Risks to Breakthrough Starshot’s interstellar ship calculated

Ars Technica : In April, Russian billionaire and physicist Yuri Milner announced that he was providing $100 million for the research and development of an interstellar probe, a project he dubbed Breakthrough Starshot. The goal of the project is to accelerate tiny spacecraft up to 20% the speed of light so they could reach the closest star system, which includes Proxima Centauri and its newly discovered planet , in just 20 years. Now a team of researchers has calculated just how risky a trip at that speed would be. The scientists found that although heavier atoms in interstellar gas, such as oxygen, magnesium, and iron, could damage the vehicle, they would probably erode the ship’s surface by only about 0.1 mm. However, interstellar dust would have a much more significant impact, eroding 1.5 mm of the spacecraft’s surface and also causing localized melting as deep as 10 mm. The researchers say that much of the damage could be minimized or avoided by adjusting the spacecraft’s design.