ChemCam, mounted on the mast of the Mars Science Laboratory (MSL) rover, uses Laser-Induced Breakdown Spectroscopy (LIBS) to perform remote-sensing science on Mars. ChemCam’s telescope is used to simultaneously focus the laser on martian rocks up to 7 meters away from the rover and collect the light emitted as the plasma plume created on the target cools down. The light is then transmitted to three spectrometers located in the body of the rover, providing spectra from which the composition of the samples is inferred on the ground. Context images of the sampled targets are captured by the Remote Micro Imager (RMI) that completes the instrument. A hardware failure that occurred a bit more than two years into the mission caused the ChemCam instrument to lose its original autofocus ability. This resulted in a degraded performance mode for several months while the ChemCam team developed a new autofocus algorithm based on the RMI images. During this period of degraded performance, several observations with different focus conditions were made on each target. This unusual set of data provides the opportunity to study the influence of less-than-optimal focus conditions on the LIBS signal created on the target and analyzed by ChemCam. To this purpose, we look at both raw ChemCam spectra and post-processed products used for scientific analysis to investigate how the quality of the focus influences the LIBS signal and the quantitative predictions of the composition of the observed targets.
| Identifer | oai:union.ndltd.org:UPSALLA1/oai:DiVA.org:ltu-67735 |
| Date | January 2017 |
| Creators | Pontoni, Angèle |
| Publisher | Luleå tekniska universitet, Rymdteknik |
| Source Sets | DiVA Archive at Upsalla University |
| Language | English |
| Detected Language | English |
| Type | Student thesis, info:eu-repo/semantics/bachelorThesis, text |
| Format | application/pdf |
| Rights | info:eu-repo/semantics/openAccess |
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