RainCube, the First Spaceborne Precipitation Radar in a 6U CubeSat

RainCube (Radar in a CubeSat) is a technology demonstration mission to enable Ka-band precipitation radar technologies on a low-cost, quick-turnaround platform. The RainCube instrument concept was conceived at the Jet Propulsion Laboratory. Initial technology development and demonstration paved the way to a mission concept to validate two key technologies in the space environment – a miniaturized Ka-band precipitation profiling radar that occupies ~3U and a 0.5m Ka-band deployable parabolic antenna stowed within 1.5U. RainCube was selected within NASA Science Mission Directorate’s Research Opportunities in Space and Earth Science 2015 In-Space Validation of Earth Science Technologies solicitation. The spacecraft bus is developed by Tyvak Nanosatellite Systems, who is responsible for integration and test of the flight system and mission operations. The radar and spacecraft were delivered on time for their scheduled ISS deployment on the ELaNa-23 launch in May 2018 from Wallops Flight Facility. The ultra-lightweight compact deployable Ka-band antenna was successfully deployed on July 28, 2018 and the radar made its first observation of precipitation on August 27, 2018. The mission continues to operate and has met all its Level 1 requirements through repeated observations of precipitation in the atmosphere. At the time of writing, the RainCube mission has been extended through August of 2019 with the spacecraft expecting to stay in orbit until summer 2020, and the potential for the mission to be extended through the end of the spacecraft’s life. This paper discusses the developments and results achieved by this novel technical approach, and its impact on mission concepts that may address the Clouds, Convection and Precipitation Designated Targeted Observable as defined in the 2017 Earth Science Decadal Survey.