A tiny space pebble just put a huge dent in an ESA satellite

In space, even tiny specks of dust are dangerous.

The European Space Agency's Copernicus Sentinel-1A satellite has new 40cm dent on one of its solar wings -- and it was caused by a tiny millimetre-size piece of space debris. The impact was discovered with the Sentinal-1A reported a slight power reduction last month. Onboard cameras quickly found the micrometeoroid impact, pictured above. Don't worry, the ESA says the satellite is fine, but the impact serves as a reminder: at orbital velocity, tiny objects can cause major damage.

This is a problem for the Breakthrough Starshot project, which aims to launch a laser powered nanocraft that travels at 1/5th the speed of light. That project hopes to reach the next solar system over in about 20 years. "Erosion of solid surfaces will be a severe problem at these speeds," says Ian Crawford of Birkbeck, University of London. "It's possible that the wafersats won't even be able to complete the journey."

For engineers, this isn't news -- NASA and other space agencies have been combating space debris for decades -- but it does mean that teams need to think of new ways to protect fast moving crafts. The faster a craft goes, the more dangerous tiny objects can be. At the speed Breakthrough Starshot is designed to reach, even microscopic space dust could be dangerous.