FACTOID # 14: North Carolina has a larger Native American population than North Dakota, South Dakota and Montana combined.
 
 Home   Encyclopedia   Statistics   States A-Z   Flags   Maps   FAQ   About 
   
 
WHAT'S NEW
 

SEARCH ALL

FACTS & STATISTICS    Advanced view

Search encyclopedia, statistics and forums:

 

 

(* = Graphable)

 

 


Encyclopedia > Geosynchronous orbit

A geosynchronous orbit is a geocentric orbit that has the same orbital period as the sidereal rotation period of the Earth. It has a semi-major axis of 42,164 km (26,200 miles). In the special case of the geostationary orbit, an observer on the ground would not perceive the satellite as moving and would see it as a fixed point in the sky. Such orbits are useful for telecommunications relays. In the more general case, when the orbit has some inclination and/or eccentricity, the satellite would appear to describe a more or less distorted figure-eight in the sky, and would rest above the same spots of the Earth's surface once per sidereal day. Wikipedia does not have an article with this exact name. ... It has been suggested that this article or section be merged with geosynchronous orbit. ... In physics, an orbit is the path that an object makes, around another object, whilst under the influence of a source of centripetal force, such as gravity. ... The orbital period is the time it takes a planet (or another object) to make one full orbit. ... On a prograde planet like the Earth, the sidereal day is shorter than the solar day. ... Earth (IPA: , often referred to as the Earth, Terra, the World or Planet Earth) is the third planet in the solar system in terms of distance from the Sun, and the fifth largest. ... The semi-major axis of an ellipse In geometry, the term semi-major axis (also semimajor axis) is used to describe the dimensions of ellipses and hyperbolae. ... It has been suggested that this article or section be merged with geosynchronous orbit. ... Telecommunication involves the transmission of signals over a distance for the purpose of communication. ... Inclination in general is the angle between a reference plane and another plane or axis of direction. ... In astrodynamics, under standard assumptions any orbit must be of conic section shape. ...


Synchronous orbits exist around all moons, planets, stars and black holes —unless they rotate so slowly that the orbit would be outside their Hill sphere. Most inner moons of planets have synchronous rotation, so their synchronous orbits are, in practice, limited to their leading and trailing Lagrange points. Objects with chaotic rotations (such as Hyperion) are also problematic, as their synchronous orbits keep changing unpredictably. A synchronous orbit is an orbit in which an orbiting body (usually a satellite) has a period equal to the average rotational period of the body being orbited (usually a planet), and in the same direction of rotation as that body. ... A Hill sphere approximates the gravitational sphere of influence of one astronomical body in the face of perturbations from another heavier body around which it orbits. ... In astronomy, synchronous rotation is a planetological term describing a body orbiting another, where the orbiting body takes as long to rotate on its axis as it does to make one orbit; and therefore always keeps the same hemisphere pointed at the body it is orbiting. ... In celestial mechanics, the Lagrangian points, (also Lagrange point, L-point, or libration point) are the five stationary solutions of the circular restricted three-body problem. ... To meet Wikipedias quality standards, this article may require cleanup. ... Hyperion (hye-peer-ee-É™n, IPA , Greek Ὑπερίων) is a moon of Saturn discovered by William Cranch Bond, George Phillips Bond and William Lassell in 1848. ...


If a geosynchronous orbit is circular and equatorial then it is also a geostationary orbit, and will maintain the same position relative to the Earth's surface. If one could see a satellite in geostationary orbit, it would appear to hover at the same point in the sky, i.e., not exhibit diurnal motion, while one would see the Sun, Moon, and stars traverse the heavens behind it. It has been suggested that this article or section be merged with geosynchronous orbit. ... Diurnal motion is an astronomical term referring to the apparent daily motion of stars in orbit around the Earth, caused by the Earths rotation around its axis. ...


A circular geosynchronous orbit in the plane of the Earth's equator has a radius of approximately 42,164 km (from the center of the Earth) or approximately 35,786 km (22,236 statute miles) above mean sea level. To help compare different orders of magnitude, this page lists lengths starting at 107 m (10,000 km). ... A mile is any of several units of distance, or, in physics terminology, of length. ... For considerations of sea level change, in particular rise associated with possible global warming, see sea level rise. ...

Contents

Circular geosynchronous orbits

Circular geosynchronous orbits at the equator are known as geostationary orbits. A perfect stable geostationary orbit is an ideal that can only be approximated. In practice the satellite will drift out of this orbit (because of perturbations such as the solar wind, radiation pressure, variations in the Earth's gravitational field, and the gravitational effect of the Moon and Sun), and thrusters are used to maintain the orbit in a process known as stationkeeping. In tourist areas, the equator is often marked on the sides of roads The Equator is an imaginary circle drawn around a planet (or other astronomical object) at a distance halfway between the poles. ... The plasma in the solar wind meeting the heliopause For the British comic, see Solar Wind (comic). ... Radiation pressure is the pressure exerted upon any surface exposed to electromagnetic radiation. ... Gravity is a force of attraction that acts between bodies that have mass. ... Bulk silicate composition (estimated wt%) SiO2 44. ... The Sun is the star of our solar system. ... In astrodynamics orbital stationkeeping is a term used to descibe a particular set of orbital maneuvers used to keep a spacecraft in assigned orbit, either low earth orbit (LEO), or geostationary orbit (GEO). ...


See Geostationary orbit. It has been suggested that this article or section be merged with geosynchronous orbit. ...


Other geosynchronous orbits

Elliptical orbits can be and are designed for communications satellites that keep the satellite within view of its assigned ground stations or receivers. A satellite in an elliptical geosynchronous orbit will appear to oscillate in the sky from the viewpoint of a ground station, tracing an analemma in the sky. Satellites in highly elliptical orbits must be tracked by steerable ground stations. Elliptical may refer to: Ellipse: a shape and mathematical construct Elliptical trainer: an exercise machine This is a disambiguation page — a navigational aid which lists other pages that might otherwise share the same title. ... U.S. military MILSTAR communications satellite A communications satellite (sometimes abbreviated to comsat) is an artificial satellite stationed in space for the purposes of telecommunications. ... The analemma photographed, looking east in the northern hemisphere. ... This page is a candidate for speedy deletion, because: Test page? If you disagree with its speedy deletion, please explain why on its talk page or at Wikipedia:Speedy deletions. ...


Theoretically an active geosynchronous orbit can be maintained if forces other than gravity are also used to maintain the orbit, such as a solar sail. Such a statite can be geosynchronous in an orbit different (higher, lower, more or less elliptical, or some other path) from the conic section orbit formed by a gravitational body. Such devices are still theoretical. Concept image of a solar sail spacecraft in the process of unfurling sails. ... A statite is a hypothetical type of artificial satellite that employs a solar sail to continuously modify its orbit in ways that gravity alone would not allow. ... Types of conic sections Table of conics, Cyclopaedia, 1728 In mathematics, a conic section (or just conic) is a curve formed by intersecting a cone (more precisely, a right circular conical surface) with a plane. ...


A further form of geosynchronous orbit is obtained by the theoretical space elevator in which one end of the structure is tethered to the ground, maintaining a longer orbital period than by gravity alone if under tension. A space elevator would consist of a cable anchored to the Earths surface, reaching into space. ...


Other definitions of geosynchronous orbit

  • Geosynchronous orbit (GEO): a circular orbit, 35786 km above Earth's surface

The following orbits are special orbits that are also used to categorize orbits:

  • Geostationary orbit (GSO): zero inclination geosynchronous orbit
  • Supersynchronous orbit - a disposal / storage orbit above GSO/GEO. Satellites will drift in a westerly direction.
  • Subsynchronous orbit - a drift orbit close to but below GSO/GEO. Used for satellites undergoing station changes in an eastern direction.

It has been suggested that this article or section be merged with geosynchronous orbit. ... Super synchronous orbit is very similar to synchronous orbit, except that the satellite moves slowly west due to its distance from the Earth. ... Unsurprisingly similar to synchronous orbit, this orbit is at a slightly different distance from the Earth, resulting in the satellite drifting slowly eastward. ...

History

Author Arthur C. Clarke is credited with popularizing the notion of using a geostationary orbit for communications satellites. The orbit is also known as the Clarke Orbit. Together, the collection of artificial satellites in these orbits is known as the Clarke Belt. Sir Arthur Charles Clarke (born December 16, 1917) is a British author and inventor, most famous for his science-fiction novel 2001: A Space Odyssey, and for collaborating with director Stanley Kubrick on the film of the same name. ...


The first communications satellite placed in a geosynchronous orbit was Syncom 2, launched in 1963. Geosynchronous orbits have been in common use ever since, including satellite television. Syncom-type satellite Syncom was a program of three experimental, active geosynchronous communication satellites which was started by NASA in 1961. ... 1963 (MCMLXIII) was a common year starting on Tuesday (the link is to a full 1963 calendar). ...


Initially, geostationary satellites also carried telephone calls but are no longer used so predominantly for voice communication, partly due to the inherent disconcerting delay in getting information to the satellite and back (it takes light or radio about a quarter of a second to make the round trip). Similarly, international Internet connectivity has shifted away from satellite links. Look up Telephone in Wiktionary, the free dictionary. ...


Nearly all land locations on the planet now have terrestrial communications facilities (microwave, fiber-optics), even undersea, with more than sufficient capacity. Satellite telephony is now mainly limited to small, isolated locations that have no terrestrial facilities, such as Canada's arctic islands, Antarctica, the far reaches of Alaska and Greenland, and ships at sea (via Inmarsat). Microwaves are electromagnetic waves with wavelengths longer than those of terahertz (THz) wavelengths, but relatively short for radio waves. ... Fiber Optic strands An optical fiber in American English or fibre in British English is a transparent thin fiber for transmitting light. ... Official language(s) English Capital Juneau Largest city Anchorage Area  Ranked 1st  - Total 663,267 sq mi (1,717,855 km²)  - Width 808 miles (1,300 km)  - Length 1,479 miles (2,380 km)  - % water 13. ... Inmarsat is an international telecommunications company founded in 1979, originally as an intergovernmental organization. ...


See also

A geosynchronous satellite is a satellite whose orbital track on the Earth repeats regularly over points on the Earth over time. ... A graveyard orbit is an orbit where spacecraft are intentionally placed at the end of their operational life. ... Molniya orbit is a class of a highly elliptic orbit with inclination of +/-63. ...

External links

  • Nasa.gov: Geosynchronous Orbit
  • Science Presse data on Geosynchronous Orbits (including historical data and launch statistics)
  • ORBITAL MECHANICS (Rocket and Space Technology)

  Results from FactBites:
 
Geosynchronous orbit (163 words)
A geosynchronous orbit may be defined as one with an orbital period (the time needed to orbit once around the Earth) that matches the rotation rate of the Earth.
A geostationary orbit is a special case of a geosynchronous orbit.
A satellite is in a geostationary orbit when it appears stationary from the point of view of an observer on the Earth's surface.
Space Elevators and Tether Systems (6985 words)
Geosynchronous orbit is special since this is the distance at which an object orbiting the earth would have to travel around the earth at the same rate the earth rotates, the point at which a geosynchronous object’s centripetal force exactly cancels out its gravitational force.
If an object is within geosynchronous orbit and is moving around the earth with the same period (time per orbit) as the period of rotation of the earth then its gravitational force would exceed its centripetal force and pull it down.
On the space leg of the trip to geosynchronous orbit high speed would be desirable so as to shorten the journey, however during the short atmospheric leg, slow speeds would reduce the lose of energy to air resistance, or even render this effect negligible.
  More results at FactBites »

 
 

COMMENTARY     


Share your thoughts, questions and commentary here
Your name
Your comments

Want to know more?
Search encyclopedia, statistics and forums:

 


Press Releases |  Feeds | Contact
The Wikipedia article included on this page is licensed under the GFDL.
Images may be subject to relevant owners' copyright.
All other elements are (c) copyright NationMaster.com 2003-5. All Rights Reserved.
Usage implies agreement with terms, 1022, m