Irchel campus, Zurich – 29/30 June 2017
The Space-Time Explorer and QUantum Equivalence Principle Space Test (STE-QUEST) was a candidate mission for the M3 launch opportunity in ESA's Cosmic Vision programme. The mission was designed to answer a range of questions in fundamental physics by performing precision measurements with high accuracy atomic sensors. In particular, STE-QUEST would test Einstein's Equivalence Principle, which underpins the theory of General Relativity; explore the boundaries with the quantum world; and search for new fundamental constituents and interactions in the Universe.
One of the basic postulates of the theory of general relativity is the Einstein equivalence principle (EEP). As a direct consequence of the EEP, time runs more slowly near massive bodies. This effect can be detected when comparing time intervals measured by identical clocks at different depths in a gravitational field.
The Einstein gravitational red-shift probe (E-GRIP) is envisaged to be a space mission with the aim to test and improve the verification of the EEP based on precise gravitational red-shift measurements.