As part of the SFB Terra-Q Relativistic and Quantum-based Geodesy, in collaboration with the Albert Einstein Institute (AEI) and the University of Ulm, we are investigating aspects for a future laser-interferometric inter-satellite ranging mission for space-based measurements of the gravitational field of the Earth and its fluctuations.

The project B04 "Advancing Inter-Spacecraft Laser Interferometry" aims at maturing the concept for laser interferometry on future GRACE-like missions . ZARM is contributing by studying quantum-based absolute frequency references for laser stabilisation and assisting on designing the next laser ranging instrument (LRI) for a future inter-spacecraft interferometer.