LISA mission and system design

Abstract

A gravitational-wave observatory is recommended as the seventh cornerstone in ESA's long-term programme in space science, known as `Horizon 2000 Plus'. A concept for such a gravitational-wave mission, LISA, was studied within ESA in order to assess its feasibility and technological requirements. Six spacecraft in a triangular configuration form a laser interferometer with baselines of . This interferometer will orbit the Sun at a heliocentric radius of approximately 1 AU, following the Earth at an angular distance of . Launch of all six spacecraft will be with an Ariane 5 launch vehicle and jettisonable propulsion modules will place the spacecraft in their respective orbits. All six spacecraft are identical and accommodate a payload module which houses a test mass with capacitive sensors, a transmit - receive telescope and lasers. The interferometer arms are determined by the test masses and the spacecraft must shield the test mass from all extraneous disturbances, requiring a `drag-free' control system which uses electric thrusters to make the spacecraft follow the test mass.