LISA Pathfinder was an ESA mission designed to test the technologies required for the future LISA gravitational-wave observatory, the agency’s third large mission (L3).
The satellite was launched in December 2015 and initially planned to operate for one year. Following its excellent first results and in response to renewed interest in gravitational-wave science with the first direct detection of gravitational waves by the Laser Interferometer Gravitational-wave Observatory (LIGO) in the autumn of 2015, announced in February 2016, ESA extended the mission a further six months.
LISA Pathfinder’s goal was to verify noise specifications with an accuracy a factor of ten better than the requirement for LISA, for detection of gravitational waves between 0.1 mHz and 1 Hz. The mission confirmed the feasibility of the noise level expected for LISA.
A range of technology experiments were also run during the extended mission to better understand the instrument and distinguish the effects of certain parameters. In April 2017, the satellite’s orbit was modified to avoid perturbations during the final weeks of the science experiments.
LISA Pathfinder has thus paved the way for the LISA mission officially selected by ESA’s Science Programme Committee (SPC) on 20-21 June. LISA is scheduled to launch in 2032.