Lessons Learned from Thermal Vacuum Testing of LISA Pathfinder over three system level Thermal Tests

The LISA Pathfinder spacecraft is undergoing an extensive thermal testing campaign over three system level thermal balance / thermal vacuum tests in 2010, 2011 and 2015 as it prepares for launch. These thermal tests have taken place at IABG in Munich, Germany, using a range of their thermal facilities including testing with solar simulation lamps and with a range of flight and structural/thermal model (STM) hardware. They have covered a range of testing requirements from simulation of Launch and Early Phase (LEOP) operations, to thermal workmanship cycling and complicated thermal noise Power Spectral Density analysis on the main payload. This paper presents the lessons learned and best practices taken from the various LISA Pathfinder test campaigns including: • Thermal noise analysis techniques for model correlation • Extrapolation and calculation of temperature stability trends • High stability payload measurements • Detailed multi-phase thermal model correlation • Techniques for predicting and analyzing many thermal data channels efficiently LISA Pathfinder is a technology demonstration mission for detecting gravity waves, funded by the European Space Agency (ESA) with Airbus Defence and Space as prime contractor, which using these techniques has been successfully shown to meet a challenging thermal design including a tight stability requirement for the sensitive instrument payload.