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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 9 ... [...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 ... [...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 developed by Lockheed Martin and has been operated by United Launch Alliance (ULA) since 2006. Primarily used to launch payloads for the United States Department of Defense, NASA, and commercial customers, Atlas V is the longest-serving active rocket in the United States. Each Atlas V vehicle consists of two main stages. The First stage (rocketry), first stage is powered by a single Russian-made RD-180 engine that burns kerosene and liquid oxygen. The Centaur (rocket stage), Centaur upper stage uses one or two American-made Aerojet Rocketdyne RL10 engines that burn liquid hydrogen and liquid oxygen. Strap-on booster, Strap-on Solid rocket booster, solid rocket boosters (SRBs) are used in several configurations. Originally equipped with AJ-60A SRBs, the vehicle switched to Graphite-Epoxy Motor (GEM 63) boosters beginning in November 2020, except for ... [...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 satellite in a par ... [...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 C ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Cape Canaveral Space Launch Complex 41
Space Launch Complex 41 (SLC-41), sometimes referred to as "Slick Forty-one," is one of two launch sites at the Integrate-Transfer-Launch Complex in Cape Canaveral Space Force Station, Florida. Originally built as Launch Complex 41 (LC-41), it and the neighboring Cape Canaveral Space Launch Complex 40, Space Launch Complex 40 were designed for the United States Air Force's Titan III rocket program, where it launched the Titan IIIC in the 1960s and the Titan IIIE in the 1970s. In the 1990s, the Air Force and Martin Marietta upgraded the pad for use by the Titan III's successor, the Titan IV. During the early 2000s, SLC-41 underwent modifications by Lockheed Martin in order to support the launch operations of the Atlas V. It was later transferred to United Launch Alliance (ULA)—a joint venture between Lockheed Martin and Boeing—who continues to use the pad today for launches of the Atlas V and its successor, Vulcan Centaur. History Titan IIIC and IIIE (1965–1977) Launch Compl ... [...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 spaceflight, 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 4179 Toutatis#Exploration, first successful asteroid exploration mission, and the landing of NASA's Mars Science Laboratory, ''Curiosity'' rover on Mars. The Vega (rocket), Vega and Unha, 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 1 ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Coordinated Universal Time
Coordinated Universal Time (UTC) is the primary time standard globally used to regulate clocks and time. It establishes a reference for the current time, forming the basis for civil time and time zones. UTC facilitates international communication, navigation, scientific research, and commerce. UTC has been widely embraced by most countries and is the effective successor to Greenwich Mean Time (GMT) in everyday usage and common applications. In specialised domains such as scientific research, navigation, and timekeeping, other standards such as Universal Time, UT1 and International Atomic Time (TAI) are also used alongside UTC. UTC is based on TAI (International Atomic Time, abbreviated from its French name, ''temps atomique international''), which is a weighted average of hundreds of atomic clocks worldwide. UTC is within about one second of mean solar time at 0° longitude, the currently used prime meridian, and is not adjusted for daylight saving time. The coordination of t ... [...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 only five were operational after launch; 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 ... [...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. The line of apsides (also called apse line, or major axis of the orbit) is the line connecting the two extreme values. Apsides pertaining to orbits around different bodies have distinct names to differentiate themselves from other apsides. Apsides pertaining to geocentric orbits, orbits around the Earth, are at the farthest point called the ''apogee'', and at the nearest point the ''perigee'', like with orbits of satellites and the Moon around Earth. Apsides pertaining to orbits around the Sun are named ''aphelion'' for the farthest and ''perihelion'' for the nearest point in a heliocentric orbit. Earth's two apsides are the farthest point, ''aphelion'', and the nearest point, ''perihelion'', of its orbit around the host Sun. The terms ''aphelion'' and ''perihelion'' apply in the same way to the orbits of Jupiter and the other planets, the comets, and the asteroids of t ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Geostationary Transfer Orbit
In space mission design, a geostationary transfer orbit (GTO) or geosynchronous transfer orbit is a highly elliptical type of geocentric orbit, usually with a perigee as low as low Earth orbit (LEO) and an apogee as high as geostationary orbit (GEO). Satellites that are destined for geosynchronous orbit (GSO) or GEO are often put into a GTO as an intermediate step for reaching their final orbit. 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. Manufacturers of launch vehicles often advertise the amount of payload the vehicle can put into GTO. Background Geostationary and geosynchronous orbits are very desirable for many communication and Earth observation satellites. However, the delta-v, and therefore financial, cost to send a spacecraft to such orbits is very high due to their high orbital radius. A GTO is an intermedia ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
United States Armed Forces
The United States Armed Forces are the Military, military forces of the United States. U.S. United States Code, federal law names six armed forces: the United States Army, Army, United States Marine Corps, Marine Corps, United States Navy, Navy, United States Air Force, Air Force, United States Space Force, Space Force, and the United States Coast Guard, Coast Guard. Since 1949, all of the armed forces, except the Coast Guard, have been permanently part of the United States Department of Defense. They form six of the eight uniformed services of the United States. Each of the different military services is assigned a role and domain. The Army conducts land operations. The Navy and Marine Corps conduct maritime operations, the Marine Corps specializing in amphibious and maritime littoral operations primarily for supporting the Navy. The Air Force conducts air operations. The Space Force conducts space operations. The Coast Guard is unique in that it specializes in maritime opera ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
