Thermal Stability Analysis in the Frequency Domain using the ESATAN Thermal Suite 2008-01-2078
An increasing number of spacecraft missions have very stringent requirements for thermal stability to avoid thermally driven noise from affecting the main observables. For example, it may be necessary to reduce temperature fluctuations in the neighbourhood of the instrument below micro-Kelvin (μK). Consequently, the influence of fluctuations in boundary temperature or internal power dissipation on temperature at the instrument detector must be precisely evaluated.
Thermal stability requirements are usually expressed as an upper limit on the linear spectrum density (LSD) of temperature fluctuations. This indicates the strength of the response to a perturbation of a given frequency, and is usually stated in units of K/√Hz. The LSD can be estimated by running a succession of transient simulations and applying Fast Fourier Transforms techniques, but this method is time-consuming and has numerical limitations. An alternative approach is to linearise the system and go directly to the frequency domain, in order to compute the transfer function from which the LSD can be obtained.
The latter analytical capability is now fully integrated into the ESATAN Thermal Suite. A new solution module computes the frequency-response transfer function from which the LSD can be calculated. This innovative integration into a thermal network software allows you to perform the core of the thermal stability analysis entirely within a single environment.