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73-635: The Timation satellites were conceived, developed, and launched by the United States Naval Research Laboratory in Washington, D.C. beginning in 1964. The concept of Timation was to broadcast an accurate time reference for use as a ranging signal to receivers on the ground. On 31 May 1967, the Timation 1 satellite was launched. This was followed by the Timation 2 (NRL-PL 169) satellite launch in 1969. In 1973
146-591: A Diamant A rocket launched from the CIEES site at Hammaguir , Algeria . With Astérix, France became the sixth country to have an artificial satellite. Early satellites were built to unique designs. With advancements in technology, multiple satellites began to be built on single model platforms called satellite buses . The first standardized satellite bus design was the HS-333 geosynchronous (GEO) communication satellite launched in 1972. Beginning in 1997, FreeFlyer
219-414: A catalyst . The most commonly used propellant mixtures on satellites are hydrazine -based monopropellants or monomethylhydrazine – dinitrogen tetroxide bipropellants. Ion thrusters on satellites usually are Hall-effect thrusters , which generate thrust by accelerating positive ions through a negatively-charged grid. Ion propulsion is more efficient propellant-wise than chemical propulsion but its thrust
292-654: A celestial body . They have a variety of uses, including communication relay, weather forecasting , navigation ( GPS ), broadcasting , scientific research, and Earth observation. Additional military uses are reconnaissance, early warning , signals intelligence and, potentially, weapon delivery. Other satellites include the final rocket stages that place satellites in orbit and formerly useful satellites that later become defunct. Except for passive satellites , most satellites have an electricity generation system for equipment on board, such as solar panels or radioisotope thermoelectric generators (RTGs). Most satellites also have
365-813: A halo orbit , three for a Lissajous orbit ). Earth observation satellites gather information for reconnaissance , mapping , monitoring the weather , ocean, forest, etc. Space telescopes take advantage of outer space's near perfect vacuum to observe objects with the entire electromagnetic spectrum . Because satellites can see a large portion of the Earth at once, communications satellites can relay information to remote places. The signal delay from satellites and their orbit's predictability are used in satellite navigation systems, such as GPS. Space probes are satellites designed for robotic space exploration outside of Earth, and space stations are in essence crewed satellites. The first artificial satellite launched into
438-1128: A launch pad , supported by a launch control center and systems such as vehicle assembly and fueling. Launch vehicles are engineered with advanced aerodynamics and technologies, which contribute to high operating costs. An orbital launch vehicle must lift its payload at least to the boundary of space, approximately 150 km (93 mi) and accelerate it to a horizontal velocity of at least 7,814 m/s (17,480 mph). Suborbital vehicles launch their payloads to lower velocity or are launched at elevation angles greater than horizontal. Practical orbital launch vehicles use chemical propellants such as solid fuel , liquid hydrogen , kerosene , liquid oxygen , or hypergolic propellants . Launch vehicles are classified by their orbital payload capacity, ranging from small- , medium- , heavy- to super-heavy lift . Launch vehicles are classed by NASA according to low Earth orbit payload capability: Sounding rockets are similar to small-lift launch vehicles, however they are usually even smaller and do not place payloads into orbit. A modified SS-520 sounding rocket
511-409: A transponder ; it creates a communication channel between a source transmitter and a receiver at different locations on Earth . Communications satellites are used for television , telephone , radio , internet , and military applications. Many communications satellites are in geostationary orbit 22,236 miles (35,785 km) above the equator , so that the satellite appears stationary at
584-591: A Satellite Vehicle", by R. R. Carhart. This expanded on potential scientific uses for satellite vehicles and was followed in June 1955 with "The Scientific Use of an Artificial Satellite", by H. K. Kallmann and W. W. Kellogg. The first artificial satellite was Sputnik 1 , launched by the Soviet Union on 4 October 1957 under the Sputnik program , with Sergei Korolev as chief designer. Sputnik 1 helped to identify
657-453: A U.S. Scout rocket from Wallops Island (Virginia, United States) with an Italian launch team trained by NASA . In similar occasions, almost all further first national satellites were launched by foreign rockets. France was the third country to launch a satellite on its own rocket. On 26 November 1965, the Astérix or A-1 (initially conceptualized as FR.2 or FR-2), was put into orbit by
730-405: A bandwidth of tens of megahertz. Satellites are placed from the surface to the orbit by launch vehicles , high enough to avoid orbital decay by the atmosphere . Satellites can then change or maintain the orbit by propulsion , usually by chemical or ion thrusters . As of 2018, about 90% of the satellites orbiting the Earth are in low Earth orbit or geostationary orbit ; geostationary means
803-484: A method of communication to ground stations , called transponders . Many satellites use a standardized bus to save cost and work, the most popular of which are small CubeSats . Similar satellites can work together as groups, forming constellations . Because of the high launch cost to space, most satellites are designed to be as lightweight and robust as possible. Most communication satellites are radio relay stations in orbit and carry dozens of transponders, each with
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#1732764709419876-540: A rocket stage may be recovered while others are not. The Space Shuttle , for example, recovered and reused its solid rocket boosters , the Space Shuttle orbiter that also acted as a second stage, and the engines used by the core stage (the RS-25 , which was located at the back of the orbiter), however the fuel tank that the engines sourced fuel from, which was separate from the engines, was not reused. For example,
949-418: A satellite's lifetime. Resource use is difficult to monitor and quantify for satellites and launch vehicles due to their commercially sensitive nature. However, aluminium is a preferred metal in satellite construction due to its lightweight and relative cheapness and typically constitutes around 40% of a satellite's mass. Through mining and refining, aluminium has numerous negative environmental impacts and
1022-449: A thin cable called a tether . Recovery satellites are satellites that provide a recovery of reconnaissance, biological, space-production and other payloads from orbit to Earth. Biosatellites are satellites designed to carry living organisms, generally for scientific experimentation. Space-based solar power satellites are proposed satellites that would collect energy from sunlight and transmit it for use on Earth or other places. Since
1095-600: A thought experiment by Isaac Newton to explain the motion of natural satellites , in his Philosophiæ Naturalis Principia Mathematica (1687). The first fictional depiction of a satellite being launched into orbit was a short story by Edward Everett Hale , " The Brick Moon " (1869). The idea surfaced again in Jules Verne 's The Begum's Fortune (1879). In 1903, Konstantin Tsiolkovsky (1857–1935) published Exploring Space Using Jet Propulsion Devices , which
1168-400: Is a commercial off-the-shelf software application for satellite mission analysis, design, and operations. After the late 2010s, and especially after the advent and operational fielding of large satellite internet constellations —where on-orbit active satellites more than doubled over a period of five years—the companies building the constellations began to propose regular planned deorbiting of
1241-610: Is currently unclear. The visibility of man-made objects in the night sky may also impact people's linkages with the world, nature, and culture. At all points of a satellite's lifetime, its movement and processes are monitored on the ground through a network of facilities. The environmental cost of the infrastructure as well as day-to-day operations is likely to be quite high, but quantification requires further investigation. Particular threats arise from uncontrolled de-orbit. Some notable satellite failures that polluted and dispersed radioactive materials are Kosmos 954 , Kosmos 1402 and
1314-399: Is dependent on rocket design and fuel type. The amount of green house gases emitted by rockets is considered trivial as it contributes significantly less, around 0.01%, than the aviation industry yearly which itself accounts for 2-3% of the total global greenhouse gas emissions. Rocket emissions in the stratosphere and their effects are only beginning to be studied and it is likely that
1387-473: Is deployed for military or intelligence purposes, it is known as a spy satellite or reconnaissance satellite. Their uses include early missile warning, nuclear explosion detection, electronic reconnaissance, and optical or radar imaging surveillance. Navigational satellites are satellites that use radio time signals transmitted to enable mobile receivers on the ground to determine their exact location. The relatively clear line of sight between
1460-647: Is developing the first stage of the orbital New Glenn LV to be reusable, with first flight planned for no earlier than 2024. SpaceX has a new super-heavy launch vehicle under development for missions to interplanetary space . The SpaceX Starship is designed to support RTLS, vertical-landing and full reuse of both the booster stage and the integrated second-stage/large-spacecraft that are designed for use with Starship. Its first launch attempt took place in April 2023; however, both stages were lost during ascent. The fifth launch attempt ended with Booster 12 being caught by
1533-517: Is most used in archaeology , cartography , environmental monitoring , meteorology , and reconnaissance applications. As of 2021, there are over 950 Earth observation satellites, with the largest number of satellites operated with Planet Labs . Weather satellites monitor clouds , city lights , fires , effects of pollution , auroras , sand and dust storms , snow cover, ice mapping, boundaries of ocean currents , energy flows, etc. Environmental monitoring satellites can detect changes in
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#17327647094191606-581: Is one of the most carbon-intensive metals. Satellite manufacturing also requires rare elements such as lithium , gold , and gallium , some of which have significant environmental consequences linked to their mining and processing and/or are in limited supply. Launch vehicles require larger amounts of raw materials to manufacture and the booster stages are usually dropped into the ocean after fuel exhaustion. They are not normally recovered. Two empty boosters used for Ariane 5 , which were composed mainly of steel, weighed around 38 tons each, to give an idea of
1679-430: Is the chemical propellant used which then releases ammonia , hydrogen and nitrogen as gas into the upper atmosphere. Also, the environment of the outer atmosphere causes the degradation of exterior materials. The atomic oxygen in the upper atmosphere oxidises hydrocarbon-based polymers like Kapton , Teflon and Mylar that are used to insulate and protect the satellite which then emits gasses like CO 2 and CO into
1752-425: Is very small (around 0.5 N or 0.1 lb f ), and thus requires a longer burn time. The thrusters usually use xenon because it is inert , can be easily ionized , has a high atomic mass and storable as a high-pressure liquid. Most satellites use solar panels to generate power, and a few in deep space with limited sunlight use radioisotope thermoelectric generators . Slip rings attach solar panels to
1825-912: The American Rocket Society , the National Science Foundation , and the International Geophysical Year, the Army and Navy worked on Project Orbiter with two competing programs. The army used the Jupiter C rocket , while the civilian–Navy program used the Vanguard rocket to launch a satellite. Explorer 1 became the United States' first artificial satellite, on 31 January 1958. The information sent back from its radiation detector led to
1898-586: The Chinese military shot down an aging weather satellite, followed by the US Navy shooting down a defunct spy satellite in February 2008. On 18 November 2015, after two failed attempts, Russia successfully carried out a flight test of an anti-satellite missile known as Nudol . On 27 March 2019, India shot down a live test satellite at 300 km altitude in 3 minutes, becoming the fourth country to have
1971-695: The European Space Agency is responsible for the Ariane V , and the United Launch Alliance manufactures and launches the Delta IV and Atlas V rockets. Launchpads can be located on land ( spaceport ), on a fixed ocean platform ( San Marco ), on a mobile ocean platform ( Sea Launch ), and on a submarine . Launch vehicles can also be launched from the air . A launch vehicle will start off with its payload at some location on
2044-627: The Netherlands , Norway , Pakistan , Poland , Russia , Saudi Arabia , South Africa , Spain , Switzerland , Thailand , Turkey , Ukraine , the United Kingdom and the United States , had some satellites in orbit. Japan's space agency (JAXA) and NASA plan to send a wooden satellite prototype called LingoSat into orbit in the summer of 2024. They have been working on this project for few years and sent first wood samples to
2117-470: The Transit 5-BN-3 . When in a controlled manner satellites reach the end of life they are intentionally deorbited or moved to a graveyard orbit further away from Earth in order to reduce space debris . Physical collection or removal is not economical or even currently possible. Moving satellites out to a graveyard orbit is also unsustainable because they remain there for hundreds of years. It will lead to
2190-576: The White House announced on 29 July 1955 that the U.S. intended to launch satellites by the spring of 1958. This became known as Project Vanguard . On 31 July, the Soviet Union announced its intention to launch a satellite by the fall of 1957. Sputnik 2 was launched on 3 November 1957 and carried the first living passenger into orbit, a dog named Laika . The dog was sent without possibility of return. In early 1955, after being pressured by
2263-444: The upper stage of the launch vehicle or launched to a geostationary transfer orbit (GTO). A direct insertion places greater demands on the launch vehicle, while GTO is more demanding of the spacecraft. Once in orbit, launch vehicle upper stages and satellites can have overlapping capabilities, although upper stages tend to have orbital lifetimes measured in hours or days while spacecraft can last decades. Distributed launch involves
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2336-472: The 2000s and launch vehicles with integrated distributed launch capability built in began development in 2017 with the Starship design. The standard Starship launch architecture is to refuel the spacecraft in low Earth orbit to enable the craft to send high-mass payloads on much more energetic missions. After 1980, but before the 2010s, two orbital launch vehicles developed the capability to return to
2409-457: The Earth's vegetation , atmospheric trace gas content, sea state, ocean color, and ice fields. By monitoring vegetation changes over time, droughts can be monitored by comparing the current vegetation state to its long term average. Anthropogenic emissions can be monitored by evaluating data of tropospheric NO 2 and SO 2 . A communications satellite is an artificial satellite that relays and amplifies radio telecommunication signals via
2482-417: The Earth's orbit was the Soviet Union 's Sputnik 1 , on October 4, 1957. As of December 31, 2022, there are 6,718 operational satellites in the Earth's orbit, of which 4,529 belong to the United States (3,996 commercial), 590 belong to China, 174 belong to Russia, and 1,425 belong to other nations. The first published mathematical study of the possibility of an artificial satellite was Newton's cannonball ,
2555-500: The Earth, called remote sensing . Most Earth observation satellites are placed in low Earth orbit for a high data resolution, though some are placed in a geostationary orbit for an uninterrupted coverage. Some satellites are placed in a Sun-synchronous orbit to have consistent lighting and obtain a total view of the Earth. Depending on the satellites' functions, they might have a normal camera , radar , lidar , photometer , or atmospheric instruments. Earth observation satellite's data
2628-553: The Moon and the Sun. Satellites utilize ultra-white reflective coatings to prevent damage from UV radiation. Without orbit and orientation control, satellites in orbit will not be able to communicate with ground stations on the Earth. Chemical thrusters on satellites usually use monopropellant (one-part) or bipropellant (two-parts) that are hypergolic . Hypergolic means able to combust spontaneously when in contact with each other or to
2701-603: The U.S. Navy Timation and the Air Force System 621B navigation system (known as the DNSS - Defense Navigation Satellite System) are consolidated by the Deputy ;Secretary of Defense. Two more advanced Timation satellites are launched. NTS-1 - Navigation Technology Satellite (Timation 3) is launched in 1974, while NTS-2 (Timation 4) is launched in 1977. The results of this program and Air Force Project 621B formed
2774-548: The accomplishment of a goal with multiple spacecraft launches. A large spacecraft such as the International Space Station can be constructed by assembling modules in orbit, or in-space propellant transfer conducted to greatly increase the delta-V capabilities of a cislunar or deep space vehicle. Distributed launch enables space missions that are not possible with single launch architectures. Mission architectures for distributed launch were explored in
2847-455: The atmosphere. Given the current surge in satellites in the sky, soon hundreds of satellites may be clearly visible to the human eye at dark sites. It is estimated that the overall levels of diffuse brightness of the night skies has increased by up to 10% above natural levels. This has the potential to confuse organisms, like insects and night-migrating birds, that use celestial patterns for migration and orientation. The impact this might have
2920-603: The atmosphere. For example, SpaceX Starlink satellites, the first large satellite internet constellation to exceed 1000 active satellites on orbit in 2020, are designed to be 100% demisable and burn up completely on their atmospheric reentry at the end of their life, or in the event of an early satellite failure. In different periods, many countries, such as Algeria , Argentina , Australia , Austria , Brazil , Canada , Chile , China , Denmark , Egypt , Finland , France , Germany , India , Iran , Israel , Italy , Japan , Kazakhstan , South Korea , Malaysia , Mexico ,
2993-732: The basis for the Global Positioning System (GPS). The Navy's contribution to the GPS program continued to be focused on ever more accurate clocks. There is a historical connection between accurate time keeping, navigation, and the Navy . In 1714, the British government passed the Longitude Act (see longitude prize ) to create an incentive to solve the problem of navigation at sea. The solution, developed by John Harrison ,
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3066-539: The booster stage of a launch vehicle. After 2010, SpaceX undertook a development program to acquire the ability to bring back and vertically land a part of the Falcon 9 orbital launch vehicle: the first stage . The first successful landing was done in December 2015, since 2017 rocket stages routinely land either at a landing pad adjacent to the launch site or on a landing platform at sea, some distance away from
3139-447: The capability to destroy live satellites. The environmental impact of satellites is not currently well understood as they were previously assumed to be benign due to the rarity of satellite launches. However, the exponential increase and projected growth of satellite launches are bringing the issue into consideration. The main issues are resource use and the release of pollutants into the atmosphere which can happen at different stages of
3212-551: The density of high atmospheric layers through measurement of its orbital change and provided data on radio-signal distribution in the ionosphere . The unanticipated announcement of Sputnik 1's success precipitated the Sputnik crisis in the United States and ignited the so-called Space Race within the Cold War . In the context of activities planned for the International Geophysical Year (1957–1958),
3285-546: The discovery of the Earth's Van Allen radiation belts . The TIROS-1 spacecraft, launched on April 1, 1960, as part of NASA's Television Infrared Observation Satellite (TIROS) program, sent back the first television footage of weather patterns to be taken from space. In June 1961, three and a half years after the launch of Sputnik 1, the United States Space Surveillance Network cataloged 115 Earth-orbiting satellites. While Canada
3358-484: The earth's climate. After deorbiting 70% of satellites end up in the ocean and are rarely recovered. Using wood as an alternative material has been posited in order to reduce pollution and debris from satellites that reenter the atmosphere. Space debris pose dangers to the spacecraft (including satellites) in or crossing geocentric orbits and have the potential to drive a Kessler syndrome which could potentially curtail humanity from conducting space endeavors in
3431-444: The further pollution of space and future issues with space debris. When satellites deorbit much of it is destroyed during re-entry into the atmosphere due to the heat. This introduces more material and pollutants into the atmosphere. There have been concerns expressed about the potential damage to the ozone layer and the possibility of increasing the earth's albedo , reducing warming but also resulting in accidental geoengineering of
3504-425: The future. Launch vehicle A launch vehicle is typically a rocket -powered vehicle designed to carry a payload (a crewed spacecraft or satellites ) from Earth's surface or lower atmosphere to outer space . The most common form is the ballistic missile -shaped multistage rocket , but the term is more general and also encompasses vehicles like the Space Shuttle . Most launch vehicles operate from
3577-442: The ground. In contrast, reusable launch vehicles are designed to be recovered intact and launched again. The Falcon 9 is an example of a reusable launch vehicle. As of 2023, all reusable launch vehicles that were ever operational have been partially reusable, meaning some components are recovered and others are not. This usually means the recovery of specific stages, usually just the first stage, but sometimes specific components of
3650-412: The impact of regulated ozone-depleting substances. Whilst emissions of water vapour are largely deemed as inert, H 2 O is the source gas for HO x and can also contribute to ozone loss through the formation of ice particles. Black carbon particles emitted by rockets can absorb solar radiation in the stratosphere and cause warming in the surrounding air which can then impact the circulatory dynamics of
3723-462: The impacts will be more critical than emissions in the troposphere. The stratosphere includes the ozone layer and pollutants emitted from rockets can contribute to ozone depletion in a number of ways. Radicals such as NO x , HO x , and ClO x deplete stratospheric O 3 through intermolecular reactions and can have huge impacts in trace amounts. However, it is currently understood that launch rates would need to increase by ten times to match
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#17327647094193796-528: The launch site (RTLS). Both the US Space Shuttle —with one of its abort modes —and the Soviet Buran had a designed-in capability to return a part of the launch vehicle to the launch site via the mechanism of horizontal-landing of the spaceplane portion of the launch vehicle. In both cases, the main vehicle thrust structure and the large propellant tank were expendable , as had been
3869-505: The launch site. The Falcon Heavy is similarly designed to reuse the three cores comprising its first stage. On its first flight in February 2018, the two outer cores successfully returned to the launch site landing pads while the center core targeted the landing platform at sea but did not successfully land on it. Blue Origin developed similar technologies for bringing back and landing their suborbital New Shepard , and successfully demonstrated return in 2015, and successfully reused
3942-400: The mid-2000s, 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 the Earth. Russia , United States , China and India have demonstrated the ability to eliminate satellites. In 2007,
4015-725: The most potent scientific tools of the Twentieth Century." The United States had been considering launching orbital satellites since 1945 under the Bureau of Aeronautics of the United States Navy . Project RAND eventually released the report, but considered the satellite to be a tool for science, politics, and propaganda, rather than a potential military weapon. In 1946, American theoretical astrophysicist Lyman Spitzer proposed an orbiting space telescope . In February 1954, Project RAND released "Scientific Uses for
4088-495: The official civilian time reference maintained by National Institute of Standards and Technology (NIST) and contributes to the International Atomic Time . This article about one or more spacecraft of the United States is a stub . You can help Misplaced Pages by expanding it . Satellite A satellite or artificial satellite is an object, typically a spacecraft , placed into orbit around
4161-477: The older satellites that reached the end of life , as a part of the regulatory process of obtaining a launch license. The largest artificial satellite ever is the International Space Station . By the early 2000s, and particularly after the advent of CubeSats and increased launches of microsats —frequently launched to the lower altitudes of low Earth orbit (LEO)—satellites began to more frequently be designed to get destroyed, or breakup and burnup entirely in
4234-550: The possible use of communications satellites for mass communications. He suggested that three geostationary satellites would provide coverage over the entire planet. In May 1946, the United States Air Force 's Project RAND released the Preliminary Design of an Experimental World-Circling Spaceship , which stated "A satellite vehicle with appropriate instrumentation can be expected to be one of
4307-412: The quantity of materials that are often left in the ocean. Rocket launches release numerous pollutants into every layer of the atmosphere, especially affecting the atmosphere above the tropopause where the byproducts of combustion can reside for extended periods. These pollutants can include black carbon , CO 2 , nitrogen oxides (NO x ), aluminium and water vapour , but the mix of pollutants
4380-551: The same booster on a second suborbital flight in January 2016. By October 2016, Blue had reflown, and landed successfully, that same launch vehicle a total of five times. The launch trajectories of both vehicles are very different, with New Shepard going straight up and down, whereas Falcon 9 has to cancel substantial horizontal velocity and return from a significant distance downrange. Both Blue Origin and SpaceX also have additional reusable launch vehicles under development. Blue
4453-427: The same point in the sky; therefore the satellite dish antennas of ground stations can be aimed permanently at that spot and do not have to move to track the satellite. Others form satellite constellations in low Earth orbit , where antennas on the ground have to follow the position of the satellites and switch between satellites frequently. When an Earth observation satellite or a communications satellite
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#17327647094194526-409: The satellite; the slip rings can rotate to be perpendicular with the sunlight and generate the most power. All satellites with a solar panel must also have batteries , because sunlight is blocked inside the launch vehicle and at night. The most common types of batteries for satellites are lithium-ion , and in the past nickel–hydrogen . Earth observation satellites are designed to monitor and survey
4599-404: 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. Astronomical satellites are satellites used for observation of distant planets, galaxies, and other outer space objects. Tether satellites are satellites that are connected to another satellite by
4672-538: The satellites stay still in the sky (relative to a fixed point on the ground). Some imaging satellites chose a Sun-synchronous orbit because they can scan the entire globe with similar lighting. As the number of satellites and space debris around Earth increases, the threat of collision has become more severe. A small number of satellites orbit other bodies (such as the Moon , Mars , and the Sun ) or many bodies at once (two for
4745-540: The space in 2021 to test the material's resilience to space conditions. Most satellites use chemical or ion propulsion to adjust or maintain their orbit , coupled with reaction wheels to control their three axis of rotation or attitude. Satellites close to Earth are affected the most by variations in the Earth's magnetic , gravitational field and the Sun's radiation pressure ; satellites that are further away are affected more by other bodies' gravitational field by
4818-458: The special conditions of space could be useful for scientific experiments. The book described geostationary satellites (first put forward by Konstantin Tsiolkovsky ) and discussed the communication between them and the ground using radio, but fell short with the idea of using satellites for mass broadcasting and as telecommunications relays. In a 1945 Wireless World article, English science fiction writer Arthur C. Clarke described in detail
4891-428: The standard procedure for all orbital launch vehicles flown prior to that time. Both were subsequently demonstrated on actual orbital nominal flights, although both also had an abort mode during launch that could conceivably allow the crew to land the spaceplane following an off-nominal launch. In the 2000s, both SpaceX and Blue Origin have privately developed a set of technologies to support vertical landing of
4964-459: The stratosphere. Both warming and changes in circulation can then cause depletion of the ozone layer. Several pollutants are released in the upper atmospheric layers during the orbital lifetime of LEO satellites. Orbital decay is caused by atmospheric drag and to keep the satellite in the correct orbit the platform occasionally needs repositioning. To do this nozzle-based systems use a chemical propellant to create thrust. In most cases hydrazine
5037-450: The surface of the Earth. To reach orbit, the vehicle must travel vertically to leave the atmosphere and horizontally to prevent re-contacting the ground. The required velocity varies depending on the orbit but will always be extreme when compared to velocities encountered in normal life. Launch vehicles provide varying degrees of performance. For example, a satellite bound for Geostationary orbit (GEO) can either be directly inserted by
5110-543: Was an accurate clock which could compare local time to Greenwich , England time. To this day, Coordinated Universal Time (UTC), the successor of Greenwich Mean Time (GMT), is the reference time for the planet, and in the United States , the official time for the Department of Defense (DoD) is kept by the United States Navy at the U.S. Naval Observatory in Washington, D.C. This is kept in synchronization with
5183-426: Was the first academic treatise on the use of rocketry to launch spacecraft. He calculated the orbital speed required for a minimal orbit, and inferred that a multi-stage rocket fueled by liquid propellants could achieve this. Herman Potočnik explored the idea of using orbiting spacecraft for detailed peaceful and military observation of the ground in his 1928 book, The Problem of Space Travel . He described how
5256-483: Was the third country to build a satellite which was launched into space, it was launched aboard an American rocket from an American spaceport. The same goes for Australia, whose launch of the first satellite involved a donated U.S. Redstone rocket and American support staff as well as a joint launch facility with the United Kingdom. The first Italian satellite San Marco 1 was launched on 15 December 1964 on
5329-596: Was used to place a 4-kilogram payload ( TRICOM-1R ) into orbit in 2018. Orbital spaceflight requires a satellite or spacecraft payload to be accelerated to very high velocity. In the vacuum of space, reaction forces must be provided by the ejection of mass, resulting in the rocket equation . The physics of spaceflight are such that rocket stages are typically required to achieve the desired orbit. Expendable launch vehicles are designed for one-time use, with boosters that usually separate from their payload and disintegrate during atmospheric reentry or on contact with
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