LISA Pathfinder Gravitational Wave Detector

'LISA Pathfinder will pave the way for future missions by testing in flight the very concept of gravitational wave detection: it will put two test masses in a near-perfect gravitational free-fall and control and measure their motion with unprecedented accuracy. LISA Pathfinder will use the latest technology to minimise the extra forces on the test masses, and to take measurements.'

Click http://sci.esa.int/lisa-pathfinder/ link to open resource.