Space

Starshot, a Billionaire’s New Mission to Get to Alpha Centauri in 20 Years

Yuri Milner announced a $100-million grant to find out if we can send thousands of sail-borne ‘nanocrafts’ speeding through space using weapons-grade lasers fired from the ground.

The bright star on the left, Alpha Centauri, is in fact two stars close together: Alpha Centauri A and B. A much dimmer star, circled in red, is Proxima Centauri and is thought to be orbiting the A/B pair. The bright star on the right is Beta Centauri, considered to be a separate stellar system. Credit: Skatebiker/Wikimedia Commons, CC BY-SA 3.0

The bright star on the left, Alpha Centauri, is in fact two stars close together: Alpha Centauri A and B. A much dimmer star, circled in red, is Proxima Centauri and is thought to be orbiting the A/B pair. The bright star on the right is Beta Centauri, considered to be a separate stellar system. Credit: Skatebiker/Wikimedia Commons, CC BY-SA 3.0

It took nearly 35 years for the Voyager 1 probe, launched by NASA in 1977, to reach the outermost edges of the Solar System. By the time it got there, it was travelling at 17 km/s, or 61,200 km/hr, having been accelerated along the way by two gravitational slingshots around Jupiter and Saturn. Now, a radical reinvention of an old technology has scientists considering something much faster – fast enough to reach the Alpha Centauri star-system 4.37 lightyears away in a single human generation.

On April 12, Russian billionaire Yuri Milner announced a $100 million grant for what he calls Breakthrough Starshot, the latest offering in his Breakthrough Initiatives portfolio. Starshot will fund research to find out how we can deploy of thousands of chip-sized ‘nanocrafts’ that will be pushed by 100-gigawatt lasers fired from Earth to relativistic speeds so they may fly by the Alpha Centauri system, the Solar System’s closest neighbour, within 20 years. The grant’s size makes it the largest investment, public or private, in interstellar research in history (by far outclassing DARPA’s $1-million ‘100 Year Starship‘). Milner’s announcement coincided with the 55th anniversary of Yuri Gagarin’s becoming the first human in space.

Together with his attendant planners, Milner is riding a wave of optimism about advances in optics and electronics miniaturisation as much as of the continuation of Moore’s Law. For example, rapid advances on at least four fronts are needed for Breakthrough Starshot to become a meaningful success. First, a 100-gigawatt laser, or multiple lasers combined to produce an equivalent effect, must be set up on ground along with adaptive optics to mitigate the effects of the atmosphere. Interestingly, Paul Gilster, who writes the popular Centauri Dreams blog focusing on interstellar travel, asked in a post about why a space-based laser wasn’t being considered, as it wouldn’t require corrective optics. In an interview to Ross Andersen of The Atlantic, Milner responded, “People who talk about lasers in space don’t think about policy issues, and they don’t think about cost. Nobody will allow you to build something that you can point in all different directions, as you would be able to in space. This is a very big laser. It can do quite a bit of damage.”

Anyway, second, a suitable metamaterial nanosail that each nanocraft will sport – upon which photons from the lasers will impart their momenta – will have to be designed to be a few atoms thick and able to withstand the lasers. Third, the nanocrafts must be equipped to stay on course and not drift apart. Fourth, scientists must figure out a way for the nanocrafts to transmit massive amounts of data over extremely large distances without increasing the weight of the crafts themselves. (In fact, in the same interview, Milner says the crafts will have a 2 MP camera that might be able to make out “continents” and transmit such images within five years to Earth.) A full list of anticipated engineering challenges is here.

“Moore’s Law tells us that now is the time.”
The Planetary Society, an international nonprofit organisation, deployed a technology-demonstrator in May-June 2015 of a 'LightSail', a 4.5-micron-thick Mylar sail attached to a small satellite called a cubesat. The cubesat was propelled in space by photons from the Sun striking and pushing on the LightSail. Shown here: the LightSail unfurled. Source: The Planetary Society

The Planetary Society, an international nonprofit organisation, deployed a technology-demonstrator in May-June 2015 of a ‘LightSail’, a 4.5-micron-thick Mylar sail attached to a small satellite called a cubesat. The cubesat was propelled in space by photons from the Sun striking and pushing on the LightSail. Shown here: the LightSail unfurled. Source: The Planetary Society

While all these problems are daunting, the $100 million provides the legitimacy of being supported by prominent personalities and, more importantly, sustained administrative supports for efforts to solve them in the relatively shorter term. In the longer term, however, Starshot will rely on Moore’s law bringing down the cost of its encompassing efforts down by 100-times within a decade. Should the law not hold (having already shown signs of stalling), the R&D costs could burgeon to 10,000-times as much. In fact, for these reasons, Starshot resembles Project Longshot of the late 1980s: to get an unmanned probe into orbit around one of the stars in the Alpha Centauri system in 100 years, powered by a nuclear reactor producing 1,000-times as much power as reactors of the size of the time did. Milner is supported in his ideas by the physicists Stephen Hawking and Freeman Dyson and in his efforts by Facebook CEO Mark Zuckerberg, among others. Together, the collaboration of twenty estimates concept verification to be completed in the next couple decades.

The hope sparked by the Starshot announcement has also lent itself to speculations about what other spinoff achievements can be expected. For example, being able to send nanocrafts across 4.37 lightyears in 20 years means sending them to Mars for observations in a few hours. Astronomers have also suggested that the corrective optics that will accompany the lasers could be used as parts of a telescope. In fact, such a telescope could potentially be used to find exoplanets in the Alpha Centauri system – comprising three stars, Alpha Centauri A/B and Proxima Centauri – for the nanocrafts to fly by. And in 2013, there was a proposal from the University of Alabama Huntsville to use lasers to stave off asteroids set for collision-courses with Earth.

Starshot follows another $100-million announcement by Milner, called Breakthrough Listen, in July 2015 to get astronomers access to time on powerful telescopes, and other resources, and press them toward searching for extraterrestrial intelligence. Milner himself shot to prominence in 2012 when he founded the annual Breakthrough Prizes in mathematics, physics and the life sciences – each with a purse of $3 million. He obtained a PhD in physics before turning to business, investing in early-stage startups of the time like Twitter and Zynga, and making a fortune.