Laser Interferometer for Thermal Expansion measurements
LITE
In the context of the SeRANIS satellite mission the LITE instrument (Laser Interferometer for Thermal Expansion measurements) is being developed to measure thermally induced deformations of novel 3D printed metallic metamaterials in space.
Contrary to the behavior of normal materials, these metamaterials were designed to contract when heated. By applying targeted heat, this metamaterial can be used in more complex mechanical connections to develop a thermally stable structure that is significantly lighter, more flexible and easier to process than the glass-ceramics traditionally used for this application.
The entire conception and realization of the LITE payload is carried out by employees of the department for Laser Interferometric Sensing. This includes the design of the interferometer, the construction of particularly temperature-insulating mounts, data readout and processing, as well as the construction, experimental testing and qualification of the instrument for later use in space.
A first LITE prototype with commercial components in the frequency range of a few Hertz already achieved a measurement accuracy of up to 100 picometers, which corresponds to about one millionth of the diameter of a human hair.
A special feature of the LITE instrument is the use of the so-called wavelength modulation technology, which requires only a minimal number of optical components as part of the interferometer. Compared to classical interferometry techniques, such as heterodyne or homodyne interferometry, only minimalistic optical setups are required. The LITE instrument and its demonstration in orbit thus represent a significant step towards a high-precision and scalable interferometry technique, opening up a wide range of new applications.
The launch of the LITE instrument into orbit is scheduled for 2025 and is being driven forward in an agile New Space approach in cooperation with industry and research institutes.
