‘Breakthrough Starshot’ aims to reach Alpha Centauri 20 years after launch

$100 million research and engineering program to study concept of using laser light beam to propel gram-scale "nanocraft" to 20 percent of light speed
April 11, 2016

Alpha Centauri (credit: ESO Online Digitized Sky Survey)

Internet investor and science philanthropist Yuri Milner and physicist Stephen Hawking announced Tuesday a $100 million research and engineering program, Breakthrough Starshot, aiming to demonstrate proof of concept for light-propelled “nanocrafts” that could travel to Alpha Centauri, our nearest star system.

The nanocrafts would fly at 20 percent of light speed and capture images of possible planets and other scientific data, arriving in just over 20 years after their launch.

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

Breakthrough Starshot program

L-R) Yuri Milner, Breakthrough Prize and DST Global Founder; Stephen Hawking, CH, CBE, FRS, Dennis Stanton Avery and Sally Tsui Wong-Avery Director of Research, University of Cambridge; Freeman Dyson, Emeritus Professor, Princeton Institute for Advanced Study; Ann Druyan, Producer, Co-Founder and CEO of Cosmos Studios; Avi Loeb, Frank B. Baird, Jr. Professor of Science at Harvard University; Mae Jamison, Nasa Astronaut, Principal 100 Year Starship Foundation; and Peter Worden, Chairman, Breaktrough Prize Foundation, Former NASA Director speak on stage as Yuri Milner And Stephen Hawking host press conference to announce Breakthrough Starshot, a new space exploration initiative, at One World Observatory on April 12, 2016 in New York City. (Photo by Bryan Bedder/Getty Images for Breakthrough Prize Foundation)

The Breakthrough Starshot program will be led by Pete Worden, the former director of NASA AMES Research Center, and advised by a committee of world-class scientists and engineers. The board will consist of Stephen Hawking, Yuri Milner, and Mark Zuckerberg.


Nanocraft, comprising Lightsail and StarChip powered by Light Beamer (credit: Breakthrough Initiatives)

The Alpha Centauri star system is 25 trillion miles (4.37 light years) away. With today’s fastest spacecraft, it would take about 30,000 years to get there. The program aims to establish whether a gram-scale nanocraft on a sail pushed by a light beam can fly more than 1,000 times faster.

Nanocrafts are gram-scale robotic spacecrafts, comprising:

Starchip (credit: Breakthrough Initiatives)

Starchip: a gram-scale wafer carrying cameras, photon thrusters, power supply, navigation, and communication equipment, and constituting a fully functional space probe.

Lightsail (credit: Breakthrough Initiatives)

Lightsail: Advances in nanotechnology are producing increasingly thin and lightweight materials, promising to enable the fabrication of meter-scale sails no more than a few hundred atoms thick and at gram-scale mass.

Light Beamer (credit: Breakthrough Initiatives)

Light Beamer. The rising power and falling cost of lasers has led to significant advances in light-beaming technology. Phased arrays of lasers (the “light beamer”) could potentially be scaled up to the 100 gigawatt level.

Breakthrough Starshot aims to bring economies of scale to the astronomical scale. The StarChip can be mass-produced at the cost of an iPhone and be sent on missions in large numbers to provide redundancy and coverage. The light beamer is modular and scalable. Once it is assembled and the technology matures, the cost of each launch is expected to fall to a few hundred thousand dollars.

Breakthrough Starshot

Path to the stars

The research and engineering phase is expected to last a number of years. Following that, development of the ultimate mission to Alpha Centauri would require a budget comparable to the largest current scientific experiments, and would involve building a ground-based kilometer-scale light beamer at high altitude in dry conditions, powered by a few gigawatt hours of energy per launch.

The plan is to launching a “mothership” carrying thousands of nanocrafts to a high-altitude orbit, taking advantage of adaptive optics technology in real time to compensate for atmospheric effects. Focusing the light beam on the lightsail would accelerate individual nanocrafts to the target speed within minutes.

The goal is to capture images of a planet and other scientific data and transmitting them back to Earth using a compact on-board laser communications system, using the same light beamer that launched the nanocrafts to receive data from them over 4 years later.

The organizers acknowledge that these and other system requirements represent significant engineering challenges, but are based on technology either already available or likely to be attainable in the near future under reasonable assumptions, the organizers say.

Kilometer-scale telescope

The proposed light propulsion system is at a scale that calls for global cooperation and support. Clearance for launches would be required from all the appropriate government and international organizations.

As the technology required for interstellar travel matures, a number of additional opportunities will emerge, including contributions to solar system exploration, using the light beamer as a kilometer-scale telescope for astronomical observations, and detection of Earth-crossing asteroids at large distances.

Astronomers estimate that there is a reasonable chance of an Earth-like planet existing in the “habitable zones” of Alpha Centauri’s three-star system. A number of scientific instruments, ground-based and space-based, are being developed and enhanced, which will soon identify and characterize planets around nearby stars. A separate Breakthrough Initiative will support some of these projects.

Getting it off the ground

The Breakthrough Starshot initiative is based entirely on research in the public domain. It will be dedicated to full transparency and open access, and open to experts in all relevant fields as well as the public to contribute ideas through its online forum.  The initiative will establish a research grant program, and will make available other funding to support relevant scientific and engineering research and development.

“We take inspiration from Vostok, Voyager, Apollo. and the other great missions,” said Pete Worden. “It’s time to open the era of interstellar flight, but we need to keep our feet on the ground to achieve this.”