RESEARCH OVERVIEW

Our research emphasizes:
(1) Identification of solid phase surface materials without benefit of ground truth
(2) Methodical analysis of lab, field, airborne, and satellite perspectives
(3) Measurement protocols and instrumentation necessary for low ambiguity identification
We research spectral effects in the field that are rarely reproduced in the laboratory, including from surface roughness on several scales, reflected downwelling radiance from non-diffuse materials, and particle mixing effects. Our unique range of spectrometers (hyperspectral) provides the greatest depth of data sets available for this research:


TOPICS

(1) Rough and weathered materials. These can be very difficult to identify when ground truth is not available. Our research uncovers why and how to address the difficulties.
(2) Methodical field spectrometer testing. We use thermal infrared hyperspectral imagers and a methodical, end-to-end approach to develop a solid foundation for field identification.
(3) Coatings. Coatings can mimic large particles. This makes them interesting to identify and for camouflage.


Infrared Field Spectroscopy

Field measurements differ fundamentally from laboratory, airborne, and satellite spectrometer measurements. Laboratory measurements alone are not sufficient to understand all the spectral effects present in field data.

We use spectrometers (hyperspectral) to research effects from:

  • viewing geometry
  • proximity
  • surface texture (smooth vs. rough)
  • reflected downwelling environmental radiance

    The results apply to:
  • hand-carried instruments
  • manned and unmanned vehicles (UGV and rovers)
  • fusion with airborne/satellite and lab data

    We apply the results to:
  • Mars
  • programs for defense against chemical warfare and terrorist attack
  • first responder capabilities

    We also develop related hyperspectral measurement protocols and instrumentation. Here we describe some of our capabilities and recent measurements. We also make field data freely available for other researchers. If you are interested in receiving data, or have suggestions for targets, field sites, or collaborations, contact Laurel Kirkland, kirkland@lpi.usra.edu, 281-486-2112.

    The Aerospace Corporation and the Lunar and Planetary Institute fund this work. NASA research programs provide no funding for any of the instrumentation, data collects, data reduction, analysis, or distribution, and no member of our group is a member of any NASA instrument team. The Aerospace Corporation owns all the equipment used here.


    Identification of Rough and Weathered Materials

    The current Mars exploration strategy calls for the identification from orbit of minerals that form in environments conducive to life or that preserve biomarkers, using infrared remote sensing. The results would then be used to select landing sites. Predictions of the instrumentation needed were based on laboratory measurements of pure minerals, or airborne measurements made by multi-channel radiometers (e.g. TIMS) combined with ground truth.


    Our research shows that rough and weathered materials are substantially more difficult to detect and identify than predictions that used lab data or ground truth predicted. However, our data sets show that these materials can be identified by a sensitive instrument that measures with high information content.
    This may explain why there has been no clear identification of materials such as carbonates and chert on Mars, including by the Global Surveyor Thermal Emission Spectrometer (TES). The results indicate that 2001 Mars Odyssey multi-channel radiometer THEMIS probably lacks the information content to identify most rough and weathered minerals.

    Our study combines laboratory spectra (2.5 - 200 Ám); unique, high quality airborne spectrometer data (Spatially Enhanced Broadband Array Spectrograph System, SEBASS); and high quality field spectrometer data (2.5-5 and 7-13 Ám). The Lunar and Planetary Institute, Houston, TX, and The Aerospace Corporation, El Segundo, CA sponsor this work.

    Additional information, including SEBASS

    How to set detection limits for unknown targets, (published in Applied Optics)

    Implications for the Mars astrobiology program (published in SPIE Proceeding 4495)

    Results from our terrestrial work, (published in Remote Sensing of Environment)


    Contact information