LISA Pathfinder is an ESA technology test mission for the LISA mission. LISA Pathfinder is testing most LISA technologies in space and will validate a complete model of all physical noise that can be extrapolated to the full LISA mission.
LISA Pathfinder places two test-masses in a nearly perfect gravitational free-fall and controls and measures their motion with unprecedented accuracy. This is achieved through state-of-the-art technology comprising inertial sensors, a laser metrology system, a drag-free control system and an ultra-precise micro-propulsion system. All these technologies are essential not only for LISA - they also lie at the heart of any future space-based test of Einstein's General Relativity. The Albert Einstein Institute is one of the leading mission partners.
LISA Pathfinder was launched on December 3, 2015, at 5:04 CET onboard a Vega rocket from the European spaceport in Kourou, French Guiana. You can find an overview of the current mission status on the LISA homepage.
In early June 2016, the LISA Pathfinder Science Team published results from the first two months of operations. They showed that LISA Pathfinder has successfully demonstrated the technology for a gravitational wave observatory in space such as LISA.