
, a satellite is an object which has been placed into orbit
by human endeavour. Such objects are sometimes called artificial satellites to distinguish them from natural satellite
s such as the Moon
.
The world's first artificial satellite, the Sputnik 1
, was launched by the Soviet Union in 1957. Since then, thousands of satellites have been launched into orbit around the Earth
; also some satellites, notably space station
s, have been launched in parts and assembled in orbit.
1957 Project Vanguard: A launchpad explosion of Vanguard TV3 thwarts the first United States attempt to launch a satellite into Earth orbit.
1958 Explorer program: ''Explorer 1'' – The first successful launch of an American satellite into orbit.
1958 The United States launches the Vanguard 1 satellite.
1958 The Soviet satellite Sputnik 2 falls from orbit after a mission duration of 162 days.
1962 First transatlantic satellite television transmission.
1962 ''Alouette 1,'' the first Canadian satellite, is launched.
1962 NASA "Relay 1" launch, first active repeater communications satellite in orbit.
1965 Launch of Early Bird, the first communications satellite to be placed in geosynchronous orbit.
1965 In the Hammaguir launch facility in the Sahara Desert, France launches a Diamant-A rocket with its first satellite, ''Asterix-1'' on board, becoming the third country to enter outer space.
1970 The first Chinese satellite, Dong Fang Hong I, is launched.


, a satellite is an object which has been placed into orbit
by human endeavour. Such objects are sometimes called artificial satellites to distinguish them from natural satellite
s such as the Moon
.
The world's first artificial satellite, the Sputnik 1
, was launched by the Soviet Union in 1957. Since then, thousands of satellites have been launched into orbit around the Earth
; also some satellites, notably space station
s, have been launched in parts and assembled in orbit. Artificial satellites originate from more than 50 countries and have used the satellite launching capabilities of ten nations. A few hundred satellites are currently operational, whereas thousands of unused satellites and satellite fragments orbit the Earth as space debris
. A few space probe
s have been placed into orbit around other bodies and become artificial satellites to the Moon, Mercury
, Venus
, Mars
, Jupiter
, Saturn
, and the Sun
.
Satellites are used for a large number of purposes. Common types include military and civilian Earth observation satellites, communications satellite
s, navigation satellites, weather satellites, and research satellites. Space station
s and human spacecraft
in orbit are also satellites. Satellite orbits vary greatly, depending on the purpose of the satellite, and are classified in a number of ways. Well-known (overlapping) classes include low Earth orbit
, polar orbit
, and geostationary orbit
.
Satellites are usually semi-independent computer-controlled systems. Satellite subsystems attend many tasks, such as power generation, thermal control, telemetry, attitude control and orbit control.
Early conceptions
The first fictional depiction of a satellite being launched into orbit is a short storyby Edward Everett Hale
, The Brick Moon
. The story is serialized in The Atlantic Monthly
, starting in 1869. The idea surfaces again in Jules Verne
's The Begum's Fortune (1879).
In 1903, Konstantin Tsiolkovsky
(1857–1935) published Means of Reaction Devices (in Russian
: Исследование мировых пространств реактивными приборами), which is the first academic treatise on the use of rocketry to launch spacecraft. He calculated the orbital speed
required for a minimal orbit around the Earth at 8 km/s, and that a multi-stage rocket fueled by liquid propellant
s could be used to achieve this. He proposed the use of liquid hydrogen
and liquid oxygen
, though other combinations can be used.
In 1928 Slovenian Herman Potočnik
(1892–1929) published his sole book, The Problem of Space Travel — The Rocket Motor (German
: Das Problem der Befahrung des Weltraums — der Raketen-Motor), a plan for a breakthrough into space and a permanent human presence there. He conceived of a space station in detail and calculated its geostationary orbit. He described the use of orbiting spacecraft for detailed peaceful and military observation of the ground and described how the special conditions of space could be useful for scientific experiments. The book described geostationary satellites (first put forward by Tsiolkovsky) and discussed communication between them and the ground using radio, but fell short of the idea of using satellites for mass broadcasting and as telecommunications relays.
In a 1945 Wireless World
article the English science fiction writer Arthur C. Clarke
(1917–2008) described in detail the possible use of communications satellite
s for mass communications. Clarke examined the logistics of satellite launch, possible orbits and other aspects of the creation of a network of world-circling satellites, pointing to the benefits of high-speed global communications. He also suggested that three geostationary satellites would provide coverage over the entire planet.
The US military studied the idea of what was referred to as the earth satellite vehicle when Secretary of Defense, James Forrestal, made a public announcement on December 29, 1948 that his office was coordinating that project between the various services.
History of artificial satellites

, launched by the Soviet Union on October 4, 1957, and initiating the Soviet Sputnik program, with Sergei Korolev as chief designer (there is a crater on the lunar far side which bears his name). This in turn triggered the Space Race
between the Soviet Union and the United States.
Sputnik 1 helped to identify the density of high atmospheric layers through measurement of its orbital change and provided data on radio-signal distribution in the ionosphere
. The unanticipated announcement of Sputnik 1s success precipitated the Sputnik crisis
in the United States and ignited the so-called Space Race
within the Cold War
.
Sputnik 2
was launched on November 3, 1957 and carried the first living passenger into orbit, a dog named Laika
.
In May, 1946, Project RAND had released the Preliminary Design of an Experimental World-Circling Spaceship
, which stated, "A satellite vehicle with appropriate instrumentation can be expected to be one of the most potent scientific tools of the Twentieth Century.
The United States had been considering launching orbital satellites since 1945 under the Bureau of Aeronautics
of the United States Navy
. The United States Air Force
's Project RAND eventually released the above report, but did not believe that the satellite was a potential military weapon; rather, they considered it to be a tool for science, politics, and propaganda. In 1954, the Secretary of Defense stated, "I know of no American satellite program."
On July 29, 1955, the White House
announced that the U.S. intended to launch satellites by the spring of 1958. This became known as Project Vanguard
. On July 31, the Soviets announced that they intended to launch a satellite by the fall of 1957.
Following pressure by the American Rocket Society
, the National Science Foundation
, and the International Geophysical Year
, military interest picked up and in early 1955 the Army and Navy were working on Project Orbiter
, two competing programs, the army's which involved using a Jupiter C rocket, and the civilian/Navy Vanguard Rocket, to launch a satellite. At first, they failed: initial preference was given to the Vanguard program whose launch vehicle had a strange and uncanny way of exploding on national television. But finally, three months after Sputnik 1
, the project succeeded; Explorer 1 thus became the United States' first artificial satellite on January 31, 1958.
In June 1961, three-and-a-half years after the launch of Sputnik 1, the Air Force used resources of the United States Space Surveillance Network
to catalog 115 Earth-orbiting satellites.
The largest artificial satellite currently orbiting the Earth is the International Space Station
.
Space Surveillance Network
The United States Space Surveillance Network (SSN), a division of The United States Strategic Command, has been tracking objects in Earth's orbit since 1957 when the Soviets opened the space age with the launch of Sputnik I. Since then, the SSN has tracked more than 26,000 objects. The SSN currently tracks more than 8,000 man-made orbiting objects. The rest have re-entered Earth's atmosphere and disintegrated, or survived re-entry and impacted the Earth. The SSN tracks objects that are 10 centimeters in diameter or larger; those now orbiting Earth range from satellites weighing several tons to pieces of spent rocket bodies weighing only 10 pounds. About seven percent are operational satellites (i.e. ~560 satellites), the rest are space debris
. The United States Strategic Command is primarily interested in the active satellites, but also tracks space debris which upon reentry might otherwise be mistaken for incoming missiles.
A search of the NSSDC Master Catalog at the end of October 2010 listed 6,578 satellites launched into orbit since 1957, the latest being Chang'e 2
, on 1 October 2010.
Non-military satellite services
There are three basic categories of non-military satellite services:Fixed satellite services
Fixed satellite serviceshandle hundreds of billions of voice, data, and video transmission tasks across all countries and continents between certain points on the Earth's surface.
Mobile satellite systems
Mobile satellite systems help connect remote regions, vehicles, ships, people and aircraft to other parts of the world and/or other mobile or stationary communications units, in addition to serving as navigation systems.Scientific research satellites (commercial and noncommercial)
Scientific research satellites provide us with meteorological information, land survey data (e.g., remote sensing), Amateur (HAM) Radio, and other different scientific research applications such as earth science, marine science, and atmospheric research.Types

- Anti-Satellite weapons/"Killer Satellites"Anti-satellite weaponAnti-satellite weapons are designed to incapacitate or destroy satellites for strategic military purposes. Currently, only the United States, the former Soviet Union, and the People's Republic of China are known to have developed these weapons. On September 13, 1985, the United States destroyed US...
are satellites that are designed to destroy enemy warheads, satellites, other space assets. - Astronomical satellites are satellites used for observation of distant planets, galaxies, and other outer space objects.
- BiosatelliteBiosatelliteA biosatellite is a satellite designed to carry life in space. The first satellite with animal was Soviet Sputnik 2 at November 3, 1957. On August 20, 1960 Soviet Sputnik 5 first time recovered animals from orbit to Earth....
s are satellites designed to carry living organisms, generally for scientific experimentation. - Communications satelliteCommunications satelliteA communications satellite is an artificial satellite stationed in space for the purpose of telecommunications...
s are satellites stationed in space for the purpose of telecommunications. Modern communications satellites typically use geosynchronous orbitGeosynchronous orbitA geosynchronous orbit is an orbit around the Earth with an orbital period that matches the Earth's sidereal rotation period...
s, Molniya orbitMolniya orbitMolniya orbit is a type of highly elliptical orbit with an inclination of 63.4 degrees, an argument of perigee of -90 degree and an orbital period of one half of a sidereal day...
s or Low Earth orbitLow Earth orbitA low Earth orbit is generally defined as an orbit within the locus extending from the Earth’s surface up to an altitude of 2,000 km...
s. - Miniaturized satellites are satellites of unusually low weights and small sizes. New classifications are used to categorize these satellites: minisatellite (500–100 kg), microsatellite (below 100 kg), nanosatellite (below 10 kg).
- Navigational satellitesGlobal Navigation Satellite SystemA satellite navigation or SAT NAV system is a system of satellites that provide autonomous geo-spatial positioning with global coverage. It allows small electronic receivers to determine their location to within a few metres using time signals transmitted along a line-of-sight by radio from...
are satellites which use radio time signals transmitted to enable mobile receivers on the ground to determine their exact location. The relatively clear line of sight between the satellites and receivers on the ground, combined with ever-improving electronics, allows satellite navigation systems to measure location to accuracies on the order of a few meters in real time. - Reconnaissance satellites are Earth observation satelliteEarth observation satelliteEarth observation satellites are satellites specifically designed to observe Earth from orbit, similar to reconnaissance satellites but intended for non-military uses such as environmental monitoring, meteorology, map making etc....
or communications satelliteCommunications satelliteA communications satellite is an artificial satellite stationed in space for the purpose of telecommunications...
deployed for militaryMilitaryA military is an organization authorized by its greater society to use lethal force, usually including use of weapons, in defending its country by combating actual or perceived threats. The military may have additional functions of use to its greater society, such as advancing a political agenda e.g...
or intelligenceEspionageEspionage or spying involves an individual obtaining information that is considered secret or confidential without the permission of the holder of the information. Espionage is inherently clandestine, lest the legitimate holder of the information change plans or take other countermeasures once it...
applications. Very little is known about the full power of these satellites, as governments who operate them usually keep information pertaining to their reconnaissance satellites classified. - Earth observation satelliteEarth observation satelliteEarth observation satellites are satellites specifically designed to observe Earth from orbit, similar to reconnaissance satellites but intended for non-military uses such as environmental monitoring, meteorology, map making etc....
s are satellites intended for non-military uses such as environmentEnvironment (biophysical)The biophysical environment is the combined modeling of the physical environment and the biological life forms within the environment, and includes all variables, parameters as well as conditions and modes inside the Earth's biosphere. The biophysical environment can be divided into two categories:...
al monitoring, meteorologyMeteorologyMeteorology is the interdisciplinary scientific study of the atmosphere. Studies in the field stretch back millennia, though significant progress in meteorology did not occur until the 18th century. The 19th century saw breakthroughs occur after observing networks developed across several countries...
, map making etc. (See especially Earth Observing SystemEarth Observing SystemThe Earth Observing System is a program of NASA comprising a series of artificial satellite missions and scientific instruments in Earth orbit designed for long-term global observations of the land surface, biosphere, atmosphere, and oceans of the Earth. The satellite component of the program was...
.) - Tether satellites are satellites which are connected to another satellite by a thin cable called a tetherTetherA tether is a cord, fixture, or signal that anchors something movable to a reference point which may be fixed or moving. There are a number of applications for tethers: balloons, kites, tethered wind-energy conversion systems, anchors, tethered water-flow energy conversion systems, towing, animal...
. - Weather satelliteWeather satelliteThe weather satellite is a type of satellite that is primarily used to monitor the weather and climate of the Earth. Satellites can be either polar orbiting, seeing the same swath of the Earth every 12 hours, or geostationary, hovering over the same spot on Earth by orbiting over the equator while...
s are primarily used to monitor Earth's weather and climateClimateClimate encompasses the statistics of temperature, humidity, atmospheric pressure, wind, rainfall, atmospheric particle count and other meteorological elemental measurements in a given region over long periods...
. - Recovery satellites are satellites that provides a recovery of reconnaissance, biological, space-production and other payloads from orbit to Earth.
- Manned spacecraftSpacecraftA spacecraft or spaceship is a craft or machine designed for spaceflight. Spacecraft are used for a variety of purposes, including communications, earth observation, meteorology, navigation, planetary exploration and transportation of humans and cargo....
(spaceships) are large satellites able for put humanHumanHumans are the only living species in the Homo genus...
into (and beyond) an orbit, being on it and recovery back to Earth. Spacecrafts, and orbital parts-spaceplaneSpaceplaneA spaceplane is a vehicle that operates as an aircraft in Earth's atmosphere, as well as a spacecraft when it is in space. It combines features of an aircraft and a spacecraft, which can be thought of as an aircraft that can endure and maneuver in the vacuum of space or likewise a spacecraft that...
s of reusable systemsReusable launch systemA reusable launch system is a launch system which is capable of launching a launch vehicle into space more than once. This contrasts with expendable launch systems, where each launch vehicle is launched once and then discarded.No true orbital reusable launch system is currently in use. The...
also, has a major propulsionSpacecraft propulsionSpacecraft propulsion is any method used to accelerate spacecraft and artificial satellites. There are many different methods. Each method has drawbacks and advantages, and spacecraft propulsion is an active area of research. However, most spacecraft today are propelled by forcing a gas from the...
or landingLandingthumb|A [[Mute Swan]] alighting. Note the ruffled feathers on top of the wings indicate that the swan is flying at the [[Stall |stall]]ing speed...
facilities, and often uses as transport to and from the orbital stations. - Space stationSpace stationA space station is a spacecraft capable of supporting a crew which is designed to remain in space for an extended period of time, and to which other spacecraft can dock. A space station is distinguished from other spacecraft used for human spaceflight by its lack of major propulsion or landing...
s are man-made orbital structures that are designed for human beingsHumanHumans are the only living species in the Homo genus...
to live on in outer spaceOuter spaceOuter space is the void that exists between celestial bodies, including the Earth. It is not completely empty, but consists of a hard vacuum containing a low density of particles: predominantly a plasma of hydrogen and helium, as well as electromagnetic radiation, magnetic fields, and neutrinos....
. A space station is distinguished from other manned spacecraft by its lack of major propulsion or landing facilities. Space stations are designed for medium-term living in orbit, for periods of weeks, months, or even years.
Orbit types

, was put into orbit around Earth and was therefore in geocentric orbit
. By far this is the most common type of orbit with approximately 2456 artificial satellites orbiting the Earth. Geocentric orbits may be further classified by their altitude, inclination
and eccentricity
.
The commonly used altitude classifications are Low Earth orbit
(LEO), Medium Earth orbit
(MEO) and High Earth orbit
(HEO). Low Earth orbit is any orbit below 2000 km, and Medium Earth orbit is any orbit higher than that but still below the altitude for geosynchronous orbit at 35786 km. High Earth orbit is any orbit higher than the altitude for geosynchronous orbit.
Centric classifications
- Geocentric orbitGeocentric orbitA geocentric orbit involves any object orbiting the Earth, such as the Moon or artificial satellites. Currently there are approximately 2,465 artificial satellites orbiting the Earth and 6,216 pieces of space debris as tracked by the Goddard Space Flight Center...
: An orbit around the planet Earth, such as the Moon or artificial satellites. Currently there are approximately 2465 artificial satellites orbiting the Earth. - Heliocentric orbitHeliocentric orbitA heliocentric orbit is an orbit around the Sun. All planets, comets, and asteroids in our Solar System are in such orbits, as are many artificial probes and pieces of debris. The moons of planets in the Solar System, by contrast, are not in heliocentric orbits as they orbit their respective planet...
: An orbit around the Sun. In our Solar SystemSolar SystemThe Solar System consists of the Sun and the astronomical objects gravitationally bound in orbit around it, all of which formed from the collapse of a giant molecular cloud approximately 4.6 billion years ago. The vast majority of the system's mass is in the Sun...
, all planets, comets, and asteroids are in such orbits, as are many artificial satellites and pieces of space debrisSpace debrisSpace debris, also known as orbital debris, space junk, and space waste, is the collection of objects in orbit around Earth that were created by humans but no longer serve any useful purpose. These objects consist of everything from spent rocket stages and defunct satellites to erosion, explosion...
. Moons by contrast are not in a heliocentric orbit but rather orbit their parent planet. - Areocentric orbitAreocentric orbitAn areocentric orbit is an orbit around the planet Mars. The Moon, by similarity, is in a geocentric orbit around Earth.The areo- prefix is derived from the ancient Greek word Ares which is the personification of the planet Mars in Greek mythology....
: An orbit around the planet MarsMarsMars is the fourth planet from the Sun in the Solar System. The planet is named after the Roman god of war, Mars. It is often described as the "Red Planet", as the iron oxide prevalent on its surface gives it a reddish appearance...
, such as by moons or artificial satellites.
The general structure of a satellite is that it is connected to the earth stations that are present on the ground and connected through terrestrial links.
Altitude classifications
- Low Earth orbitLow Earth orbitA low Earth orbit is generally defined as an orbit within the locus extending from the Earth’s surface up to an altitude of 2,000 km...
(LEO): Geocentric orbits ranging in altitude from 0–2000 km (0–1240 miles) - Medium Earth orbitMedium Earth OrbitMedium Earth orbit , sometimes called intermediate circular orbit , is the region of space around the Earth above low Earth orbit and below geostationary orbit ....
(MEO): Geocentric orbits ranging in altitude from 2000 km (1,242.7 mi) to just below geosynchronous orbit at 35786 km (22,236.4 mi). Also known as an intermediate circular orbit. - High Earth orbitHigh Earth orbitA High Earth Orbit is a geocentric orbit whose apogee lies above that of a geosynchronous orbit .Highly Elliptical Orbits are a subset of High Earth Orbits.-Examples of satellites in High Earth Orbit:...
(HEO): Geocentric orbits above the altitude of geosynchronous orbit 35786 km (22,236.4 mi).

Inclination classifications
- Inclined orbitInclined orbitA satellite is said to occupy an inclined orbit around the Earth if the orbit exhibits an angle other than zero degrees with the equatorial plane. This angle is called the orbit's inclination...
: An orbit whose inclination in reference to the equatorial plane is not zero degrees.Polar orbitA polar orbit is an orbit in which a satellite passes above or nearly above both poles of the body being orbited on each revolution. It therefore has an inclination of 90 degrees to the equator...
: An orbit that passes above or nearly above both poles of the planet on each revolution. Therefore it has an inclination of (or very close to) 90 degreeDegree (angle)A degree , usually denoted by ° , is a measurement of plane angle, representing 1⁄360 of a full rotation; one degree is equivalent to π/180 radians...
s. - Polar sun synchronous orbit: A nearly polar orbit that passes the equatorEquatorAn equator is the intersection of a sphere's surface with the plane perpendicular to the sphere's axis of rotation and containing the sphere's center of mass....
at the same local time on every pass. Useful for imageImageAn image is an artifact, for example a two-dimensional picture, that has a similar appearance to some subject—usually a physical object or a person.-Characteristics:...
taking satellites because shadowShadowA shadow is an area where direct light from a light source cannot reach due to obstruction by an object. It occupies all of the space behind an opaque object with light in front of it. The cross section of a shadow is a two-dimensional silhouette, or reverse projection of the object blocking the...
s will be nearly the same on every pass.
Eccentricity classifications
- Circular orbitCircular orbitA circular orbit is the orbit at a fixed distance around any point by an object rotating around a fixed axis.Below we consider a circular orbit in astrodynamics or celestial mechanics under standard assumptions...
: An orbit that has an eccentricityOrbital eccentricityThe orbital eccentricity of an astronomical body is the amount by which its orbit deviates from a perfect circle, where 0 is perfectly circular, and 1.0 is a parabola, and no longer a closed orbit...
of 0 and whose path traces a circleCircleA circle is a simple shape of Euclidean geometry consisting of those points in a plane that are a given distance from a given point, the centre. The distance between any of the points and the centre is called the radius....
.Hohmann transfer orbitIn orbital mechanics, the Hohmann transfer orbit is an elliptical orbit used to transfer between two circular orbits, typically both in the same plane....
: An orbital maneuver that moves a spacecraft from one circular orbit to another using two engine impulses. This maneuver was named after Walter HohmannWalter HohmannWalter Hohmann was a German engineer who made an important contribution to the understanding of orbital dynamics. In a book published in 1925, Hohmann demonstrated a very fuel-efficient path to move a spacecraft between two different orbits, now called a Hohmann transfer orbit. He received his Ph.D...
.
: An orbit with an eccentricity greater than 0 and less than 1 whose orbit traces the path of an ellipse
.
is at the altitude of a Low Earth orbit
(LEO) and the apogee at the altitude of a geosynchronous orbit.
: An elliptic orbit where the perigee is at the altitude of a Low Earth orbit (LEO) and the apogee at the altitude of a geostationary orbit.
: A highly elliptic orbit with inclination of 63.4° and orbital period
of half of a sidereal day (roughly 12 hours). Such a satellite spends most of its time over a designated area of the planet
.
: A highly elliptic orbit with inclination of 63.4° and orbital period of one sidereal day (roughly 24 hours). Such a satellite spends most of its time over a designated area of the planet.
Synchronous classifications
- Synchronous orbitSynchronous orbitA synchronous orbit is an orbit in which an orbiting body has a period equal to the average rotational period of the body being orbited , and in the same direction of rotation as that body.-Properties:...
: An orbit where the satellite has an orbital period equal to the average rotational period (earth's is: 23 hours, 56 minutes, 4.091 seconds) of the body being orbited and in the same direction of rotation as that body. To a ground observer such a satellite would trace an analemmaAnalemmaIn astronomy, an analemma is a curve representing the angular offset of a celestial body from its mean position on the celestial sphere as viewed from another celestial body relative to the viewing body's celestial equator...
(figure 8) in the sky. - Semi-synchronous orbitSemi-synchronous OrbitSemi-Synchronous Orbit: An orbit with approximately a 12-hour period. A circular Semi-Synchronous Orbit is at an altitude of approximately 20,200 km....
(SSO): An orbit with an altitude of approximately 20200 km (12,551.7 mi) and an orbital period equal to one-half of the average rotational period (earth's is approximately 12 hours) of the body being orbited - Geosynchronous orbitGeosynchronous orbitA geosynchronous orbit is an orbit around the Earth with an orbital period that matches the Earth's sidereal rotation period...
(GSO): Orbits with an altitude of approximately 35786 km (22,236.4 mi). Such a satellite would trace an analemmaAnalemmaIn astronomy, an analemma is a curve representing the angular offset of a celestial body from its mean position on the celestial sphere as viewed from another celestial body relative to the viewing body's celestial equator...
(figure 8) in the sky.Geostationary orbitA geostationary orbit is a geosynchronous orbit directly above the Earth's equator , with a period equal to the Earth's rotational period and an orbital eccentricity of approximately zero. An object in a geostationary orbit appears motionless, at a fixed position in the sky, to ground observers...
(GEO): A geosynchronous orbit with an inclination of zero. To an observer on the ground this satellite would appear as a fixed point in the sky.Arthur C. ClarkeSir Arthur Charles Clarke, CBE, FRAS was a British science fiction author, inventor, and futurist, famous for his short stories and novels, among them 2001: A Space Odyssey, and as a host and commentator in the British television series Mysterious World. For many years, Robert A. Heinlein,...
.
: A drift orbit close to but below GSO/GEO. Satellites will drift east.
: An orbit a few hundred kilometers above geosynchronous that satellites are moved into at the end of their operation.
: A synchronous orbit around the planet Mars
with an orbital period equal in length to Mars' sidereal day, 24.6229 hours.
(ASO): A circular areosynchronous orbit
on the equatorial plane and about 17000 km(10557 miles) above the surface. To an observer on the ground this satellite would appear as a fixed point in the sky.
(0.1628 AU
) around the Sun, a little less than half of the orbital radius of Mercury
.
Special classifications
- Sun-synchronous orbitSun-synchronous orbitA Sun-synchronous orbit is a geocentric orbit which combines altitude and inclination in such a way that an object on that orbit ascends or descends over any given point of the Earth's surface at the same local mean solar time. The surface illumination angle will be nearly the same every time...
: An orbit which combines altitude and inclination in such a way that the satellite passes over any given point of the planets's surface at the same local solar timeSolar timeSolar time is a reckoning of the passage of time based on the Sun's position in the sky. The fundamental unit of solar time is the day. Two types of solar time are apparent solar time and mean solar time .-Introduction:...
. Such an orbit can place a satellite in constant sunlight and is useful for imagingSatellite imagerySatellite imagery consists of photographs of Earth or other planets made by means of artificial satellites.- History :The first images from space were taken on sub-orbital flights. The U.S-launched V-2 flight on October 24, 1946 took one image every 1.5 seconds...
, spySpy satelliteA spy satellite is an Earth observation satellite or communications satellite deployed for military or intelligence applications....
, and weather satelliteWeather satelliteThe weather satellite is a type of satellite that is primarily used to monitor the weather and climate of the Earth. Satellites can be either polar orbiting, seeing the same swath of the Earth every 12 hours, or geostationary, hovering over the same spot on Earth by orbiting over the equator while...
s. - Moon orbit: The orbital characteristics of Earth's Moon. Average altitude of 384403 kilometres (238,857.5 mi), elliptical–inclined orbit.
Pseudo-orbit classifications
- Horseshoe orbitHorseshoe orbitA horseshoe orbit is a type of co-orbital motion of a small orbiting body relative to a larger orbiting body . The orbital period of the smaller body is very nearly the same as for the larger body, and its path appears to have a horseshoe shape in a rotating reference frame as viewed from the...
: An orbit that appears to a ground observer to be orbiting a certain planet but is actually in co-orbit with the planet. See asteroids 37533753 Cruithne3753 Cruithne is an asteroid in orbit around the Sun in approximate 1:1 orbital resonance with the Earth. It is a periodic inclusion planetoid orbiting the Sun in an apparent horseshoe orbit. It has been incorrectly called "Earth's second moon", but it is only a quasi-satellite. Cruithne never...
(Cruithne) and 2002 AA292002 AA29' is a small near-Earth asteroid that was discovered on January 9, 2002 by the LINEAR automatic sky survey. The diameter of the asteroid is only about 50 to 110 metres . It revolves about the Sun on an almost circular orbit very similar to that of the Earth...
. - Exo-orbit: A maneuver where a spacecraft approaches the height of orbit but lacks the velocity to sustain it.
, few satellites are launched into retrograde orbit because the quantity of fuel required to launch them is much greater than for a prograde orbit. This is because when the rocket starts out on the ground, it already has an eastward component of velocity equal to the rotational velocity of the planet at its launch latitude
.
and Lissajous orbit
: Orbits "around" Lagrangian point
s.
Satellite subsystems
The satellite's functional versatility is imbedded within its technical components and its operations characteristics. Looking at the "anatomy" of a typical satellite, one discovers two modules. Note that some novel architectural concepts such as Fractionated Spacecraftsomewhat upset this taxonomy.
Spacecraft bus or service module
This bus module consist of the following subsystems:- The Structural Subsystems
The structural subsystem provides the mechanical base structure, shields the satellite from extreme temperature changes and micro-meteorite damage, and controls the satellite's spin functions.
- The Telemetry Subsystems (aka Command and Data Handling, C&DH)
The telemetry subsystem monitors the on-board equipment operations, transmits equipment operation data to the earth control station, and receives the earth control station's commands to perform equipment operation adjustments.
- The Power Subsystems
The power subsystem consists of solar panels and backup batteries that generate power when the satellite passes into the Earth's shadow. Nuclear power sources (Radioisotope thermoelectric generator
s) have been used in several successful satellite programs including the Nimbus program
(1964–1978).
- The Thermal Control Subsystems
The thermal control subsystem helps protect electronic equipment from extreme temperatures due to intense sunlight or the lack of sun exposure on different sides of the satellite's body (e.g. Optical Solar Reflector
)
- The Attitude and Orbit Control Subsystems
The attitude and orbit control subsystem consists of small rocket thrusters that keep the satellite in the correct orbital position and keep antennas positioning in the right directions.
Communication payload
The second major module is the communication payload, which is made up of transponders. A transponder is capable of :- Receiving uplinked radio signals from earth satellite transmission stations (antennas).
- Amplifying received radio signals
- Sorting the input signals and directing the output signals through input/output signal multiplexers to the proper downlink antennas for retransmission to earth satellite receiving stations (antennas).
End of life
When satellites reach the end of their mission, satellite operators have the option of de-orbiting the satellite, leaving the satellite in its current orbit or moving the satellite to a graveyard orbit. Historically, due to budgetary constraints at the beginning of satellite missions, satellites were rarely designed to be de-orbited. One example of this practice is the satellite Vanguard 1. Launched in 1958, Vanguard 1
, the 4th manmade satellite put in Geocentric orbit, was still in orbit as of August 2009.
Instead of being de-orbited, most satellites are either left in their current orbit or moved to a graveyard orbit. As of 2002, the FCC now requires all geostationary satellites to commit to moving to a graveyard orbit at the end of their operational life prior to launch.
Launch-capable countries

Order | Country | Year of first launch | Rocket | Satellite |
---|---|---|---|---|
1 | ![]() |
1957 | Sputnik-PS | Sputnik 1 Sputnik 1 Sputnik 1 ) was the first artificial satellite to be put into Earth's orbit. It was launched into an elliptical low Earth orbit by the Soviet Union on 4 October 1957. The unanticipated announcement of Sputnik 1s success precipitated the Sputnik crisis in the United States and ignited the Space... |
2 | ![]() |
1958 | Juno I Juno I The Juno I was a four-stage American booster rocket which launched America's first satellite, Explorer 1, in 1958. A member of the Redstone rocket family, it was derived from the Jupiter-C sounding rocket... |
Explorer 1 |
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1965 | Diamant Diamant The Diamant rocket was the first exclusively French expendable launch system and at the same time the first satellite launcher not built by either the USA or USSR. As such it is the main predecessor of all subsequent European launcher projects... |
Astérix Astérix (satellite) Astérix, the first French satellite, was launched on November 26, 1965 by a rocket of type Diamant A from Hammaguir in Algeria. It was originally designated A-1, as the French Army's first satellite, but later renamed after the popular French cartoon character Astérix... |
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1970 | Lambda-4S Lambda (rocket) Lambda is the name of a series of Japanese rockets. It consisted of the types Lambda 2, LS-A, LSC-3, Lambda 3, Lambda 4 and LS-C.On February 11, 1970 the first Japanese satellite Ōsumi was launched using a Lambda 4 rocket.... |
Ōsumi Osumi (satellite) Ōsumi is the name of the first Japanese artificial satellite put into orbit, named after the Ōsumi Province in the southern islands of Japan. It was launched on February 11, 1970 at 04:25 UTC with a Lambda 4S-5 rocket from Uchinoura Space Center by Institute of Space and Aeronautical Science,... |
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1970 | Long March 1 Long March 1 Long March 1 is 1st member of China's Long March 1 .The study of Long March 1 began in 1965. Long March 1's first flight put China's first satellite Dong Fang Hong 1 to space on April 24, 1970.* Stages: 3... |
Dong Fang Hong I Dong Fang Hong I Dong Fang Hong I , also known as China 1, was the People's Republic of China's first space satellite, launched successfully on April 24, 1970 as part of the PRC's Dong Fang Hong space satellite program. At 173 kg , it was heavier than the first satellites of other countries. The satellite carried... |
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1971 | Black Arrow Black Arrow Black Arrow, officially capitalised BLACK ARROW, was a British satellite carrier rocket. Developed during the 1960s, it was used for four launches between 1969 and 1971... |
Prospero X-3 Prospero X-3 -External links:* from "Woomera on the Web"* from Encyclopedia Astronautica* in the Global Frequency Database... |
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1980 | SLV Satellite Launch Vehicle The Indian Satellite Launch Vehicle or SLV was a project started in the early 1970s by Indian Space Research Organisation to develop the technology needed to launch satellites. The project was headed by Dr. APJ Abdul Kalam. SLV was intended to reach a height of 400 km and carry a payload of... |
Rohini |
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1988 | Shavit Shavit Shavit is a space launch vehicle produced by Israel to launch small satellites into low earth orbit. It was first launched on September 19, 1988 , making Israel the eighth country to have a space launch capability after the USSR, United States, France, Japan, People's Republic of China, United... |
Ofeq 1 Ofeq Ofeq, also spelled Offek or Ofek is the designation of a series of Israeli reconnaissance satellites first launched in 1988. All Ofeq satellites have been carried on top of Shavit rockets from Palmachim Airbase in Israel, on the Mediterranean coast. The Low Earth Orbit satellites complete one... |
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1992 | Soyuz-U Soyuz-U The Soyuz-U launch vehicle is an improved version of the original Soyuz LV. Soyuz-U is part of the R-7 family of rockets based on the R-7 Semyorka missile. Members of this rocket family were designed by the TsSKB design bureau and constructed at the Progress Factory in Samara, Russia.... |
Kosmos 2175 Kosmos 2175 Kosmos 2175 was a Russian Yantar-4K2 photo reconnaissance satellite. It was the first satellite to be launched by the Russian Federation, following the breakup of the Soviet Union. It was launched by a Soyuz-U carrier rocket, flying from the Plesetsk Cosmodrome, on 21 January 1992.It was the 63rd... |
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1992 | Tsyklon-3 Tsyklon-3 The Tsyklon-3, also known as Tsiklon-3, GRAU index 11K68, was a Soviet, and subsequently Ukrainian orbital carrier rocket. A derivative of the R-36 ICBM, and a member of the Tsyklon family, it made its maiden flight on 24 June 1977, and was retired on 30 January 2009... |
Strela Strela (satellite) Strela is a Russian military communications satellite constellation operating in low Earth orbit.-History:The first three satellites, Kosmos 38 , Kosmos 39 and Kosmos 40 , were launched on 18 August 1964... |
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2009 | Safir-2 | Omid |
Launch capable private entities
- Orbital Sciences CorporationOrbital Sciences CorporationOrbital Sciences Corporation is an American company which specializes in the manufacturing and launch of satellites. Its Launch Systems Group is heavily involved with missile defense launch systems...
is conducting launches using its Taurus I rocket. - On September 28, 2008, the private aerospace firm SpaceXSpaceXSpace Exploration Technologies Corporation, or more popularly and informally known as SpaceX, is an American space transport company that operates out of Hawthorne, California...
successfully launched its Falcon 1 rocket in to orbit. This marked the first time that a privately built liquid-fueled booster was able to reach orbit. The rocket carried a prism shaped 1.5 m (5 ft) long payload mass simulator that was set into orbit. The dummy satellite, known as Ratsat, will remain in orbit for between five and ten years before burning up in the atmosphere.
A few other private companies are capable of sub-orbital launches.
First satellites of countries
Country | Year of first launch | First satellite | Payloads in orbit in 2010-2011 |
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1957 (1992) |
Sputnik 1 Sputnik 1 Sputnik 1 ) was the first artificial satellite to be put into Earth's orbit. It was launched into an elliptical low Earth orbit by the Soviet Union on 4 October 1957. The unanticipated announcement of Sputnik 1s success precipitated the Sputnik crisis in the United States and ignited the Space... (Cosmos 2175) |
1437 |
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1958 | Explorer 1 | 1099 |
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1962 | Ariel 1 Ariel 1 Ariel 1, also known as UK-1 and S-55, was the first British satellite, and the first satellite in the Ariel programme. Its launch in 1962 made the United Kingdom the third country to operate a satellite, after the Soviet Union and the USA... |
29 |
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1962 | Alouette 1 Alouette 1 Alouette 1 was Canada's first satellite, and the first satellite constructed by a country other than the USSR or the United States. Occasionally, Alouette 1 is misrepresented as the third satellite successfully put in orbit, rather than being from the third country to have one of its own in space,... |
32 |
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1964 | San Marco 1 San Marco 1 San Marco 1, also known as San Marco A, was the first Italian satellite, and one of the earliest non-Soviet/US spacecraft. Built in-house by the Italian Space Research Commission on behalf of the National Research Council, it was the first of five as part of the Italian-US San Marco programme.The... |
17 |
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1965 | Astérix Astérix (satellite) Astérix, the first French satellite, was launched on November 26, 1965 by a rocket of type Diamant A from Hammaguir in Algeria. It was originally designated A-1, as the French Army's first satellite, but later renamed after the popular French cartoon character Astérix... |
49 |
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1967 | WRESAT WRESAT WRESAT was the name of the first Australian satellite. It was named after its designer.... |
11 |
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1969 | Azur Azur (satellite) Azur was Germany's first scientific satellite. Launched on 8 November 1969 it studied the Van Allen belts, solar particles, and aurorae.... |
42 |
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1970 | Ōsumi Osumi (satellite) Ōsumi is the name of the first Japanese artificial satellite put into orbit, named after the Ōsumi Province in the southern islands of Japan. It was launched on February 11, 1970 at 04:25 UTC with a Lambda 4S-5 rocket from Uchinoura Space Center by Institute of Space and Aeronautical Science,... |
126 |
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1970 | Dong Fang Hong I Dong Fang Hong I Dong Fang Hong I , also known as China 1, was the People's Republic of China's first space satellite, launched successfully on April 24, 1970 as part of the PRC's Dong Fang Hong space satellite program. At 173 kg , it was heavier than the first satellites of other countries. The satellite carried... |
111 |
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1973 | Intercosmos Copernicus 500 | 1 |
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1974 | ANS Astronomical Netherlands Satellite The Astronomical Netherlands Satellite was a space-based X-ray and ultraviolet telescope. It was launched into Earth orbit on 30 August 1974 at 14:07:39 UTC in a Scout rocket from Vandenberg Air Force Base, United States... |
5 |
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1974 | Intasat | 9 |
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1975 | Aryabhata Aryabhata (satellite) Aryabhatta was India's first satellite, named after the great Indian astronomer of the same name. It was launched by the Soviet Union on 19 April 1975 from Kapustin Yar using a Cosmos-3M launch vehicle. It was built by the Indian Space Research Organization to gain experience in building and... |
45 |
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1976 | Palapa A1 | 10 |
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1978 | Magion 1 | 5 |
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1981 | Intercosmos Bulgaria 1300 Bulgaria 1300 Interkosmos 22, more commonly known as Bulgaria 1300 , is the first artificial satellite of Bulgaria.- Description :The satellite was developed by the Bulgarian Space Agency around the "Meteor" bus, provided by the Soviet Union as part of the Interkosmos program. Assembly took place in Bulgaria,... |
1 |
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1985 | Brasilsat A1 | 11 |
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1985 | Morelos 1 | 7 |
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1986 | Viking Viking (satellite) Viking was Sweden's first satellite. It was launched on an Ariane 1 rocket as a piggyback payload together with the French satellite SPOT 1, on February 22, 1986. Operations ended on May 12, 1987... |
11 |
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1988 | Ofeq 1 Ofeq Ofeq, also spelled Offek or Ofek is the designation of a series of Israeli reconnaissance satellites first launched in 1988. All Ofeq satellites have been carried on top of Shavit rockets from Palmachim Airbase in Israel, on the Mediterranean coast. The Low Earth Orbit satellites complete one... |
10 |
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1988 | Astra 1A Astra 1A Astra 1A was the first satellite launched and operated by SES . During its early days, it was often referred to as the Astra Satellite, as SES only operated one satellite originally.... |
15 |
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1990 | Lusat | 10 |
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1990 | Badr-1 | 5 |
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1992 | Kitsat A Kitsat A Kitsat Ais Republic of Korea's first satellite.August 11, 1992 Republic of Korea's first satellite in adults Kitsat A arc Guiana Space Centre launch weight was 48.5kg, Size 35.2 X 35.6 X 67cm small scientific satellite of the University of Surrey in the UK UoSAT-5 satellite console was used.South... |
12 |
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1993 | PoSAT-1 PoSAT-1 PoSAT-1, the first Portuguese satellite, was launched into orbit on September 26, 1993, on the 59th flight of the Ariane 4 rocket. The launch took place in the Kourou Space Centre, French Guiana... |
1 |
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1993 | Thaicom 1 Thaicom Thaicom is the name of a series of communications satellites operated out of Thailand and the name of Thaicom Public Company Limited, which is the company that owns and operates the THAICOM satellite fleet and other telecommunication businesses in Thailand and throughout the... |
6 |
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1994 | Turksat 1B | 5 |
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1995 | Sich-1 Sich-1 Sich-1 is first Ukrainian Earth observation satellite.... |
6 |
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1995 | FASat-Alfa FASat-Alfa FASat-Alfa was to become the first Chilean satellite, and was constructed under a Technology Transfer Program between the Chilean Air Force and Surrey Satellite Technology Ltd of the United Kingdom. The primary goal of the Program was to obtain for Chile the basic scientific and technological... |
1 |
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1996 | MEASAT MEASAT MEASAT Satellite Systems Sdn. Bhd., formerly Binariang Satellite Systems Sdn. Bhd is a Malaysian communications satellite operator.MEASAT is the name of a line of communications satellites owned and operated by the company.As of 2006, the MEASAT satellite network consists of three geostationary... |
4 |
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1997 | Thor 2 | 3 |
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1997 | Mabuhay 1 Agila 2 Agila 2 , named after the critically endangered Philippine eagle, is a communications satellite launched in 1997. It provides telecommunications services for the Mabuhay Philippines Satellite Corporation. It is the first Filipino space satellite... |
2 |
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1998 | Nilesat 101 Nilesat 101 Nilesat 101 is an Egyptian owned geosynchronous communications satellite.Launched by an Ariane 4 rocket from Kourou, French Guiana on 28 April 1998 at 22:53:00 UTC by the European Space Agency, it was manufactured by the European company Matra Marconi Space , and started official broadcasting on 31... |
3 |
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1998 | ST-1 ST-1 ST-1 is a communications satellite owned by Singapore Telecom and Taiwan's Chunghwa Telecom Company, Ltd. It was placed launched on 25 August 1998, by an Ariane 4 rocket. The two companies jointly operate the spacecraft from control centres located in Seletar, Singapore and Taipei, Taiwan,... |
3 |
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1999 | ROCSAT-1 | 9 |
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1999 | Ørsted | 4 |
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1999 | SUNSAT SUNSAT The Stellenbosch UNiversity SATellite is the first miniaturized satellite designed and manufactured in South Africa. It was launched aboard a Delta II rocket from the Vandenberg Air Force Base on 23 February 1999. Sunsat was built by post-graduate engineering students at the University of... |
2 |
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2000 | Saudisat 1A | 12 |
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2000 | Thuraya 1 | 3 |
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2001 | Maroc-Tubsat | 1 |
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2002 | Alsat 1 | 1 |
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2003 | Hellas Sat 2 | 2 |
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2003 | Hellas Sat 2 | 2 |
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2003 | Nigeriasat 1 | 4 |
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2005 | Sina-1 | 4 |
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2006 | KazSat 1 KazSat KazSat 1 , the first Kazakh space satellite, was launched on June 18, 2006 by Proton-K rocket . It contains 12 Ku-band transponders . It is a communications satellite occupying geosynchronous orbit approximately 36 000 km above the Earth... |
2 |
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2006 | BelKA BelKA BelKA was intended to be the first satellite of independent Belarus.... |
1 |
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2007 | Libertad 1 Libertad 1 Libertad 1 is a single CubeSat built by the Space Program of the Sergio Arboleda University in the South American country of Colombia. It was launched aboard a Dnepr rocket on April 17, 2007 from the Baikonur Cosmodrome, Kazakhstan and became the first Colombian satellite to orbit the Earth. It... |
1 |
2007 | Rascom-QAF 1 | 2 | |
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2008 | VINASAT-1 | 1 |
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2008 | Venesat-1 Venesat-1 Venesat-1, also known as Simón Bolívar, is the first Venezuelan satellite. It was designed, built, launched, controlled and monitored by the CGWIC subsidiary of the China Aerospace Science and Technology Corporation. It is a communications satellite, which will be operated from a geosynchronous orbit... |
1 |
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2009 | SwissCube-1 SwissCube-1 SwissCube-1 is a Swiss satellite operated by Ecole Polytechnique Fédérale de Lausanne. The spacecraft is a single unit CubeSat, which was designed to conduct research into nightglow within the Earth's atmosphere, and to develop technology for future spacecraft. It has also been used for amateur radio... |
1 |
While Canada was the third country to build a satellite which was launched into space, it was launched aboard a U.S. rocket from a U.S. spaceport. The same goes for Australia, who launched on-board a donated Redstone rocket. The first Italian-launched was San Marco 1
, launched on 15 December 1964 on a U.S. Scout rocket from Wallops Island (VA,USA) with an Italian Launch Team trained by NASA. Australia's launch project (WRESAT
) involved a donated U.S. missile and U. S. support staff as well as a joint launch facility with the United Kingdom. The first satellite built by Singapore, X-SAT
, was launched aboard a PSLV rocket on April 20, 2011.
Planned first satellites
The micro-satellite BRITE-AUSTRIA (TUG-SAT-1) plans to start in September 2011. is developing its space satellite Azerspace. According to the approved plan, the Azerspace satellite will be launched into orbit in 2012. announced in 2009 that it intends to launch its first satellite into space by 2011. Its nano-satellite OUFTI-1within European University program CubeSat for test radio protocol in space are under construction in University of Liege. New Bolivian Space Agency plans a first satellite to 2012 by Chinese help Royal Group plans to purchase for 250-350 billion $ and launch in the beginning of 2013 the telecommunication satellite http://4infos.blogspot.com/2011/04/royal-group-receives-right-to-launch.html has a goal to construct a satellite by 2013–2014. Launch into Earth orbit would be done by a foreign provider. presented its first satellite in April 4, 2011, the NEE-01 Pegasus
designed and built by the Ecuadorian Space Agency. The pico-satellite will be launched into orbit by 2012, and will have an expected 1-year lifespan. it has 16 missions and 3 payloads, it is the first known CubeSat to be able to send real-time video from orbit, both visible and infrared. It also carries a thermal and radiation shield. The nano-satellite ESTCube-1 plans by University of Tartu within student CubeSat projects https://sites.google.com/a/estcube.eu/estonian-student-satellite-program/estcube-1 Aalto-1
with solar panels is a funded by EU student nano-satellite project of Aalto University, Finland and Finnish Meteorological Institute http://www.electric-sailing.fi/. When launched (plan to 2013), it would be the first Finnish satellite. The nano-satellite MaSat-1
within student CubeSat projects plans to launch in 2011 by Technical University of Budapest First satellite will be telecommunication and will be built and launched in 2013 for $250 billion by China Asia-Pacific Mobile Communications Company (China-APMT) http://www.voanews.com/lao/news/a-52-2010-01-19-voa6-90693964.html http://www.spacedaily.com/reports/China_to_build_launch_satellite_for_Laos_999.html The 5 kg nano-satellite Venta-1 is built in Latvia in cooperation with the German engineers. The data received from satellite will be received and processed in Irbene radioastronomical centre (Latvia); satellite will have software defined radio capabilities. "Venta-1" will serve mainly as a means for education in Ventspils University College with additional functions, including an automatic system of identification of the ships of a sailing charter developed by OHB-System AG. The launch of the satellite was planned for the end of 2009 using the Indian carrier rocket. Due to the financial crisis the launch has been postponed until late 2011. Started preparations to produce the next satellite "Venta-2". New national Space Science and Technology Institute plans nano-satellite with space capsule
s by Russian help The remote sensing
satellite plans to start in 2013 by Space centre at national Technical University. plans to purchase for $200 billion the own telecommunication satellite http://www.mizzima.com/news/breaking-and-news-brief/5414-burma-to-launch-first-state-owned-satellite-expand-communications.html Private New Zealand Satellite Opportunities company since 2005 plans to launch in 2010 or later a commercial satellite NZLSAT for $200 billion. http://www.redorbit.com/news/technology/334482/nz_satellite_closer_after_approval_given_to_use_dedicated_orbital/ http://www.nzherald.co.nz/technology/news/article.cfm?c_id=5&objectid=10360387 Radio enthusiasts federation at Massey University http://www.kiwisat.org.nz/ since 2003 hopes for $400,000 to launch a nano-satellite KiwiSAT
to relay a voice and data signals http://www.nzherald.co.nz/nz/news/article.cfm?c_id=1&objectid=3051966 Also another RocketLab company works under suborbital space launcher and may use a further version of one to launch into low polar orbit a nano-satellite http://www.stuff.co.nz/science/2946619/NZ-set-to-join-the-space-age http://www.rocketlab.co.nz/rocket-lab-news.html will launch several more satellites according to national space program of Korean Committee of Space Technology
is developing its space satellite with the National Engineering University, called Chasqui 1
. The nano-satellite will be launched into orbit by 2011, and will have an expected 60-day lifespan. As payload are installed two small VGA cameras. One of both will have a NIR filter. announced that it has finished construction of its first satellite for Earth imaging and space environment measuring, called Goliat, within European program CubeSat of Universities. The nano-satellite will be launched into orbit in 2011. has a goal to construct two satellites. Sri Lankan Telecommunications Regulatory Commission has signed an agreement with Surrey Satellite Technology Ltd to get relevant help and resources. Launch into Earth orbit would be done by a foreign provider. is developing its first satellite, ERPSat01. Consisting of a CubeSat
of 1 kg weight, it will be developed by the Sfax
School of Engineering. ERPSat satellite is planned to be launched into orbit in 2013. New National Space Agency
plans a first satellite by help of SpaceX
to 2014 Uzbek State Space Research Agency (UzbekCosmos) announced in 2001 about intention of launch in 2002 first remote sensing satellite http://www.satnews.com/stories/3may2001-4.html Later in 2004 was stated that two satellites (remote sensing and telecommunication) will be build by Russia for 60-70 billion $ each http://www.redorbit.com/news/space/62825/uzbekistan_planning_to_launch_two_satellites_with_russian_help/
Attacks on satellites
In recent times satellites have been hacked by militant organizations to broadcast propaganda and to pilfer classified information from military communication networks.For testing purposes, satellites in low earth orbit have been destroyed by ballistic missiles launched from earth. Russia, the United States and China have demonstrated the ability to eliminate satellites. In 2007 the Chinese
military shot down an aging weather satellite, followed by the US Navy shooting down a defunct spy satellite in February 2008.
Jamming
Due to the low received signal strength of satellite transmissions, they are prone to jammingby land-based transmitters. Such jamming is limited to the geographical area within the transmitter's range. GPS satellites are potential targets for jamming, but satellite phone and television signals have also been subjected to jamming.
Also, it is trivial to transmit a carrier radio signal to a geostationary satellite and thus interfere with the legitimate uses of the satellite's transponder. It is common for Earth stations to transmit at the wrong time or on the wrong frequency in commercial satellite space, and dual-illuminate the transponder, rendering the frequency unusable. Satellite operators now have sophisticated monitoring that enables them to pinpoint the source of any carrier and manage the transponder space effectively.
Satellite services
- Satellite Internet accessSatellite Internet accessSatellite Internet access is Internet access provided through satellites. The service can be provided to users world-wide through low Earth orbit satellites. Geostationary satellites can offer higher data speeds, but their signals can not reach some polar regions of the world...
- Satellite phoneSatellite phoneA satellite telephone, satellite phone, or satphone is a type of mobile phone that connects to orbiting satellites instead of terrestrial cell sites...
- Satellite radioSatellite radioSatellite radio is an analogue or digital radio signal that is relayed through one or more satellites and thus can be received in a much wider geographical area than terrestrial FM radio stations...
- Satellite televisionSatellite televisionSatellite television is television programming delivered by the means of communications satellite and received by an outdoor antenna, usually a parabolic mirror generally referred to as a satellite dish, and as far as household usage is concerned, a satellite receiver either in the form of an...
- Satellite navigation
See also
- 2009 satellite collision2009 satellite collisionThe 2009 satellite collision was the first accidental hypervelocity collision between two intact artificial satellites in Earth orbit. The collision occurred at 16:56 UTC on February 10, 2009, at above the Taymyr Peninsula in Siberia, when Iridium 33 and Kosmos-2251 collided...
- Footprint (satellite)Footprint (satellite)The footprint of a communications satellite is the ground area that its transponders offer coverage, and determines the satellite dish diameter required to receive each transponder's signal...
- Fractionated SpacecraftFractionated SpacecraftA fractionated spacecraft is a satellite architecture where the functional capabilities of a conventional monolithic spacecraft are distributed across multiple modules which interact through wireless links...
- International DesignatorInternational DesignatorThe International Designator, also known as COSPAR designation, and in the United States as NSSDC ID, is an international naming convention for satellites...
- IMINTIMINTImagery Intelligence , is an intelligence gathering discipline which collects information via satellite and aerial photography. As a means of collecting intelligence, IMINT is a subset of intelligence collection management, which, in turn, is a subset of intelligence cycle management...
- Space explorationSpace explorationSpace exploration is the use of space technology to explore outer space. Physical exploration of space is conducted both by human spaceflights and by robotic spacecraft....
- List of Earth observation satellites
- List of communications satellite firsts
- Satellite Catalog NumberSatellite Catalog NumberThe Satellite Catalog Number is a sequential 5-digit number assigned by USSPACECOM to all Earth orbiting satellites in order of identification. Before USSPACECOM, the catalog was maintained by NORAD...
- Satellite formation flyingSatellite formation flyingSatellite formation flying is the concept that multiple satellites can work together in a group to accomplish the objective of one larger, usually more expensive, satellite...
- USA 193USA 193USA-193, also known as NRO launch 21 , was an American military spy satellite launched on December 14, 2006. It was the first launch conducted by the United Launch Alliance...
(2008 American anti-satellite missile test) - SpaceportSpaceportA spaceport or cosmodrome is a site for launching spacecraft, by analogy with seaport for ships or airport for aircraft. The word spaceport, and even more so cosmodrome, has traditionally been used for sites capable of launching spacecraft into orbit around Earth or on interplanetary trajectories...
(including list of spaceports with achieved satellite launches) - Echo 1
- Pioneer 10Pioneer 10Pioneer 10 is a 258-kilogram robotic space probe that completed the first interplanetary mission to Jupiter, and became the first spacecraft to achieve escape velocity from the Solar System. The project was managed by the NASA Ames Research Center and the contract for the construction of the...
- Mariner 10Mariner 10Mariner 10 was an American robotic space probe launched by NASA on November 3, 1973, to fly by the planets Mercury and Venus. It was launched approximately two years after Mariner 9 and was the last spacecraft in the Mariner program...
- Viking I
- Viking II
- Satellites on stampsU.S. space exploration history on U.S. stampsWith the advent of unmanned and manned space flight a whole new era of American history had presented itself. Keeping with the tradition of honoring the country's history on the face of U.S. postage stamps, the U.S. Post Office began honoring the various events with its commemorative postage stamp...
External links
- Satellite Ground Tracks Real time satellite tracks (Full catalog of satellite orbit).
- Real Time Satellite Tracking provides real-time tracks for about 17000 satellites, as well as 5-day predicitions of visibility
- Heavens Above provides 10-day predictions of satellite visibility
- 'Eyes in the Sky' Free video by the Vega Science Trust and the BBC/OU Satellites and their implications over the last 50 years.
- How Stuff Works.com How satellites work
- UCS Satellite Database Lists operational satellites currently in orbit around the Earth. Updated quarterly.
- Current and Historical Launch Calendar
- Satellite launch schedule