The participants of this JPL briefing were:
John Grotzinger, California Institute of Technology, Pasadena; Mars Science Laboratory Project Scientist
David Blake, NASA Ames Research Center, Moffett Field, Calif.; CheMin Principal Investigator
David Vaniman, Planetary Science Institute, Tucson, Ariz.; CheMin Deputy Principal Investigator
David Bish, Indiana University, Bloomington; CheMin Co-investigator
Doug Ming, NASA Johnson Space Center, Houston; CheMin Co-investigator
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The following four images were discussed by David Blake of NASA Ames, who is the CheMin Principal Investigator.
X-ray Diffraction, Big and Small
A conventional X-ray diffraction instrument (left) is the size of a large refrigerator, in contrast to the compact size of the Chemistry and Mineralogy (CheMin) instrument on NASA’s Curiosity rover (top right) and the spin-off commercial portable instrument (lower right, orange case).
Both of the more compact X-ray diffraction instruments were made possible by NASA technology innovations.
The CheMin instrument is a cube of about 25 centimeters (10 inches) on each side. It is shown here in the red circle as technicians install it on the rover in the cleanroom at NASA’s Jet Propulsion Laboratory, Pasadena, California.
Detector for CheMin
This charged couple device (CCD) is part of the Chemistry and Mineralogy (CheMin) instrument on NASA’s Curiosity rover. When CheMin directs X-rays at a sample of soil, this imager, which is the size of a postage stamp, detects both the position and energy of each X-ray photon. The technology in this CCD was originally developed by NASA and has become widely used in commercial digital cameras.
CheMin vibrating chamber
This image shows the cells that hold the soil samples that are vibrated by the Chemistry and Mineralogy (CheMin) instrument on NASA’s Curiosity rover. When the rover delivers samples to CheMin, they are funneled into one of the windowed areas in the cell assemblies. (There are 16 pairs of dual-cell assemblies in CheMin.) These cell pairs act like a tuning fork, vibrated at about 2,000 times per second by a piezoelectric device placed between the two arms of the fork. When vibrated, the particles flow like liquid. This movement enables the instrument’s X-ray beams to hit all of the grains in random orientations over time. This innovative technology has been spun off for commercial use in miniaturized portable X-ray diffraction instruments. The powder vibration system enables poorly prepared or as-received samples to be analyzed without further sample preparation. This is useful in cases where extensive sample preparation is either not possible (e.g., on Mars) or when delicate materials (such as pharmaceutical products) would be destroyed or altered by extensive grinding. Implementation of the powder vibration system was a crucial step in enabling small portable X-ray diffraction instruments because many of the moving parts in conventional X-ray diffraction instruments could be eliminated.
Alternative use of the CheMin instrument in King Tutankhamen’s Tomb
Giacomo Chiari, head of the science department at the Getty Conservation Institute, examines the painting on the west wall in the tomb of King Tutankhamen with an X-ray diffraction instrument. The commercial instrument used here was adapted from technology developed for the Chemistry and Mineralogy instrument on NASA’s Curiosity rover.
The following images were discussed by David Vaniman, of the Planetary Science Institute, Tucson, Arizona, the Deputy Principal Investigator of CheMin.
Wind-Blown Martian Sand
This pair of images from the Mast Camera on NASA’s Curiosity rover shows the upper portion of a wind-blown deposit dubbed “Rocknest.” The rover team recently commanded Curiosity to take a scoop of soil from a region located out of frame, below this view. The soil was then analyzed with the Chemistry and Mineralogy instrument, or CheMin.
The colors in the image at left are unmodified, showing the scene as it would appear on Mars, which has a dusty red-colored atmosphere. The image at right has been white-balanced to show what the same area would look like under the lighting conditions on Earth.
The rounded rock located at the upper center portion of the images is about 8 inches (0.2 meters) across.
Curiosity’s scoop of soil
This pair of images shows a “bite mark” where NASA’s Curiosity rover scooped up some Martian soil (left), and the scoop carrying soil. The first scoop sample was taken from the “Rocknest” patch of dust and sand on Oct. 7, 2012, the 61st sol, or Martian day, of operations. A third scoop sample was collected on Sol 69 (Oct. 15), and deposited into the Chemistry and Mineralogy (CheMin) instrument on Sol 71 (Oct. 17).
These images were taken by Curiosity’s Mast Camera. Scientists enhanced the color in this version to show the Martian scene as it would appear under lighting conditions on Earth, which helps in analyzing the terrain.
The following images were discussed by David Bish, Indiana University, Bloomington, a co-investigator of CheMin.
First X-ray View of Martian Soil
This graphic shows results of the first analysis of Martian soil by the Chemistry and Mineralogy (CheMin) experiment on NASA’s Curiosity rover. The image reveals the presence of crystalline feldspar, pyroxenes and olivine mixed with some amorphous (non-crystalline) material. The soil sample, taken from a wind-blown deposit within Gale Crater, where the rover landed, is similar to volcanic soils in Hawaii.
Curiosity scooped the soil on sol 69 (Oct. 15, 2012). It was delivered to CheMin for X-ray diffraction analysis on sol 71. By directing an X-ray beam at a sample and recording how X-rays are scattered by the sample at an atomic level, the instrument can definitively identify and quantify minerals on Mars for the first time. Each mineral has a unique pattern of rings, or “fingerprint,” revealing its presence.
Olivine on Earth
The Martian soil examined by the Chemistry and Mineralogy (CheMin) instrument on Curiosity shows the diffraction signature, or “fingerprint,” of the mineral olivine, shown here on Earth in the form of tumbled crystals several millimeters (about a quarter-inch) in size. The semi-precious gem peridot is a variety of olivine.
This image of Mauna Kea in Hawaii shows an area of volcanic soils that contain minerals similar to those identified in the “Rocknest” region on Mars by NASA’s Curiosity rover.
The following images were discussed by Doug Ming from NASA Johnson Space Center, Houston, a co-investigator of CheMin.
A Dust Storm on Mars
Occasional globe-encircling storms distribute dust all over Mars. A soil sample analyzed in October 2012 by the Chemistry and Mineralogy (CheMin) instrument on Curiosity is likely a blend of globally distributed dust and larger sand-sized particles derived from local sources.
Dust Devils Stirring It Up
This set of images from Mars Exploration Rover Spirit shows dust devils tearing across the Martian landscape inside Gusev Crater. These wind-driven events stir up the soil and can be part of globe-encircling storms that transport dust and soil.