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89-688: Eutelsat 36A (formerly Eutelsat W4 and Eutelsat 3 F-4 ) is a French communications satellite operated by Eutelsat Communications . It was constructed by Alcatel Space and is based on the Spacebus-3000B2 satellite bus . Eutelsat W4 was launched on the maiden flight of the Atlas III launch vehicle , which used the Atlas IIIA configuration. The launch was contracted by International Launch Services (ILS), and occurred on 24 May 2000, at 23:10:05 UTC from Space Launch Complex 36B at

178-632: A Master of Science degree typically is hired at a salary in the GS-11 range; someone with a PhD typically is hired at a salary in the GS-12 range. NRL has the flexibility to offer partial student loan repayments for new hires. According to the NRL Fact Book (2016), of NRL civilian full-time permanent employees, 870 had a doctorate, 417 had a master's, and 576 had a bachelor's as their highest degree. The laboratory also hosts post-doctoral researchers and

267-455: A data network aiming to provide a „Lunar Internet for cis-lunar spacecraft and Installations. The Moonlight Initiative is an equivalent ESA project that is stated to be compatible and providing navigational services for the lunar surface. Both programmes are satellite constellstions of several satellites in various orbits around the Moon. Other orbits are also planned to be used. Positions in

356-683: A mansion on the highlands to the east. Zachariah Berry purchased the land in 1827, who rented it out for various purposes including a fishery at Blue Plains . The mansion was demolished during the Civil War to build Fort Greble . In 1873 the land was purchased by the federal government as the Bellevue Annex to the Naval Gun Factory , and several buildings were constructed including the Commandant's house, "Quarters A", which

445-630: A marking dye to help locate survivors of disasters at sea. A thermal diffusion process was conceived and used to supply some of the U-235 isotope needed for one of the first atomic bombs. Also, many new devices that developed from booming wartime industry were type tested and then certified as reliable for the Fleet. As a result of the scientific accomplishments of the WWII, the United States emerged into

534-518: A medium Earth orbit satellite is about 16,000 kilometres (10,000 mi) above Earth. In various patterns, these satellites make the trip around Earth in anywhere from 2 to 8 hours. To an observer on Earth, a satellite in a gestationary orbit appears motionless, in a fixed position in the sky. This is because it revolves around the Earth at Earth's own angular velocity (one revolution per sidereal day , in an equatorial orbit ). A geostationary orbit

623-591: A more precise match for the capabilities of geosynchronous comsats. Two satellite types are used for North American television and radio: Direct broadcast satellite (DBS), and Fixed Service Satellite (FSS). The definitions of FSS and DBS satellites outside of North America, especially in Europe, are a bit more ambiguous. Most satellites used for direct-to-home television in Europe have the same high power output as DBS-class satellites in North America, but use

712-687: A number of satellites for various purposes; for example, METSAT for meteorological satellite, EUMETSAT for the European branch of the program, and METOP for meteorological operations. These orbits are Sun synchronous, meaning that they cross the equator at the same local time each day. For example, the satellites in the NPOESS (civilian) orbit will cross the equator, going from south to north, at times 1:30 P.M., 5:30 P.M., and 9:30 P.M. There are plans and initiatives to bring dedicated communications satellite beyond geostationary orbits. NASA proposed LunaNet as

801-621: A period (time to revolve around the Earth) of about 90 minutes. Because of their low altitude, these satellites are only visible from within a radius of roughly 1,000 kilometres (620 mi) from the sub-satellite point. In addition, satellites in low Earth orbit change their position relative to the ground position quickly. So even for local applications, many satellites are needed if the mission requires uninterrupted connectivity. Low-Earth-orbiting satellites are less expensive to launch into orbit than geostationary satellites and, due to proximity to

890-545: A radio signal to a telephone system. In this example, almost any type of satellite can be used. Satellite phones connect directly to a constellation of either geostationary or low-Earth-orbit satellites. Calls are then forwarded to a satellite teleport connected to the Public Switched Telephone Network . As television became the main market, its demand for simultaneous delivery of relatively few signals of large bandwidth to many receivers being

979-558: A range of R&D facilities. 2014 additions included the NRL Nanoscience Institute's 5,000 sq ft (460 m ) Class 100 nanofabrication cleanroom; quiet and ultra-quiet measurement labs; and the Laboratory for Autonomous Systems Research (LASR). The Naval Research Laboratory has a long history of spacecraft development. This includes the second, fifth and seventh American satellites in Earth orbit,

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1068-588: A small squadron of research aircraft termed Scientific Development Squadron (VXS) 1 . Its missions include, for example, Rampant Lion, which used sophisticated airborne instrumentation (gravimeters, magnetometers and hyperspectral cameras) to collect precise 3D topography of two-thirds of Afghanistan and locate natural resources (underground gas and mineral deposits, vegetation types, etc.) there and in Iraq and Colombia. The Division of Plasma Physics conducts research and development into ionized matter. NRL currently holds

1157-523: A tactical necessity, and the ultimate goal of this project was the creation of the longest communications circuit in human history, with the Moon, Earth's natural satellite, acting as a passive relay. After achieving the first transoceanic communication between Washington, D.C. , and Hawaii on 23 January 1956, this system was publicly inaugurated and put into formal production in January 1960. The first satellite purpose-built to actively relay communications

1246-696: A wide variety of basic research and applied research relevant to the US Navy. NRL scientists and engineers author over 1200 openly published research papers in a wide range of conferences, symposia, and journals each year. It has a history of scientific breakthroughs and technological achievements dating back to its foundation in 1923. In some instances the laboratory's contributions to military technology have been declassified decades after those technologies have become widely adopted. In 2011, NRL researchers published 1,398 unclassified scientific and technical articles, book chapters and conference proceedings. In 2008,

1335-682: Is also involved in weather forecasting models such as the Hurricane Weather Research and Forecasting model released in 2007. NRL has a long history of contributions to materials science, dating back to the use of Industrial radiography with gamma rays for the nondestructive inspection of metal casings and welds on Navy vessels beginning in the 1920s. Modern mechanical fracture mechanics were pioneered at NRL and were subsequently applied to solve fracture problems in Navy vessels, commercial aircraft and Polaris missiles. That knowledge

1424-553: Is also possible to offer discontinuous coverage using a low-Earth-orbit satellite capable of storing data received while passing over one part of Earth and transmitting it later while passing over another part. This will be the case with the CASCADE system of Canada's CASSIOPE communications satellite. Another system using this store and forward method is Orbcomm . A medium Earth orbit is a satellite in orbit somewhere between 2,000 and 35,786 kilometres (1,243 and 22,236 mi) above

1513-518: Is also used for high-efficiency solar cells like those aboard NASA's Spirit and Opportunity rovers currently on Mars. NRL discovered solar-wind hydrogen in Apollo lunar soil samples provided by a NASA-funded research mission. Fundamental aspects of stealth technology were developed at NRL, including the radar absorption mechanisms in ferrite-containing materials. Metal bearing surface treatments using Cr ion implantation researched at NRL nearly tripled

1602-565: Is carried out under the auspices of the International Telecommunication Union (ITU). To facilitate frequency planning, the world is divided into three regions: Within these regions, frequency bands are allocated to various satellite services, although a given service may be allocated different frequency bands in different regions. Some of the services provided by satellites are: The first and historically most important application for communication satellites

1691-593: Is equivalent to GS-11 Step 1 through GS-13 Step 10. NRL's Pay Band IV corresponds to the GS-14 Step 1 to GS-15 Step 10 pay grades, inclusive, while NRL's Pay Band V can pay above GS-15 Step 10 and corresponds to the Senior Technologist (ST) pay grade elsewhere in the civil service. For new graduates, someone with a Bachelor of Science degree typically is hired at a salary in the GS-7 range; someone with

1780-492: Is highly inclined, guaranteeing good elevation over selected positions during the northern portion of the orbit. (Elevation is the extent of the satellite's position above the horizon. Thus, a satellite at the horizon has zero elevation and a satellite directly overhead has elevation of 90 degrees.) The Molniya orbit is designed so that the satellite spends the great majority of its time over the far northern latitudes, during which its ground footprint moves only slightly. Its period

1869-935: Is in Washington, D.C., near the southernmost part of the District. It is on the Potomac River and is immediately south of (but is not part of) Joint Base Anacostia-Bolling . This campus is immediately north of the Blue Plains site of the DC Water Authority. Exit 1 of northbound I-295 leads directly to Overlook Avenue and the NRL Main Gate. The U.S. Postal Service operates a post office on the NRL main campus. In addition, NRL operates several field sites and satellite facilities: Artifacts found on

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1958-565: Is in widespread use today in applications ranging from design of nuclear reactors to aircraft, submarines and toxic material storage tanks. NRL developed the synthesis of high-purity GaAs crystals used in a myriad of modern high frequency transceivers including cellular phones, satellite communication systems, commercial and military radar systems including those aboard all US combat aircraft and ARM, Phoenix, AIM-9L and AMRAAM missiles. NRL's GaAs inventions were licensed by Rockwell, Westinghouse, Texas Instruments and Hughes Research. High-purity GaAs

2047-558: Is known as a satellite constellation . Two such constellations, intended to provide satellite phone and low-speed data services, primarily to remote areas, are the Iridium and Globalstar systems. The Iridium system has 66 satellites, which orbital inclination of 86.4° and inter-satellite links provide service availability over the entire surface of Earth. Starlink is a satellite internet constellation operated by SpaceX , that aims for global satellite Internet access coverage. It

2136-576: Is one half day, so that the satellite is available for operation over the targeted region for six to nine hours every second revolution. In this way a constellation of three Molniya satellites (plus in-orbit spares) can provide uninterrupted coverage. The first satellite of the Molniya series was launched on 23 April 1965 and was used for experimental transmission of TV signals from a Moscow uplink station to downlink stations located in Siberia and

2225-671: Is one of the first US government scientific R&D laboratories, having opened in 1923 at the instigation of Thomas Edison , and is currently under the Office of Naval Research . As of 2016, NRL was a Navy Working Capital Fund activity, which means it is not a line-item in the US Federal Budget. Instead of direct funding from Congress, all costs, including overhead, were recovered through sponsor-funded research projects. NRL's research expenditures were approximately $ 1 billion per year. The Naval Research Laboratory conducts

2314-435: Is responsible for research and development in support of the Navy's tactical electronic warfare requirements and missions. These include electronic warfare support measures, electronic countermeasures, and supporting counter-countermeasures, as well as studies, analyses, and simulations for determining and improving the performance of Electronic Warfare systems. NRL TEW includes aerial, surface, and ground EW within its scope. NRL

2403-489: Is responsible for the identification, friend or foe (IFF) system and a number of other advances. The Information Technology Division features an information security R&D group, which is where the IETF's IP Security ( IPsec ) protocols were originally developed. The Encapsulating Security Payload (ESP) protocol developed at NRL is widely used for virtual private network (VPN) connections worldwide. The projects developed by

2492-510: Is still in use today. The Naval Research Laboratory came into existence from an idea that originated from Thomas Edison . In a May 1915 editorial piece in the New York Times Magazine , Edison wrote; "The Government should maintain a great research laboratory... In this could be developed...all the technique of military and naval progression without any vast expense." This statement addressed concerns about World War I in

2581-410: Is that a MEO satellite's distance gives it a longer time delay and weaker signal than a LEO satellite, although these limitations are not as severe as those of a GEO satellite. Like LEOs, these satellites do not maintain a stationary distance from the Earth. This is in contrast to the geostationary orbit, where satellites are always 35,786 kilometres (22,236 mi) from Earth. Typically the orbit of

2670-485: Is useful for communications because ground antennas can be aimed at the satellite without their having to track the satellite's motion. This is relatively inexpensive. In applications that require many ground antennas, such as DirecTV distribution, the savings in ground equipment can more than outweigh the cost and complexity of placing a satellite into orbit. By 2000, Hughes Space and Communications (now Boeing Satellite Development Center ) had built nearly 40 percent of

2759-856: The Cape Canaveral Air Force Station (CCAFS). Following its launch and on-orbit testing, it was placed in geostationary orbit at 36° East, from where it provides communications services to Russia and Africa. It carries thirty-one transponders , and has an expected on-orbit lifespan of 12 years. In December 2011, Eutelsat announced, that their satellite assets will be renamed under a unified brand name effective from March 2012. This satellite became Eutelsat 36A . Eutelsat 70C at 70.5° East in 2016 and at 70.3° East in 2018–2019. Eutelsat 80A at 80.5° East in 2017–2018. Eutelsat 48E at 48° East since 2019. Communications satellite The radio waves used for telecommunications links travel by line of sight and so are obstructed by

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2848-569: The Earth-Moon-Libration points are also proposed for communication satellites covering the Moon alike communication satellites in geosynchronous orbit cover the Earth. Also, dedicated communication satellites in orbits around Mars supporting different missions on surface and other orbits are considered, such as the Mars Telecommunications Orbiter . Communications Satellites are usually composed of

2937-595: The NP pay system, 103 civilian technicians in the NR pay system, 383 civilian administrative specialists/professionals in the NO pay system, and 238 civilian administrative support staff in the NC pay system. NRL scientists & engineers typically are in the (NP) pay group in NRL's Pay Band system. The NP-II pay band is equivalent to GS-5 Step 1 through GS-10 Step 10. The NP-III pay band

3026-423: The Earth faster, they do not remain visible in the sky to a fixed point on Earth continually like a geostationary satellite, but appear to a ground observer to cross the sky and "set" when they go behind the Earth beyond the visible horizon. Therefore, to provide continuous communications capability with these lower orbits requires a larger number of satellites, so that one of these satellites will always be visible in

3115-415: The Earth's surface. MEO satellites are similar to LEO satellites in functionality. MEO satellites are visible for much longer periods of time than LEO satellites, usually between 2 and 8 hours. MEO satellites have a larger coverage area than LEO satellites. A MEO satellite's longer duration of visibility and wider footprint means fewer satellites are needed in a MEO network than a LEO network. One disadvantage

3204-797: The K u band. The Intelsat Americas 5 , Galaxy 10R and AMC 3 satellites over North America provide a quite large amount of FTA channels on their K u band transponders . United States Naval Research Laboratory The United States Naval Research Laboratory ( NRL ) is the corporate research laboratory for the United States Navy and the United States Marine Corps . It was founded in 1923 and conducts basic scientific research, applied research, technological development and prototyping. The laboratory's specialties include plasma physics , space physics , materials science , and tactical electronic warfare . NRL

3293-702: The Lincoln Laboratory on behalf of the United States Department of Defense . The LES-1 active communications satellite was launched on 11 February 1965 to explore the feasibility of active solid-state X band long-range military communications. A total of nine satellites were launched between 1965 and 1976 as part of this series. In the United States, 1962 saw the creation of the Communications Satellite Corporation (COMSAT) private corporation, which

3382-518: The Manhattan Project and guided the design of Oak Ridge National Laboratory 's Uranium enrichment plant. NRL is currently developing laser focusing techniques aimed at inertial confinement fusion technology. The static discharger seen on trailing edges of virtually all modern aircraft was originally developed by NRL scientists during World War II. After the war, the laboratory developed modern synthetic lubricants initially for use in

3471-533: The NRL campus, such as stone tools and ceramic shards, show that the site had been inhabited since the Late Archaic Period . Cecil Calvert, 2nd Baron Baltimore , granted the tract of land which includes the present NRL campus to William Middleton in 1663. It became part of the District of Columbia in 1791, and was purchased by Thomas Grafton Addison in 1795, who named the area Bellevue and built

3560-482: The NRL jumped from 396 in 1941 to 4400 in 1946, expenditures from $ 1.7 million to $ 13.7 million, the number of buildings from 23 to 67, and the number of projects from 200 to about 900. During World War II, scientific activities necessarily were concentrated almost entirely on applied research. Advances were made in radio , radar , and sonar . Countermeasures were devised. New lubricants were produced, as were antifouling paints, luminous identification tapes, and

3649-1103: The NRL was ranked No. 3 among all U.S. institutions holding nanotechnology -related patents, behind IBM and the University of California . Current areas of research at NRL include, for example: In 2014, the NRL was researching: armor for munitions in transport, high-powered lasers, remote explosives detection, spintronics, the dynamics of explosive gas mixtures, electromagnetic railgun technology, detection of hidden nuclear materials, graphene devices, high-power extremely high frequency (35–220 GHz) amplifiers, acoustic lensing, information-rich orbital coastline mapping, arctic weather forecasting, global aerosol analysis & prediction, high-density plasmas, millisecond pulsars , broadband laser data links, virtual mission operation centers, battery technology, photonic crystals, carbon nanotube electronics, electronic sensors, mechanical nano-resonators, solid-state chemical sensors, organic opto-electronics, neural-electronic interfaces and self-assembling nanostructures. The laboratory includes

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3738-930: The Nanoscience Institute while still performing research for their respective divisions. Opened March 2012, the Laboratory for Autonomous Systems Research (LASR) is a 50,000 square foot facility that supports basic and applied research in autonomous systems. The facility supports a wide range of interdisciplinary basic and applied research in autonomous systems to include research in autonomous systems, intelligent autonomy, human-autonomous system interaction and collaboration, sensor systems, power and energy systems, networking and communications, and platforms. LASR provides unique facilities and simulated environmental high bays (littoral, desert, tropical, and forest) and instrumented reconfigurable high bay spaces to support integration of science and technology components into research prototype systems. The main campus of NRL

3827-478: The Navy's jet aircraft but subsequently adopted by the commercial jet industry. In the late 1960s, NRL researched low-temperature physics, achieving for the first time a temperature within one millionth of a degree of absolute zero in 1967. In 1985 two scientists at the laboratory, Herbert A. Hauptman and Jerome Karle , won the Nobel Prize for devising direct methods employing X-ray diffraction analysis in

3916-800: The Russian Far East, in Norilsk , Khabarovsk , Magadan and Vladivostok . In November 1967 Soviet engineers created a unique system of national TV network of satellite television , called Orbita , that was based on Molniya satellites. In the United States, the National Polar-orbiting Operational Environmental Satellite System (NPOESS) was established in 1994 to consolidate the polar satellite operations of NASA (National Aeronautics and Space Administration) NOAA (National Oceanic and Atmospheric Administration). NPOESS manages

4005-783: The Strontium Iodide Radiation Instrumentation (SIRI) and RAM Angle and Magnetic field sensor (RAMS) aboard STPSat-5, the Wide-field Imager for Solar PRobe (WISPR) aboard the Parker Solar Probe , and the Large Angle and Spectrometric Coronagraph Experiment (LASCO) aboard the Solar and Heliospheric Observatory (SOHO). NASA's Fermi Gamma-ray Space Telescope (FGST) [formerly called Gamma-ray Large Area Space Telescope (GLAST)]

4094-494: The United States. Edison then agreed to serve as the head of the Naval Consulting Board that consisted of civilians who had achieved expertise. The focus of the Naval Consulting Board was as advisor to the U.S. Navy pertaining to science and technology. The board brought forward a plan to create a modern facility for the Navy. In 1916 Congress allocated $ 1.5 million for implementation. However, construction

4183-403: The completion of a fully global network with Intelsat 3 in 1969–70. By the 1980s, with significant expansions in commercial satellite capacity, Intelsat was on its way to become part of the competitive private telecommunications industry, and had started to get competition from the likes of PanAmSat in the United States, which, ironically, was then bought by its archrival in 2005. When Intelsat

4272-462: The curve of the Earth. The purpose of communications satellites is to relay the signal around the curve of the Earth allowing communication between widely separated geographical points. Communications satellites use a wide range of radio and microwave frequencies . To avoid signal interference, international organizations have regulations for which frequency ranges or "bands" certain organizations are allowed to use. This allocation of bands minimizes

4361-411: The determination of crystal structures. Their methods form the basis for the computer packages used in pharmaceutical labs and research institutions worldwide for the analysis of more than 10,000 new substances each year. NRL has most recently published research on quantum computing, quantum dots, plasma shockwaves, thermodynamics of liquids, modeling of oil spills and other topics. NRL operates

4450-619: The dipoles properly separated from each other, the project was able to successfully experiment and communicate using frequencies in the SHF X band spectrum. An immediate antecedent of the geostationary satellites was the Hughes Aircraft Company 's Syncom 2 , launched on 26 July 1963. Syncom 2 was the first communications satellite in a geosynchronous orbit . It revolved around the Earth once per day at constant speed, but because it still had north–south motion, special equipment

4539-455: The edges of Antarctica and Greenland . Other land use for satellite phones are rigs at sea, a backup for hospitals, military, and recreation. Ships at sea, as well as planes, often use satellite phones. Satellite phone systems can be accomplished by a number of means. On a large scale, often there will be a local telephone system in an isolated area with a link to the telephone system in a main land area. There are also services that will patch

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4628-692: The equator and therefore appear lower on the horizon as the receiver gets farther from the equator. This will cause problems for extreme northerly latitudes, affecting connectivity and causing multipath interference (caused by signals reflecting off the ground and into the ground antenna). Thus, for areas close to the North (and South) Pole, a geostationary satellite may appear below the horizon. Therefore, Molniya orbit satellites have been launched, mainly in Russia, to alleviate this problem. Molniya orbits can be an appealing alternative in such cases. The Molniya orbit

4717-473: The first artificial satellite used for passive relay communications in Echo 1 on 12 August 1960. Echo 1 was an aluminized balloon satellite acting as a passive reflector of microwave signals. Communication signals were bounced off the satellite from one point on Earth to another. This experiment sought to establish the feasibility of worldwide broadcasts of telephone, radio, and television signals. Telstar

4806-447: The first practical radar equipment built in the United States. They performed basic research, participating in the discovery and early exploration of the ionosphere . The NRL gradually worked towards its goal of becoming a broadly based research facility. By the beginning of World War II , five new divisions had been added: Physical Optics, Chemistry, Metallurgy, Mechanics and Electricity, and Internal Communications. Total employment at

4895-412: The first privately sponsored space launch. Another passive relay experiment primarily intended for military communications purposes was Project West Ford , which was led by Massachusetts Institute of Technology 's Lincoln Laboratory . After an initial failure in 1961, a launch on 9 May 1963 dispersed 350 million copper needle dipoles to create a passive reflecting belt. Even though only about half of

4984-439: The first solar-powered satellite, the first surveillance satellite, the first meteorological satellite and the first GPS satellite. Project Vanguard , the first American satellite program, tasked NRL with the design, construction and launch of an artificial satellite, which was accomplished in 1958. As of 2024 , Vanguard I and its upper launch stage are still in orbit, making them the longest-lived man-made satellites. Vanguard II

5073-479: The following subsystems: The bandwidth available from a satellite depends upon the number of transponders provided by the satellite. Each service (TV, Voice, Internet, radio) requires a different amount of bandwidth for transmission. This is typically known as link budgeting and a network simulator can be used to arrive at the exact value. Allocating frequencies to satellite services is a complicated process which requires international coordination and planning. This

5162-404: The ground, do not require as high signal strength (signal strength falls off as the square of the distance from the source, so the effect is considerable). Thus there is a trade off between the number of satellites and their cost. In addition, there are important differences in the onboard and ground equipment needed to support the two types of missions. A group of satellites working in concert

5251-436: The laboratory often become mainstream applications without public awareness of the developer; an example in computer science is onion routing , the core principle of the anonymizing Tor software. Nuclear power research was initiated at NRL as early as 1939, six years before the first atomic bomb, for the purpose of powering submarines. Uranium enrichment methods sponsored by NRL over the course of World War II were adopted by

5340-917: The laboratory was divided into four research directorates, one financial directorate, and one executive directorate. All the directorates are headquartered in Washington, D.C. Many directorates have other facilities elsewhere, primarily at either the Stennis Space Center in Bay St Louis, Mississippi or in Monterey, California. Most NRL staff are civilians in the civil service , with a relatively small number of Navy enlisted personnel or officers. Virtually all NRL staff are US citizens and are not dual-nationals. In addition, there are some support contractors that work on-site at NRL. As of 31 December 2015, across all NRL locations, NRL had 2540 civilian employees (i.e., not including civilian contractors). On

5429-515: The late 20th century. Satellite communications are still used in many applications today. Remote islands such as Ascension Island , Saint Helena , Diego Garcia , and Easter Island , where no submarine cables are in service, need satellite telephones. There are also regions of some continents and countries where landline telecommunications are rare to non existent, for example large regions of South America, Africa, Canada, China, Russia, and Australia. Satellite communications also provide connection to

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5518-566: The more than one hundred satellites in service worldwide. Other major satellite manufacturers include Space Systems/Loral , Orbital Sciences Corporation with the Star Bus series, Indian Space Research Organisation , Lockheed Martin (owns the former RCA Astro Electronics/GE Astro Space business), Northrop Grumman , Alcatel Space, now Thales Alenia Space , with the Spacebus series, and Astrium . Geostationary satellites must operate above

5607-470: The northern hemisphere. This orbit provides a long dwell time over Russian territory as well as over Canada at higher latitudes than geostationary orbits over the equator. Communications satellites usually have one of three primary types of orbit , while other orbital classifications are used to further specify orbital details. MEO and LEO are non-geostationary orbit (NGSO). As satellites in MEO and LEO orbit

5696-564: The other hand, amplify the received signal before retransmitting it to the receiver on the ground. Passive satellites were the first communications satellites, but are little used now. Work that was begun in the field of electrical intelligence gathering at the United States Naval Research Laboratory in 1951 led to a project named Communication Moon Relay . Military planners had long shown considerable interest in secure and reliable communications lines as

5785-512: The postwar era determined to consolidate its wartime gains in science and technology and to preserve the working relationship between its armed forces and the scientific community. While the Navy was establishing the Office of Naval Research (ONR) in 1946 as a liaison with and supporter of basic and applied scientific research, the Navy encouraged NRL to broaden its scope since it was the Navy Department's corporate research laboratory. NRL

5874-487: The risk of signal interference. In October 1945, Arthur C. Clarke published an article titled "Extraterrestrial Relays" in the British magazine Wireless World . The article described the fundamentals behind the deployment of artificial satellites in geostationary orbits to relay radio signals. Because of this, Arthur C. Clarke is often quoted as being the inventor of the concept of the communications satellite, and

5963-791: The same date, there were 35 military officers on-board NRL and 58 enlisted on-board NRL, most of whom are with NRL's VXS-1 Scientific Flight Detachment, which is located at the Patuxent River ('Pax River') Naval Air Station (NAS) in southern Maryland. NRL has special authority to use a Pay-Band pay system instead of using the traditional General Schedule (GS) pay system for its civilian employees. This gives NRL more ability to pay employees based on performance and merit, rather than time-in-grade or some other seniority metric. There are several different pay-band groups at NRL, each being for different categories of civilian employees. As of 31 December 2015, NRL had 1615 civilian scientists/engineers in

6052-1047: The same linear polarization as FSS-class satellites. Examples of these are the Astra , Eutelsat , and Hotbird spacecraft in orbit over the European continent. Because of this, the terms FSS and DBS are more so used throughout the North American continent, and are uncommon in Europe. Fixed Service Satellites use the C band , and the lower portions of the K u band . They are normally used for broadcast feeds to and from television networks and local affiliate stations (such as program feeds for network and syndicated programming, live shots , and backhauls ), as well as being used for distance learning by schools and universities, business television (BTV), Videoconferencing , and general commercial telecommunications. FSS satellites are also used to distribute national cable channels to cable television headends. Free-to-air satellite TV channels are also usually distributed on FSS satellites in

6141-692: The service life of Navy turbine engine parts and was adopted for Army helicopter parts as well. Fluorinated polyurethane coatings developed at NRL are used to line fuel storage tanks throughout the US Navy, reducing leakage and environmental and fuel contamination. The same polymer films are used in Los Angeles-class submarine radomes to repel water and enable radar operation soon after surfacing. Scientists at NRL frequently contribute theoretical and experimental research on novel materials, particularly magnetic materials and nanomaterials and thermoplastic . The first modern U.S. radar

6230-408: The signal coming from the source, toward the direction of the receiver. With passive satellites, the reflected signal is not amplified at the satellite, and only a small amount of the transmitted energy actually reaches the receiver. Since the satellite is so far above Earth, the radio signal is attenuated due to free-space path loss , so the signal received on Earth is very weak. Active satellites, on

6319-402: The sky for transmission of communication signals. However, due to their closer distance to the Earth, LEO or MEO satellites can communicate to ground with reduced latency and at lower power than would be required from a geosynchronous orbit. A low Earth orbit (LEO) typically is a circular orbit about 160 to 2,000 kilometres (99 to 1,243 mi) above the Earth's surface and, correspondingly,

6408-697: The success of surveillance satellites, the iconic parabolic antenna atop NRL's main headquarters in Washington, D.C. was part of Communication Moon Relay , a project that utilized signals bounced off the Moon both for long-distance communications research and surveillance of internal Soviet transmissions during the Cold War . NRL's spacecraft development program continues today with the TacSat-4 experimental tactical reconnaissance and communication satellite. In addition to spacecraft design, NRL designs and operates spaceborne research instruments and experiments, such as

6497-590: The term 'Clarke Belt' is employed as a description of the orbit. The first artificial Earth satellite was Sputnik 1 , which was put into orbit by the Soviet Union on 4 October 1957. It was developed by Mikhail Tikhonravov and Sergey Korolev , building on work by Konstantin Tsiolkovsky . Sputnik 1 was equipped with an on-board radio transmitter that worked on two frequencies of 20.005 and 40.002 MHz, or 7 and 15 meters wavelength. The satellite

6586-665: The world record for most energetic rail gun projectile (33 MJ, 9.2 kWh) and fastest man-made projectile (2.24 million mph, 3.60 million km/h). NRL established the Navy Center for Applied Research in Artificial Intelligence in 1981, which conducts basic and applied research in artificial intelligence, cognitive science, autonomy, and human-centered computing. Among its achievements are advances in cognitive architectures , human-robot interaction , and machine learning . As of 2017,

6675-515: Was Project SCORE , led by Advanced Research Projects Agency (ARPA) and launched on 18 December 1958, which used a tape recorder to carry a stored voice message, as well as to receive, store, and retransmit messages. It was used to send a Christmas greeting to the world from U.S. President Dwight D. Eisenhower . The satellite also executed several realtime transmissions before the non-rechargeable batteries failed on 30 December 1958 after eight hours of actual operation. The direct successor to SCORE

6764-429: Was another ARPA-led project called Courier. Courier 1B was launched on 4 October 1960 to explore whether it would be possible to establish a global military communications network by using "delayed repeater" satellites, which receive and store information until commanded to rebroadcast them. After 17 days, a command system failure ended communications from the satellite. NASA 's satellite applications program launched

6853-546: Was delayed until 1920 because of the war and internal disagreements within the board. The U.S. Naval Research Laboratory, the first modern research institution created within the United States Navy, began operations at 1100 on 2 July 1923. The Laboratory's two original divisions – Radio and Sound – performed research in the fields of high-frequency radio and underwater sound propagation. They produced communications equipment, direction-finding devices, sonar sets, and

6942-530: Was designed and constructed at NRL. NRL pioneered the study of the sun Ultraviolet and X-Ray spectrum and continues to contribute to the field with satellites like Coriolis launched in 2003. NRL is also responsible for the Tactical Satellite Program with spacecraft launched in 2006, 2009 and 2011. The NRL designed the first satellite tracking system, Minitrack , which became the prototype for future satellite tracking networks. Prior to

7031-428: Was in intercontinental long distance telephony . The fixed Public Switched Telephone Network relays telephone calls from land line telephones to an Earth station , where they are then transmitted to a geostationary satellite. The downlink follows an analogous path. Improvements in submarine communications cables through the use of fiber-optics caused some decline in the use of satellites for fixed telephony in

7120-622: Was invented and developed at NRL in Washington, DC in 1922. By 1939, NRL installed the first operational radar aboard the USS New York, in time for radar to contribute to naval victories of the Coral Sea , Midway and Guadalcanal . NRL then further developed over-the-horizon radar as well as radar data displays. NRL's Radar Division continues important research & development contributing to US Navy and US Department of Defense capabilities. NRL's Tactical Electronic Warfare (TEW) Division

7209-492: Was launched, the United States was the only launch source outside of the Soviet Union , who did not participate in the Intelsat agreements. The Soviet Union launched its first communications satellite on 23 April 1965 as part of the Molniya program. This program was also unique at the time for its use of what then became known as the Molniya orbit , which describes a highly elliptical orbit , with two high apogees daily over

7298-493: Was needed to track it. Its successor, Syncom 3 , launched on 19 July 1964, was the first geostationary communications satellite. Syncom 3 obtained a geosynchronous orbit, without a north–south motion, making it appear from the ground as a stationary object in the sky. A direct extension of the passive experiments of Project West Ford was the Lincoln Experimental Satellite program, also conducted by

7387-500: Was not placed in orbit to send data from one point on Earth to another, but the radio transmitter was meant to study the properties of radio wave distribution throughout the ionosphere. The launch of Sputnik 1 was a major step in the exploration of space and rocket development, and marks the beginning of the Space Age . There are two major classes of communications satellites, passive and active . Passive satellites only reflect

7476-528: Was placed under the administrative oversight of ONR after ONR was created. NRL's Commanding Officer reports to the Navy's Chief of Naval Research (CNR) . The Chief of Naval Research leads the Office of Naval Research, which primarily is located in the Ballston area of Arlington, Virginia. The reorganization also caused a parallel shift of the Laboratory's emphasis to one of long-range basic and applied research in

7565-644: Was subject to instruction by the US Government on matters of national policy. Over the next two years, international negotiations led to the Intelsat Agreements, which in turn led to the launch of Intelsat 1, also known as Early Bird, on 6 April 1965, and which was the first commercial communications satellite to be placed in geosynchronous orbit. Subsequent Intelsat launches in the 1960s provided multi-destination service and video, audio, and data service to ships at sea (Intelsat 2 in 1966–67), and

7654-632: Was tested at NRL spacecraft testing facilities. NRL scientists have most recently contributed leading research to the study of novas and gamma ray bursts. The Marine Meteorology Division (Naval Research Lab–Monterey, NRL–MRY), located in Monterey, California , contributes to weather forecasting in the United States and around the world by publishing imagery from 18 weather satellites. Satellite images of severe weather (e.g. hurricanes and cyclones) that are used for advanced warning often originate from NRL–MRY, as seen in 2017 during Hurricane Harvey . NRL

7743-591: Was the first active, direct relay communications commercial satellite and marked the first transatlantic transmission of television signals. Belonging to AT&T as part of a multi-national agreement between AT&T, Bell Telephone Laboratories , NASA, the British General Post Office , and the French National PTT (Post Office) to develop satellite communications, it was launched by NASA from Cape Canaveral on 10 July 1962, in

7832-423: Was the first satellite to observe the Earth's cloud cover and therefore the first meteorological satellite. NRL's Galactic Radiation and Background I (GRAB I) was the first U.S. intelligence satellite , mapping out Soviet radar networks from space. The Global Positioning System (GPS) was invented at NRL and tested by NRL's Timation series of satellites. The first operational GPS satellite, Timation IV (NTS-II)

7921-527: Was voted #15 in the Best Places to Work PostDocs 2013 survey. The four research directorates within NRL were: The two support directorates were: In April 2001, in a departure from traditional working relationships between NRL scientists, the Institute for Nanoscience was established to conduct multidisciplinary research in the fields of materials, electronics and biology. Scientists may be part of

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