ESA’s New Flyeye Telescope to Begin Construction in Sicily

An important milestone has been reached for the ESA Flyeye-1 telescope, a vital project to monitor potentially dangerous Near Earth Objects (NEOs). The structure had been in development for years, and a last-minute legal battle was fought over it in the last few weeks. It was won on Sept. 24, 2024, and the telescope is now approved to begin construction in Sicily, Italy.

Looking for Near Earth Objects

“Near Earth Objects” are bodies such as asteroids or comets orbiting the Sun, whose trajectories could potentially intersect or pass near the Earth’s orbit. Objects of this kind range from sizes of a few meters to some kilometers. We’re already aware of more than half a million, but as object size gets smaller, there’s a large predicted population of bodies we haven’t detected yet.

Asteroidal typologies near Earth. Credits: ESA — *Types of Near Earth Asteroids. Credits: ESA*

NASA, ESA, and other Space Agencies have been developing solutions to tackle this factor of risk, with activities spanning from closer cooperation on the matter, sky surveillance and data exchange, to the construction of telescopes, and even dedicated space missions to prove asteroid safeguard concepts, such as the successful DART mission.

The European Space Agency Planetary Defence division has been working on a network of advanced observatories. They are dedicated to continuously surveying the sky, each night, and helping discover and catalog NEOs.

The ESA Flyeye Telescope, a render showing the telescope pointing an (enlarged) asteroid in the night sky — *The ESA Flyeye-1 telescope. Credits: ESA*

The first telescope of this kind, named Flyeye-1 has been designed by OHB Italy, working with ESA and the Italian Space Agency (ASI). Its deeply innovative design allows a large Field of View with much more detail and resolution than conventional telescopes. The observatory will be constructed on Mt. Mufara, on the Madonie mountains in Sicily, Italy.

A design inspired by nature

The design of the Flyeye telescope had to offer a large Field of View of the night sky, since it aims to accelerate the cataloging phase of new NEOs. When in operation, Flyeye-1 will automatically take exposures of the night sky every few minutes. The observation facility software will then quickly elaborate the gathered data on-site. If a difference is detected, it will be submitted to the Planetary Defence Near-Earth Object Coordination Centre (NEOCC). Further analysis from scientists will begin from there, with more precise, smaller FoV telescopes around the globe.

The Flyeye-1 Telescope completed at the OHB Italy facility in Turate — *The complete Flyeye telescope out the OHB facility in Turate. Credits: OHB Italy*

An image resolution as high from a single sensor would have been almost impossible, therefore ESA and its partners developed a new design inspired by the compound eyes of insects like flies or bees: the light reaching the telescope’s 1-meter diameter primary mirror, will be then split by a prism into 16 different segments of focused light. Each segment will have a dedicated sensor, therefore permitting a view of 45 square degrees: as wide as 16 times the diameter of the Moon in our night sky.

An illustration of the light path inside Flyeye — *An illustration of the light path inside the Flyeye telescope. Credits: ESA*

The telescope development began in 2016, it has been completely built in Italy’s OHB facilities in Lombardy and was moved to the ASI Centre for Space Geodesy near Matera for testing in July of this year. According to ESA, the agency has started the development of a second-generation Flyeye telescope for the network. It will have a similar Field of View and an even higher resolution. Since the project is focused on a planet-wide network, Flyeye-2 will be deployed in the Southern Hemisphere by 2028.

A troubled procedure for construction approval

The telescope location had been approved for the summit of Mount Mufara, near a smaller telescope from the GAL Hassin centre, and some skiing facilities, back in 2018. The observatory facility designs were then assigned to the EIE group the following year. The Madonie mountains host numerous protected natural areas, and were chosen as they have limited human presence and little light pollution.

The groundbreaking ceremony for construction should have happened on September 6th, 2024. However, some weeks before, a joint group of representatives from the Italian Alpine Club and various Environmental Associations presented an appeal to the Sicilian Regional Administrative Court (TAR), which elected to temporarily pause the construction while examining the case. The group called for a rediscussion of the facility design, deemed too invasive for the area, or to consider another (not specified) location to place the telescope.

The render of the finished Telescope complex for the Flyeye 1 NEO monitoring observatory from ESA — *An official render of the Flyeye facility, on Mount Mufara, Italy. Credits: ESA*

Therefore as days passed, the ceremony was postponed to a still unspecified date, while the involved parties dealt with the situation. Designers argued the telescope facility was intrinsically built to release as little light as possible, and therefore would not disturb the environment. However, given the nature of the observatory and its necessity for on-site data elaboration, and ease of accessibility, a road leading to the site will need to be constructed. On September 24, the TAR finally decided to reject the appeal, permitting the project to start construction in the following weeks.