UF Length Stability Testing for the LISA Telescope Structural Thermal Model

The Laser Interferometry Space Antenna (LISA) is an upcoming space-based ESA lead gravitational wave (GW) detection mission, with high sensitivity in the milliHertz GW gap left between earth based GW detectors and pulsar timing arrays. The mission consists of 3 spacecraft (SC) in heleocentric orbit, with exchanged laser beams between each pair of SC monitoring displacements at the level of picometers in the LISA band between housed test masses. This requires LISA's telescopes, provided by NASA, demonstrate picometer level stability along the optical path. To test this University of Florida's (UF) LISA Telescope team had developed procedures to measure length stability in a fully functional copy of the LISA telescope, the Engineering Developement Unit (EDU). These plans and methodologies were adapted due to scheduling to accomodate the testing of the more simple Structural Thermal Model (STM) of the telescope. This is a non-functional equivalent containing all bonds and mounting but none of the polished mirror surfaces. In this presentation I go over how we've adapted the original EDU testing procedures for STM length stability testing, and the current status of such tests.