Illustration by Chris Philpott

How it works: Breakthrough Starshot

It's one of humanity's most ambitions projects, but how exactly will it work?

It would take standard rockets 100,000 years to reach the Solar System’s nearest star, Alpha Centauri. Breakthrough Starshot hopes to do it in 22. A spacecraft carrying 1,000 ultralight probes, weighing 10g each, would be launched into Earth orbit. The ‘mothership’ would release the tiny probes one at a time, which would then ride the beams of a colossal ground-based laser array. The project has received £70m from entrepreneur Yuri Milner, and backing from Prof Stephen Hawking.

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1. Mothership

Releases the probes.

2. Light sail

Probes are released one at a time and unfurl reflective sails. These are 4m across but just a few hundred atoms thick. At the centre of each sail is a chip the size of a postage stamp, containing a camera, processor, battery and transmitter.

3. Laser array

A ground-based grid of lasers, at least a kilometre across, fires more than a gigawatt of laser energy into the sky.

4. Acceleration

The beams converge and shine on each probe for 10 minutes, accelerating them to between 15 and 20 per cent of the speed of light.

5. 22-year journey

The probes cannot steer or slow down, so they must be precisely aimed for a close flyby with distant planets.


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