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Task Group | Next Generation Gravity Field Missions

Prototype optical bench for an inter-satellite laser interferometer in the cleanroom. Photo: Marina Dehne

If one looks close enough, the gravity field of the earth is neither homogeneous in space nor constant in time. The tiny variations contain a wealth of information about, for example the subsurface structure, variations in the global water cycle or the thickness of ice layers near the poles.Observation of the earth’s gravity field with dedicated satellites began in 2000 and includes now the missions CHAMP (Challenging Minisatellite Payload for Geoscience and Application), GRACE (Gravity Recovery And Climate Experiment) and GOCE (Gravity Field and Steady-State Ocean Circulation Explorer).

These missions provide new and unique data, for example on ice melting in Greenland, groundwater depletion in Northern India, and many other fields. In particular the US-German GRACE mission has demonstrated the enormous potentialof the concept, but has at the same time clearly shown how much more could be done with more precise data with higher spatial resolution. Furthermore, for many questions on variations in the earth system, continued observations over many years are essential.

This Task Group plays a central role in the ongoing efforts to design a new mission with better resolution that will continue and improve the observation time series. This is only possible in a truly multidisciplinary collaboration, which has now been established in QUEST. Our tasks within QUEST include the detailed analysis of noise sources in the GRACE data, the design of a laser interferometer (based on LISA and LISA Pathfinder technology) that will replace the microwave ranging system and reduce the ranging noise by a factor of at least 10, and design studies for the satellites.

Involved Research projects and institutes

  • Precision Geodesy on Earth and in Space (Prof. Dr. Jakob Flury)
  • Next Generation Geodesy Missions (Dr. Benjamin Sheard)
  • Global Geodetic Observing System (GGOS) (Prof. Dr. Jürgen Müller)
  • Atomic and Photonic Quantum Sensors (Prof. Dr. Ernst Rasel)
  • Centre of Applied Space Technology and Microgravity (ZARM), Bremen
  • Physikalisch-Technische Bundesanstalt (PTB)