LISA & LISA Pathfinder - Gravitational wave detection from space 

About the project

The proof of the 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.

LISA Mission ©ESA–C.Carreau

In order to be able 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 will use 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 - all key techniques of the LISA mission could be tested in space under the existing conditions.

LISA optical bench ©University of Glasgow and University of Birmingham

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 component of the interferometer was also supplied by Heraeus: Two cubes made of a gold-platinum alloy served as end mirrors for the system. The distance between the cubes, and thus between the different spacecrafts, is controlled by highly accurate measurement technology and with the help of laser beams. In this way it is possible to detect space-time changes in the minute range and the resulting changes in the distance between the satellites, caused by gravitational waves. 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.

Related links:

  • Official  website of project LISA
  •  Video of Max Planck Institute for Gravitational Physics & Milde Marketing Science Communication about the interferometer