GRACE-FO: The Gravity Recovery and Climate Experiment Follow-On Mission

The Gravity Recovery and Climate Experiment Follow-On mission was conceived to continue the successful legacy of the recently decommissioned Gravity Recovery and Climate Experiment mission and, at the same time, serve as a platform to demonstrate the first-ever in-space intersatellite laser ranging interferometer as a technology pathfinder for future gravity mapping missions. Launched in May of 2018, the Gravity Recovery and Climate Experiment Follow-On observatory builds on the design of the original Gravity Recovery and Climate Experiment satellites, but incorporates a number of improvements based on lessons learned, and features significantly increased complexity due to the accommodation of the laser ranging interferometer. This paper provides an overview of the challenging requirements levied on the observatory, and the mission and spacecraft design necessary to meet them. As the original Gravity Recovery and Climate Experiment spacecraft design has not been, to date, broadly discussed in the engineering literature, this paper further highlights original design rationales, where still applicable. As future satellite-based geodesy missions with similar constraints and challenges emerge, the implementation of the Gravity Recovery and Climate Experiment Follow-On observatory described herein can serve as a pathfinder and guide for the successful realization of these endeavors.