The Advanced Composite Solar Sail System, which launched in April 2024, and deployed its reflective sail in August, is currently orbiting approximately 600 miles (1,000 kilometers) above Earth and is frequently visible in the night sky to observers in the Northern Hemisphere. Fans of the spacecraft can look for the sail in the night sky using a new feature in the NASA mobile app. Visibility may be intermittent, and the spacecraft could appear at variable levels of brightness as it moves in orbit.