200,000 LIBS Scans from Mars

Mon - 20/06/16

NASA’s Mars Science Laboratory Curiosity Rover, has recorded its 200,000 spectra from the onboard Laser Induced Breakdown Spectroscopy (LIBS) instrument. The LIBS is part of the ChemCam module which is integrated with other analytical instruments including XRD and XRF spectrometers.

LIBS laser in ChemCamThe LIBS laser is located on a mast above the Rover base. The optics have the ability to focus the laser at the target sampling point up to 7 metres distant from the Rover. The laser is pulsed at 5 nanoseconds with a power loading of 15mW/mm2 and an adjustable sample spot size of 0.3 – 0.6mm diameter. The high power focused beam, atomises the rock/soil sample to temperatures exceeding 14,000 deg C.

 

Beechey The elemental spectra created in the plasma, are focussed into a fibre optic cable that is connected to a spectrometer. The spectrometer disperses the wavelengths over a range of 240 – 850 nm, allowing the measurement of the different elements associated with specific wavelengths. The images above show the ‘before’ and ‘after’ results of the LIBS process.

 

 

LIBS spectrum of

Thousands of spectra per day can be recorded by the ChemCam unit, providing the ability to screen large areas of the Mars surface and allow cross verification with other Curiosity analysers for areas of interest.

Laser Induced Breakdown Spectroscopy (LIBS) is an excellent tool for elemental analysis as it allows analysis of samples with a wide range of chemical composition from parts per million (ppm) to high % levels. Typical elemental analysis by LIBS on Mars, can be grouped into major oxides (SiO2, Al2O3, FeO, MgO, CaO, Na2O, K2O, TiO2) and minor elements such as Cu, Mn, Ni, Cr, Zn, Li, Ba, Sr, Rb.

 Jake-Matijevic

As well as the standard metal oxides, ChemCam with it LIBS analyser, has detected hydrogen and non metallic elements S, P, O, and Carbon.

In addition to the wide dynamic range, LIBS also is able to:

  • Remove and analyse surface dust/weathered layer from the sample
  • No sample preparation
  • Able to identify water/hydrated minerals by H detection
  • Simultaneous analysis of elements with every laser pulse
  • Multiple shots in second/s
  • Elemental depth analysis

Curiosity is currently analysing rock structures around Mount Sharp and will continue to profile on the side of the mountain.

NASA is planning on at least 2 more missions to Mars, Mars 2020 & ExoMars 2020. Both will be deployed with new generation LIBS systems on board.




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