Interstellar Travel is not Science Fiction Anymore

Alpha Centauri. Credit: European Southern Observatory

Can we literally reach the stars? Can we do it in our lifetimes? A team of scientists and luminaries led by Russian philanthropist Yuri Milner, British cosmologist Stephen Hawking, and Facebook founder Mark Zuckerberg are confident that by employing technology available today or “just over the horizon”, humanity will be able to send small spacecrafts to Alpha Centauri, our nearest star system — 4.37 light-years away — within a generation. Breakthrough Starshot is the first realistic interstellar travel initiative.

“For the first time in human history we can do more than just gaze at the stars. We can actually reach them.”
— Yuri Milner

In order to accomplish this seemingly impossible task, Mr. Milner and his colleagues plan to launch the lightest spacecraft ever built, a nanocraft consisting of a stamp-sized starchip weighing less than a gram and an extremely thin lightsail. This interstellar sailboat will be accelerated to about 20% the speed of light towards the stars by an enormous ground-based laser array. At this unprecedented velocity, the spacecraft will reach the Alpha Centauri star system in approximately 20 years. The probes will be equipped with miniaturized electronics, including cameras, photon thrusters for navigation, and a laser for communication. The hundreds or even thousands of robotic explorers will take pictures while they zip by our nearest stars.

“I believe what makes us unique is transcending our limits […] 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 launch a mission 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.”
— Stephen Hawking

There are many challenges that will need to be overcome, but none of them are unsurmountable based on the laws of physics. One of the major challenges is constructing a laser array of several miles that is capable of producing a beam on the scale of 100 Gigawatts — similar to the power needed to launch the Space Shuttle. Scientists will need to significantly improve current adaptive optics technology in order to reduce the blurring caused by our turbulent atmosphere. They will also have to manufacture an exceptionally light sail, one able to withstand the world’s most powerful laser without disintegrating. Once the nanocrafts reach our nearest star system, they will need to actually send their images back to Earth (“If a tree falls in the forest and no one is there, does it still make a sound?”). Lastly, the spacecrafts — at least a few of them — need to survive the journey through interstellar dust particles at relativistic speeds.

Nanocraft. Credit: Reuters
“We don’t see any showstoppers, any deal breakers based on fundamental physics principles. We think we can overcome all these challenges with enough innovation and ingenuity.”
Dr. Loeb, Harvard Astronomer and Chairman of Breakthrough Starshot Advisory Committee

In order to address these challenges, Mr. Milner hopes to attract the brightest scientists and engineers around the world through an initial investment of $100 million for research and development. Mr. Milner and his colleagues estimate that it could take 20 years to get the mission off the ground, 20 years to reach Alpha Centauri, and another 4 years for the information to reach us here on Earth. The initial stage involves developing a proof of concept that can demonstrate this endeavor is possible.

“It’s not about a single country beating another rival. It’s about how we collectively as humans can do this.”
Mae Jemison, Former NASA Astronaut and Principal of 100 Year Starship

Until recently, an initiative like this would have simply been a great subject for a science fiction film, but three technological advancements have brought us closer to the stars. Advancements in microfabrication, nanotechnology, and photonics have suddenly brought interstellar travel within our reach.

Laser array. Credit: Breakthrough Starshot

The total cost of the project is estimated to be between $5 billion and $10 billion, comparable with the largest international scientific collaborations to date, including the Large Hadron Collider and the James Webb Space Telescope. Most of the money would go towards building the giant laser array. In addition to its primary purpose, the laser could be used to send probes to our own solar system, perhaps to fly through the ice plumes of Saturn’s moon Enceladus, a moon that might contain microbial life. The light beamer can also be employed as a telescope. It would be the most capable on Earth by a factor of 1000, capable of obtaining better astronomical data than ever before possible.

Ultimately, Breakthrough Starshot will teach us as much about ourselves as it will about Alpha Centauri. It will test the limits of our imagination and innovation, and most importantly, our ability to work together as human beings.

Further reading:


Breakthrough Starshot webpage:

Images: NASA, European Southern Observatory, Reuters

Published in Spanish at IQ Latino

Pradiip Alvarez is an Astrophysicist, Social Entrepreneur, and Youth Leader. Click here to subscribe to his Science and Technology Blog.