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DSCS
The Defense Satellite Communications System (DSCS) is a United States Space Force satellite constellation that provides the United States with military communications to support globally distributed military users. Beginning in 2007, DSCS is being replaced by the Wideband Global SATCOM system. A total of 14 DSCS-III satellites were launched between the early 1980s and 2003. Two satellites were launched aboard the Space Shuttle Space Shuttle Atlantis, ''Atlantis'' in 1985 during the STS-51-J flight. As of 14 September 2021, six DSCS-III satellites were still operational. DSCS operations are currently run by the 4th Space Operations Squadron out of Schriever Space Force Base. Background DSCS went through three major phases — IDCSP (Interim Defense Communication Satellite Program), DSCS-II, and DSCS-III. Since the first launch, DSCS has been the "workhorse" of Military satellite, military Communications satellite, satellite communications. All DSCS III satellites have exc ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Wideband Global SATCOM
The Wideband Global SATCOM system (WGS) is a high capacity United States Space Force satellite communications system planned for use in partnership by the United States Department of Defense (DoD), Canadian Department of National Defence (DND) and the Australian Department of Defence. The system is composed of the ''Space Segment'' satellites, the ''Terminal Segment'' users and the ''Control Segment'' operators. DoD wideband satellite communication services are currently provided by a combination of the existing Defense Satellite Communications System (DSCS) and Global Broadcast Service (GBS) satellites. According to United Launch Alliance, quoted on ''Spaceflight Now'', "A single WGS spacecraft has as much bandwidth as the entire existing DSCS constellation." WGS operations are currently run by the 4th Space Operations Squadron, out of Schriever Space Force Base, as well as the 53rd Space Operations Squadron. Mission The constellation of WGS satellites increases the commun ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
STS-51-J
STS-51-J was the 21st NASA Space Shuttle mission and the first flight of Space Shuttle ''Atlantis''. It launched from Kennedy Space Center, Florida, on October 3, 1985, carrying a payload for the U.S. Department of Defense (DoD), and landed at Edwards Air Force Base, California, on October 7, 1985. Crew Backup crew Crew notes All five astronauts on the secret mission were active-duty military officers. Before William A. Pailes was assigned to the STS-51-J flight, Mike Mullane was rumored to have been assigned as Mission Specialist 3 on his second trip to space. Mission summary STS-51-J launched on October 3, 1985, at 15:15:30 UTC (11:15:30 a.m. EDT), from Launch Pad 39A at the Kennedy Space Center. The launch was delayed by 22 minutes and 30 seconds due to a problem with a main engine liquid hydrogen prevalve close remote power controller; the controller was showing a faulty "on" indication. The mission was the second shuttle flight totally dedicated to dep ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Initial Defense Communications Satellite Program
The Initial Defense Communications Satellite Program or IDCSP was the first United States Department of Defense communications satellite constellation and the first stage of the Defense Communications Satellite Program (DCSP). Launched in five groups by Titan IIIC launch vehicles to near equatorial, subsynchronous orbits between 1966 and 1968, they were intended to be experimental testbeds. They were so successful that, by the time of the launch of the last set of eight satellites, the IDCSP was deemed operational and renamed Initial Defense Satellite Communications System or IDSCS. This system allowed real-time collection of battlefield intelligence during the Vietnam War. A total of 35 IDCSP satellites were launched, 27 successfully. Background The Initial Defense Communications Satellite Program or IDCSP was the first stage in the Defense Communications Satellite Program (DCSP) commissioned by United States Secretary of Defense Robert McNamara in 1962. Under the DCSP, se ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Amundsen–Scott South Pole Station
The Amundsen–Scott South Pole Station is the United States scientific research station at the South Pole of the Earth. It is the southernmost point under the jurisdiction (not sovereignty) of the United States. The station is located on the high plateau of Antarctica at above sea level. It is administered by the Office of Polar Programs of the National Science Foundation, specifically the United States Antarctic Program (USAP). It is named in honor of Norwegian Roald Amundsen and Briton Robert F. Scott, who led separate teams that raced to become the first to the pole in the early 1900s. The original Amundsen–Scott Station was built by Navy Seabees for the federal government of the United States during November 1956, as part of its commitment to the scientific goals of the International Geophysical Year, an effort lasting from January 1957 through June 1958 to study, among other things, the geophysics of the polar regions of Earth. Before November ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Defense Information Systems Agency
The Defense Information Systems Agency (DISA), known as the Defense Communications Agency (DCA) until 1991, is a United States Department of Defense (DoD) combat support agency composed of military, federal civilians, and contractors. DISA provides information technology (IT) and communications support to the President, Vice President, Secretary of Defense, the military services, the combatant commands, and any individual or system contributing to the defense of the United States. Headquarters From January to July 2011, DISA relocated more than 4,500 military and civilian employees and supporting onsite contractors, 700 workstation suites with 11,000 pieces of IT equipment, and 58,000 square feet of lab equipment in accordance with the Base Realignment and Closure legislation of 2005. The relocation to Fort George G. Meade, Md., consolidated DISA headquarters elements that were housed in multiple locations in Arlington and Falls Church, Va. In April 2011, DISA held a ribbo ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Communications Satellite
A communications satellite is an artificial satellite that relays and amplifies radio telecommunication signals via 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 above the equator, so that the satellite appears stationary at 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. The high frequency radio waves used for telecommunications links travel by line of sight and so are obstructed by the curve of the Earth. The purpose of communications sate ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Space Shuttle Atlantis
Space Shuttle ''Atlantis'' (Orbiter Vehicle designation: OV‑104) is a Space Shuttle orbiter vehicle which belongs to NASA, the spaceflight and space exploration agency of the United States. ''Atlantis'' was manufactured by the Rockwell International company in Southern California and was delivered to the Kennedy Space Center in Eastern Florida in April 1985. ''Atlantis'' is also the fourth operational and the second-to-last Space Shuttle built. Its maiden flight was STS-51-J made from October 3 to 7, 1985. ''Atlantis'' embarked on its 33rd and final mission, also the final mission of a space shuttle, STS-135, on July 8, 2011. STS-134 by ''Endeavour'' was expected to be the final flight before STS-135 was authorized in October 2010. STS-135 took advantage of the processing for the STS-335 Launch on Need mission that would have been necessary if STS-134's crew became stranded in orbit. ''Atlantis'' landed for the final time at the Kennedy Space Center on July 21, 2011. By th ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Research And Development
Research and development (R&D or R+D), known in Europe as research and technological development (RTD), is the set of innovative activities undertaken by corporations or governments in developing new services or products, and improving existing ones. Research and development constitutes the first stage of development of a potential new service or the production process. R&D activities differ from institution to institution, with two primary models of an R&D department either staffed by engineers and tasked with directly developing new products, or staffed with industrial scientists and tasked with applied research in scientific or technological fields, which may facilitate future product development. R&D differs from the vast majority of corporate activities in that it is not intended to yield immediate profit, and generally carries greater risk and an uncertain return on investment. However R&D is crucial for acquiring larger shares of the market through the marketisation ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Antenna (radio)
In radio engineering, an antenna or aerial is the interface between radio waves propagating through space and electric currents moving in metal conductors, used with a transmitter or receiver. In transmission, a radio transmitter supplies an electric current to the antenna's terminals, and the antenna radiates the energy from the current as electromagnetic wave In physics, electromagnetic radiation (EMR) consists of waves of the electromagnetic (EM) field, which propagate through space and carry momentum and electromagnetic radiant energy. It includes radio waves, microwaves, infrared, (visib ...s (radio waves). In Receiver (radio), reception, an antenna intercepts some of the power of a radio wave in order to produce an electric current at its terminals, that is applied to a receiver to be Amplifier, amplified. Antennas are essential components of all radio equipment. An antenna is an array of conductor (material), conductors (Driven element, elements), elect ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Transponder
In telecommunications, a transponder is a device that, upon receiving a signal, emits a different signal in response. The term is a blend word, blend of ''transmitter'' and ''responder''. In air navigation or radio frequency identification, a Transponder (aeronautics), flight transponder is an automated transceiver in an aircraft that emits a coded identifying signal in response to an interrogating received signal. In a communications satellite, a Transponder (satellite communications), satellite transponder receives signals over a range of uplink frequencies, usually from a satellite ground station; the transponder amplifies them, and re-transmits them on a different set of downlink frequencies to receivers on Earth, often without changing the content of the received signal or signals. Satellite/broadcast communications A communications satellite’s Communication channel, channels are called transponders because each is a separate transceiver or repeater. With digital video d ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Data Transmission
Data transmission and data reception or, more broadly, data communication or digital communications is the transfer and reception of data in the form of a digital bitstream or a digitized analog signal transmitted over a point-to-point or point-to-multipoint communication channel. Examples of such channels are copper wires, optical fibers, wireless communication using radio spectrum, storage media and computer buses. The data are represented as an electromagnetic signal, such as an electrical voltage, radiowave, microwave, or infrared signal. Analog transmission is a method of conveying voice, data, image, signal or video information using a continuous signal which varies in amplitude, phase, or some other property in proportion to that of a variable. The messages are either represented by a sequence of pulses by means of a line code (''baseband transmission''), or by a limited set of continuously varying waveforms (''passband transmission''), using a digital modulat ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
X Band
The X band is the designation for a band of frequencies in the microwave radio region of the electromagnetic spectrum. In some cases, such as in communication engineering, the frequency range of the X band is rather indefinitely set at approximately 7.0–11.2 GHz. In radar engineering, the frequency range is specified by the Institute of Electrical and Electronics Engineers (IEEE) as 8.0–12.0 GHz. The X band is used for radar, satellite communication, and wireless computer networks. Radar X band is used in radar applications including continuous-wave, pulsed, single- polarization, dual-polarization, synthetic aperture radar, and phased arrays. X band radar frequency sub-bands are used in civil, military, and government institutions for weather monitoring, air traffic control, maritime vessel traffic control, defense tracking, and vehicle speed detection for law enforcement. X band is often used in modern radars. The shorter wavelengths of the X band allow ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
