LISA & LISA Pathfinder - Gravitational wave detection from space

About the project

The proof of gravitational waves predicted by Einstein is regarded as one of the greatest milestones in the history of physics. In 2017, the first measurement within the LIGO & VIRGO project was awarded the Nobel Prize in Physics.

In order to measure even more sensitively and, above all, with less interference, scientists of the European Space Agency (ESA) are working on the space-based measurement of gravitational waves as part of the LISA (Laser Interferometer Space Antenna) mission. While the measurements in the LIGO project are earth-based, LISA uses satellites to take measurements from space for the first time. This offers the advantage of detecting even lower frequency ranges of gravitational waves and eliminating disturbing influences on the earth.

Astronomers tested the LISA mission as early as 2016 using the predecessor project LISA Pathfinder. As part of LISA Pathfinder, scientists sent a test satellite into space with a smaller replica of the future measurement and control systems. The mission was successful - testing all key techniques of the LISA mission in space under the existing conditions was possible.

A photo showcasing the LISA Pathfinder ESA mission

Our contribution

The heart of the LISA Pathfinder measurement and control system, and of the future LISA mission, is an interferometer whose optics are made of Heraeus Suprasil quartz glass. Suprasil enabled measurement results that far exceeded the scientists' expectations of accuracy. Another interferometer component supplied by Heraeus was two cubes made of a gold-platinum alloy to serve as end mirrors for the system. Highly accurate measurement technology with the help of lasers controls the distance between the cubes, and thus between the different spacecraft. In this way the detection of space-time changes in the diminutive range and the resulting changes in the distance between the satellites caused by gravitational waves is possible. These distances serve as a reference and are therefore essential for the measurement of gravitational waves.

Over the next few years, ESA will prepare the LISA mission based on the knowledge gained – it is expected to launch in 2034. Heraeus will also supply high-purity, extremely radiation-resistant quartz glass for the optical components for this project.

A picture of the LISA optical bench, a vital component in Heraeus' gravitational wave detection research
©University of Glasgow and University of Birmingham