S-NGGM | Studies for Next Generation Gravity Missions: GFZ

S-NGGM | Studies for Next Generation Gravity Missions

Between 2002 and 2017, the US/German GRACE satellite mission provided monthly time series of gravity field models describing mass transport in the Earth system. These models are used by a broad scientific community to observe and analyze seasonal and sub-seasonal variations in the continental hydrological cycle, ice mass loss in Antarctica or Greenland, or surface and deep ocean currents. Since 2018, this time series has been extended by the GRACE Follow-on (GRACE-FO) mission and now spans more than 22 years. GRACE-FO was jointly realized and now operated in NASA/GFZ partnership.

There is a broad consensus in the scientific user community that these time series need to be a) extended over several decades to improve the plausibility of the climate-related trends and variations derived so far and b) that at the same time the spatial and temporal resolution as well as the measurement accuracy need to be further improved.

For this reason, the GFZ, together with the German Space Agency at the German Aerospace Center (DLR) and German industry (Airbus Defence and Space GmbH; SpaceTech GmbH), and in close coordination with JPL/NASA, has conducted various studies between 2020 and 2022 for the realization of a GRACE-FO successor mission with the primary goal of ensuring data continuity. This mission is therefore called GRACE-C (Continuity) and will again be realized in close US-German partnership to be launched in December 2028.

To increase spatial and temporal resolution, ESA, together with NASA, is planning a Mass change And Geosciences International Constellation (MAGIC). MAGIC will consist of a double pair, with the polar-flying GRACE-C and the inclined Next Generation Gravity Mission (NGGM) to be launched by ESA in 2032. NGGM will fly deeper (ca. 400 km) than GRACE-C (initial orbital height 500 km) to be more sensitive for the gravity signal and will have more precise accelerometers onboard to improve the observation of non-gravitational perturbation forces.

Section 1.2 was and is still involved in several national and ESA funded studies, all of which had or still have the goal to realize data continuity and increased resolution of future gravity missions. Some short details about these studies can be found in the following project descriptions.

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