The value of mass change observations for understanding the Earth system has been highlighted in multiple community reports. Including the 2007 Earth Science and Applications from Space (ESAS) Decadal Survey (DS) with the recommendation of a higher capability GRACE-II Tier-3 mission, 2010 NASA Climate-Centric Architecture report with the recommendation of GRACE Follow-On (2018-present) as a gap-filler mission to continue critical observations from the Gravity Recovery and Climate Experiment (GRACE; 2002-2017), and most recently in the 2017 ESAS DS in which Mass Change is listed as a Designated Observable. The Mass Change Designated Observable will “ensure continuity of measurements of groundwater and water storage mass change, land ice contributions to sea-level rise, ocean mass change, ocean heat content, glacial isostatic adjustment, and earthquake mass movement,” as summarized in the 2017 DS. In response to this designation, NASA initiated a multi-center study team led by JPL to study and recommend high-value observing systems for mass change that can be implemented within the next decade and are responsive to the DS science and applications objectives. This talk provides an overview of the study process and key findings. These include the creation of a community-vetted Science and Applications Traceability Matrix, the assessment via numerical simulations of the science value of over 50+ observing system variants, and the utilization of a value framework process that takes into account science value, cost, risk, technology readiness level, schedule, and international partnerships to discriminate between architectures. The study process has led to the identification of a small subset of high-value observing systems to move forward for more in-depth study in Pre-Phase A. Expected science outcomes from this small subset of architectures will be discussed in detail. Speaker Bio: Dr. David Wiese is a member of the Solar System Dynamics Group at JPL. He currently serves as the deputy study coordinator for the Mass Change Designated Observable Study, is a principal investigator on the GRACE and GRACE-FO Science Team, and is the primary developer of the JPL Mascon solution as a member of the GRACE and GRACE-FO Science Data Systems team. He has authored over 30 papers spanning the life cycle of mass change observations; ranging from optimization of mission design and data processing approaches, to scientific interpretation of the data within the broader context of Earth system science. Wiese has served on several international working groups focused on implementation of future mass change observing systems. He is a recipient of the JPL Lew Allen Award and the NASA Early Career Achievement Medal. Originally presented as an online talk for the JPL Center for Climate Sciences Friday Seminar Series, May 28, 2021.