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PSSC-2
PSSC-2, or Pico-Satellite Solar Cell Testbed 2, also known as PSSC-Testbed 2, is a miniaturised satellite which was operated by the United States Air Force as part of a technology demonstration programme. It was the last satellite to be deployed from a Space Shuttle. Overview PSSC-2 was launched aboard on its final mission, STS-135. The launch took place from Launch Complex 39A at the Kennedy Space Center, at 15:29 UTC on 8 July 2011. PSSC-2, along with a deployment mechanism, was carried to orbit in the payload bay of the Shuttle, attached to the right wall behind the Orbiter Docking System. It remained attached during ''Atlantis''' visit to the International Space Station, and was originally scheduled to be deployed at 07:11 UTC on 19 July, the day after undocking. With the extension of the STS-135 mission, undocking, and hence deployment, was delayed by one day. PSSC-2 is the second PSSC satellite, following PSSC-1 which was deployed from during STS-126 in 2008. It carries ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
STS-135 Picosat Deployment
STS-135 ( ISS assembly flight ULF7) was the 135th and final mission of the American Space Shuttle program. It used the orbiter '' Atlantis'' and hardware originally processed for the STS-335 contingency mission, which was not flown. STS-135 launched on 8 July 2011, and landed on 21 July 2011, following a one-day mission extension. The four-person crew was the smallest of any shuttle mission since STS-6 in April 1983. The mission's primary cargo was the Multi-Purpose Logistics Module (MPLM) ''Raffaello'' and a Lightweight Multi-Purpose Carrier (LMC), which were delivered to the International Space Station (ISS). The flight of ''Raffaello'' marked the only time that ''Atlantis'' carried an MPLM. Although the mission was authorized, it initially had no appropriation in the NASA budget, raising questions about whether the mission would fly. On 20 January 2011, program managers changed STS-335 to STS-135 on the flight manifest. This allowed for training and other mission specific ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
STS-135
STS-135 ( ISS assembly flight ULF7) was the 135th and final mission of the American Space Shuttle program. It used the orbiter ''Atlantis'' and hardware originally processed for the STS-335 contingency mission, which was not flown. STS-135 launched on 8 July 2011, and landed on 21 July 2011, following a one-day mission extension. The four-person crew was the smallest of any shuttle mission since STS-6 in April 1983. The mission's primary cargo was the Multi-Purpose Logistics Module (MPLM) ''Raffaello'' and a Lightweight Multi-Purpose Carrier (LMC), which were delivered to the International Space Station (ISS). The flight of ''Raffaello'' marked the only time that ''Atlantis'' carried an MPLM. Although the mission was authorized, it initially had no appropriation in the NASA budget, raising questions about whether the mission would fly. On 20 January 2011, program managers changed STS-335 to STS-135 on the flight manifest. This allowed for training and other mission specific pr ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
STS-126
STS-126 was the one hundred and twenty-fourth NASA Space Shuttle mission, and twenty-second orbital flight of the ''Space Shuttle Endeavour'' (OV-105) to the International Space Station (ISS). The purpose of the mission, referred to as ULF2 by the ISS program, was to deliver equipment and supplies to the station, to service the Solar Alpha Rotary Joints (SARJ), and repair the problem in the starboard SARJ that had limited its use since STS-120. STS-126 launched on 15 November 2008 at 00:55:39 UTC from Launch Pad 39A (LC-39A) at NASA's Kennedy Space Center (KSC) with no delays or issues. ''Endeavour'' successfully docked with the station on 16 November 2008. After spending 15 days, 20 hours, 30 minutes, and 30 seconds docked to the station, during which the crew performed four spacewalks, and transferred cargo, the orbiter undocked on 28 November 2008. Due to poor weather at Kennedy Space Center, ''Endeavour'' landed at Edwards Air Force Base on 30 November 2008 at 21:25:09 U ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Solid Rocket Motor
A solid-propellant rocket or solid rocket is a rocket with a rocket engine that uses solid propellants (fuel/oxidizer). The earliest rockets were solid-fuel rockets powered by gunpowder; they were used in warfare by the Arabs, Chinese, Persians, Mongols, and Indians as early as the 13th century. All rockets used some form of solid or powdered propellant up until the 20th century, when liquid-propellant rockets offered more efficient and controllable alternatives. Solid rockets are still used today in military armaments worldwide, model rockets, solid rocket boosters and on larger applications for their simplicity and reliability. Since solid-fuel rockets can remain in storage for an extended period without much propellant degradation and because they almost always launch reliably, they have been frequently used in military applications such as missiles. The lower performance of solid propellants (as compared to liquids) does not favor their use as primary propulsion in modern ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Ammonium Perchlorate
Ammonium perchlorate ("AP") is an inorganic compound with the formula NH4 ClO4. It is a colorless or white solid that is soluble in water. It is a powerful oxidizer. Combined with a fuel, it can be used as a rocket propellant called ammonium perchlorate composite propellant. Its instability has involved it in a number of accidents, such as the PEPCON disaster. Production Ammonium perchlorate (AP) is produced by reaction between ammonia and perchloric acid. This process is the main outlet for the industrial production of perchloric acid. The salt also can be produced by salt metathesis reaction of ammonium salts with sodium perchlorate. This process exploits the relatively low solubility of NH4ClO4, which is about 10% of that for sodium perchlorate.Helmut Vogt, Jan Balej, John E. Bennett, Peter Wintzer, Saeed Akbar Sheikh, Patrizio Gallone "Chlorine Oxides and Chlorine Oxygen Acids" in Ullmann's Encyclopedia of Industrial Chemistry 2002, Wiley-VCH. AP crystallises as colorle ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Adaptive Communication
Adaptive communications can mean any communications system, or portion thereof, that automatically uses feedback information obtained from the system itself or from the signals carried by the system to modify dynamically one or more of the system operational parameters to improve system performance or to resist degradation. The modification of a system parameter may be discrete, as in hard-switched diversity reception, or may be continuous, as in a predetection combining algorithm. See also *Automatic Link Establishment * Channel use *CALM M5 CALM M5 is the ISO 21215 standard that incorporates WAVE (WAVE PHY/MAC is IEEE 802.11p standard) and adds the following features: * Global (European) 5 GHz spectrum * Regulatory domain (border) management * Directivity and EMC control * Regiona ... Telecommunications techniques {{telecomm-stub ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Ionosphere
The ionosphere () is the ionized part of the upper atmosphere of Earth, from about to above sea level, a region that includes the thermosphere and parts of the mesosphere and exosphere. The ionosphere is ionized by solar radiation. It plays an important role in atmospheric electricity and forms the inner edge of the magnetosphere. It has practical importance because, among other functions, it influences radio propagation to distant places on Earth. History of discovery As early as 1839, the German mathematician and physicist Carl Friedrich Gauss postulated that an electrically conducting region of the atmosphere could account for observed variations of Earth's magnetic field. Sixty years later, Guglielmo Marconi received the first trans-Atlantic radio signal on December 12, 1901, in St. John's, Newfoundland (now in Canada) using a kite-supported antenna for reception. The transmitting station in Poldhu, Cornwall, used a spark-gap transmitter to produce a signal with a freq ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Global Positioning System
The Global Positioning System (GPS), originally Navstar GPS, is a satellite-based radionavigation system owned by the United States government and operated by the United States Space Force. It is one of the global navigation satellite systems (GNSS) that provides geolocation and time information to a GPS receiver anywhere on or near the Earth where there is an unobstructed line of sight to four or more GPS satellites. It does not require the user to transmit any data, and operates independently of any telephonic or Internet reception, though these technologies can enhance the usefulness of the GPS positioning information. It provides critical positioning capabilities to military, civil, and commercial users around the world. Although the United States government created, controls and maintains the GPS system, it is freely accessible to anyone with a GPS receiver. The GPS project was started by the U.S. Department of Defense in 1973. The first prototype spacecraft was lau ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Occulting
An occultation is an event that occurs when one object is hidden from the observer by another object that passes between them. The term is often used in astronomy, but can also refer to any situation in which an object in the foreground blocks from view (occults) an object in the background. In this general sense, occultation applies to the visual scene observed from low-flying aircraft (or computer-generated imagery) when foreground objects obscure distant objects dynamically, as the scene changes over time. If the closer body does not entirely conceal the farther one, the event is called a ''Transit (astronomy), transit''. Both transit and occultation may be referred to generally as ''occlusion''; and if a shadow is cast onto the observer, it is called an eclipse. The symbol for an occultation, and especially a solar eclipse, is file:Occultation symbol.svg (U+1F775 🝵). Occultations by the Moon The term occultation is most frequently used to describe lunar occultatio ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
United States Air Force
The United States Air Force (USAF) is the air service branch of the United States Armed Forces, and is one of the eight uniformed services of the United States. Originally created on 1 August 1907, as a part of the United States Army Signal Corps, the USAF was established as a separate branch of the United States Armed Forces in 1947 with the enactment of the National Security Act of 1947. It is the second youngest branch of the United States Armed Forces and the fourth in order of precedence. The United States Air Force articulates its core missions as air supremacy, global integrated intelligence, surveillance and reconnaissance, rapid global mobility, global strike, and command and control. The United States Air Force is a military service branch organized within the Department of the Air Force, one of the three military departments of the Department of Defense. The Air Force through the Department of the Air Force is headed by the civilian Secretary of the Air Force ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
