Alpha Centauri mission: Stephen Hawking and Yuri Milner plan to send tiny spacecrafts to the stars

Stephen Hawking and Yuri Milner at the Breakthrough Starshot announcement

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Professor Stephen Hawking and tycoon Yuri Milner have revealed plans to develop a method of space travel that will go 100 million miles per hour – with the potential of reaching the stars within a generation. The Breakthrough Starshot concept, announced at the One World Observatory in New York, will use light beams to propel 'nanocrafts' (or tiny spacecrafts) to around 20% of light speed.

If the technology is successful, it would mean reaching our closest neighbouring star Alpha Centauri 20 years after launch. Announcing the project, Russian entrepreneur, venture capitalist and physicist, Milner said: "Can we reach the stars? Can we literally reach the stars? Can we do it in our lifetimes?

"The problem is space travel as we know it is slow. If voyager left our planet when humans first left Africa, it would be arriving at Alpha Centauri just now. How do we go faster and further? How do we make next leap?"

He said we now have three existing technologies that can be combined to produce high speed space travel - microfabrication, nanotechnology and photonics. "Early proposals focused on sails driven by sun. Our own star, as big as it is, cannot produce the force required. For interstellar on human timescales, stronger wind on smaller boat," Milner said.
Alpha Centauri is four light years away, or 25 trillion miles. Using today's technology, it would take 30,000 years to reach it. Should the technology being proposed in Breakthrough Starshot prove successful, we could get there within 20 years.

The Breakthrough Starshot panel, including Freeman Dyson

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Hawking said: "What makes humans unique? I believe what makes us unique is transcending our limits. Gravity pins us to the ground, but I just flew to America. I lost my voice but I can speak thanks to my voice synthesiser. How do we transcend these limits? With our minds and machines."

"The limit that confronts us now is the great void between us and the stars. But now we can transcend it. With light beams, light sails and the lightest spacecraft ever built we can send to Alpha Centauri within a generation. Today we commit to this next great leap into the cosmos. Because we are human and our nature is to fly."

The Breakthrough Starshot initiative will see £100m invested into developing this technology. The programme is being led by Pete Worden, the former director of Nasa AMES Research Centre. It is being backed by scientists and engineers, with a board consisting of Milner, Hawking and Facebook founder Mark Zuckerberg. They plan to work out if a nanocraft travelling on a sail pushed by a light beam can go 1,000 times faster than anything we have produced so far.

Douglas Vakoch, president of METI International, told IBTimes UK: "By sending hundreds or thousands of space probes the size of postage stamps, Breakthrough Starshot gets around the hazards of spaceflight that could easily end a mission relying on a single spacecraft. Only one nanocraft needs to make its way to Alpha Centauri and send back a signal for the mission to be successful. When that happens, Starshot will make history."

He said Starshot will expand our understanding of life in space by sending humans there through their proxies (these nanocrafts). "In 1610, Kepler proposed sending ships with sails into space, but he never imagined sails the size of postage stamps. The key to Starshot's propulsion system is to leave the fuel behind," he explained.

"Early proposals for light-powered space travel suggested solar sails, driven by our Sun's energy. But as we target other stars, as we get far from our solar system, the Sun's light becomes too dim for a successful boost. As an alternative, Starshot relies on an array of many small lasers, combined into a single beam, to drive these light sails across interstellar space. A ground-based array of lasers propels Starshot into space."

He said that Freeman Dyson's Project Orion (using fusion propulsion) would have gotten us to Alpha Centauri in about 50 years. "But interstellar travel relying on fusion remains a fantasy today. We need to look to new technological advances for a realistic path to the stars," he said.

"Fittingly for one of the Breakthrough Initiatives, Starshot relies on the latest breakthroughs in technology. Miniaturisation provides the foundation for Starshot's nanocraft. Redundancy is the key to Starshot's success. Hundreds or thousands of nanocraft will be launched. Only one needs to arrive and send back data for the mission to be a success."

The research and engineering phase will last for a number of years, and a huge financial investment will be required to get the project to a stage where a mission to Alpha Centauri would be possible.

"Earth is a wonderful place, but it might not last forever", Hawking said, "Sooner or later, we must look to the stars. Breakthrough Starshot is a very exciting first step on that journey."