Numerical Verification of Thermal Stability Requirements for LISA Inertial Sensor in the Frequency Domain

This paper describes the thermal modeling and analyses performed on the LISA Technology Package (LTP), with special attention to the frequency domain requirements on the sensitive instrumentation. The new approach is presented, and the modeling and analysis phases are described in detail.

Results about LTP thermal stability in the frequency domain are shown, and obtained though two alternate approaches. The first one consists in the study of the transient response of the system to a periodic input with a frequency equal to the minimum frequency of interest, using the well known low-pass filtering properties of the thermal systems. The second is based on the generation of a time dependent input, starting from its Power Spectral Density definition: this input is used to run a transient thermal analysis and finally transform its results into the frequency domain.

Thermal stability assessment studies have been performed also at spacecraft level and are well described in [ref. 3].