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Artist's impression of a Milstar Block I spacecraft
|Manufacturer|| Lockheed Martin (prime)|
Boeing (formerly Hughes)
|Country of origin||United States|
|Operator||U.S. Air Force|
|Bus|| Milstar Block I |
Milstar Block II
|Design life||10 years|
|Launch mass||4,500 kilograms (9,900 lb)|
|Status||Out of production|
|Operational||5[ citation needed ]|
|First launch||USA-99, 1994-02-07|
|Last launch||USA-169, 2003-04-08|
Milstar (Military Strategic and Tactical Relay) [ not verified in body ] Six spacecraft were launched between 1994 and 2003, of which five are currently operational;[ not verified in body ] the third launch failed, both damaging the satellite and leaving it in an unusable orbit.is a constellation of military communications satellites in geostationary orbit, which are operated by the United States Air Force, and provide secure and jam-resistant worldwide communications to meet the requirements of the Armed Forces of the United States.
A satellite constellation is a group of artificial satellites working in concert. Such a constellation can be considered to be a number of satellites with coordinated ground coverage, operating together under shared control, synchronized so that they overlap well in coverage, the period in which a satellite or other spacecraft is visible above the local horizon.
A military satellite is an artificial satellite used for a military purpose. The most common missions are intelligence gathering, navigation and military communications.
A geostationary orbit, often referred to as a geosynchronous equatorial orbit (GEO), is a circular geosynchronous orbit 35,786 km (22,236 mi) above Earth's equator and following the direction of Earth's rotation. An object in such an orbit appears motionless, at a fixed position in the sky, to ground observers. Communications satellites and weather satellites are often placed in geostationary orbits, so that the satellite antennae that communicate with them do not have to rotate to track them, but can be pointed permanently at the position in the sky where the satellites are located. Using this characteristic, ocean-color monitoring satellites with visible and near-infrared light sensors can also be operated in geostationary orbit in order to monitor sensitive changes of ocean environments.
Milstar Block I spacecraft, or Milstar Developmental Flight Satellite (DFS)-1 and -2, were designed with a Low Data Rate (LDR) payload in the +X 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 -X wing. The DFS-1 satellite was launched on 7 February 1994 aboard the first Titan IV(401)A rocket, but with the classified -X wing payload deactivated. It was followed by the DFS-2 spacecraft on 7 November 1995. DFS-2 was similar to DFS-1, but the classified payload was replaced by ballast in the form of a precision machined aluminum block to maintain the weight and balance characteristics of the satellite. Both Block I satellites (USA-99 and USA-115) are still operational as of August 2016, over 20 years since they were launched.
The Titan IV family of rockets were used by the U.S. Air Force. They were launched from Cape Canaveral Air Force Station, Florida, and Vandenberg Air Force Base, California. At the time of its introduction, the Titan IV was the "largest unmanned space booster used by the Air Force."
Ballast is material that is used to provide stability to a vehicle or structure. Ballast, other than cargo, may be placed in a vehicle, often a ship or the gondola of a balloon or airship, to provide stability. A compartment within a boat, ship, submarine, or other floating structure that holds water is called a ballast tank. Water should move in and out from the ballast tank to balance the ship. In a vessel that travels on the water, the ballast will remain below the water level, to counteract the effects of weight above the water level. The ballast may be redistributed in the vessel or disposed of altogether to change its effects on the movement of the vessel.
The four later satellites were Block II spacecraft, which featured an additional medium data-rate payload. The first Block II satellite (DFS-3m, a hybrid mix of largely Block I support systems and LDR payload and a MDR (Medium Data Rate) Block II payload) was launched on 30 April 1999, using a Titan IV(401)B rocket. Due to a database error affecting the attitude control system of the Centaur upper stage of its carrier rocket, it was placed into a lower orbit than had been planned, and damaged by deployment at excessive rates. It could not be raised into its operational orbit due to fuel limitations. Its orbit was raised as much as possible to increase the expected lifetime and then it was permanently turned off after 10 days. It was the third consecutive, and last, failure of a Titan IV rocket. The remaining three satellites (DFS-4, -5, and -6) were launched on 27 February 2001, 15 January 2002, and 8 April 2003.
The Centaur is a family of rocket propelled upper stages currently produced by U.S. launch service provider United Launch Alliance. The 3.8 m diameter Common Centaur/Centaur III is the upper stage of the Atlas V launch vehicle, and the 5.4 m Centaur V is being developed as the upper stage of ULA's new Vulcan rocket.
The Milstar system consists of three segments; the space segment which consists of the six satellites, ground terminals and users, and stations to command and control the satellites. The Military Satellite Communications Systems Wing (MCSW) division of the United States Air Force Space Command Space and Missile Systems Center, located at Los Angeles AFB was responsible for development and acquisition of the Milstar space and mission control segments. The Electronic Systems Center at Hanscom AFB is responsible for the US Air Force portion of the terminal segment development and acquisition. The 4th Space Operations Squadron at Schriever AFB and the 148th Space Operations Squadron at Vandenberg AFB are responsible for providing real-time satellite control and communications payload management.
The Military Satellite Communications Systems Wing (MCSW) is a United States Air Force organization headquartered at Los Angeles Air Force Base, California. It is one of several wings and other units that make up the Air Force Space Command's Space and Missile Systems Center (SMC).
The Space and Missile Systems Center (SMC) is a part of Air Force Space Command of the United States Air Force, located at Los Angeles Air Force Base in El Segundo, Los Angeles County, California. SMC is the Air Force's product center for the development and acquisition of space and missile systems.
Electronic Systems Center was a product center of Air Force Materiel Command (AFMC) headquartered at Hanscom Air Force Base, Massachusetts. Its mission was to develop and acquire command and control, communications, computer, and intelligence systems. ESC consisted of professional teams specializing in engineering, computer science, and business management. The teams supervised the design, development, testing, production, and deployment of command and control systems. Two of ESC's most well-known developments were the Airborne Warning and Control System (AWACS), developed in the 1970s, and the Joint Surveillance Target Attack Radar System (JointSTARS), developed in the 1980s.
In August 2010 control of the Milstar system was transferred to the Advanced Extremely High Frequency program, in preparation for the launch of the first AEHF satellite, USA-214. Advanced Extremely High Frequency satellites are intended to replace Milstar.[ citation needed ]
Advanced Extremely High Frequency (AEHF) is a series of communications satellites operated by the United States Air Force Space Command. They will be used to relay secure communications for the Armed Forces of the United States, the British Armed Forces, the Canadian Armed Forces and the Royal Netherlands Armed Forces. The system will consist of six satellites in geostationary orbits, four of which have been launched. AEHF is backward compatible with, and will replace, the older Milstar system and will operate at 44 GHz Uplink and 20 GHz Downlink. AEHF systems is a joint service communications system that will provide survivable, global, secure, protected, and jam-resistant communications for high-priority military ground, sea and air assets. It is the follow-on to the Milstar system. AEHF systems' uplinks and crosslinks will operate in the extremely high frequency (EHF) range and downlinks in the super high frequency (SHF) range.
USA-214, known before launch as Advanced Extremely High Frequency 1 or AEHF SV-1, is a military communications satellite operated by the United States Air Force. It is the first of four spacecraft to be launched as part of the Advanced Extremely High Frequency program, which will replace the earlier Milstar system.
Milstar satellites provide secure, jam resistant, worldwide communications to meet the requirements of the United States military. They were built by Lockheed Martin Missiles and Space Corporation, at a cost of US$800 million each. Each satellite has a design life of 10 years. Six were built, of which five reached their operational geostationary orbits, and remain in service. Launches were made using Titan IV rockets with Centaur upper stages, and all six occurred from Space Launch Complex 40 at the Cape Canaveral Air Force Station. The satellites are designed to provide communications which are hard to detect and intercept, and to be survivable in the event of nuclear warfare.
Lockheed Martin Corporation is an American global aerospace, defense, security and advanced technologies company with worldwide interests. It was formed by the merger of Lockheed Corporation with Martin Marietta in March 1995, and Loral Federal Systems in 1996. It is headquartered in North Bethesda, Maryland, in the Washington, DC, area. Lockheed Martin employs approximately 100,000 people worldwide as of December 2017.
Cape Canaveral Air Force Station Space Launch Complex 40 (SLC-40), previously Launch Complex 40 (LC-40) is a launch pad for rockets located at the north end of Cape Canaveral, Florida.
Nuclear warfare is a military conflict or political strategy in which nuclear weaponry is used to inflict damage on the enemy. Nuclear weapons are weapons of mass destruction; in contrast to conventional warfare, nuclear warfare can produce destruction in a much shorter time and can have a long-lasting radiological warfare result. A major nuclear exchange would have long-term effects, primarily from the fallout released, and could also lead to a "nuclear winter" that could last for decades, centuries, or even millennia after the initial attack. Some analysts dismiss the nuclear winter hypothesis, and calculate that even with nuclear weapon stockpiles at Cold War highs, although there would be billions of casualties, billions more rural people would nevertheless survive. However, others have argued that secondary effects of a nuclear holocaust, such as nuclear famine and societal collapse, would cause almost every human on Earth to starve to death.
The spacecraft have a mass of 4,500 kilograms (9,900 lb), and are equipped with solar panels which generate eight kilowatts of electric power to power its transponders. Both Block I and Block II satellites provide low data-rate communications at bandwidths between 75 bit/s and 2,400 bit/s, whilst the Block II spacecraft can also provide medium data-rate communications between 4.8 kbit/s and 1.544 Mbit/s. The satellites' uplinks operate in the Q band, while their downlinks operate within the Ka band. The uplink corresponds to the extremely high frequency band while downlink corresponds to the super high frequency radio band.[ citation needed ]
Each Milstar satellite serves as a switchboard to direct traffic between terminals on the Earth. The satellites process the signals transmitted to them, and can link with other Milstar satellites through crosslinks, to reduce the requirement for ground-controlled switching. The spacecraft are used for encrypted voice, data, teletype, and facsimile communications, which are interoperable between the United States Army, Navy, Air Force, Marine Corps, and Coast Guard.[ citation needed ]
|USA ID||Name||Block||Launch date/time (UTC)||COSPAR ID||Rocket||Remarks|
|USA-99||DFS-1||Block I||1994-02-07, 21:47:01||1994-009A||Titan IV(401)A|
|USA-115||DFS-2||Block I||1995-11-06, 05:15:01||1995-060A||Titan IV(401)A|
|USA-143||DFS-3M||Block I/II hybrid||1999-04-30, 16:30:00||1999-023A||Titan IV(401)B||Launch failure|
|USA-157||DFS-4||Block II||2001-02-27, 21:20||2001-009A||Titan IV(401)B|
|USA-164||DFS-5||Block II||2002-01-16, 00:30:00||2002-001A||Titan IV(401)B|
|USA-169||DFS-6||Block II||2003-04-08, 13:43:00||2003-012A||Titan IV(401)B|
Titan was a family of United States expendable rockets used between 1959 and 2005. A total of 368 rockets of this family were launched, including all the Project Gemini manned flights of the mid-1960s. Titans were part of the US Air Force's intercontinental ballistic missile fleet until 1987, and lifted other American military payloads as well as civilian agency intelligence-gathering satellites. Titans also were used to send highly successful interplanetary scientific probes throughout the Solar System.
The SM-65 Atlas was the first operational intercontinental ballistic missile (ICBM) developed by the United States and the first member of the Atlas rocket family. It was built for the U.S. Air Force by Convair Division of General Dynamics at the Kearny Mesa assembly plant north of San Diego. Atlas became operational as an ICBM in October 1959 and was used as a first stage for satellite launch vehicles for half a century. The Atlas missile's warhead was over 100 times more powerful than the bomb dropped over Nagasaki in 1945.
The RM-81 Agena was an American rocket upper stage and satellite bus which was developed by Lockheed initially for the canceled WS-117L reconnaissance satellite program. Following the split-up of WS-117L into SAMOS and Corona for image intelligence, and MIDAS for early warning, the Agena was later used as an upper stage, and an integrated component, for several programs, including Corona reconnaissance satellites and the Agena Target Vehicle used to demonstrate rendezvous and docking during Project Gemini. It was used as an upper stage on the Atlas, Thor, Thorad and Titan IIIB rockets, and considered for others including the Space Shuttle and Atlas V. A total of 365 Agena rockets were launched between February 28, 1959 and February 1987. Only 33 Agenas carried NASA payloads and the vast majority were for DoD programs.
Air Force Space Command (AFSPC) is a major command of the United States Air Force (USAF), with its headquarters at Peterson Air Force Base, Colorado. AFSPC supports U.S. military operations worldwide through the use of many different types of space operations. AFSPC is subordinate to U.S. Strategic Command (USSTRATCOM). As of 2019 it is the primary space force for the U.S. Armed Forces.
Orbital Sciences Corporation is an American company specializing in the design, manufacture and launch of small- and medium- class space and rocket systems for commercial, military and other government customers. In 2014 Orbital merged with Alliant Techsystems to create a new company called Orbital ATK, Inc., which in turn was purchased by Northrop Grumman in 2018. Orbital Sciences Corporation today is a subsidiary of Northrop Grumman.
Lockheed Martin Space is one of the four major business divisions of Lockheed Martin. It has its headquarters in Denver, Colorado with additional sites in Sunnyvale, California; Santa Cruz, California; Huntsville, Alabama; and elsewhere in the US and UK. 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 Multi-Purpose Crew Vehicle, and the Space Shuttle External Tank.
The Aerospace Corporation is a California nonprofit corporation that operates a federally funded research and development center (FFRDC) headquartered in El Segundo, California. The corporation provides technical guidance and advice on all aspects of space missions to military, civil, and commercial customers. As the FFRDC for national-security space, Aerospace works closely with organizations such as the United States Air Force Space and Missile Systems Center (SMC) and the National Reconnaissance Office (NRO) to provide "objective technical analyses and assessments for space programs that serve the national interest". Although SMC and NRO are the primary customers, Aerospace also performs work for civil agencies as well as international organizations and governments in the national interest.
Before the Project Apollo Moon landing in 1969, NASA began studies of Space Shuttle designs as early as October 1968. The early studies were denoted "Phase A", and in June 1970, "Phase B", which were more detailed and specific. The primary intended use of the Space Shuttle was supporting the future space station, ferrying a minimum crew of four and about 20,000 pounds (9,100 kg) of cargo, and able to be rapidly turned around for future flights.
Space Launch Complex 6 at Vandenberg Air Force Base in California is a launch pad and support area. The site was originally developed for the Titan III and Manned Orbiting Laboratory, which was cancelled before construction of SLC-6 was complete. The complex was later rebuilt to serve as the west coast launch site for the Space Shuttle, but again went unused due to budget, safety and political considerations. The pad was subsequently used for several Athena launches before being modified to support the Delta IV launch vehicle family, which have used the pad since 2006.
The Defense Satellite Communications System (DSCS) 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 Atlantis in 1985 during the STS-51-J flight. As of 23 November 2015, seven DSCS-III satellites were still operational. DSCS operations are currently run by the 4th Space Operations Squadron out of Schriever Air Force Base.
The Wideband Global SATCOM system (WGS) is a high capacity satellite communications system planned for use in partnership by the United States Department of Defense (DoD) and the Australian Department of Defence. The system is composed of the Space Segment satellites, the Terminal Segment users and the Control Segment operators.
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