LISA ORBIT SELECTION AND STABILITY

The Laser Interferometer Space Antenna (LISA) is a space mission desig ned to detect gravitational waves in the frequency range from below 0. 0001 Hz to 1 Hz by measuring changes in the distance between spacecraf t separated by several million kilometres. The spacecraft orbit in a t riangular formation forming three (not independent) interferometers wi th arm lengths determined by the distances between the vertices. The n ominal orbit configuration is described and contrasted with an alterna tive configuration. Changes in the distances between the vertices caus e a Doppler shift in the laser signals between spacecraft. The size of the measurement error introduced by this Doppler shift is dependent o n the stability of the spacecraft formation.