Testmassen
Testmassen (test masses) are physical bodies used in experiments to probe external forces, such as gravity or electromagnetism, while perturbing the field as little as possible. In many contexts a test mass is treated as a point-like object with negligible own field compared to the field it experiences, so its motion serves as a faithful indicator of the external force or metric.
In gravitational physics and general relativity, a test mass is expected to follow a geodesic of spacetime
On Earth, test masses appear in precision experiments and gravitational-wave detectors. In LIGO and Virgo, for
In space, drag-free missions employ freely floating test masses to provide an inertial reference. LISA Pathfinder
Key design goals for test masses include minimizing non-gravitational forces, controlling charge and magnetic interactions, and