Curiosity's ChemCam's laser has zapped more than 600 rock and soil targets on Mars since Curiosity landed in the planet's Gale Crater in August 2012 to assess ancient habitable environments and major changes in Martian environmental conditions. On Saturday, July 12 by the Mars Hand Lens Imager (MAHLI) camera on the arm of NASA's Curiosity Mars Rover's Chemistry and Camera (ChemCam) instrument fired multiple laser shots to investigate a target rock's composition created the first observed plasma plume flashes. Preliminary analysis of the ChemCam spectra from this target rock, appropriately named "Nova," indicates a composition rich in silicon, aluminum and sodium, beneath a dust layer poor in those elements. This is typical of rocks that Curiosity is encountering on its way toward Mount Sharp (above).
MAHLI Deputy Principal Investigator Aileen Yingst of the Planetary Science Institute, Tucson, Arizona, said, "One of the reasons we took these images is that they allow the ChemCam folks to compare the plume to those they imaged on Earth. Also, MAHLI has captured images of other activities of Curiosity, for documentation purposes, and this was an opportunity to document the laser in action."
In the first two years since Curiosity landed in Mars' Gale Crater in August 2012, researchers have used ChemCam's laser and spectrometers to examine more than 600 rock or soil targets. The process, called laser-induced breakdown spectroscopy, hits a target with pulses from a laser to generate sparks, whose spectra provide information about which chemical elements are in the target. Multiple laser shots are fired in sequence, each blasting away a thin layer of material so that the following shot examines a slightly deeper layer.
The photograph at left is from ChemCam's Remote Micro-Imager camera, taken during the 687th Martian day, or sol, of Curiosity's work on Mars (July 12, 2014). It shows a portion of the surface of Nova about 1.6 inches (4 centimeters) wide, centered at the spot where laser shots hit the baseball-size rock that same sol.
The graph at right show the brightness of the resulting spark at a range of wavelengths detected from each of the first 10 laser shots out of 100 total shots fired at the same point on the rock. The initial shots generated less brightness at a wavelength that is diagnostic for aluminum content, compared to shots after the dust coating on the rock had been cleared away by those first few shots.
ChemCam's laser zapping of this rock was the first ever during which Curiosity's arm-mounted Mars Hand Lens Imager (MAHLI) camera took images that caught the spark generated by a laser hitting a rock on Mars (see PIA18401).
ChemCam is one of 10 instruments in Curiosity's science payload. The U.S. Department of Energy's Los Alamos National Laboratory, in Los Alamos, New Mexico, developed ChemCam in partnership with scientists and engineers funded by the French national space agency (CNES), the University of Toulouse and the French national research agency (CNRS). More information about ChemCam is available at http://www.msl-chemcam.com.
The Daily Galaxy via http://www.nasa.gov/msl and http://mars.jpl.nasa.gov/msl/