Solar sails are a method of spacecraft propulsion using radiation pressure exerted by sunlight on large surfaces. A number of spaceflight missions to test solar propulsion and navigation have been proposed since the 1980s. The first spacecraft to make use of the technology was IKAROS, launched in 2010.
IKAROS space-probe with solar sail in flight (artist's depiction) showing a typical square sail configuration
NASA illustration of the unlit side of a half-kilometre solar sail, showing the struts stretching the sail.
An artist's depiction of a Cosmos 1-type spaceship in orbit
Proposed material for the construction of solar sails - carbon fiber.
Spacecraft propulsion is any method used to accelerate spacecraft and artificial satellites. In-space propulsion exclusively deals with propulsion systems used in the vacuum of space and should not be confused with space launch or atmospheric entry.
A remote camera captures a close-up view of an RS-25 during a test firing at the John C. Stennis Space Center in Hancock County, Mississippi.
SpaceX's Kestrel engine is tested.
NASA's 2.3 kW NSTAR ion thruster for the Deep Space 1 spacecraft during a hot fire test at the Jet Propulsion Laboratory
6 kW Hall thruster in operation at the NASA Jet Propulsion Laboratory