NASA is preparing a giant gravity wave observatory that will be placed in space

NASA is preparing a giant gravity wave observatory that will be placed in space. The Laser Interferometer Space Antenna (LISA) consists of three spacecraft forming a equilateral triangle with 5 million km armlength. Changes in the armlength of 20pm will be detected. The ends of each interferometer arm are formed by freely floating masses that must be kept inertial (i.e. free of non-gravitational forces) at an unprecedented level. The spacecraft that shield the proof masses are servoed to exactly follow the proof masses. Small stray forces that could act between the spacecraft and the proof mass must be understood at an extremely delicate level. From our fundamental physics research we have gained the necessary expertise to build ultra-sensitive torsion balances to study these forces. Students working on this project will learn a broad spectrum of the experimental techniques necessary to measure forces that compete with gravitational waves, but they will also be introduced to the overarching physics.