Friday, August 24, 2012

LIBS on Mars: nice plasma indeed

While everyone knows that ambient conditions on Mars are vastly different than those on Earth, it's interesting to see the practical results of this fact. For example, when laser-induced-breakdown spectroscopy (LIBS) is done on Mars, as with the ChemCam on NASA's Curiosity rover, the process unfolds differently than it does here in the great out-of-doors. The photo below shows this (but for now please put aside the fact that these images were taken of laser plasmas in a Los Alamos National Laboratory test chamber under atmospheric pressures typical of Earth and Mars). The image size is 75 x 75 mm; the target in both cases is a piece of metal. The Mars-like atmospheric pressure is about one-hundredth of the Earth-like pressure.

(Image: LANL)

And now the results, please. The ChemCam's LIBS setup has three spectrometers that work in the UV, the violet, and the visible and near-IR, respectively. The first analyzed rock, dubbed Coronation, is (or maybe by now, was) 2.7 m away from Curiosity. The resulting spectrum of 30 laser shots, seen below in squashed form (the larger version can be found at shows many lines of metals and other elements, including carbon and hydrogen. Interestingly, the hydrogen only showed up in the first laser shot, indicating that it was only on the rock's surface. Note the sensitivity (very small peaks for titanium and manganese) as well as the fact that the x-axis scale is somewhat nonlinear.


However, as I mentioned earlier, conditions are quite different here on Earth: instead of vaporizing rock, curiosity merely killed the cat.

No comments:

Post a Comment