Breakthrough Starshot is one of the more exciting scientific ideas that has popped up in the past decade, with its promise to deliver hardware to the nearest star in time for many people currently alive to see it. While the idea would work on paper as an extrapolation of existing technology, there are a lot of details that need to be thoroughly checked out, because it's possible that one of them could present a show-stopper.
There's a bit of good news there: Breakthrough Starshot is apparently funding the needed research to give its concept a thorough vetting. A recent posting to the arXiv describes a careful look at the odds of a spacecraft surviving an extended journey at the speeds planned for the trip. Overall, things look good, but a bit of shielding will be needed, and there's the potential for a catastrophic collision with a speck of dust.
The work, done by a team of four astronomers, focuses on one of the most basic issues: spacecraft survival. The goal of Breakthrough Starshot is to accelerate its craft to about 20 percent the speed of light. At that speed, even individual atoms can damage the vehicle, and a collision with a bit of dust could be catastrophic. So the team set out to quantify just how risky these collisions could be.