NASA's solar sail spacecraft is visible in the night sky. Here's how to see it NASA's Advanced Composite Solar Sail System (ACS3) can be seen with the naked eye as it orbits Earth, and can be tracked with a helpful app. https://cdn.mos.cms.futurecdn.net/8aHhTe4MGPJU9F9Gxnpom9.jpg https://www.space.com/nasa-solar-sail-how-to-see-night-sky