NASA Tropics Pathfinder and Constellation Mission Preparations for Launches in 2021 and 2022

The Time-Resolved Observations of Precipitation structure and storm Intensity with a Constellation of Smallsats (TROPICS) mission was selected by NASA as part of the Earth Venture–Instrument (EVI-3) program. The TROPICS Engineering Qualification Unit has been refurbished for flight, and a launch is planned for June 2021 on a SpaceX Falcon 9 to a 550-km sun synchronous orbit. This Pathfinder mission will provide risk reduction for the subsequent TROPICS constellation mission, which comprises six CubeSats in three low-Earth low-inclination orbital planes, with launches planned beginning in early 2022. Each of these identical CubeSats will host a high performance radiometer to provide temperature profiles using seven channels near the 118.75 GHz oxygen absorption line, water vapor profiles using three channels near the 183 GHz water vapor absorption line, imagery in a single channel near 90 GHz for precipitation measurements (when combined with higher resolution water vapor channels), and a single channel at 205 GHz that is more sensitive to precipitation-sized ice particles. The TROPICS mission highlights a number of aspirations of future earth observing sysems, including high revisit rate, system resilience, rapid technology infusion, and low cost. This paper presents these elements with an eye toward future operational architectures for weather and climate monitoring.