NEA Scout, NASA's solar sail mission to an asteroid

Highlights
NEA Scout is a NASA mission launching in 2021 that will use a solar sail spacecraft to visit a near-Earth asteroid.
NEA Scout will demonstrate a low-cost method of asteroid reconnaissance for human and robotic missions and add to our scientific knowledge of small worlds
NASA and The Planetary Society collaborate and exchange data between the NEA Scout and LightSail programs.

Why do we need NEA Scout?

Solar sails are spacecraft that use large, thin sails to reflect sunlight, giving them a gentle push and unlimited fuel. They are well-suited to small, low-cost spacecraft that hitch rides to space on rockets carrying larger missions. Thanks to advances in technology miniaturization, small spacecraft are growing increasingly capable, but they have limited propulsion, which often bounds them to the trajectories of the rockets that carry them into space.

NEA Scout will demonstrate the ability to hitch a ride to one destination and then use a solar sail to fly somewhere else. The small spacecraft will initially ride to the Moon before using a solar sail to leave for a near-Earth asteroid.

Asteroids, comets, and other small worlds are like time capsules that have been largely unchanged since the birth of our solar system. Sample return missions like NASA’s OSIRIS-REx and Japan’s Hayabusa2 are revealing these worlds’ secrets, but both encountered unexpectedly rocky terrain that complicated the mission. NEA Scout will demonstrate how a low-cost solar sail spacecraft could scout an asteroid for human and robotic exploration long before a future mission leaves the launch pad.

NEA Scout builds on a heritage of NASA small satellite solar sails that includes Nanosail-D2, which test-deployed a solar sail in Earth orbit in 2011. The Planetary Society's LightSail program built on that concept, demonstrating controlled solar sailing for the first time in Earth orbit and for the first time with a small spacecraft. NASA and The Planetary Society collaborate and exchange data on NEA Scout and the LightSail program through a Space Act Agreement.

Asteroid Itokawa Asteroid Itokawa, seen here by Japan's Hayabusa spacecraft in 2005, is in the same family of near-Earth asteroids as the target NEA Scout may visit.Image: JAXA / Edited by The Planetary Society

How NEA Scout works

NEA Scout launches to the Moon in 2021 with a fleet of other small satellites aboard Artemis 1, the inaugural test flight of the Space Launch System (SLS). The giant NASA rocket will blast an uncrewed Orion spacecraft to lunar orbit and back.

At the Moon, NEA Scout will deploy its 86-square-meter (926 square feet) solar sail and slowly spiral out of lunar orbit. It will travel to a near-Earth asteroid and perform a slow fly-by, capturing up-close images of the surface. The target asteroid named in the past is 1991 VG, but the actual asteroid chosen will depend on the Artemis 1 launch date.