Lessons Learned from the NASA TROPICS CubeSat Constellation Mission

The NASA TROPICS CubeSat constellation mission is currently providing wide-swath microwave observations of tropical cyclones in twelve channels spanning 90–205 GHz at unprecedented revisit rates to improve our basic scientific understanding of how storms form and evolve and to improve our ability to forecast storm track and intensity. Four satellites were successfully placed into orbit on Rocket Lab Electron launch vehicles on May 8 and May 26 (NZST) 2023 - two satellites were deployed in each launch, resulting in two equally-spaced 33-degree inclined orbital planes at 550-km altitude. In advance of the constellation mission, the TROPICS engineering qualification unit was launched as part the Transporter-2 rideshare mission on a SpaceX Falcon 9 launch vehicle into a sun-synchronous orbit at 530-km altitude. This TROPICS “Pathfinder” satellite operated successfully for 2.5 years and has provided a vast data record to validate and optimize all the aspects of the TROPICS constellation mission, including the flight segment, ground segment, and science data segment. These five satellites have demonstrated the first ever microwave data record provided with better than 60-minute median revisit rate, and these observations have been downlinked to users with latencies of approximately 45 minutes on average, permitting the use of these data by operational forecasting centers. The mission has utilized a wide array of commercial products and services, from cubesat buses, command and control, ground stations, and launch to implement the mission at much lower costs than traditional, operational weather satellite systems. Many technical innovations combined with a new paradigm for high-performance earth observation have come with many challenges, obstacles, and setbacks over the course of mission planning, development, implementation, and operation. In this paper, we describe many of these problems in some detail and present observations, lessons learned, and a look at how the solutions that were conceived to overcome the issues could be used to improve future missions in a wide variety of application areas.