NASA loaded a microwave-sized device packed with a four-piece, 860-square-foot, ultra-thin solar sail aboard a rocket and launched it on April 23. That same day, the rocket delivered the object—called the Advanced Composite Solar Sail System (ACS3)—into low Earth orbit.

NASA's app allows skygazers to track sightings of the solar sail from their location, providing the direction of the sky it will be visible, its celestial altitude, and the duration of each sighting. The app also features a built-in augmented reality tool that points users to the location of the spacecraft in real-time.

Four months after it blasted off into space, Nasa's solar spacecraft has spread it's sails - and now you can spot it from Earth! The Advanced Composite Solar Sail System (or ACS3 for short) is a special test spacecraft which will orbit around the Earth for a few weeks..

For those interested in getting a peek, they can find out when the solar sail is passing above their location via NASA’s mobile app. According to NASA, the app provides not just a list of all the upcoming times the spacecraft will be visible from a user’s location,