Mass Change as a core element of NASA’s Earth System Observatory: update and progress on pre-formulation activities

The 2017-2027 US National Academy of Sciences Decadal Survey (DS) for Earth Science and Applications from Space classified mass change as one of five Designated Observables having the highest priority in terms of Earth observations required to better understand the Earth system over the next decade.  In response to this designation, NASA initiated multi-center studies with an overarching goal of defining observing system architectures for each Designated Observable.  The Mass Change Designated Observable study concluded in 2021, after identifying a small subset of high value observing system architectures for further study during Pre-Phase A formulation.  Mass Change is in the process of concluding Pre-Phase A activities and transitioning to Phase A, after successfully passing a Mission Concept Review in June 2022.  The baseline architecture is a partnership between NASA and DLR with an architecture design similar in nature to GRACE-FO.  This concept meets the primary goal of maintaining continuity in the mass change data record.  In parallel, ESA is continuing their Phase A studies focused on launching an inclined pair of satellites to complement this baseline architecture which would result in a demonstration of the Bender constellation and thus enhance the overall science and applications value of the observing system.  In this talk, an overview of Mass Change pre-formulation activities will be provided, as well as a status update on next steps and associated milestones.