Miniaturization of Comprehensive Energetic Charged Particle Detectors for Anomaly Attribution

TECHNOLOGY AREA(S): Space Platforms OBJECTIVE: Drive Size, Weight, and Power lower by a factor of 2x to 4x for Energetic Charged Particle sensors over current designs. DESCRIPTION: With new policy requiring Energetic Charged Particle (ECP) sensors on all new Air Force satellite acquisitions, it is incumbent to miniaturize the system to allow implementation across the fleet as the Air Force moves toward smaller and disaggregated constellations. While current designs (4kg, 10W, 3600cc) are acceptable for large space systems, many missions will be accomplished in the small satellite class (100kg). For systems this small, either the ECP policy will need to be waived, leaving a gap in attribution capability, or a miniaturized sensor with SWaP reduction by a factor of 2x to 4x needs to be developed while still meeting ECP requirements. Space environment impacts are rare, and typically only happen during times of extreme particle flux.[1] However, a space environment sensor also needs to conclusively measure a normal environment to rule out environmental impacts. This means an ECP sensor for anomaly resolution will be required to differentiate between various extreme environments while still also measuring the normal environment. This has created extreme requirements in terms of flux and energy range. Additionally, the environment must be measured with sufficient resolution to differentiate a hazardous from a non-hazardous environment. The net requirement is to measure electrons from 100eV to 5MeV and protons from 2MeV to 100MeV from median to the 99th percentile climatology (roughly four orders of magnitude at a given energy channel). Energy channel spacing must be better than a factor of 1.8 across the sensor range, and the detectors must be able to determine the omnidirectional flux as well as estimate the peak directional flux (if within the field of view) within a factor of 4 accounting for all error sources and within a factor 2 for the combination of systematic error with uncertainties resulting from field of view limitations, including background fluxes and cross-contamination. The design must not saturate within the required flux ranges and the response shall not roll over for fluxes exceeding these ranges. Current designs deal with this by dividing the energy range between multiple sensors so the flux range each sensor has to deal with are manageable. [e.g. 2,3] Additionally, the instruments must be rated to survive in space for the mission life of the host vehicle, often up to 15 years. The initial goal is to identify candidate technologies and innovative concepts that would allow a reduction in SWaP, for example by increasing the energy and flux range of single sensors, enhancing the speed at which the detectors and associated electronics can count particles, or reducing the size of the detector. The final goal is to develop and qualify for spaceflight technologies enabling a reduction in ECP SWaP by a factor of 2x to 4x. PHASE I: Review sensor technologies and provide estimates of how to best accomplish reductions in SWaP for ECP sensors. Review candidate technologies and provide a recommended technical approach for Phase II. PHASE II: Develop prototype sensors and perform high-fidelity modeling of performance, verifying response under laboratory and calibration facility test. PHASE III: Refine concept and develop space-qualified detector(s) capable of integration into future ECP systems or direct integration on AF satellites by SMC prime contractors. It is expected that there will be commercial interest in sensor technologies as well. REFERENCES: 1. OBrien, T. P. (2009), SEAES-GEO: A spacecraft environmental anomalies expert system for geo-synchronous orbit, Space Weather, 7, S09003, doi:10.1029/2009SW000473.2. Dichter, B. K. et. al, Compact Environmental Anomaly Sensor (CEASE): A Novel Spacecraft Instrument for In Situ Measurement of Environmental Conditions, IEEE Trans. On Nucl. Sci., 45(6), 2758-2764, 1998.3. Lindstrom, C.D. et. al, Characterization of Teledyne microdosimeters for space weather applications, Proc. SPIE 8148, Solar Physics and Space Weather Instrumentation IV, 814806 (September 29, 2011); doi:10.1117/12.893814 KEYWORDS: Spacecraft, Anomaly, Attribution, Energetic Charged Particle, ECP