Space-Time Research in QUEST comprises a whole spectrum ranging from fundamental theories proposing the emergence of space-time from microscopic constituents until the advancement of geodetic technology for an improved understanding of the system earth and its complex processes. The research groups in this area influence each other in more than one way.

Einstein's general relativity (Prof. Domenico Giulini) is being challenged by lunar laser ranging (Prof. Dr. Jürgen Müller). The cutting-edge interferometers and clocks developed for the gravitational wave astronomy (Prof. Dr. Bernard Schutz, Prof. Dr. Bruce Allen) should fly on the satellites of new geodesy missions (Dr. Benjamin Sheard) for which geodetic quantities are modelled at the millimetre  accuracy level (Prof. Dr. Jakob Flury). String cosmology (Jun.-Prof. Marco Zagermann) suggests an imprint of inflation and of cosmic strings on the gravitational wave background (Prof. Dr. Bernard Schutz, Prof. Dr. Bruce Allen), but also proposes a cosmological variation of fundamental constants (Prof. Domenico Giulini) which is targeted in QUEST (Prof. Dr. Jakob Flury and others). A next-generation gravity field mission (Dr. Benjamin Sheard) will test the equivalence principle (Prof. Domenico Giulini) and contribute to refining the GNSS (Global Navigation Satellite Systems) (Prof. Dr. Steffen Schön).