Gerhard+Heinzel

LISA (Laser Interferometer Space Antenna) is the joint NASA/ESA project for the detection of gravitational waves (GWs). It consists of three spacecraft in an equilateral triangle of 5 million km sides, orbiting on an Earth-like orbit around the sun. Each spacecraft houses two free-falling test masses that determine the distances to the other spacecraft. Distance changes due to GWs are monitored by laser interferometry, down to minute relative changes in the order of 10−23. The extremely small GW signals make a technology demonstrator, the “LISA Pathfinder” LPF, very desirable, to verify that the employed technologies of (1) laser stability, (2) picometer interferometry, (3) drag-free control, and (4) micronewton thrusters can meet the challenge. The LPF will be carried on the ESA Smart-2 mission to be placed near the Lagrange point L1, with launch expected for 2009. LPF will consist of one spacecraft with two independent test masses; the distances between these two test masses, and the position changes with respect to the optical bench (spacecraft) will be monitored with a resolution only one power of ten away from the requirements of LISA proper. A flight module of the optical bench has been built and has passed the necessary tests for space qualification.
 * LISA Pathfinder **ppt/pdf
 * Gerhard Heinzel and Albrecht Rüdiger, **** Max-Planck-Institut für Gravitationsphysik (Albert Einstein Institut), Hannover **