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Remote sensing and characterization of high temperature targets on the Earth’s surface is required for many cross-disciplinary science investigations and applications including fire and volcano impacts on ecology, the carbon cycle, and atmospheric composition. For decades this research has been hindered by insufficient spatial resolution and/or detector saturation of satellite sensors operating at short and mid-infrared wavelengths (1-5 μm) where the spectral radiance from high temperature (>800 K) surfaces is most significant.
To address this critical need, the Jet Propulsion Laboratory is developing a compact modular high dynamic range (HDR) multispectral imager concept, with the flexibility to operate in the short, mid- or long-wavelength infrared spectral bands. The goal of this project is to demonstrate this novel technology through the maturation of a mid-wavelength infrared (MWIR) imager, the Compact Fire Infrared Radiance Spectral Tracker (c-FIRST), which leverages digital focal plane array (DFPA) developed under the Advanced Component Technology (ACT) Program of the NASA Earth Science Technology Office. The DFPA is comprised of a state-of-the-art high operating temperature barrier infrared detector (HOT-BIRD) and a digital readout integrated circuit (D-ROIC), which features an in-pixel digital counter to prevent current saturation, and thereby provides very high dynamic range (>100 dB). The DFPA will thus enable unsaturated, high-resolution imaging and quantitative retrievals of targets with a large variation in temperatures, ranging from 300 K (background) to >1600 K (hot flaming fires). With the resolution to resolve 50 m-scale thermal features on the Earth’s surface from a nominal orbital altitude of 400 km, the full temperature and area distribution of fires and active volcanic eruptions and the cool background are captured in a single observation, increasing science content per returned byte. The use of a non-saturating detector is novel, overcomes previous problems where high radiance values saturate detectors (which diminishes the science content and usefulness of the data), and demonstrates a breakthrough capability in remote sensing – one with broad applicability in both terrestrial and planetary settings. By incorporating this technology, c-FIRST is suitable for quantifying emissions from fires and volcanic eruptions of different temperatures and intensities, which is critical for establishing their impact on ecosystems, carbon fluxes, and air-quality at local scales and climate at global scales. In this presentation we will discuss the properties of the c-FIRST focal plane array. The research was carried out at the Jet Propulsion Laboratory, California Institute of Technology, under a contract with the National Aeronautics and Space Administration. © 2023. All rights reserved.
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