Adam Hibberd

Spinning a sling, we whirl a stone. Its speed builds, and if released at the lowest point, it flies farthest. In space, the gravity of the Sun acts as the strap: the probe dives as close to the star as possible, and at the moment of maximum speed, a brief engine thrust, like a yank of the hand, gives it a huge boost.

A handful of coins accelerates to one-fifth the speed of light. That's what Coracle interstellar probes will be like — tiny spacecraft weighing just a few grams, each with an ultrathin sail film. A powerful laser beam pushes them forward: light presses on the sail like wind fills a yacht's sails, except instead of air, it's a stream of photons.

In July 1988, the automatic station Phobos 1 lifted off from Earth. Its target was Mars and its mysterious moon, Phobos. Two months after launch, an incorrect command was sent, communication was lost, and the probe fell silent forever. Since then, it was considered lost. Decades later, astronomers spotted a strange object—1998 KY26.