LISA Pathfinder shows promise for space-based gravitational-wave detectors

Nature : In December the European Space Agency launched the LISA Pathfinder satellite to test whether a space-based gravitational-wave detector would be practical. The €400 million ($440 million) mission is just a proof of concept to show that the efforts to isolate the detectors from the local environment could be successful; the final version of the mission has an estimated cost of €1 billion. Unlike the Laser Interferometer Gravitational-Wave Observatory, which recently detected the first known gravitational wave , Pathfinder does not use an interferometer. Instead, it has two 2 kg cubes, set 38 cm apart, which it keeps floating free from all interactions except gravity. Sensors measure the cubes’ movements to within 1 picometer. So far the satellite has performed exceptionally well, according to project leader Stefano Vitale of the University of Trento in Italy. Beyond just proof of concept, he says that the satellite is also being used to better anticipate the sources of noise that will have to be accounted for in the full mission.