A Feasible and Affordable Interstellar Mission Capability is Coming Together

Chairman of the Breakthrough Prize Foundation and Chairman of Breakthrough Initiatives, Dr. Pete Worden, discusses the Breakthrough Starshot work on the laser propelled solar sail to Proxima Centauri.

Billionaire Yuri Milner committed $100 million for Breakthrough Starshot. They probably had about $10 million worth of contracts around the world to answer these three questions.

1. Build the laser or laser array
2. Get the materials for the sail and it would need to be able to take 10-100 Gigawatts of laser energy
3. Communicate a signal back from the nearby star system

The big Photon engine will be kilometers in scale. The most amazing set of breakthrough is one is that the Australia National University show that you could you could phase the signal you have to to in order to get the laser array to focus on the light sail.

The light sail which would initially be about 60,000 kilometers out and then accelerated over a few tens of minutes to 0.2 C (60,000 kilometers per second. We need to be able to phase the the signal across kilometers uh Australia national university did research and showed us that yes indeed this can be done. Professor Lubin has got another contract with us and he also showed that it could be done at UC Santa Barbara

The big question is can we build the laser array cheap enough. There are a set of Technologies being developed and one is integrated laser diodes. Another one is actually photonics where this is a chip that produces a laser signal. It can be phased you could you can build a something that looks a lot like a solar panel but instead of receiving power, it is translating it to energy. this you put

We think that we can affordably produced in kilometer scales. We know today we have kilometer scale solar arrays that are affordable.

The third one is to build a light sail that can take this. Professor Harry Atwater at Caltech has led our effort on that and it appears that there are materials. One of them is silicon hydride and it seems to have the right characteristics. Today we can build these in a few millimeter scales and we have to build them in 10 meter scales but as scientist I’m fond of saying that’s just an engineering problem.

The biggest challenge is how do we get the signal back from Alpha centuri. tthe entire spacecraft that’s a few gram. How do we focus the laser light.

Professor Phil Moff at Arizona State University is working on it. It appears the answer is yes. Basically what we do is that the light sail itself becomes an integrated sort of electronic element and embedded in it is the everything the spacecraft needs.

Transmitters laser Photons can be electronically focused so that that you take a few square meters of this and actually focus a laser beam back on the earth. The power is a challenge but we think a combination of very small nuclear radiation elements could provide the power.

We need to build receiver that is a good fraction of a square kilometer. The biggest telescopes we can build are maybe you know 30 to 40 meters in diameter and those cost billions. There’s some amazing breakthroughs that are being made in in building telescopes that are really cheap.

Two groups in particular. One is Professor Jeff at the University of Hawaii and another one is Professor Roger Angel at the University of Arizona. They developed capabilities that look like we could build a a half square kilometer Optical element for again of order of a billion or two. Those all look very promising. Hopefully our sponsor will agree to go forward with this program. There are other sponsors funding some of these other parts of these efforts.

Hopeful that you know we can begin building prototypes of some of these within a decade. The full system within a few decades.