Point Ahead Angle Mechanism (PAAM) Stability Testing for LISA at the University of Florida

The future gravitational wave detector, LISA, consists of three spacecraft forming a triangular constellation in orbit around the Sun. The arm length of the constellation is 2.5 Gm, resulting in a 8.3 second time delay for light sent between spacecraft. Furthermore, the triangular constellation evolves throughout its orbit. This means that light must be sent to where the receiving spacecraft will be using an adjustable point-ahead angle. The Point Ahead Angle Mechanism (PAAM) will provide an adjustable point-ahead angle out of the plane of the constellation to compensate for the travel time of light between spacecraft and the evolution of LISA’s orbit.

As with all components in the optical path of the interferometer, the PAAM must meet length (picometer) and angular (nanoradian) stability requirements. The LISA group at the University of Florida is preparing to conduct a series of stability tests on the PAAM Engineering Model 1 (EM 1). In this talk I will discuss the progress in preparing and validating the PAAM performance testbed, which integrates EM 1 to perform a series of positional and angular stability tests, and the current status of such tests.