260-3 Optimization and Calibration of STELLA: Lab and Field Methods for Local Spectroscopy Measurements

Session: Advances in Geospatial Applications for Environmental and Engineering Geology (Posters)

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The Climate Adaptation and Resilience Monitoring Alliance (CARMA) is a team utilizing NASA’s STELLA (Science and Technology Education for Land/Life Assessment) device to study the impacts of climate change on plant health in a variety of vulnerable environments. By measuring the reflectance spectra, STELLA can determine the health of the plant by observing the relative levels of twelve unique Near-Infrared and Visible wavelengths. STELLA was originally intended for educational community science purposes, but it has the potential to contribute to professional research and sustainability efforts.  

The STELLA unit is designed to be built by students or research teams. As the CARMA team began building the STELLA 1.1, it became clear that more in-depth instructions would assist future students. CARMA recorded a series of video tutorials to provide this instruction and guidance.  

Once the unit was built, the CARMA team tackled the issue of reliable calibration of the sensors. Spectrally neutral balance cards were used as a reference material with which to compare the STELLA’s measurements. Two 6500K, 50W LED bulbs were used to illuminate the balance cards and a light box was used to create a static and controlled environment to ensure consistent measurements. Additionally, for a full assessment of STELLA’s variability, readings of the same halogen lamp were taken with a laboratory-grade spectral radiometer and the STELLA, then compared.  

Once the laboratory calibration tests were completed, a field calibration and measurement procedure were developed to ensure quality and continuity of data. Colloquially known as a “Calibration Sandwich”, field calibration consists of taking a measurement of a static reference material before and after taking a measurement of the desired subject. The reference material is placed as close to the same distance and incidence angle as the subject being measured as reasonably possible without disturbing the subject. The team plans to follow the same route with the new STELLA 1.2 design. Together, these tools will help enable student teams and researchers to build and utilize the STELLA units more easily. CARMA is part of the Colorado Space Grant Consortium, and next steps include hosting workshops for Space Grant affiliates and students. 

Geological Society of America Abstracts with Programs. Vol. 57, No. 6, 2025

doi: 10.1130/abs/2025AM-7959

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