The LISA mission
LISA - Laser Interferometer Space Antenna - has been selected by the European Space Agency as the third L3 Large-Class space mission in the "Cosmic Vision" program. LISA is going to be the first completely space-based low-frequency Gravitational Wave observatory. The nominal launch date is set to 2035.
It's going to be a triangular constellation of satellites, located at the vertexes of a 2.5 million km triangle, on an Earth-trailing orbit around the sun, about 20° behind the Earth.
LISA is going to be sensitive to Gravitational Waves (GW) from extreme astrophysical phenomena in the low-frequency band, such as the inspiral of Binary Black Holes and Extreme Mass Ratio Inspirals. LISA will open a new window on the low-frequency GW spectrum, that can not be accessed from Earth because of the terrestrial seismic noise. A space-based GW detector would also allow for joint detection of gravitational signals together with the ground-based detectors of the LIGO-Virgo-KAGRA collaboration.