A giant mirror drifts slowly through space between the Earth’s surface and the sun, intercepting the rays of sunlight before they reach the Earth, and deflecting them safely away.

The mirror, made up of millions of silicon chips, is situated at a point in space where the sun’s gravity and the Earth’s cancel each other. This vast structure, assembled painstakingly for years by spacecraft, drifts naturally away from its starting point over time, but complex on-board systems nudge it gradually back to resume its vital role in keeping us safe.