The European Space Agency's LISA Pathfinder mission has officially concluded, and it has been a resounding, unmitigated success. The probe was designed to test the incredibly delicate technology required to build a space-based gravitational wave observatory.



To detect the subtle ripples in spacetime caused by colliding black holes, we need to measure the distance between free-falling test masses with mind-boggling precision. LISA Pathfinder proved that we can isolate these masses from all external forces—solar wind, radiation pressure, thermal shifts—well beyond the necessary requirements. It lays the groundwork for the magnificent full-scale LISA observatory planned for the 2030s.