Wiktionary
n. (context astronautics English) A sail-like structure on a spacecraft consisting of enormous ultrathin mirrors, propulsion being achieved by the radiation pressure of light from a star or laser.
Wikipedia
Solar sails (also called light sails or photon sails) are a form of spacecraft propulsion using radiation pressure exerted by sunlight on large mirrors. A useful analogy may be a sailing boat; the light exerting a force on the mirrors is akin to a sail being blown by the wind. High-energy laser beams could be used as an alternative light source to exert much greater force than would be possible using sunlight, a concept known as beam sailing.
Solar sail craft offer the possibility of low-cost operations combined with long operating lifetimes. Since they have few moving parts and use no propellant, they can potentially be used numerous times for delivery of payloads.
Solar sails use a phenomenon that has a proven, measured effect on spacecraft. Solar pressure affects all spacecraft, whether in interplanetary space or in orbit around a planet or small body. A typical spacecraft going to Mars, for example, will be displaced by thousands of kilometres by solar pressure, so the effects must be accounted for in trajectory planning, which has been done since the time of the earliest interplanetary spacecraft of the 1960s. Solar pressure also affects the orientation ( Aircraft attitude) of a craft, a factor that must be included in spacecraft design.
The total force exerted on an 800 by 800 meter solar sail, for example, is about at Earth's distance from the Sun, making it a low-thrust propulsion system, similar to spacecraft propelled by electric engines, but as it uses no propellant, that force is exerted almost constantly and the collective effect over time is great enough to be considered a potential manner of propelling spacecraft.
Usage examples of "solar sail".
If a hive gets trapped in a star's gravity well, for whatever reason, it needs a more energetic propulsion system to escape than a solar sail.
Other spots of light around it, some things large enough to be seen: station powersails, then a real solar sail half-deployed near a construction station.
It's solar sail material harvested from the skyhook tree's leaves.
She might have spied it, too, as a star that moved among stars, by the solar sail.
A group of transnationals, led by Subarashii, had built a circular slatted array of solar sail mirrors, placed between the sun and Mars and aligned to focus inward sunlight that would have just missed the planet.
The material of the two silicate asteroids was transformed by their robot crews into sheets of solar sail material.
Mars development activity schedules vied with Solar Sail reports and a hologram of the proposed Proxima Centauri probe.