CubeSat Based Sensors for Global Weather Forecasting

Lavanya Periasamy (1), Albin J. Gasiewski (1), Glenda Alvarenga (2) Brian T. Sanders (2) and David Gallaher (3)

Abstract
The importance of acquiring meteorological data at high spatial and temporal resolution, which has been emphasized in the U.S NRC Decadal Survey's Precipitation, Atmospheric, Temperature and Humidity (PATH) mission requirements, arises from a need for weather forecasting to cope with rapidly evolving weather patterns. The positive impact of passive microwave observations of tropospheric temperature, water vapor and surface variables on short-term weather forecasts has been clearly demonstrated in recent forecast anomaly growth studies. The development of a fleet of such passive microwave sensors especially at V-band and higher frequencies in low earth orbit using 3U and 6U CubeSats could help accomplish the aforementioned objectives at low system cost and risk as well as provide for regularly updated radiometer technology. The University of Colorado’s PolarCube satellite is intended to serve as a demonstrator for such a fleet of MMW and higher frequency passive sounders and imagers. PolarCube is a 3U CubeSat based on an existing bus design (CU All-STAR) supporting an eight channel, double sideband 118.7503 GHz passive microwave sounder, MiniRad with an antenna subsystem comprising a spinning offset paraboloidal main reflector and a stationary corrugated feed. The mission is focused primarily on sounding in Arctic and Antarctic regions with the following key remote sensing science and engineering objectives: (i) Collect coincident tropospheric temperature profiles above sea ice, open polar ocean, and partially open areas to develop joint sea ice concentration and lower tropospheric temperature mapping capabilities in clear and cloudy atmospheric conditions. This goal will be accomplished in conjunction with data from existing passive microwave sensors operating at complementary bands; and (ii) Assess the capabilities of small passive microwave satellite sensors for environmental monitoring in support of the future development of inexpensive Earth science missions and (possibly) operational satellites supporting the NRC PATH and Aerosol/ Cloud/Ecosystem (ACE) goals. In this poster the design characteristics of the PolarCube satellite will be discussed, along with the ramifications of the CubeSat envelope restrictions on the cost, sampling characteristics, scanning capabilities, communications requirements, and expected measurement precision of a CubeSat passive microwave fleet for microwave weather forecasting under all weather conditions. The feasibility of 3D printing techniques to manufacture the antenna system of such a CubeSat radiometer is also being investigated. Presently, a 3D printed (aluminum) conical horn is being tested and its performance compared to a standard gain gold-plated horn. The antenna system performance of PolarCube will be evaluated at the NIST Configurable Robotic Millimeter-wave Antenna facility (CROMMA) in Boulder, CO.