GRACE/GRACE-FO Science Team Meeting 2020
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the Creative Commons Attribution 4.0 License.

Realization of a satellite mission “GRACE-I” for parallel observation of changing global water resources and biodiversity

Frank Flechtner1 and the GRACE-I Team*
Frank Flechtner and the GRACE-I Team
  • 1Helmholtz Centre Potsdam, GFZ German Research Centre for Geosciences, Geodesy and Remote Sensing, Wessling, Germany (
  • *A full list of authors appears at the end of the abstract

The actual NASA Earth Science Decadal Survey Report highlights mass transport monitoring as one of five top priorities in Earth Observation for the next decade. To realize such as Mass Change Mission (MCM) NASA is seeking for international partnership. A future continuation of the very successful technological and scientific GRACE/GRACE-FO partnership between the U.S. and Germany is in the involved partners’ highest interest and would be based on a strong heritage in the fields of satellite manufacturing, laser ranging interferometry (LRI) or science data utilization.

The goal of a study, jointly performed in summer 2020 between DLR, industry and HGF and MPG scientists, was to bundle up an attractive scientific and technological German package for further discussions with NASA which 1) compares the cost and benefit of technical modifications with respect to GRACE-FO, 2) is not only attractive for a future MCM but also for the Laser Interferometer Space Antenna (LISA) and 3) strengthens at the same time Germany´s role towards ESA´s Next Generation Gravity Mission (NGGM) implementation.

An ICARUS (International Cooperation for Animal Research Using Space) payload system on a future polar-orbiting GRACE-like “GRACE-ICARUS” (or short “GRACE-I”) mission could provide a much-desired scientific extension of biodiversity monitoring, which is another designated observable in NASA´s Decadal Survey.

Three mission options have been investigated:

1)    A reference design based on the GRACE-FO platform and technology with a redundant LRI as the main satellite-to-satellite tracking instrument

2)    Add-on of the ICARUS payload, and

3)    Implementation of further technology options such as (i) spacecraft and mission related enhancements, (ii) LRI related issues and (iii) inclusion of technology demonstrators based on quantum technologies.

The nominal spacecraft separation for all options was 220 km at an altitude of 490 km with free-decay (Options 1a, 2a and 3a), or alternatively 420 km maintained using electric propulsion (Options 1b, 2b and 3b).

The presentation summarizes the most important findings of our study and discusses possible steps forward towards implementation with NASA.


Frank Flechtner(1), Stefanie Bremer(3), Meike List(4), Gerhard Heinzel(5), Martin Wikelski(6), Ralf Münzenmayer(7), Wolfgang Pitz(8), Peter Schaadt(2) (1) Helmholtz Center Potsdam GFZ German Research Centre for Geosciences (2) German Aerospace Center (DLR), Space Administration, Bonn (3) German Aerospace Center (DLR), Institute for Satellite Geodesy and Inertial Sensing (SI), Hannover (4) German Aerospace Center (DLR), Institute for Space Systems (RY), Bremen (5) Max-Planck-Institute for Gravitational Physics, Hannover (6) Max-Planck-Institute of Animal Behavior, Konstanz (7) Airbus Defence and Space GmbH, Immenstaad (8) SpaceTech GmbH (STI), Immenstaad

How to cite: Flechtner, F. and the GRACE-I Team: Realization of a satellite mission “GRACE-I” for parallel observation of changing global water resources and biodiversity, GRACE/GRACE-FO Science Team Meeting 2020, online, 27–29 Oct 2020, GSTM2020-6,, 2020.


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