Title: SRI CubeSat Imaging Radar for Earth Science (SRI-CIRES)
Presenting Author: Lauren Wye
Organization: SRI International
Co-Author(s): Simon Lee

Abstract:
Ground deformation measurements obtained with interferometric synthetic aperture radar (InSAR) technologies have the potential to improve short-term forecasting of natural hazards and enable more effective management of natural resources. For maximum impact, InSAR measurements must be precise (sub-cm level) and timely. Frequent acquisitions (sub-weekly) are needed to achieve both requirements. More observations per unit time provide enhanced deformation precision through averaging, and ensure that an event is properly captured and characterized. Yet, single-platform sensors cannot simultaneously achieve frequency and wide-area coverage, and traditional InSAR sensors are too expensive (> $300M) to replicate. SRI is working to provide high-precision ground deformation measurement capabilities in an affordable package ($1-2M) that can be used to form a constellation of InSAR sensors capable of rapid-repeat (daily) coverage of science targets. Such achievements are made possible through developments in nanosatellite technology, specifically the emergence of the CubeSat standard. Under a 2015-2016 ESTO ACT grant, we have designed and developed an S-band radar subsystem capable of moderate-resolution (25 m), high-fidelity InSAR performance (sub-cm deformation precision, SNR > 14 dB). The radar fits within 1U of a 6U CubeSat and satisfies the power and thermal requirements of the CubeSat environment. We call this subsystem the SRI CubeSat Imaging Radar for Earth Science (SRI-CIRES). We have advanced the SRI-CIRES RF and digital electronic subassemblies to achieve a functional flight-ready prototype (TRL 6). In this presentation, we review the initial test results of SRI-CIRES, showing that the prototype can meet the science objectives and performance requirements of an operational mission (e.g., can correct atmospheric artifacts and ionospheric effects to achieve sub-cm level accuracy). We pay particular attention to test results concerning power and thermal support.