NEOSTEL

The Near Earth Object Survey TELescope (NEOSTEL), also known as "Flyeye", is an astronomical survey and early-warning system for detecting near-Earth objects sized 40 metres (130 feet) and above a few weeks before they impact Earth.

NEOSTEL is a project founded by the European Space Agency (ESA), starting with an initial prototype currently under construction at OHB in Italy. The telescope is of a new "fly-eye" design inspired by the wide field of vision from a fly's eye. The design combines a single objective reflector with multiple sets of optics and CCDs, giving a very wide field of view (around 45 deg2, or 220 times the area of the full moon). When complete it will have one of the widest fields of view of any telescope and be able to survey the majority of the visible sky in a single night. If the initial prototype is successful, three more telescopes are planned, in complementary positions around the globe close to the equator.

In terms of light gathering power, the size of the primary mirror is not directly comparable to more conventional telescopes because of the novel design, but is equivalent to a conventional 1-metre telescope and should have a limiting magnitude of around 21.

The project is part of the NEO Segment of ESA's Space Situational Awareness Programme. The telescope itself should be complete by end of 2024, and installation on Mount Mufara, Sicily should be complete in 2025, having been agreed with the Italian Space Agency in October 2018. The first light of the telescope was on 20 May 2025. Development of the telescope was reported as on track in Feb 2019.