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USA-235
USA-235, also known as Advanced Extremely High Frequency 2 or AEHF-2, is a military communications satellite operated by the United States Air Force. It is the second of six satellite to be launched as part of the Advanced Extremely High Frequency program, which replaced the earlier Milstar system. Satellite description The USA-235 satellite was constructed by Lockheed Martin Space, and is based on the A2100 satellite bus. The satellite has a mass of and a design life of 14 years. It will be used to provide super high frequency (SHF) and extremely high frequency (EHF) communications for the United States Armed Forces, as well as those of the United Kingdom, the Netherlands, and Canada. Launch USA-235 was launched by United Launch Alliance, aboard an Atlas V 531 flying from Space Launch Complex 41 (SLC-41) at the Cape Canaveral Air Force Station (CCAFS). The launch occurred at 18:24 UTC on 4 May 2012, first placing the satellite in a parking orbit of 185 kilometers by 90 ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Advanced Extremely High Frequency
Advanced Extremely High Frequency (AEHF) is a constellation of communications satellites operated by the United States Space Force. They are used to relay secure communications for the United States Armed Forces, the British Armed Forces, the Canadian Armed Forces, the Netherlands Armed Forces and the Australian Defence Force. The system consists of six satellites in geostationary orbits. The final satellite was launched on 26 March 2020. AEHF is backward compatible with, and replaces, the older Milstar system and will operate at 44 GHz uplink (extremely high frequency (EHF) band) and 20 GHz downlink (super high frequency (SHF) band). The AEHF system is a joint service communications system that provides survivable, global, secure, protected, and jam-resistant communications for high-priority military ground, sea and air assets. Overview AEHF satellites use many narrow spot beams directed towards the Earth to relay communications to and from users. Crosslinks between the satel ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Atlas V
Atlas V is an expendable launch system and the fifth major version in the Atlas (rocket family), Atlas launch vehicle family. It was originally designed by Lockheed Martin, now being operated by United Launch Alliance (ULA), a joint venture between Lockheed Martin and Boeing. Atlas V is also a major NASA launch vehicle. It is America's longest-serving active rocket. In August 2021, ULA announced that Atlas V would be retired, and all 29 remaining launches had been sold. , 19 launches remain. Each Atlas V launch vehicle consists of two main stages. The first stage (rocketry), first stage is powered by a Russian RD-180 engine manufactured by NPO Energomash, Energomash and burning kerosene and liquid oxygen. The Centaur (rocket stage), Centaur upper stage is powered by one or two American RL10 engine(s) manufactured by Aerojet Rocketdyne and burns liquid hydrogen and liquid oxygen. The Star 48 upper stage was used on the ''New Horizons'' mission as a third stage. strap-on booster, ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
USA-246
USA-246, also known as Advanced Extremely High Frequency 3 or AEHF-3, is a military communications satellite operated by the United States Air Force. It is the third of six satellites to be launched as part of the Advanced Extremely High Frequency program, which replaced the earlier Milstar system. Satellite The USA-246 satellite was constructed by Lockheed Martin Space, and is based on the A2100 satellite bus. The satellite has a mass of and a design life of 14 years. It will be used to provide super high frequency (SHF) and extremely high frequency (EHF) communications for the United States Armed Forces, as well as those of the United Kingdom, the Netherlands, and Canada. Launch USA-246 was launched by United Launch Alliance, aboard an Atlas V 531 flying from Space Launch Complex 41 (SLC-41) at the Cape Canaveral Air Force Station (CCAFS). After a number of weather-related delays, the launch occurred at 08:10:00 UTC on 18 September 2013, placing the satelli ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
USA-214
USA-214, also known as Advanced Extremely High Frequency-1 or AEHF-1, is a military communications satellite operated by the United States Air Force. It is the first of six satellites to be launched as part of the Advanced Extremely High Frequency program, which will replace the earlier Milstar system. Satellite description The USA-214 satellite was constructed by Lockheed Martin Space, and is based on the A2100 satellite bus. The satellite has a mass of and a design life of 14 years. It will be used to provide super high frequency (SHF) and extremely high frequency (EHF) communications for the United States Armed Forces, as well as those of the United Kingdom, the Netherlands, and Canada. Launch Though initially scheduled for launch on 30 July 2010, delays with the launch vehicle pushed flight back to 10 August 2010, and finally to 14 August 2010. USA-214 was launched by United Launch Alliance, aboard an Atlas V 531 flying from Space Launch Complex-41 (SLC-41) at the ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
2012 In Spaceflight
The year 2012 saw a number of significant events in spaceflight. In May and October, the first Commercial Orbital Transportation Services resupply missions took place, during which the SpaceX Dragon became the first private spacecraft to dock with the International Space Station (ISS). In June, China launched the crewed Shenzhou 9 orbital mission, and North Korea achieved its first successful orbital launch in December. 2012 also saw China's first successful asteroid exploration mission, and the landing of NASA's ''Curiosity'' rover on Mars. The Vega and Unha-3 rockets made their maiden flights in 2012, while the Proton-K made its last. A total of 77 orbital launches were attempted in 2012, of which 72 were successful, three were partially successful and two were failures. Five crewed orbital missions were conducted over the course of the year, all successfully, carrying a total of 15 individuals into orbit. The year also saw five EVAs by ISS astronauts. The majority of th ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Lockheed Martin Space
Lockheed Martin Space is one of the four major business divisions of Lockheed Martin. It has its headquarters in Littleton, Colorado, with additional sites in Valley Forge, Pennsylvania; Sunnyvale, California; Santa Cruz, California; Huntsville, Alabama; and elsewhere in the United States and United Kingdom. The division currently employs about 16,000 people, and its most notable products are commercial and military satellites, space probes, missile defense systems, NASA's Orion spacecraft, and the Space Shuttle external tank. History The Lockheed Missile Systems Division was established in Van Nuys, California, in late 1953 to consolidate work on the Lockheed X-17 and X-7. The X-17 was a three-stage solid-fuel research rocket designed to test the effects of high mach atmospheric reentry. The X-17 was also used as the booster for the Operation Argus series of three high-altitude nuclear tests conducted in the South Atlantic in 1958. The Lockheed X-7 (dubbed the "Flying Stove ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Milstar
Milstar (Military Strategic and Tactical Relay) is a constellation of military communications satellites in geosynchronous orbit, which are operated by the United States Space Force, and provide secure and jam-resistant worldwide communications to meet the requirements of the Armed Forces of the United States. Six spacecraft were launched between 1994 and 2003, of which five are currently operational; the third launch failed, both damaging the satellite and leaving it in an unusable orbit. History Milstar Block I spacecraft, or Milstar Developmental Flight Satellite (DFS)-1 and -2, were designed with a Low Data Rate (LDR) payload in the wing of the satellite that broadcast in the Super High Frequency (SHF) and Extremely High Frequency (EHF) ranges, and also a classified communication payload in the wing. The DFS-1 satellite was launched on 7 February 1994 aboard the first Titan IV(401)A rocket, but with the classified wing payload deactivated. It was followed by the DFS-2 s ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Orbital Inclination
Orbital inclination measures the tilt of an object's orbit around a celestial body. It is expressed as the angle between a reference plane and the orbital plane or axis of direction of the orbiting object. For a satellite orbiting the Earth directly above the Equator, the plane of the satellite's orbit is the same as the Earth's equatorial plane, and the satellite's orbital inclination is 0°. The general case for a circular orbit is that it is tilted, spending half an orbit over the northern hemisphere and half over the southern. If the orbit swung between 20° north latitude and 20° south latitude, then its orbital inclination would be 20°. Orbits The inclination is one of the six orbital elements describing the shape and orientation of a celestial orbit. It is the angle between the orbital plane and the plane of reference, normally stated in degrees. For a satellite orbiting a planet, the plane of reference is usually the plane containing the planet's equator. For pla ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Apsis
An apsis (; ) is the farthest or nearest point in the orbit of a planetary body about its primary body. For example, the apsides of the Earth are called the aphelion and perihelion. General description There are two apsides in any elliptic orbit. The name for each apsis is created from the prefixes ''ap-'', ''apo-'' (), or ''peri-'' (), each referring to the farthest and closest point to the primary body the affixing necessary suffix that describes the primary body in the orbit. In this case, the suffix for Earth is ''-gee'', so the apsides' names are ''apogee'' and ''perigee''. For the Sun, its suffix is ''-helion'', so the names are ''aphelion'' and ''perihelion''. According to Newton's laws of motion, all periodic orbits are ellipses. The barycenter of the two bodies may lie well within the bigger body—e.g., the Earth–Moon barycenter is about 75% of the way from Earth's center to its surface. If, compared to the larger mass, the smaller mass is negligible (e.g., f ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Geostationary Transfer Orbit
A geosynchronous transfer orbit or geostationary transfer orbit (GTO) is a type of geocentric orbit. Satellite, Satellites that are destined for geosynchronous orbit, geosynchronous (GSO) or geostationary orbit (GEO) are (almost) always put into a GTO as an intermediate step for reaching their final orbit. A GTO is highly Elliptic orbit, elliptic. Its perigee (closest point to Earth) is typically as high as low Earth orbit (LEO), while its apogee (furthest point from Earth) is as high as geostationary (or equally, a geosynchronous) orbit. That makes it a Hohmann transfer orbit between LEO and GSO. Larson, Wiley J. and James R. Wertz, eds. Space Mission Design and Analysis, 2nd Edition. Published jointly by Microcosm, Inc. (Torrance, CA) and Kluwer Academic Publishers (Dordrecht/Boston/London). 1991. While some geostationary orbit, GEO satellites are launched direct to that orbit, often the launch vehicle lacks the power to put both the rocket and the satellite into that orbit. I ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
United States Armed Forces
The United States Armed Forces are the military forces of the United States. The armed forces consists of six service branches: the Army, Marine Corps, Navy, Air Force, Space Force, and Coast Guard. The president of the United States is the commander-in-chief of the armed forces and forms military policy with the Department of Defense (DoD) and Department of Homeland Security (DHS), both federal executive departments, acting as the principal organs by which military policy is carried out. All six armed services are among the eight uniformed services of the United States. From their inception during the American Revolutionary War, the U.S. Armed Forces have played a decisive role in the history of the United States. They helped forge a sense of national unity and identity through victories in the First Barbary War and the Second Barbary War. They played a critical role in the American Civil War, keeping the Confederacy from seceding from the republic and preserving the uni ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Extremely High Frequency
Extremely high frequency (EHF) is the International Telecommunication Union (ITU) designation for the band of radio frequencies in the electromagnetic spectrum from 30 to 300 gigahertz (GHz). It lies between the super high frequency band and the far infrared band, the lower part of which is the terahertz band. Radio waves in this band have wavelengths from ten to one millimetre, so it is also called the millimetre band and radiation in this band is called millimetre waves, sometimes abbreviated MMW or mmWave. Millimetre-length electromagnetic waves were first investigated by Indian physicist Jagadish Chandra Bose, who generated waves of frequency up to 60GHz during experiments in 18941896. Compared to lower bands, radio waves in this band have high atmospheric attenuation: they are absorbed by the gases in the atmosphere. Absorption increases with frequency until at the top end of the band the waves are attenuated to zero within a few meters. Absorption by humidity in the atmosp ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
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