NASA's Ames Research Center in Moffett Field, California, has won the 2013 NASA Government Invention of the Year award for the Chemistry and Mineralogy (CheMin) X-ray diffraction instrument aboard the Mars Science Laboratory rover Curiosity. CheMin’s identification of minerals in rocks and soil is crucial to the mission's goal of assessing past environmental conditions and habitable environments.
The CheMin instrument was invented by David Blake of Ames; Phillipe Sarrazin of the SETI Institute and Inxitu Inc. in Mountain View, California, as well as Olympus Corp. in Scotts Valley, California; Friedemann Freund of the SETI Institute; and Charles Bryson of Apparati Inc. in Hollister, California.
"The outstanding work of the CheMin team has made a significant and lasting contribution to Ames' technology portfolio and offers game-changing capability to NASA missions and other government programs," said S. Pete Worden, Ames Center Director. "As a center, we have enjoyed great success in previous NASA Invention of the Year competitions; this award adds to our proud legacy."
More than 20 years ago, Blake began working on a compact X-ray diffraction instrument for use in planetary missions. CheMin and a number of commercial portable instruments that use its technology on Earth are the result of Blake's and his colleagues' work. In addition to remote field geology, these instruments also have innovative spinoff uses, such as the identification of counterfeit pharmaceuticals, the curation and preservation of art and antiquities, and homeland security.
"Our team is elated with the results from our instrument and excited about future CheMin analyses in the months and miles ahead," said Blake. "We are also very pleased that our analyses came back from Mars in the centennial year of the discovery of X-ray diffraction by Max von Laue in 1912."
CheMin uses X-ray diffraction, the “gold standard” for identifying minerals on Earth. X-ray diffraction works by directing an X-ray beam at a sample and recording how the X-rays are scattered by the sample's atoms. All minerals are crystalline, and in crystalline materials, atoms are arranged in an orderly, periodic structure, causing the X-rays to be scattered at predictable angles. From those angles, researchers can deduce the spacing between planes of atoms in the crystal, and from that, the identity of the mineral. The temperature, pressure, and chemistry of an environment -- including the presence of water -- determine what minerals form and how they are altered. Each mineral records the conditions under which it formed.
"CheMin represents the first use of X-ray diffraction for a Mars mission and it was critical in the identification of the first habitable environment on another planet," said Blake. "CheMin also provides a more definitive method to identify minerals than any instrument on previous missions."
Laboratory X-ray diffraction instruments are the size of large refrigerators and consume thousands of watts of power; CheMin is the size of a breadbox and operates on 40 watts of power. CheMin generates X-rays by aiming high-energy electrons at a target of cobalt, then aligning the cobalt X-rays into a narrow beam. The detector is a charge-coupled device (CCD) like the ones in electronic cameras, but sensitive to X-ray wavelengths and cooled to minus 76 degrees Fahrenheit.
CheMin includes a number of novel methods and mechanisms, including the first use of a CCD to record the positions and energies of diffracted and fluoresced X-ray photons, a compact space-qualified X-ray source, and a vibrating sample holder which allows powder X-ray diffraction patterns to be collected without complex and precise movements of source, sample and detector components. The Powder Movement System for Analytical Instruments, which is now a part of the CheMin instrument, won NASA's Commercial Invention of the Year in 2010.
A sample wheel mounted between the X-ray source and detector holds 32 disc-shaped sample cells, each about the diameter of a shirt button and the thickness of a business card, with transparent plastic walls. Rotating the wheel can position any cell into the X-ray beam. Five cells hold reference samples from Earth to help calibrate the instrument. The other 27 are reusable holders for Martian samples. Samples of gritty powder delivered from Curiosity’s sample acquisition and processing system to CheMin's inlet funnel each contain about as much material as in a baby aspirin.
"As a result of CheMin technology, discussions of the analyzed rocks and soil on Mars now revolve around the interpretation of the environment of formation of the minerals, rather than a discussion of what the mineralogy might be," said Blake.
NASA's Jet Propulsion Laboratory in Pasadena, California manages NASA's Mars Science Laboratory Project for NASA's Science Mission Directorate at the agency’s headquarters in Washington, and built the project's Curiosity rover.
Each NASA field center submits nominations for the awards, which are evaluated by NASA's Inventions and Contributions Board. The board determines which nominations qualify for each category, ranks the nominees and makes recommendations to the NASA Office of the General Counsel for review and approval.
Ames previously earned the NASA Government Invention of the Year award in the following years:
- 2007, for low-density, lightweight heat shield materials
- 2008, for a high-speed 3-D laser scanner with real time processing
- 2010, for software that creates simulations for managing air traffic scenarios
- 2011, for a low-cost, lightweight, two-piece, thermal protection system for use on space vehicles during atmospheric re-entry at hypersonic speed
- 2012, for a tiny sensor that can detect chemicals in the air.
Ames also won NASA Commercial Invention of the Year in 2010 for the Powder Handling Device for Analytical Instruments, and has won or been a co-winner of the NASA Software of the Year award 10 times since it was initiated in 1994.
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