all provided information about the site's wet
past.

The camera installed on the end of Curiosity's arm this month is the
Mars Hand Lens Imager, or MAHLI. Its work will include the same type of
close-up inspections accomplished by the comparable camera on
Opportunity, but MAHLI has significantly greater capabilities:
full-color photography, adjustable focus, lights, and even video. Also,
it sits on a longer arm, one that can hold MAHLI up higher than the
cameras on the rover's mast. MAHLI will use those capabilities as one of
10 science instruments to study the area of Mars where NASA's Mars
Science Laboratory mission lands Curiosity in August 2012.

The Mars Hand Lens Imager takes its name from the magnifying tool that
every field geologist carries. Ken Edgett of Malin Space Science
Systems, San Diego, is the principal investigator for the instrument. He
said, "When you???re out in the field and you want to get a quick idea
what minerals are in a rock, you pick up the rock in one hand and hold
your hand lens in the other hand. You look through the lens at the
colors, the crystals, the cleavage planes: features that help you
diagnose what minerals you see.

"If it's a sedimentary rock, such as the sandstone you see at Arches
National Park in Utah, or shale -- which is basically petrified mud --
like in the Painted Desert in Arizona, you use the hand lens not just to
see what minerals are in it but also the sizes and shapes of the grains
in the rock. You also look at the fine-scale layering in the rock to get
an idea of the sequence of events. Sedimentary rocks record past events
and environments."

While other instruments on Curiosity will provide more information about
what minerals are in rocks, the Mars Hand Lens Imager will play an
important role in reading the environmental history recorded in
sedimentary rocks. The mission's science team will use the instruments
to assess whether the selected landing area has had environmental
conditions favorable for life and for preserving evidence about whether
life existed.

The team currently assembling and testing Curiosity and other parts of
the Mars Science Laboratory spacecraft at NASA's Jet Propulsion
Laboratory, Pasadena, Calif., is continuing tests of MAHLI this month,
now that the camera is mounted beside other tools on the robotic arm.
The spacecraft will launch from Florida between Nov. 25 and Dec. 18, 2011.

Edgett led the preparation in early 2004 of a proposal to include MAHLI
in the Mars Science Laboratory's payload. During those same months, the
camera on Opportunity's arm -- that mission's Microscopic Imager -- was
demonstrating the potential value of a successor, and generating ideas
for improvements. Opportunity's Microscopic Imager has a fixed focus. To
get targets in focus, it always needs to be placed the same distance
from the target, recording a view of an area 3 centimeters (1.2 inches)
across. To view a larger area, the camera takes multiple images,
sometimes more than a dozen, each requiring a repositioning of
Opportunity's arm.

"When I was writing the proposal, the Microscopic Imager took about 40
images for a mosaic of one rock," Edgett said. "That's where the idea
came from to make the focus adjustable. With adjustable focus, the
science team has more flexibility for trade-offs among the rover's
resources, such as power, time, data storage and data downlink. For
example, the camera could take one or two images from farther away to
cover a larger area, then go in and sample selected parts in higher
resolution from closer up."

MAHLI can focus on targets as close as about 21 millimeters (0.8 inch)
and as distant as the horizon or farther. JPL's Ashwin Vasavada, deputy
project scientist for the Mars Science Laboratory, said, "MAHLI is
really a fully functional camera that happens to be on the end of the
arm. The close-up capability is its specialty, but it will also be able
to take images or videos from many viewpoints inaccessible to the
cameras on the mast, such as up high, down low, under the rover and on
the rover deck. Think of it like a hand-held camera with a macro lens,
one that you could use for taking pictures of the Grand Canyon, of
yourself, or of a bumblebee on a flower."

Edgett is looking forward to what the camera will reveal in rock
textures. "Just like larger rocks in a river, grains of sand carried in
a stream get rounded from bouncing around and colliding with each
other," he said. "If you look at a sandstone with a hand lens and see
rounded grains, that tells you they came from a distance. If they are
more angular, they didn't come as far before they were deposited in the
sediment that became the rock. Where an impact excavated a crater,
particles of the material ejected from the crater would be very angular.

"When you're talking about ancient rocks as clues for assessing
habitability," he continued, "you're talking about the environments the
sediments were deposited in -- whether a lake, a desert, an ice field.
Also, what cemented the particles together to become rocks, and what
changes have affected the rock after the sediments were deposited? All
these things are relevant to whether an environment was favorable for
life and also whether it was favorable for preserving the record of that
life. Earth is a planet teeming with life, but most rocks have not
preserved ancient organisms; Mars will be even more challenging than
Earth in this sense."

Edgett says he is eager to see an additional image from this camera
besides the details of rock textures. With the arm extended upwards, the
camera can look down at the rover for a dramatic self-portrait on Mars.
But as for the most important image the Mars Hand Lens Imager will take:
"That will be something that surprises us, something we're not expecting."

Mars Science Laboratory is managed by NASA???s Jet Propulsion Laboratory,
Pasadena, Calif. JPL also manages the Mars Exploration Rovers Spirit and
Opportunity. JPL is a division of the California Institute of Technology
in Pasadena.
More information about NASA's Mars Science Laboratory is at:
http://www.nasa.gov/msl .

Guy Webster 818-354-6278
Jet Propulsion Laboratory, Pasadena, Calif.
Guy.webster at jpl.nasa.gov

2010-384
Received on Tue 16 Nov 2010 08:10:55 PM PST