In the context of
spaceflightSpaceflight is the act of travelling into or through outer space. Spaceflight can occur with spacecraft which may, or may not, have humans on board. Examples of human spaceflight include the Russian Soyuz program, the U.S. Space shuttle program, as well as the ongoing International Space Station...
, a
satellite is an object which has been placed into
orbitIn physics, an orbit is the gravitationally curved path of an object around a point in space, for example the orbit of a planet around the center of a star system, such as the Solar System...
by human endeavour. Such objects are sometimes called
artificial satellites to distinguish them from
natural satelliteA natural satellite or moon is a celestial body that orbits a planet or smaller body, which is called its primary. The two terms are used synonymously for non-artificial satellites of planets, of dwarf planets, and of minor planets....
s such as the
MoonThe Moon is Earth's only known natural satellite,There are a number of near-Earth asteroids including 3753 Cruithne that are co-orbital with Earth: their orbits bring them close to Earth for periods of time but then alter in the long term . These are quasi-satellites and not true moons. For more...
.
The world's first artificial satellite, the
Sputnik 1Sputnik 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...
, was launched by the Soviet Union in 1957. Since then, thousands of satellites have been launched into orbit around the
EarthEarth is the third planet from the Sun, and the densest and fifth-largest of the eight planets in the Solar System. It is also the largest of the Solar System's four terrestrial planets...
; also some satellites, notably
space 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, 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 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...
. A few
space probeA robotic spacecraft is a spacecraft with no humans on board, that is usually under telerobotic control. A robotic spacecraft designed to make scientific research measurements is often called a space probe. Many space missions are more suited to telerobotic rather than crewed operation, due to...
s have been placed into orbit around other bodies and become artificial satellites to the Moon,
MercuryMercury is the innermost and smallest planet in the Solar System, orbiting the Sun once every 87.969 Earth days. The orbit of Mercury has the highest eccentricity of all the Solar System planets, and it has the smallest axial tilt. It completes three rotations about its axis for every two orbits...
,
VenusVenus is the second planet from the Sun, orbiting it every 224.7 Earth days. The planet is named after Venus, the Roman goddess of love and beauty. After the Moon, it is the brightest natural object in the night sky, reaching an apparent magnitude of −4.6, bright enough to cast shadows...
,
MarsMars 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...
,
JupiterJupiter is the fifth planet from the Sun and the largest planet within the Solar System. It is a gas giant with mass one-thousandth that of the Sun but is two and a half times the mass of all the other planets in our Solar System combined. Jupiter is classified as a gas giant along with Saturn,...
,
SaturnSaturn is the sixth planet from the Sun and the second largest planet in the Solar System, after Jupiter. Saturn is named after the Roman god Saturn, equated to the Greek Cronus , the Babylonian Ninurta and the Hindu Shani. Saturn's astronomical symbol represents the Roman god's sickle.Saturn,...
, and the
SunThe Sun is the star at the center of the Solar System. It is almost perfectly spherical and consists of hot plasma interwoven with magnetic fields...
.
Satellites are used for a large number of purposes. Common types include military and civilian Earth observation satellites,
communications satelliteA communications satellite is an artificial satellite stationed in space for the purpose of telecommunications...
s, navigation satellites, weather satellites, and research satellites.
Space 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 and human
spacecraftA 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....
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 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...
,
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...
, and
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...
.
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 storyA short story is a work of fiction that is usually written in prose, often in narrative format. This format tends to be more pointed than longer works of fiction, such as novellas and novels. Short story definitions based on length differ somewhat, even among professional writers, in part because...
by
Edward Everett HaleEdward Everett Hale was an American author, historian and Unitarian clergyman. He was a child prodigy who exhibited extraordinary literary skills and at age thirteen was enrolled at Harvard University where he graduated second in his class...
,
The Brick Moon"The Brick Moon" is a short story by Edward Everett Hale, published serially in The Atlantic Monthly starting in 1869. It is a work of speculative fiction containing the first known depiction of an artificial satellite.- Synopsis :...
. The story is serialized in
The Atlantic MonthlyThe Atlantic is an American magazine founded in Boston, Massachusetts, in 1857. It was created as a literary and cultural commentary magazine. It quickly achieved a national reputation, which it held for more than a century. It was important for recognizing and publishing new writers and poets,...
, starting in 1869. The idea surfaces again in
Jules VerneJules Gabriel Verne was a French author who pioneered the science fiction genre. He is best known for his novels Twenty Thousand Leagues Under the Sea , A Journey to the Center of the Earth , and Around the World in Eighty Days...
's The Begum's Fortune (1879).
In 1903,
Konstantin TsiolkovskyKonstantin Eduardovich Tsiolkovsky was an Imperial Russian and Soviet rocket scientist and pioneer of the astronautic theory. Along with his followers the German Hermann Oberth and the American Robert H. Goddard, he is considered to be one of the founding fathers of rocketry and astronautics...
(1857–1935) published Means of Reaction Devices (in
RussianRussian is a Slavic language used primarily in Russia, Belarus, Uzbekistan, Kazakhstan, Tajikistan and Kyrgyzstan. It is an unofficial but widely spoken language in Ukraine, Moldova, Latvia, Turkmenistan and Estonia and, to a lesser extent, the other countries that were once constituent republics...
: Исследование мировых пространств реактивными приборами), which is the first academic treatise on the use of rocketry to launch spacecraft. He calculated the
orbital speedThe orbital speed of a body, generally a planet, a natural satellite, an artificial satellite, or a multiple star, is the speed at which it orbits around the barycenter of a system, usually around a more massive body...
required for a minimal orbit around the Earth at 8 km/s, and that a multi-stage rocket fueled by liquid
propellantA propellant is a material that produces pressurized gas that:* can be directed through a nozzle, thereby producing thrust ;...
s could be used to achieve this. He proposed the use of
liquid hydrogenLiquid hydrogen is the liquid state of the element hydrogen. Hydrogen is found naturally in the molecular H2 form.To exist as a liquid, H2 must be pressurized above and cooled below hydrogen's Critical point. However, for hydrogen to be in a full liquid state without boiling off, it needs to be...
and
liquid oxygenLiquid oxygen — abbreviated LOx, LOX or Lox in the aerospace, submarine and gas industries — is one of the physical forms of elemental oxygen.-Physical properties:...
, though other combinations can be used.
In 1928 Slovenian
Herman PotočnikHerman Potočnik was an Austro-Hungarian rocket engineer and pioneer of cosmonautics . He is chiefly remembered for his work addressing the long-term human habitation of space.- Early life :Potočnik was born in Pola, southern Istria, Austria-Hungary...
(1892–1929) published his sole book, The Problem of Space Travel — The Rocket Motor (
GermanGerman is a West Germanic language, related to and classified alongside English and Dutch. With an estimated 90 – 98 million native speakers, German is one of the world's major languages and is the most widely-spoken first language in the European Union....
: 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 WorldWireless World was the pre-eminent British magazine for radio and electronics enthusiasts. It was one of the very few "informal" journals which were tolerated as a professional expense.- History :...
article the English science fiction writer
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,...
(1917–2008) described in detail the possible use of
communications satelliteA communications satellite is an artificial satellite stationed in space for the purpose of telecommunications...
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
The first artificial satellite was
Sputnik 1Sputnik 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...
, 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 RaceThe Space Race was a mid-to-late 20th century competition between the Soviet Union and the United States for supremacy in space exploration. Between 1957 and 1975, Cold War rivalry between the two nations focused on attaining firsts in space exploration, which were seen as necessary for national...
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
ionosphereThe ionosphere is a part of the upper atmosphere, comprising portions of the mesosphere, thermosphere and exosphere, distinguished because it is ionized by solar radiation. It plays an important part in atmospheric electricity and forms the inner edge of the magnetosphere...
. The unanticipated announcement of Sputnik 1s success precipitated the
Sputnik crisisThe Sputnik crisis is the name for the American reaction to the success of the Sputnik program. It was a key event during the Cold War that began on October 4, 1957 when the Soviet Union launched Sputnik 1, the first artificial Earth satellite....
in the United States and ignited the so-called
Space RaceThe Space Race was a mid-to-late 20th century competition between the Soviet Union and the United States for supremacy in space exploration. Between 1957 and 1975, Cold War rivalry between the two nations focused on attaining firsts in space exploration, which were seen as necessary for national...
within the
Cold WarThe Cold War was the continuing state from roughly 1946 to 1991 of political conflict, military tension, proxy wars, and economic competition between the Communist World—primarily the Soviet Union and its satellite states and allies—and the powers of the Western world, primarily the United States...
.
Sputnik 2Sputnik 2 , or Prosteyshiy Sputnik 2 ), was the second spacecraft launched into Earth orbit, on November 3, 1957, and the first to carry a living animal, a dog named Laika. Sputnik 2 was a 4-meter high cone-shaped capsule with a base diameter of 2 meters...
was launched on November 3, 1957 and carried the first living passenger into orbit, a dog named
LaikaLaika was a Soviet space dog that became the first animal to orbit the Earth – as well as the first animal to die in orbit.As little was known about the impact of spaceflight on living creatures at the time of Laika's mission, and the technology to de-orbit had not yet been developed, there...
.
In May, 1946, Project RAND had released the
Preliminary Design of an Experimental World-Circling SpaceshipThe Preliminary Design of an Experimental World-Circling Spaceship was a 1946 proposal, by Project RAND, for a United States satellite program. Dr. Robert M...
, 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 AeronauticsThe Bureau of Aeronautics was the U.S. Navy's material-support organization for Naval Aviation from 1921 to 1959. The bureau had "cognizance" for the design, procurement, and support of Naval aircraft and related systems...
of the
United States NavyThe United States Navy is the naval warfare service branch of the United States Armed Forces and one of the seven uniformed services of the United States. The U.S. Navy is the largest in the world; its battle fleet tonnage is greater than that of the next 13 largest navies combined. The U.S...
. The
United States Air ForceThe United States Air Force is the aerial warfare service branch of the United States Armed Forces and one of the American uniformed services. Initially part of the United States Army, the USAF was formed as a separate branch of the military on September 18, 1947 under the National Security Act of...
'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 HouseThe White House is the official residence and principal workplace of the president of the United States. Located at 1600 Pennsylvania Avenue NW in Washington, D.C., the house was designed by Irish-born James Hoban, and built between 1792 and 1800 of white-painted Aquia sandstone in the Neoclassical...
announced that the U.S. intended to launch satellites by the spring of 1958. This became known as
Project VanguardProject Vanguard was a program managed by the United States Naval Research Laboratory , which intended to launch the first artificial satellite into Earth orbit using a Vanguard rocket as the launch vehicle from Cape Canaveral Missile Annex, Florida....
. On July 31, the Soviets announced that they intended to launch a satellite by the fall of 1957.
Following pressure by the
American Rocket SocietyThe American Rocket Society began its existence on April 4, 1930, under the name of the American Interplanetary Society. It was founded by science fiction writers G. Edward Pendray, David Lasser, Laurence Manning and others. The members originally conducted their own rocket experiments in New York...
, the
National Science FoundationThe National Science Foundation is a United States government agency that supports fundamental research and education in all the non-medical fields of science and engineering. Its medical counterpart is the National Institutes of Health...
, and the
International Geophysical YearThe International Geophysical Year was an international scientific project that lasted from July 1, 1957, to December 31, 1958. It marked the end of a long period during the Cold War when scientific interchange between East and West was seriously interrupted...
, military interest picked up and in early 1955 the Army and Navy were working on
Project OrbiterProject Orbiter was a proposed United States spacecraft, an early competitor to Project Vanguard. It was jointly run by the United States Army and United States Navy. It was ultimately rejected by the Ad Hoc Committee on Special Capabilities, which selected Project Vanguard instead...
, 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 1Sputnik 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...
, 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 NetworkThe United States Space Surveillance Network is a critical part of United States Strategic Command's mission and involves detecting, tracking, cataloging and identifying artificial objects orbiting Earth, i.e. active/inactive satellites, spent rocket bodies, or fragmentation debris...
to catalog 115 Earth-orbiting satellites.
The largest artificial satellite currently orbiting the Earth is the
International Space StationThe International Space Station is a habitable, artificial satellite in low Earth orbit. The ISS follows the Salyut, Almaz, Cosmos, Skylab, and Mir space stations, as the 11th space station launched, not including the Genesis I and II prototypes...
.
Space Surveillance Network
The United States Space Surveillance Network (
SSNThe United States Space Surveillance Network is a critical part of United States Strategic Command's mission and involves detecting, tracking, cataloging and identifying artificial objects orbiting Earth, i.e. active/inactive satellites, spent rocket bodies, or fragmentation debris...
), 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 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...
. 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 2Chang'e 2 is a Chinese unmanned lunar probe that was launched on 1 October 2010. It was a follow-up to the Chang'e 1 lunar probe, which was launched in 2007. Chang'e 2 was part of the first phase of the Chinese Lunar Exploration Program, and conducted research from a 100-kilometer-high lunar orbit...
, on 1 October 2010.
Non-military satellite services
There are three basic categories of non-military satellite services:
Fixed satellite services
Fixed satellite servicesFixed Service Satellite , is the official classification for geostationary communications satellites used for broadcast feeds for television stations and radio stations and broadcast networks, as well as for telephony, telecommunications and data communications.FSS satellites have also been used...
handle 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 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.
- Biosatellite
A 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 satellite
A 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 orbitA geosynchronous orbit is an orbit around the Earth with an orbital period that matches the Earth's sidereal rotation period...
s, Molniya 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 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 satellites
A 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 satellite
Earth 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 satelliteA communications satellite is an artificial satellite stationed in space for the purpose of telecommunications...
deployed for militaryA 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 intelligenceEspionage 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 satellite
Earth 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 environmentThe 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, meteorologyMeteorology 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 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 tether
A 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 satellite
The 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 climateClimate 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 spacecraft
A 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 humanHumans 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-spaceplaneA 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 systemsA 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 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 landingthumb|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 station
A 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 beingsHumans are the only living species in the Homo genus...
to live on in outer 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
The first satellite,
Sputnik 1Sputnik 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...
, was put into orbit around Earth and was therefore in
geocentric 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...
. 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,
inclinationInclination in general is the angle between a reference plane and another plane or axis of direction.-Orbits:The inclination is one of the six orbital parameters describing the shape and orientation of a celestial orbit...
and
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...
.
The commonly used altitude classifications are
Low 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),
Medium 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) and
High 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). 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 orbit
A 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 orbit
A 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 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 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 orbit
An 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 MarsMars 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 orbit
A 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 orbit
Medium 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 orbit
A 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 orbit
A 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 degreeA 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 equator
An 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 imageAn 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 shadowA 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 orbit
A 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 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 circleA 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 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...
.
Elliptic orbitIn astrodynamics or celestial mechanics an elliptic orbit is a Kepler orbit with the eccentricity less than 1; this includes the special case of a circular orbit, with eccentricity equal to zero. In a stricter sense, it is a Kepler orbit with the eccentricity greater than 0 and less than 1 . In a...
: An orbit with an eccentricity greater than 0 and less than 1 whose orbit traces the path of an ellipseIn geometry, an ellipse is a plane curve that results from the intersection of a cone by a plane in a way that produces a closed curve. Circles are special cases of ellipses, obtained when the cutting plane is orthogonal to the cone's axis...
.
Geosynchronous transfer orbit: An elliptic orbit where the perigeePerigee is the point at which an object makes its closest approach to the Earth.. Often the term is used in a broader sense to define the point in an orbit where the orbiting body is closest to the body it orbits. The opposite is the apogee, the farthest or highest point.The Greek prefix "peri"...
is at the altitude of a Low 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) and the apogee at the altitude of a geosynchronous orbit.
Geostationary transfer orbitA geosynchronous transfer orbit or geostationary transfer orbit is a Hohmann transfer orbit used to reach geosynchronous or geostationary 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.
Molniya 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...
: A highly elliptic orbit with inclination of 63.4° and orbital periodThe orbital period is the time taken for a given object to make one complete orbit about another object.When mentioned without further qualification in astronomy this refers to the sidereal period of an astronomical object, which is calculated with respect to the stars.There are several kinds of...
of half of a sidereal day (roughly 12 hours). Such a satellite spends most of its time over a designated area of the planetA planet is a celestial body orbiting a star or stellar remnant that is massive enough to be rounded by its own gravity, is not massive enough to cause thermonuclear fusion, and has cleared its neighbouring region of planetesimals.The term planet is ancient, with ties to history, science,...
.
Tundra orbitTundra orbit is a type of highly elliptical geosynchronous orbit with a high inclination and an orbital period of one sidereal day . A satellite placed in this orbit spends most of its time over a chosen area of the Earth, a phenomenon known as apogee dwell...
: 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 orbit
A 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 analemmaIn 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 orbit
Semi-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 orbit
A 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 analemmaIn 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.
Clarke orbit: Another name for a geostationary orbit. Named after scientist and writer 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,...
.
Supersynchronous orbit: A disposal / storage orbit above GSO/GEO. Satellites will drift west. Also a synonym for Disposal orbit.
Subsynchronous orbitA subsynchronous orbit is an orbit of a satellite that is nearer the planet than it would be if it were in synchronous orbit, i.e. the orbital period is less than the sidereal day of the planet. An Earth satellite that is in subsynchronous orbit will appear to drift eastward as seen from the...
: A drift orbit close to but below GSO/GEO. Satellites will drift east.
Graveyard orbitA graveyard orbit, also called a supersynchronous orbit, junk orbit or disposal orbit, is an orbit significantly above synchronous orbit, where spacecraft are intentionally placed at the end of their operational life...
: An orbit a few hundred kilometers above geosynchronous that satellites are moved into at the end of their operation.
Disposal orbit: A synonym for graveyard orbit.
Junk orbit: A synonym for graveyard orbit.
Areosynchronous orbitAreosynchronous orbits are class of synchronous orbits for artificial satellites around the planet Mars. As with all synchronous orbits, an areosynchronous orbit has an orbital period equal in length to Mars' sidereal day...
: A synchronous orbit around the planet MarsMars 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...
with an orbital period equal in length to Mars' sidereal day, 24.6229 hours.
Areostationary orbitAn areostationary orbit is a circular areosynchronous orbit in the Martian equatorial plane about above the surface, any point on which revolves about Mars in the same direction and with the same period as the Martian surface...
(ASO): A circular areosynchronous orbitAreosynchronous orbits are class of synchronous orbits for artificial satellites around the planet Mars. As with all synchronous orbits, an areosynchronous orbit has an orbital period equal in length to Mars' sidereal day...
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.
Heliosynchronous orbit: A heliocentric orbit about the Sun where the satellite's orbital period matches the Sun's period of rotation. These orbits occur at a radius of 24,360 GmA gigametre is a unit of length in the metric system, equal to one billion meters, the SI base unit of length, hence to 1,000,000 km or approximately 621,370 miles....
(0.1628 AUAn astronomical unit is a unit of length equal to about or approximately the mean Earth–Sun distance....
) around the Sun, a little less than half of the orbital radius of MercuryMercury is the innermost and smallest planet in the Solar System, orbiting the Sun once every 87.969 Earth days. The orbit of Mercury has the highest eccentricity of all the Solar System planets, and it has the smallest axial tilt. It completes three rotations about its axis for every two orbits...
.
Special classifications
- Sun-synchronous orbit
A 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 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 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...
, spyA spy satellite is an Earth observation satellite or communications satellite deployed for military or intelligence applications....
, and weather 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 orbit
A 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 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 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.
Suborbital spaceflight: A synonym for exo-orbit.
Lunar transfer orbit (LTO)
Prograde orbit: An orbit with an inclination of less than 90°. Or rather, an orbit that is in the same direction as the rotation of the primary.
Retrograde orbit: An orbit with an inclination of more than 90°. Or rather, an orbit counter to the direction of rotation of the planet. Apart from those in sun-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...
, 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 latitudeIn geography, the latitude of a location on the Earth is the angular distance of that location south or north of the Equator. The latitude is an angle, and is usually measured in degrees . The equator has a latitude of 0°, the North pole has a latitude of 90° north , and the South pole has a...
.
Halo orbitA halo orbit is a periodic, three-dimensional orbit near the , , or Lagrange points in the three-body problem of orbital mechanics. A spacecraft in a halo orbit does not technically orbit the Lagrange point itself , but travels in a closed, repeating path near the Lagrange point...
and Lissajous orbitIn orbital mechanics, a Lissajous orbit, , named after Jules Antoine Lissajous, is a quasi-periodic orbital trajectory that an object can follow around a Lagrangian point of a three-body system without requiring any propulsion. Lyapunov orbits around a libration point are curved paths that lie...
: Orbits "around" Lagrangian pointThe Lagrangian points are the five positions in an orbital configuration where a small object affected only by gravity can theoretically be stationary relative to two larger objects...
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 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...
somewhat 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 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 generatorA radioisotope thermoelectric generator is an electrical generator that obtains its power from radioactive decay. In such a device, the heat released by the decay of a suitable radioactive material is converted into electricity by the Seebeck effect using an array of thermocouples.RTGs can be...
s) have been used in several successful satellite programs including the
Nimbus programThe Nimbus satellites were second-generation U.S. robotic spacecraft used for meteorological research and development. The spacecraft were designed to serve as stabilized, Earth-oriented platforms for the testing of advanced systems to sense and collect atmospheric science data...
(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 ReflectorAn Optical Solar Reflector consists of a top layer made out of quartz, over a reflecting layer made of metal.OSR is used for radiators on space craft. The quartz outer layer lets the solar light through which reflects on the metal layer. This results in a low absorption coefficient. The quartz...
)
- 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 1Vanguard 1 was the fourth artificial Earth satellite launched and the first satellite to be solar powered. Although communication with it was lost in 1964, it remains the oldest manmade satellite still in orbit...
. Launched in 1958,
Vanguard 1Vanguard 1 was the fourth artificial Earth satellite launched and the first satellite to be solar powered. Although communication with it was lost in 1964, it remains the oldest manmade satellite still in orbit...
, 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
This list includes countries with an independent capability to place satellites in orbit, including production of the necessary launch vehicle. Note: many more countries have the capability to design and build satellites but are unable to launch them, instead relying on foreign launch services. This list does not consider those numerous countries, but only lists those capable of launching satellites indigenously, and the date this capability was first demonstrated. Does not include consortium satellites or multi-national satellites.
First launch by country
| Order |
Country |
Year of first launch |
Rocket |
Satellite |
| 1 |
 Soviet Union |
1957 |
Sputnik-PS |
Sputnik 1Sputnik 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 |
 United States |
1958 |
Juno IThe 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 |
| 3 |
 Early Modern France |
1965 |
DiamantThe 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, 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...
|
| 4 |
 Japan |
1970 |
Lambda-4S 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....
|
ŌsumiŌsumi 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,...
|
| 5 |
 Mainland China |
1970 |
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 , 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...
|
| 6 |
 United Kingdom |
1971 |
Black ArrowBlack 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-External links:* from "Woomera on the Web"* from Encyclopedia Astronautica* in the Global Frequency Database...
|
| 7 |
 India |
1980 |
SLVThe 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 |
| 8 |
 Israel |
1988 |
ShavitShavit 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, 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...
|
| _ |
 Russia |
1992 |
Soyuz-UThe 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 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...
|
| _ |
 Ukraine |
1992 |
Tsyklon-3The 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 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...
|
| 9 |
 Iran |
2009 |
Safir-2 |
Omid |
Launch capable private entities
- Orbital Sciences Corporation
Orbital 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 SpaceX
Space 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
First satellites of countries including launched indigenously or by help of other
| Country |
Year of first launch |
First satellite |
Payloads in orbit in 2010-2011 |
Soviet Union
( Russia) |
1957
(1992) |
Sputnik 1Sputnik 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 |
| United States |
1958 |
Explorer 1 |
1099 |
| United Kingdom |
1962 |
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...
|
0029 |
 Canada |
1962 |
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,...
|
0032 |
 Italy |
1964 |
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...
|
0017 |
| Early Modern France |
1965 |
Astérix 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...
|
0049 |
 Australia |
1967 |
WRESAT WRESAT was the name of the first Australian satellite. It was named after its designer....
|
0011 |
 Germany |
1969 |
Azur Azur was Germany's first scientific satellite. Launched on 8 November 1969 it studied the Van Allen belts, solar particles, and aurorae....
|
0042 |
| Japan |
1970 |
ŌsumiŌsumi 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,...
|
0126 |
| Mainland China |
1970 |
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...
|
0111 |
 Poland |
1973 |
Intercosmos Copernicus 500 |
00001 |
 Netherlands |
1974 |
ANSThe 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...
|
0005 |
 Spain |
1974 |
Intasat |
0009 |
| India |
1975 |
AryabhataAryabhatta 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...
|
0045 |
 Indonesia |
1976 |
Palapa A1 |
0010 |
 Czechoslovakia |
1978 |
Magion 1 |
0005 |
 Kingdom of Bulgaria |
1981 |
Intercosmos 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,...
|
0001 |
 Brazil |
1985 |
Brasilsat A1 |
0011 |
 Mexico |
1985 |
Morelos 1 |
0007 |
 Sweden |
1986 |
Viking 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...
|
0011 |
| Israel |
1988 |
Ofeq 1 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...
|
00010 |
 Luxembourg |
1988 |
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....
|
0015 |
 Argentina |
1990 |
Lusat |
0010 |
 Pakistan |
1990 |
Badr-1 |
0005 |
 South Korea |
1992 |
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...
|
0012 |
 Portugal |
1993 |
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...
|
0001 |
 Thailand |
1993 |
Thaicom 1 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...
|
0006 |
 Turkey |
1994 |
Turksat 1B |
0005 |
| Ukraine |
1995 |
Sich-1 Sich-1 is first Ukrainian Earth observation satellite....
|
0006 |
 Chile |
1995 |
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...
|
0001 |
 Malaysia |
1996 |
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...
|
0004 |
 Norway |
1997 |
Thor 2 |
0003 |
 Philippines |
1997 |
Mabuhay 1Agila 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...
|
0002 |
 Egypt |
1998 |
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...
|
0003 |
 Singapore |
1998 |
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,...
|
0003 |
 Republic of China |
1999 |
ROCSAT-1 |
0009 |
 Denmark |
1999 |
Ørsted |
0004 |
 South Africa |
1999 |
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...
|
0002 |
 Saudi Arabia |
2000 |
Saudisat 1A |
0012 |
 United Arab Emirates |
2000 |
Thuraya 1 |
0003 |
 Morocco |
2001 |
Maroc-Tubsat |
0001 |
 Algeria |
2002 |
Alsat 1 |
0001 |
 Greece |
2003 |
Hellas Sat 2 |
0002 |
 Cyprus |
2003 |
Hellas Sat 2 |
0002 |
 Nigeria |
2003 |
Nigeriasat 1 |
0004 |
| Iran |
2005 |
Sina-1 |
0004 |
 Kazakhstan |
2006 |
KazSat 1 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...
|
0002 |
 Belarus |
2006 |
BelKA BelKA was intended to be the first satellite of independent Belarus....
|
0001 |
 Colombia |
2007 |
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...
|
0001 |
| |
2007 |
Rascom-QAF 1 |
0002 |
 Vietnam |
2008 |
VINASAT-1 |
0001 |
 Venezuela |
2008 |
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...
|
0001 |
 Switzerland |
2009 |
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...
|
0001 |
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 1San 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...
, 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 (
WRESATWRESAT was the name of the first Australian satellite. It was named after its designer....
) 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-SATX-Sat is a microsatellite developed and built by the NTU in collaboration with Defence Science Organisation singapore....
, 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-1A CubeSat is a type of miniaturized satellite for space research that usually has a volume of exactly one liter , has a mass of no more than 1.33 kilograms, and typically uses commercial off-the-shelf electronics components...
within 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 PegasusNEE-01 Pegasus Is the first Ecuadorian satellite, built by the Ecuadorian Space Agency and presented officially in April 4, 2011The NEE-01 PEGASUS is a nano satellite, of the cubesat 1U class, it has a cubic shape and two solar panel wings with 3 panels on each side for a total of 6 panels per...
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-1Aalto-1 is a student-built nanosatellite, created by Aalto University, Finland. Based on the CubeSat architecture, it is scheduled to be launched in 2013, and will become Finland's first indigenous satellite. The solar-powered satellite will weigh approximately , and will carry a miniature...
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-1MaSat-1 will be the first indigenous Hungarian satellite, developed and built by students of the Technical University of Budapest. The 1U CubeSat-type satellite is planned to be launched into low Earth orbit in second quarter of 2012...
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 capsuleA space capsule is an often manned spacecraft which has a simple shape for the main section, without any wings or other features to create lift during atmospheric reentry....
s by Russian help The
remote sensingRemote sensing is the acquisition of information about an object or phenomenon, without making physical contact with the object. In modern usage, the term generally refers to the use of aerial sensor technologies to detect and classify objects on Earth by means of propagated signals 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
KiwiSATKiwiSAT, an Amateur Radio project by AMSAT-ZL, is to be New Zealand's first satellite. It is being designed and built by New Zealand Radio Amateurs supported by Massey University and various corporate sponsors....
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 TechnologyThe Korean Committee of Space Technology is the state-controlled space agency of North Korea. Very little information on it is publicly available. It is known to be founded sometime in the 1980s, and most likely is connected to the Artillery Guidance Bureau of the Korean People's Army...
is developing its space satellite with the National Engineering University, called
Chasqui 1Chasqui I is a one-kilogram satellite equipped with two cameras, a visible and an infrared, which will take photos of the Earth. Nanotechnology can adapt to this satellite very small size electronic circuits, and cells that capture solar energy and transform it into energy to operate the device.The...
. 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
CubeSatA CubeSat is a type of miniaturized satellite for space research that usually has a volume of exactly one liter , has a mass of no more than 1.33 kilograms, and typically uses commercial off-the-shelf electronics components...
of 1 kg weight, it will be developed by the
SfaxThe University of Sfax is a university located in Sfax, Tunisia. It was founded in 1986 and is organized in 8 Faculties.The University of Sfax is a university based in Sfax ....
School of Engineering. ERPSat satellite is planned to be launched into orbit in 2013. New
National Space AgencyTurkmenistan National Space Agency , is a governmental body that coordinates all Turkmenistan space research programs with scientific and commercial goals. It was established in 2011.-Space Programme:...
plans a first satellite by help of
SpaceXSpace Exploration Technologies Corporation, or more popularly and informally known as SpaceX, is an American space transport company that operates out of Hawthorne, California...
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
ChineseChinese civilization may refer to:* China for more general discussion of the country.* Chinese culture* Greater China, the transnational community of ethnic Chinese.* History of China* Sinosphere, the area historically affected by Chinese culture...
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
jammingRadio jamming is the transmission of radio signals that disrupt communications by decreasing the signal to noise ratio. Unintentional jamming occurs when an operator transmits on a busy frequency without first checking whether it is in use, or without being able to hear stations using the frequency...
by 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 access
Satellite 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 phone
A satellite telephone, satellite phone, or satphone is a type of mobile phone that connects to orbiting satellites instead of terrestrial cell sites...
- Satellite radio
Satellite 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 television
Satellite 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 collision
The 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)
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 Spacecraft
A 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 Designator
The International Designator, also known as COSPAR designation, and in the United States as NSSDC ID, is an international naming convention for satellites...
- IMINT
Imagery 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 exploration
Space 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 Number
The 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 flying
Satellite 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 193
USA-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)
- Spaceport
A 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 10
Pioneer 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 10
Mariner 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 stamps
With 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