archiv~1.txt: SETI [ASTRO] Laser Probes Planetary Surfaces

SETI [ASTRO] Laser Probes Planetary Surfaces

Larry Klaes ( lklaes@bbn.com )
Fri, 19 Mar 1999 12:00:23 -0500

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>Date: Fri, 19 Mar 1999 16:22:58 GMT
>From: Ron Baalke <BAALKE@kelvin.jpl.nasa.gov>
>To: astro@lists.mindspring.com
>Subject: [ASTRO] Laser Probes Planetary Surfaces
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>Reply-To: Ron Baalke <BAALKE@kelvin.jpl.nasa.gov>
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>Public Affairs (PA)
>Los Alamos National Laboratory
>
>CONTACT: John Gustafson, 505-665-9197, pogo@lanl.gov
>
>99-045
>
>Laser probes planetary surfaces
>
>LOS ALAMOS, N.M., Mar. 18, 1999 -- Zap!
>
>With a spark from a small laser, researchers from the Department of Energy's
>Los Alamos National Laboratory can analyze soils and rocks from more than
>50 feet away.
>
>The prototype instrument they are developing for planetary exploration
>combines a laser the size of a small flashlight, optics and a spectral
>analyzer into a compact, low-power package.
>
>"We can fire the laser every five seconds and within three minutes get
>enough data for an accurate measurement," said Los Alamos' David Cremers,
>principal investigator on the NASA-funded development effort. "The
>scientific returns for planetary exploration increase dramatically when
>you can conduct such rapid analyses."
>
>In a related effort, a Los Alamos team led by Roger Wiens is combining a
>laser and a mass spectrometer to conduct standoff analyses of asteroids
>or other airless bodies.
>
>Cremers and Wiens provided reports on their development efforts today at
>the Lunar and Planetary Science Conference in Houston.
>
>Cremers' laser-induced breakdown spectroscopy technology has been under
>development at Los Alamos for 18 years, but up to now has been applied to
>Earth-based purposes. It has been field tested for elemental analysis of
>rocks, soils, gases and airborne aerosol particles. A private company is
>developing a field-portable LIBS unit for mining and environmental
>monitoring applications.
>
>LIBS works by firing a brief, intense laser pulse at the surface of an
>object. The laser heats and vaporizes a small spot -- about as wide as a
>pencil eraser -- on the surface. A small telescope co-mounted with the
>laser captures light from the glowing vapor and feeds it into the spectral
>analyzer. Elements create unique spectral signatures that signal their
>presence; with correct calibration, the intensity of the emissions reveals
>the relative abundance of the elements.
>
>Cremers and his colleagues have shown in lab tests they can get accurate
>measurements for a variety of key elements from a sample some 60 feet
>away, and expect the technique would be even more effective in the thin
>atmosphere of Mars.
>
>"We didn't know going in how well we'd do with such a small laser,"
>Cremers said. "This time nature was nice to us."
>
>The LIBS technique could be especially useful for planetary exploration
>because of its ability to conduct analyses at a distance. A rover would not
>have to cross hazardous terrain to sample important rocks or strata. LIBS
>could reach up to cliff faces or across craters or peek inside cracks and
>crevices.
>
>The laser also can blast through the weathered veneer on a rock and reveal
>the true composition hidden beneath.
>
>The end product of the three-year, $1.1 million development effort will be
>a prototype LIBS instrument for field tests in the Mohave Desert. A flight
>model of the instrument would require additional development work to
>reduce the instrument's size and power requirements and increase its
>ruggedness.
>
>Wiens leads a related development effort for LIMS, or laser ionization mass
>spectrometry. In this system, the laser ablates material from the surface of
>an object and the freed, ionized atoms enter a mass spectrometer, which can
>provide compositional measurements based on the mass of an ion. The LIMS
>and LIBS techniques are complementary and both can use the same laser to
>ablate a sample for analysis.
>
>Los Alamos has a history of advances in lightweight, low-power mass
>spectrometers and currently has such instruments flying on NASA's Cassini
>and Deep Space 1 instruments.
>
>"In fact, our development work will make use of spares from the space
>plasma mass spectrometers on Cassini and Deep Space 1," Wiens said.
>
>The Los Alamos team has installed rock and soil targets and a mass
>spectrometer in a vacuum system and started gathering initial data. A
>more complicated spectrometer will be used starting in a few months.
>
>The team will use the test results to optimize the overall system for
>effective collection of ions kicked free by the laser and high-resolution
>mass measurements. The team also will study tradeoffs between the
>distance at which the instrument can make reliable measurements and
>overall mass and cost.
>
>"Our intention through this effort is come up with an instrument that
>eventually could be incorporated into a lander craft for the moon, an
>asteroid or an outer solar system body," Wiens said.
>
>NASA funding for the LIMS effort totals $360,000 over two years.
>
>Others involved in these development efforts include James Blacic, Monty
>Ferris, Herb Funsten, Andrew Knight, Jane E. Nordholt and Steve Ritzau of
>Los Alamos and Wendy Calvin of the U.S. Geological Survey.
>
>Los Alamos National Laboratory is operated by the University of California
>for the U.S. Department of Energy.
>
>