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| Press Release Images: Opportunity |
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25-Jan-2004
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Opportunity Slices into the Surface of Mars
The semi-circular depression on the right side of this microscopic
image resulted from Opportunity's first grinding of a rock on Mars.
The rock abrasion tool sliced into the surface about 4 millimeters
(0.16 inches) deep and ground off a patch 45.5 millimeters (1.8
inches) in diameter on a rock called "McKittrick" during Opportunity's
30th sol on Mars, Feb. 23, 2004. The hole exposed fresh interior
material of the rock for close inspection by the
rover's microscopic imager and two spectrometers on the robotic arm.
Scientists and engineers got a nice bonus in that two spherical features nicknamed "blueberries"
were unexpectedly cut in half within this rock. Team members had
noticed the blueberries in earlier pictures on other rocks in the outcrop and had wanted to attempt to cut one in half
sometime during the future of the mission. As luck would have it,
two blueberries were hidden in the depths of "McKittrick." The
one blueberry shown in the bottom right of this picture appears to
have been scratched by the grinding wheel, which is further explained
in image #2.
The two rectangular boxes in the lower left and upper middle parts of
this image are "drop outs," where the data packets inadvertently did
not make it back to Earth during the initial communications relay via
the Deep Space Network antennas. The missing data packets should be
resent to Earth within the next few days. Just above each of the black
"drop out" rectangles is another rectangular area filled with a
cluster of smaller rectangles in different shades of gray, which are
image compression artifacts.
For more information about the "blueberries," please see JPL's Press
Release dated February
9, 2004.
For more microscopic images of the results from Opportunity's first
use of the rock abrasion tool, please see the raw images for sol 30.
The rock abrasion tools on both Mars Exploration Rovers were supplied
by Honeybee Robotics, New York, N.Y.
Image credit: NASA/JPL/Cornell/US Geological Survey
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Grinding Wheel Profile
This graphic dubbed by engineers as the "Grinding Wheel Profile" is
the detective's tool used by the Opportunity team to help them
understand one of the processes that formed the interior of a rock called
"McKittrick." Scientists are looking for clues as to how layers,
grains and minerals helped create this rock, and the engineers who
built the rock abrasion tool (RAT) wanted to ensure that their
instrument's handiwork did not get confused with natural processes.
In the original microscopic image underlaying the graphics, engineers
and scientists noticed "layers" or "scratches" on the spherical
object nicknamed "blueberry" in the lower right part of the image.
The designers of the rock abrasion tool noticed that the arc length
and width of the scratches were similar to the shape and size of the
rock abrasion tool's grinding wheel, which is made out of a pad of
diamond teeth.
The scrapes on the bottom right blueberry appear to be caused by the
fact that the berry got dislodged slightly and its surface was
scraped with the grinding pad. In this image, the largest yellow
circle is the overall diameter of the hole ground by the rock abrasion tool and the largest yellow rectangular shape is the area of the grinding wheel bit. The smaller yellow semi-circle is the path that the center of the
grinding tool follows. The orange arrow arcing around the solid yellow circle (center of grinding tool) indicates the direction that the grinding tool
spins around its own center at 3,000 revolutions per minute. The tool simultaneously spins in an orbit around the center of the hole, indicated by the larger orange arrow to the left.
The grinding tool is 22 millimeters (0.9 inches) in length and the
actual grinding surface, which consists of the diamond pad, is 1.5
millimeters (0.06 inches) in length, indicated by the two smaller
rectangles. You can see that the smaller bottom rectangle fits
exactly the width of the scrape marks.
The grooves on the blueberry are also the same as the curvature of
the arced pathway in which the grinding tool spins.
By overlaying appropriately scaled representations of the rock
abrasion tool schematics, the evidence reveals a strong indication
that the scrapes on the blueberry were induced by the tool, rather than
caused by some natural geologic process.
The two rectangular boxes in the lower left and upper middle parts of
this image are "drop outs," where the data packets inadvertently did
not make it back to Earth during the initial communications relay via
the Deep Space Network antennas. The missing data packets should be
resent to Earth within the next few days. Just above each of the black
"drop out" rectangles is another rectangular area filled with a
cluster of smaller rectangles in different shades of gray, which are
image compression artifacts.
The rock abrasion tools on both Mars Exploration Rovers were supplied
by Honeybee Robotics, New York, N.Y.
Image credit: NASA/JPL/Cornell/US Geological Survey
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