Duration: 18 months
Improved remote optical detection is urgently needed in order to more rapidly localise and extinguish the wildfires that plague our planet. Since IR detectors are subject to confounding signals from background heat sources, optical fire sensors usually couple them with solar-blind UVC sensors which are not susceptible to such false positives. These are vacuum tube photomultipliers (PM) which are highly sensitive but bulky, fragile, expensive and require high voltage operation. Up till now solid-state sensors have not displaced PM because none of the commercial options are intrinsically solar blind (GaN requires Al alloying and Si & SiC require filters) which leads to poor efficiency and a need for pre-amps and/or high voltage avalanche operation. Recently the authors developed groundbreaking UVC sensors which went up on a French cubesat mission in April 2023 [1, 3, 6-8, 11]. Based on a next generation semiconductor, Ga2O3, these sensors have intrinsic solar blindness and state-of-the-art gain. Hence they do not need solar filters, pre-amps or high operating voltages and thus offer greatly reduced mass, size and cost compared to PMs. In the qualification tests for use on smallsats the sensors were also observed to be highly reliable and robust to heat/cold, vibrations and radiation. PROMETHEUS will capitalize on this development to realize a Ga2O3 UVC imaging array for LEO early warning/localisation of fire ignition. It will have game changing, filter- and pre-amp-free operation and, a peak response/width specifically optimized for fire sensing. Novel optical, electronic and image processing solutions will be implemented in order to exploit the extreme sensitivity and add the functionality of IR image fusion. Comparable UVC imaging arrays are not commercially available and they will enable a number of space and terrestrial applications: e.g. UV astronomy, missile launch detection/localization, free path gas sensing/localisation and various inspection systems.
