Odyssey/ Becquerel
These images from Mars Odyssey look at the Becquerel crater in
different lights -- visible, daytime infrared and nighttime infrared. The
daytime images (left and center) were acquired on March 28, 2002 and
the nighttime image (right) was acquired on March 2, 2002, by the
thermal emission imaging system aboard Mars Odyssey. Thermal infrared is
the wavelength range associated with heat. Looking at the Martian
surface in the infrared wavelengths allows scientists to identify and
distinguish bedrock from sand or dust covered areas.
The Becquerel deposit is relatively bright in the visible wavelengths. Its
surface has been scoured by windblown sand to produce the ridged
topography seen in the visible image, which spans an 18-kilometer
(11 mile)-wide portion of the deposit. Dark sand is seen in the lower
right of the visible image. This same scene in the 32-kilometer (20 mile)-wide
daytime infrared image looks remarkably similar to a photographic negative
of the visible image due to the effects of solar heating. Darker tones
represent cooler surfaces, brighter tones are warmer ones. During the
day, visibly dark surfaces heat up much more efficiently than bright
surfaces. The relatively bright sediments of the mound reflect more solar
energy than the darker sand, allowing the mound to stay cooler than
the sand.
In the nighttime infrared image, the mound and the sand are warmer
than their surroundings. The dark portions of the image represent cold
surfaces that are covered in dust particles. Dust does not retain heat
during the cold Martian night and quickly gives up any heat received
during the day. Sand particles, because they are larger than dust
particles, are able to retain heat better, producing the brighter swath
around the mound. The infrared image has a resolution of 100 meters
(328 feet) per pixel and is 32 kilometers (20 miles) wide. The visible image
has a resolution of 18 meters per pixel and is approximately 18 kilometers
(11 miles) wide. The images are centered at 21.4 degrees north latitude
and 351.8 degrees east longitude.
NASA's Jet Propulsion Laboratory manages the 2001 Mars Odyssey
mission for NASA's Office of Space Science, Washington, D.C. The Thermal
Emission Imaging System was developed by Arizona State University,
Tempe, in collaboration with Raytheon Santa Barbara Remote Sensing.
Lockheed Martin Astronautics, Denver, is the prime contractor for the
Odyssey project, and developed and built the orbiter. Mission operations
are conducted jointly from Lockheed Martin and from JPL, a division of
the California Institute of Technology in Pasadena.
Credit: NASA/JPL/Arizona State University
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