Speaker
Description
The Laser Interferometer Space Antenna (LISA) mission is the first scientific space mission to detect and study gravitational waves from sources such as supermassive black hole binaries and intermediate mass black holes. Through a constellation of three spacecrafts orbiting the Sun and forming an accurate equilateral triangle in space of 2.5 million km long, these LISA spacecrafts exchange laser beams and measure their distance fluctuations (about 10-11 m) with their instruments MOSA (Moving Optical Sub Assembly) to detect gravitational waves. The launch is planned for 2035, on an Ariane 6 rocket.
Led by ESA, LISA is a collaborative effort involving ESA, its Member State space agencies, NASA, and an international consortium of scientists. CNES leads a community of French laboratories to jointly undertake major responsibilities in the mission and especially the performance test at CNES Toulouse of the MOSA instrument's metrological core named IDS (Interferometric Detection System). This test setup requires a dedicated development of thermal vacuum chamber and specific thermal test setup to minimize thermal noises impact from various ground and test sources: AIT room ambient temperature fluctuations, electronic temperature fluctuations, chamber active regulation, IDS thermal auto perturbations, harnesses, etc…
The main thermal objective and challenge of this IDS performance test are to achieve a very stable thermal environment with temperature fluctuations lower than 50 µK/√Hz at 30mHz and 20°C (no frequency domain analysis required). To anticipate the test setup design, CNES performs a methodological study to understand and evaluate the main drivers of thermal noise attenuation both by conduction and radiation using analytical studies. The numerical simulation of these thermal noise attenuations with high-precision calculations and associated interfaces for thermo-mechanical stability studies is also addressed. This involves software selection and recommendations in terms of modeling and approach (meshing and temporal convergence, noise wave propagation, reduced model integration, digit precision on output files etc…). This papers gives an overview of this methodology and simulation of the thermal noise attenuation to support the test setup thermal architecture of LISA IDS performance test.
