Development of a compact laser-interferometric displacement sensor for space applications

Kurzfassung

The aim of this thesis is to develop a compact laser-interferometric displacement sensor for space applications based on requirements of the ongoing SeRANIS mission. Alongside missions like GRACE and LISA, this finalized displacement sensor on the SeRANIS mission could represent one of the pioneering optical interferometers in space. The displacement sensor will be designed to be adaptable for utilization in other missions in space as well. The initial phase aims to establish a prototype demonstrating sub-micron displacement measurements across centimeters to meters [34]. Therefore, four interferometer-based setups will be be demonstrated and tested for their ability to reproduce a generated displacement. Subsequent noise measurements will be conducted based on the chosen prototype. The challenge of adapting a standard interferometer for space applications lies in ensuring its resilience to harsh environmental conditions. This necessitates careful selection of space-certified optical components. Individual components will undergo additional tests to quantify the emitted magnetic fields, which can cause disturbances with magnetometer readings on the satellite. Furthermore, the laser beam will undergo further tests to ensure its quality and stability. A first version of an engineering model (EM) will be developed, that will encounter several tests regarding its thermal and vibration stability. Optical simulations are conducted to assess the performance of the components undergoing tilting movements and rotations. Then, rotation tests are performed using rotation mounts to evaluate the stability of individual components and entire systems in the laboratory. Finalizing, heat stress tests are conducted inside an oven to assess thermal stability.