ESA’s “fly-eye” telescope to watch for Earth-threatening asteroids

One property of the housefly is that swatting one is hard. One of the reasons for this is flies have eyes designed for avoiding such a day-ruining event by detecting motion over a wide field of vision. ESA is developing a telescope based on a fly’s eye as a new asteroid-hunting tool that could be the basis for a new asteroid defense network.
The prospect of a rogue asteroid slamming into the Earth is certainly an unsettling one, so its small wonder that ESA, NASA and others are keen on identifying any potential candidates that might need dealing with in the future. Ideally, the solution would be to set up a telescope to repeatedly scan the entirety of the heavens, but it’s very big sky and an approaching asteroid might not give much notice. It’s a bit like a ship’s lookout. One person can’t look at the entire horizon without a good chance of missing something, but a team has a better chance.
In the case of asteroid hunting, the lookouts would need to be a global network of telescopes because the targets are far too small and faint to be seen with the naked eye. But it would be fantastically expensive just to buy all the telescopes required for such a network, and those scopes wouldn’t necessarily be the best instruments for hunting asteroids. That’s because telescopes are very good for capturing images, but what an asteroid hunter needs is the ability to track movement across the sky.