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Breakthrough Starshot plans to sail to closest star

Humanity is doing an increasingly good job of zipping around our solar system to probe things. Data is flowing back. Myriad questions, unanswerable for centuries, are being answered. But we are not yet an interstellar species. This is set to change in our lifetime.

Breakthrough Starshot – a project launched this week – wants to send a swarm of tiny robot spacecraft weighing just one gram each to our closest star, Alpha Centauri, which is about 40-trillion kilometres away.

To make that more palatable, Starshot talks about Centauri as only being 4.37 light years away.

Given their small scale, a thousand probes could be packed into a rocket and blasted into orbit. Once there, each one will unfurl thin sails. Earth-based laser beams will then fire a charge at the probes, powering them up so they can start moving towards Alpha Centauri. That will accelerate them to 20% of the speed of light. The trip will then take 20 years.

The scattershot effect of sending so many probes means hundreds can be lost to space debris, or break down. Those that make it will then take photos and send data back to Earth. Power for this process will come from miniscule radioactive sources in the probes and from their foil sails.

Backing the project is Russian philanthropist Yuri Milner, named after Yuri Gagarin – the first human in space. He has assembled a team of renowned scientists to back the project and his board includes Stephen Hawking and Mark Zuckerberg.

Speaking at the launch this week, Hawking said: “I believe that what makes us [humans] unique is transcending our limits.”   

But there are still some issues to be ironed out. Project costs will be R1.5-billion, mostly for the laser array on Earth. The nonfinancial issues have been opened to the public to solve, with “20 challenges” shared with anyone willing to give solutions. These include powering the laser array – it will need the equivalent of 100 nuclear power station’s worth of power for two minutes a shot. This energy will then have to be focused down a small beam, through the Earth’s atmosphere.

These are, however, small problems according to Breakthrough Starshot. If that is the case, Alpha Centauri could be in our sights this century.  

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Sipho Kings
Sipho Kings is the acting editor-in-chief of the Mail & Guardian

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