More than €18 million for the extension of the CSL (Centre Spatial de Liège)

View of the future extensions on either side of the current CSL building. Credit: Atelier Architecture Lavaux

The Centre Spatial de Liège / Liège Space Centre (CSL, ULiège) today presented the project to extend its infrastructure and test capacities, an investment of more than 18 million euros, during the joint visit of the Walloon Minister for the Economy and Research, Willy Borsus, and the Secretary of State for Recovery and Strategic Investments, responsible for Science Policy, Thomas Dermine.


allonia and the Federal State, through Belspo (Federal Science Policy), are providing this major investment, which will enable the CSL to strengthen its position as a recognised centre of expertise in Europe for the optical calibration of future 'large' missions of the European Space Agency (ESA).

An additional 1580 m2

CSL will construct two new buildings on either side of its current facilities:

  1. A new 580 m2 storage hall (height 12m) for test equipment (support structures, thermal panels, ...) and CSL customer containers during test campaigns.
  2. A new clean room for the integration and preparation of space instruments in a suitable clean environment. This new clean room will be subdivided into an ISO7 part (standard level of cleanliness), of 580 m2, and an ISO5 part (optimised level of cleanliness, 100 times higher than ISO7), of 420 m2. It will also house the new 7m diameter vacuum chamber.

A new test chamber: FOCAL-7

The new 7-metre diameter vacuum chamber will be the largest at the CSL. FOCAL-7 (acronym for Facilité Optique de CAlibration à Liège, 7 for its diameter) will be nearly 14m long, including a 12m long by 4m wide, hyper-stable optical bench, placed on a seismic slab. The connection to a new nitrogen thermal system and to cryogenic loops will allow optical calibrations of future space, scientific or Earth observation instruments to be carried out in the required ultra-cold thermal environments (approaching absolute zero).

A budget of 18.4 million euros

The Federal Science Policy (Belspo) is financing this investment to the tune of 11 million euros, covered by a contract with ESA. Wallonia is contributing 7.4 million euros, which will be used mainly for the acquisition of the FOCAL-7 vacuum chamber.

The commissioning of this new infrastructure is planned for 2024.

Meeting the challenges of ESA's future large missions

Future European Space Agency (ESA) missions will require increasingly large optics (telescopes), often with a hyper-cold environment to improve the accuracy of measurements. The limitations of existing test facilities are a constraint in the definition and design of a future scientific space mission. FOCAL-7 will guarantee the best environmental conditions for these future missions while giving more freedom to the experts during the pre-design phases. In doing so, the CSL will consolidate its position on the European and global map of expertise in optical space calibration.

Thomas Dermine, Secretary of State for Recovery and Strategic Investments, in charge of Science Policy: "The Liège Space Centre is a key player in the Belgian space sector and is a major partner in space activities managed by the Federal Science Policy. I am pleased to confirm federal support for the FOCAL-7 project to the tune of 11 million euros. This infrastructure is necessary for the Belgian space industry, but also for European industrial players and ESA. This investment demonstrates once again the driving role that Belgium plays in the space field and particularly within ESA, of which it is a founding member and one of the main contributors."

Willy Borsus, Vice-President of the Walloon Government, Minister for the Economy and Research: "For more than 50 years, the Liège Space Centre has acquired internationally recognised experience and embodies a sector that occupies a prominent place in the Walloon economy. Indeed, the aerospace sector in Wallonia has 1,800 direct full-time employees and an annual turnover of 350 million euros. Through its Walloon Recovery Plan, the Walloon Government intends to develop a Walloon space value chain, for example in the launcher sector, as part of the New Space dynamic, and thus defend - and strengthen - its position as international leader. The CSL has a key role to play in this ambition."


Christophe GRODENT



The EUCLID telescope is a space mission of ESA's Cosmic Vision programme. The instrument will help to better understand how our Universe came into being by making measurements related to dark matter and dark energy. Experts estimate that dark matter makes up 27% of our Universe and dark energy 68%.

EUCLID is currently being tested at CSL. The centre is providing Airbus with the test facility (FOCAL-5, a 5-metre diameter vacuum chamber with hyper-cold thermal panels and extreme cleanliness) to qualify the instrument before its launch.

The test started on 17 May 2021 for a duration of 50 days under vacuum.


About the CSL (Liège Space Center)

Created in 1964 by the University of Liege, the Centre Spatial de Liège / Liège Space Center (CSL) is an applied research centre focused on the design of space observation instruments with environmental testing facilities serving the European Space Agency (ESA), the space industry and regional companies. For nearly 60 years, the CSL has been developing advanced technologies in optics, electronics, mechanics and thermics.

Among the CSL's remarkable equipment are its vacuum chambers (FOCAL: Facilité Optique de Calibration à Liège) of different diameters, which are installed in ultra-clean rooms and which allow the simulation of the severe space environment in order to test the operation of satellites and their instruments. The CSL also has at its disposal the stimuli and optical calibration systems necessary for the validation of the systems and instruments that it designs or that are entrusted to it. In addition, CSL is developing expertise in coating and surface engineering technologies (micro-texturing, ion beam polishing, etc.).

CSL maintains an approved quality management system based on the requirements of the European EN9100 and ESA (ECSS) systems to ensure the highest quality of its services. Many of the scientific instruments for notable ESA and some NASA missions have been designed, built and tested at CSL. Others have also undergone space qualification in its clean rooms: EIT-SOHO, OM-XMM, FUV-SI-IMAGE, OMC-Integral, HI-STEREO, COROT, PACS-HERSCHEL, PLANCK, SWAP-Lyra-Proba-2, JUNO, GAIA, Tropomi, MIRI-JWST, EUI-HI- Solar Orbiter, CHEOPS, WISPR-Solar Probe Plus, FUV-ICON, MSI, Aeolus, Atlid, EUCLID, etc.

As a world-renowned centre of expertise, the CSL collaborates with numerous European and international institutions (ESA, CNES, Thales Alenia Space, Belgospace, NASA, JAXA, ISRO, KARI, Airbus Defense and Space, FEDER, Wallonie, BELSPO, Wallonie Espace, etc.) and works on the continuous development of its performances in order to prepare for the evolutions of the space industry and to remain a key partner in space instrumentation and associated calibration as well as in the value chain of space data processing.

As a university research centre, the CSL allows students from the University of Liège, supervised by their teachers, to develop and build their scientific projects.

The CSL, located in the heart of the Liège Science Park, employs around one hundred highly qualified people.

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