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Explorer S-56 (satellite)
Explorer S-56 was a NASA satellite launched on 4 December 1960, at 21:14 GMT as part of the Explorer program. The satellite was composed of a diameter inflatable sphere, and was intended to study the density of the upper atmosphere. The Scout X-1 rocket used to launch Explorer S-56 failed in flight, and the satellite never reached orbit. Spacecraft design The spacecraft consisted of alternating layers of aluminium foil and Mylar polyester film. Uniformly distributed over the aluminium surface were -diameter dots of white paint for thermal control. The sphere was packed in a tube in diameter and long and mounted in the nose of the fourth stage of its Scout X-1 launch vehicle. Upon separation of the fourth stage, the sphere will be inflated by a nitrogen gas bottle, and a separation spring will eject it out into its own orbit. The two hemispheres of aluminium foil will be separated with a gap of Mylar at the spacecraft's equator and will serve as the antenna. A 136 MHz, 15 ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Explorer 9
Explorer 9, known as S-56A before launch, was a NASA satellite which was launched in February 1961 to study the density and composition of the upper thermosphere and lower exosphere. It was a reflight of the failed Explorer S-56 mission, and consisted of a , balloon which was deployed into a medium Earth orbit. The mission was conducted by NASA's Langley Research Center. Spacecraft The spacecraft consisted of alternating layers of aluminium foil and Mylar polyester film. Uniformly distributed over the aluminium surface were -diameter dots of white paint for thermal control. The sphere was packed in a tube in diameter and long and mounted in the nose of the fourth stage of its Scout X-1 launch vehicle. Experiment Satellite Drag Atmospheric Density Because of its symmetrical shape, Explorer 9 was selected for use in determining upper atmospheric densities as a function of altitude, latitude, season, and solar activity. Density values near perigee were deduced from se ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Explorer 8
Explorer 8 was a NASA research satellite launched on 3 November 1960. It was intended to study the temporal and spatial distribution of the electron density, the electron temperature, the ion concentration, the ion mass, the micrometeorite distribution, and the micrometeorite mass in the ionosphere at altitudes between and and their variation from full sunlit conditions to full shadow, or nighttime, conditions. Spacecraft Explorer 8 was a mercury-battery-powered satellote. The payload was in the form of two truncated cones with the bases attached to a cylindrical equator. The outer shell was aluminum and had a diameter of and a height of . The 108.00 MHz transmitter had 100 mW average power, and it functioned for the life of the battery pack (54 days). The data system included telemetry consisting of continuous operation with real-time transmission. To avoid the possibility of effects on the experiments by asymmetrical charging on solar cell surfaces, solar cells were n ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Density Of Air
The density of air or atmospheric density, denoted '' ρ'', is the mass per unit volume of Earth's atmosphere. Air density, like air pressure, decreases with increasing altitude. It also changes with variation in atmospheric pressure, temperature and humidity. At 101.325 kPa (abs) and 20 °C (68 °F), air has a density of approximately , according to the International Standard Atmosphere (ISA). At 101.325kPa (abs) and , air has a density of approximately , which is about that of water, according to the International Standard Atmosphere (ISA). Pure liquid water is . Air density is a property used in many branches of science, engineering, and industry, including aeronautics;Olson, Wayne M. (2000) AFFTC-TIH-99-01, Aircraft Performance FlightICAO, Manual of the ICAO Standard Atmosphere (extended to 80 kilometres (262 500 feet)), Doc 7488-CD, Third Edition, 1993, .Grigorie, T.L., Dinca, L., Corcau J-I. and Grigorie, O. (2010) Aircrafts' Altitude Measurement Using Pressure Information:Ba ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Atlantic Ocean
The Atlantic Ocean is the second-largest of the world's five oceans, with an area of about . It covers approximately 20% of Earth's surface and about 29% of its water surface area. It is known to separate the " Old World" of Africa, Europe and Asia from the "New World" of the Americas in the European perception of the World. The Atlantic Ocean occupies an elongated, S-shaped basin extending longitudinally between Europe and Africa to the east, and North and South America to the west. As one component of the interconnected World Ocean, it is connected in the north to the Arctic Ocean, to the Pacific Ocean in the southwest, the Indian Ocean in the southeast, and the Southern Ocean in the south (other definitions describe the Atlantic as extending southward to Antarctica). The Atlantic Ocean is divided in two parts, by the Equatorial Counter Current, with the North(ern) Atlantic Ocean and the South(ern) Atlantic Ocean split at about 8°N. Scientific explorations of the A ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Wallops Island
Wallops Island is a island in Accomack County, Virginia, part of the Virginia Barrier Islands that stretch along the eastern seaboard of the United States of America. It is just south of Chincoteague Island, a popular tourist destination. Wallops Island proper, originally known as Kegotank Island, was granted to John Wallop by the Crown on April 29, 1692. Ownership was divided through the years, until the Commonwealth of Virginia seized the property in 1876 and 1877 in lieu of unpaid taxes. From 1877, ownership was again divided and subdivided until 1889, when it was held by various trustees for the Wallops Island Club. The Club was incorporated and assumed ownership in 1933 as the Wallops Island Association, Inc. Association members and their families spent the summers fishing and swimming on the island. The Association grazed sheep, cattle, and ponies on the area until the mid-1940s. In 1947, the U.S. Navy began using the upper two-thirds of the island on a lease-rental bas ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Solid-propellant Rocket
A solid-propellant rocket or solid rocket is a rocket with a rocket engine that uses Rocket propellant#Solid chemical propellants, solid propellants (fuel/oxidizer). The earliest rockets were solid-fuel rockets powered by gunpowder; they were used in warfare by the Mamluk Sultanate, Arabs, Dynasties in Chinese history, Chinese, Ilkhanate, Persians, Mongol Empire, Mongols, and Delhi Sultanate, 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 ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Schmidt Camera
A Schmidt camera, also referred to as the Schmidt telescope, is a catadioptric astrophotographic telescope designed to provide wide fields of view with limited aberrations. The design was invented by Bernhard Schmidt in 1930. Some notable examples are the Samuel Oschin telescope (formerly Palomar Schmidt), the UK Schmidt Telescope and the ESO Schmidt; these provided the major source of all-sky photographic imaging from 1950 until 2000, when electronic detectors took over. A recent example is the Kepler space telescope exoplanet finder. Other related designs are the Wright camera and Lurie–Houghton telescope. Invention and design The Schmidt camera was invented by German–Estonian optician Bernhard Schmidt in 1930. Its optical components are an easy-to-make spherical primary mirror, and an aspherical correcting lens, known as a Schmidt corrector plate, located at the center of curvature of the primary mirror. The film or other detector is placed inside the camera, at the ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Watt
The watt (symbol: W) is the unit of power or radiant flux in the International System of Units (SI), equal to 1 joule per second or 1 kg⋅m2⋅s−3. It is used to quantify the rate of energy transfer. The watt is named after James Watt (1736–1819), an 18th-century Scottish inventor, mechanical engineer, and chemist who improved the Newcomen engine with his own steam engine in 1776. Watt's invention was fundamental for the Industrial Revolution. Overview When an object's velocity is held constant at one metre per second against a constant opposing force of one newton, the rate at which work is done is one watt. : \mathrm In terms of electromagnetism, one watt is the rate at which electrical work is performed when a current of one ampere (A) flows across an electrical potential difference of one volt (V), meaning the watt is equivalent to the volt-ampere (the latter unit, however, is used for a different quantity from the real power of an electrical circuit). : ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Hertz
The hertz (symbol: Hz) is the unit of frequency in the International System of Units (SI), equivalent to one event (or cycle) per second. The hertz is an SI derived unit whose expression in terms of SI base units is s−1, meaning that one hertz is the reciprocal of one second. It is named after Heinrich Rudolf Hertz (1857–1894), the first person to provide conclusive proof of the existence of electromagnetic waves. Hertz are commonly expressed in multiples: kilohertz (kHz), megahertz (MHz), gigahertz (GHz), terahertz (THz). Some of the unit's most common uses are in the description of periodic waveforms and musical tones, particularly those used in radio- and audio-related applications. It is also used to describe the clock speeds at which computers and other electronics are driven. The units are sometimes also used as a representation of the energy of a photon, via the Planck relation ''E'' = ''hν'', where ''E'' is the photon's energy, ''ν'' is its freq ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Polyester
Polyester is a category of polymers that contain the ester functional group in every repeat unit of their main chain. As a specific material, it most commonly refers to a type called polyethylene terephthalate (PET). Polyesters include naturally occurring chemicals, such as in plants and insects, as well as synthetics such as polybutyrate. Natural polyesters and a few synthetic ones are biodegradable, but most synthetic polyesters are not. Synthetic polyesters are used extensively in clothing. Polyester fibers are sometimes spun together with natural fibers to produce a cloth with blended properties. Cotton-polyester blends can be strong, wrinkle- and tear-resistant, and reduce shrinking. Synthetic fibers using polyester have high water, wind and environmental resistance compared to plant-derived fibers. They are less Fireproofing, fire-resistant and can melt when ignited. Liquid crystalline polyesters are among the first industrially used liquid crystal polymers. They are use ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
BoPET
BoPET (biaxially-oriented polyethylene terephthalate) is a polyester film made from stretched polyethylene terephthalate (PET) and is used for its high tensile strength, chemical and dimensional stability, transparency, reflectivity, gas and aroma barrier properties, and electrical insulation. A variety of companies manufacture boPET and other polyester films under different brand names. In the UK and US, the best-known trade names are Mylar, Melinex, and Hostaphan. History BoPET film was developed in the mid-1950s,Izard, Emmette Farr"Production of polyethylene terephthalate" U.S. patent no. 2,534,028 (filed: 1948 May 13; issued: 1950 December 12). originally by DuPont, Imperial Chemical Industries (ICI), and Hoechst. In 1955 Eastman Kodak used Mylar as a support for photographic film and called it "ESTAR Base". The very thin and tough film allowed reels to be exposed on long-range U-2 reconnaissance flights. In 1964, NASA launched Echo II, a diameter balloon constructed ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Aluminium Foil
Aluminium foil (or aluminum foil in North American English; often informally called tin foil) is aluminium prepared in thin metal leaves with a thickness less than ; thinner gauges down to are also commonly used. Standard household foil is typically thick, and heavy duty household foil is typically . The foil is pliable, and can be readily bent or wrapped around objects. Thin foils are fragile and are sometimes laminated with other materials such as plastics or paper to make them stronger and more useful. Annual production of aluminium foil was approximately in Europe and in the U.S."Foil & Packaging" . The Aluminum Association (USA). in 2003. Approximately 75% of aluminium foil is used for |
