Demonstrating the Potential for CubeSat Microwave Radiometers for Weather Observation: TEMPEST-D Performance after 1.5 Years On-Orbit

The demonstration satellite for the Temporal Experiment for Storms and Tropical Systems (TEMPEST) mission has been operating in-orbit since July 2018. TEMPEST-D is a 90-183 GHz five channel mm-wave imaging radiometer in a 6U CubeSat, with a mass of only 3.8 kg and using just 6.5W of power. Similar to the NOAA ATMS, it scans cross-track and has a spatial resolution of 15km at 183 GHz and 25km at 90 GHz. The radiometer has been operating nearly continuously since first turn on. CubeSat or small satellite solutions have been proposed for constellation deployment or even as supplements to the traditional operational sensors. The relative longevity of TEMPEST-D for a CubeSat mission enables an evaluation of this system for routine weather observation or focused science missions.

We will present an evaluation of the TEMPEST-D radiometer performance over the mission to date relative that achieved by similar operational sensors, such as the NOAA ATMS. Our analysis to date shows that the radiometer is extremely stable over time with an absolute calibration that is statically equivalent to that of ATMS. We will show highlights of the TEMPEST-D observations, including several co-incident observations of storms with the RainCube Ka-band radar in a CubeSat. Additionally, we will highlight a first-of-a-kind along-track scanning data set acquired with the TEMPEST-D system. To acquire these data, we operate the spacecraft yawed by 92 degrees to align the scan direction with the ground track. This provides a unique dataset where any location on the ground is viewed at incidence angles between 0 to 65 degrees in both the forward and aft directions. These data are used to demonstrate the benefits of multi-angle atmospheric sounding, a promising technique for improving temperature/humidity observation in the planetary boundary layer. We will show the first results from this growing dataset.