ET Germany Newsletter #3 – ETC Infos

Update from the International Einstein Telescope (ET) Collaboration

Our international Collaboration continues to grow steadily. We are now more than 2,000 members from 291 institutions across 34 countries. This broad community is one of our greatest assets as we move into the next decisive phase of the project.

This year, a transition in leadership is approaching. After many years of service in building and shaping both the project and the Collaboration, Michele Punturo and I will hand over responsibilities to a new team. Our mandate concluded on 22 March 2026, and the new team took over: Michele Maggiore and Angelique Lartaux. Their election statement is available on the ET Wiki (https://wiki.et-gw.eu/CB/ElectionSPDSP2026), and they also presented their vision for the future of ET at the last ET Monthly Meeting.

ET at the governance level: As one of the largest international astronomy projects of the future, ET is supported at the governance level by the Board of Governmental Representatives (BGR), its highest decision-making body. The BGR brings together representatives of those nations that proposed ET during the ESFRI process, have committed substantial funding, and/or are connected to the potential sites.
Recently, the BGR issued a new mandate to the Einstein Telescope Organisation (ETO), defining clear and time-critical objectives for 2026. Importantly, this document formally recognises the ET Collaboration as a key stakeholder — particularly in the areas of observational science and instrumentation. This recognition underscores the central role of our scientific community in shaping the project’s future.
The overall process leading to a decision on site and detector geometry is scheduled for completion in the third quarter of 2027. Two major activities are currently underway to support this milestone:

• Site Selection Criteria: A dedicated committee is developing a comprehensive framework to guide the site decision. The criteria will address scientific and technical performance as well as cost, risk, environmental considerations, and other relevant factors. They will form the basis for bid book preparation and ensure a structured, transparent, and robust evaluation process.
• Geometry Comparison: At the request of the BGR, ETO — in close collaboration with the ET Collaboration — is preparing a detailed report comparing the two geometry options: a triangular configuration and a configuration based on two L-shaped interferometers. This assessment will examine scientific reach, technical and programmatic risks, and cost implications. 

On the scientific and technical side, the Preliminary Detector Technical Design Report (Pre-TDR) is nearing completion. It has successfully passed internal review and will soon be submitted for external evaluation within the EU-funded ET Preparatory Project (ET-PP). As a central deliverable of ET-PP, the Pre-TDR marks a major milestone and is due in April.

In parallel, the Collaboration is preparing an additional document examining the impact of site quality on ET’s detector design and its innovation potential.

Overall, the Collaboration is in excellent shape. It brings together outstanding and highly committed scientists from around the world and continues to inspire the next generation to join and contribute. ET is not only a groundbreaking project in fundamental physics; it is also a powerful driver of innovation, technological development, and knowledge transfer. At the same time, it captures the imagination of the broader public and strengthens curiosity about our Universe.

Let me conclude by expressing my sincere gratitude to you, the German members of the Collaboration, for your dedication and contributions. Your engagement is vital to ET’s success. I very much look forward to seeing ET continue to grow and flourish in the years ahead.