hide
Free keywords:
Astrophysics, Instrumentation and Methods for Astrophysics, astro-ph.IM
Abstract:
The tilt-to-length coupling during the LISA Pathfinder mission has been
numerically and analytically modeled for particular timespans. In this work, we
investigate the long-term stability of the coupling coefficients of this noise.
We show that they drifted slowly (by 1\,$\mu$m/rad and 6$\times10^{-6}$ in 100
days) and strongly correlated to temperature changes within the satellite
(8\,$\mu$m/rad/K and 30$\times10^{-6}$/K). Based on analytical TTL coupling
models, we attribute the temperature-driven coupling changes to rotations of
the test masses and small distortions in the optical setup. Particularly, we
show that LISA Pathfinder's optical baseplate was bent during the cooldown
experiment, which started in late 2016 and lasted several months.
