Humanity needs to explore the stars. Just for the sake of space booze and scientific advancement, it needs to happen. But how to get there? In a big announcement yesterday, a consortium of scientists and investors, including Stephen Hawking, announced Breakthrough Starshot, essentially a pilot program to get probes to far-flung galaxies. But while the idea makes sense, there are a bunch of challenges that need to be addressed.
The basic idea boils down to strapping a smartphone to a light-powered sail, what the initiative is calling a nano-craft, and flinging it into space. We’d use the sail and a gigantic laser array to push said smartphone to 20% of the speed of light and fling a whole bunch of them towards as many star systems as possible. As silly as that may sound, it’s a pretty smart idea; it’s a lot easier to get something light and small going really fast than a manned mission, and as designed, these things will be cheap to make, roughly the cost of the smartphone in your pocket, and thus easy to fire off. That said, there are a few engineering challenges that need to be licked before Breakthrough Starshot is a reality.
The Laser Array
This is really the heart of the idea: Using a solar sail, we blast these things with a 100 gigawatt laser to get them moving at one fifth the speed of light. Needless to say, that’s a lot of power, and it’s an open question what kind of laser could even support that much energy without generating enough waste heat to melt what’s left of the Arctic. It would also more or less be a death ray, so there are a few legal problems that might need to be overcome.
There’s also the problem of keeping the beam focused as you blast it through the atmosphere, hitting the proper phase, and just generally building this thing so that it’s not ridiculously dangerous to be near.
Engineering The Craft
The electronics Breakthrough Starshot needs are no problem; anything they don’t already have, Moore’s Law will square away rather efficiently. The real issue is two-fold; ensuring this thing stays on target and doesn’t get destroyed, and figuring out how it’ll power itself when it gets there.
The former is an issue of space being full of crud: Even a speck of dust is pretty dangerous when you’re moving at roughly 60 million meters per second. It’ll need a tough coating to deal with impacts, and strong telemetry to not slam into a planet when it arrives.
Communicating With Earth
The final major issue is just how these tiny little spacecraft will communicate with Earth and get us their findings. Even using lasers, there’s an enormous amount of power needed to send a signal across the gulfs of space; the battery in your iPhone isn’t going to cut it. The best way to power it is by cramming what amounts to a little nuclear battery in there, but even then, it’ll need some clever design to stay powered and send us anything useful.
All that said, this is shockingly feasible, and all the research will be public domain. If we can overcome a few challenges, Breakthrough Starshot might push humanity forward by leaps and bounds, even if we never get one of those little craft to the stars.