LISA optics model

The LISA experiment has six telescopes, in three spacecrafts, in separate orbits about the sun. There is a continuous laser link between all the spacecrafts. The use of standard optical design and analysis of computer codes is not possible because of the large, 5 million km, distances between the spacecrafts, the fact that the spacecrafts are in separate orbits and the need for subpicometre accuracies. A description of the approach used to model the optics in the spacecraft in orbit is presented and use of this model in acquisition and control strategies is briefly discussed.