LISA Pathfinder (LPF) was a space mission by the European Space Agency (ESA). It was launched on 3 December 2015 on a Vega rocket, and operated until July 2017. The mission tested key technologies needed for the Laser Interferometer Space Antenna (LISA), an ESA gravitational wave observatory planned to be launched in 2035. Formerly, the mission was known as Small Missions for Advanced Research in Technology-2 (SMART-2) of the Small Missions for Advanced Research in Technology ESA scientific programme. The LISA Pathfinder scientific phase started on 1 March 2016 and lasted almost sixteen months. In June 2016, ESA announced that LISA Pathfinder demonstrated that the LISA mission is feasible, paving the way for the official adoption of the LISA mission.