A statite (a

portmanteau In linguistics, a blend—also known as a blend word, lexical blend, or portmanteau—is a word formed by combining the meanings, and parts of the sounds, of two or more words together.

of the words ''static'' and ''satellite'') is a hypothetical type of

artificial satellite A satellite or an artificial satellite is an object, typically a spacecraft, placed into orbit around a celestial body. They have a variety of uses, including communication relay, weather forecasting, navigation ( GPS), broadcasting, scienti ...

that employs a

solar sail Solar sails (also known as lightsails, light sails, and photon 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 navigati ...

to continuously modify its

orbit In celestial mechanics, an orbit (also known as orbital revolution) is the curved trajectory of an object such as the trajectory of a planet around a star, or of a natural satellite around a planet, or of an artificial satellite around an ...

in ways that

gravity In physics, gravity (), also known as gravitation or a gravitational interaction, is a fundamental interaction, a mutual attraction between all massive particles. On Earth, gravity takes a slightly different meaning: the observed force b ...

alone would not allow. Typically, a statite would use the solar sail to "hover" in a location that would not otherwise be available as a stable

geosynchronous orbit A geosynchronous orbit (sometimes abbreviated GSO) is an Earth-centered orbit with an orbital period that matches Earth's rotation on its axis, 23 hours, 56 minutes, and 4 seconds (one sidereal day). The synchronization of rotation and orbital ...

. Statites have been proposed that would remain in fixed locations high over

Earth Earth is the third planet from the Sun and the only astronomical object known to Planetary habitability, harbor life. This is enabled by Earth being an ocean world, the only one in the Solar System sustaining liquid surface water. Almost all ...

's poles, using reflected

sunlight Sunlight is the portion of the electromagnetic radiation which is emitted by the Sun (i.e. solar radiation) and received by the Earth, in particular the visible spectrum, visible light perceptible to the human eye as well as invisible infrare ...

to counteract the gravity pulling them down. Statites might also employ their sails to change the shape or velocity of more conventional orbits, depending upon the purpose of the particular statite. The concept of the statite was invented independently and at about the same time by Robert L. Forward (who coined the term "statite") and Colin McInnes, who used the term "halo orbit" (not to be confused with the type of halo orbit discovered by Robert Farquhar). Subsequently, the terms "non- Keplerian orbit" and "artificial

Lagrange point In celestial mechanics, the Lagrange points (; also Lagrangian points or libration points) are points of equilibrium for small-mass objects under the gravitational influence of two massive orbiting bodies. Mathematically, this involves t ...

" have been used as a generalization of the above terms. No statites have been deployed to date, as solar sail technology remains in its infancy. NASA's cancelled '' Sunjammer'' solar sail mission had the stated objective of flying to an artificial Lagrange point near the Earth/Sun L1 point, to demonstrate the feasibility of the Geostorm

geomagnetic storm A geomagnetic storm, also known as a magnetic storm, is a temporary disturbance of the Earth's magnetosphere that is driven by interactions between the magnetosphere and large-scale transient Plasma (physics), plasma and magnetic field structur ...

warning mission concept proposed by NOAA's Patricia Mulligan. A constellation of statites have been proposed for performing a rendezvous with an

interstellar object An interstellar object is an astronomical object in interstellar space that is not gravitationally bound to a star. Applicable objects include asteroids, comets, and rogue planets, but not a star or stellar remnant. This term can also be appli ...

References

Astrodynamics Hypothetical technology Spaceflight concepts {{Spacecraft-stub

See also

References