Technology developer and manufacturer Demcon, together with TNO, delivered the first Laser Projection System last week. Destination is the European Southern Observatory (ESO), where TNO and ESO will test the system. In total, Demcon company Focal and TNO will build nine systems for ESO's Very Large Telescope and Extremely Large Telescope in Chile. The systems project so-called 'laser guide stars' into the atmosphere to help the large telescopes better focus on astronomical objects far away. This will give astronomers sharper images of the universe. In doing so, they hope to make new discoveries, for example about the evolution of the universe after the Big Bang and the formation of stars and galaxies.

Telescopes on Earth suffer from the atmosphere, which obscures the view due to turbulence. That is why mega-telescopes such as the Very Large Telescope (VLT) and the Extremely Large Telescope (ELT) are located on top of a mountaintop. That is in Chile for the VLT, which consists of four telescopes, and the ELT, which is still under construction as the world's largest telescope.

Artificial star as benchmark

To further reduce the effect of the remaining atmospheric disturbance, the Laser Projection System (LPS) has been developed. This instrument projects an artificial star at the outer edge of the atmosphere at an altitude of ninety kilometres. Since the properties of this 'laser guide star' are known, the influence of the atmosphere can be deduced from observations of it. Astronomers use this information to correct the images they are really interested in.

Follow-up to successful deployment

The 'laser guide star' technology was developed more than a decade ago by ESO in collaboration with TNO, which built four LPS systems for one of the VLT telescopes. In fact, these were still prototypes, but they work well and indeed provide better observations. Reason for ESO to order another nine systems from TNO: three for the VLT (one for each of the three other telescopes) and six for the ELT. TNO decided to develop an improved, industrially mature version of the LPS, paying close attention to reliability, availability, maintainability and safety. For this complex feat of precision optics and mechanics, TNO turned to Demcon focal, a specialist in optomechatronic systems. Demcon focal took care of the laser adjustment and control electronics. Naturally, there was close cooperation with TNO, as the various components had to fit together perfectly.

Improved system

The main improvement of the laser adjustment concerns maintenance, says Marko van Dalfsen, project leader at Demcon focal. "For service and maintenance, submodules can now be replaced very quickly and easily. As a result, the system has much less downtime. Astronomers can thus make more observations with their precious telescopes." In addition, the performance of the LPS has been improved, adds TNO project manager Wouter Jonker. "Moreover, it has now become a robust system, making it easy for us to build it in series. If ESO wants nine, we deliver nine." Construction is done at Demcon focal, reports Van Dalfsen. "This is where we build the parts supplied by TNO and Focal together into a complete system."

Testing and training

For the first system, the assembly has recently been completed. ESO did a 'test readiness review', an important milestone before shipping to ESO in Garching, near Munich (D). There, TNO will conduct tests in a climate chamber, to test the system under the conditions that occur on top of a mountain peak, reports Jonker. "We will also train ESO personnel in service, maintenance and use of the system. ESO is then expected to officially take delivery of the system in the summer and use it for the first time in observations with a VLT telescope in mid-2025. A team from Demcon focal and TNO will be in Chile to help integrate the LPS on the telescope." Meanwhile, Demcon focal and TNO can start building systems two to nine. ESO is in a hurry to do so, as astronomers are eager for telescopes that deliver even sharper images. 'First light' on the ELT is planned for 2027.

More work for Demcon focal

With the delivery of nine systems to ESO, the story is not over yet, Jonker knows. "We are now putting the final touches to a licence agreement with ESO. That stipulates that we can use everything we developed in this project in systems for other clients. Globally, our system is absolutely unique. ESO will soon have the very best equipment and we know there are other observatories that would like to have it. I estimate that we can sell about 20 more units." So a lot of work for Demcon focal could result from that.

Knowledge transfer to industry

Albert Borreman, managing director of Demcon focal, is happy with all the work coming to him and also appreciates the knowledge transfer. "We often see that knowledge from TNO gradually trickles down to industry, in this case to Demcon focal. Think about how designs are made and how certain lens views and connection principles are applied. I think it's golden, how industry is taken on board to slowly pick up new technology. For us, it was also important to meet ESO's standards so that we can position ourselves as a partner for astronomy projects from now on. With help from with TNO, we learned that in this project."

Equal partners

Above all, Borreman is proud of the final result. "We put a lot of time into it and carefully developed the design, with the result that a lot of parts were 'right first time'. We started at the time of Covid-19 and then there were the supply problems for crucial components that affected the whole industry; we survived those too. I attribute that to the commitment of the project team and great collaboration." There was by no means a standard customer-supplier relationship, confirms Wouter Jonker of TNO. "Contractually it might have been, but in practice we worked together as equal partners."

Source image: TNO