An artist's concept of NASA's Advanced Composite Solar Sail System spacecraft in orbit as the Sun crests Earth's horizon.

An artist’s concept of NASA’s Advanced Composite Solar Sail System spacecraft in orbit as seen from directly above the spacecraft looking down at Earth below.

An artist’s concept of NASA’s Advanced Composite Solar Sail System spacecraft in Earth orbit with the Sun in the background.

An artist’s concept of NASA’s Advanced Composite Solar Sail System spacecraft in Earth orbit.

An artist’s concept of NASA’s Advanced Composite Solar Sail System spacecraft orbiting Earth, showing a configuration with solar arrays deployed and the sails and the booms stowed.

This artist’s concept shows the Advanced Composite Solar Sail System spacecraft sailing in space using the energy of the Sun.