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Spacecraft Thermal Control
In spacecraft design, the function of the thermal control system (TCS) is to keep all the spacecraft's component systems within acceptable temperature ranges during all mission phases. It must cope with the external environment, which can vary in a wide range as the spacecraft is exposed to the extreme coldness found in the shadows of deep space or to the intense heat found in the unfiltered direct sunlight of outer space. A TCS must also moderate the internal heat generated by the operation of the spacecraft it serves. A TCS can eject heat passively through the simple and natural infrared radiation of the spacecraft itself, or actively through an externally mounted infrared radiation coil. Thermal control is essential to guarantee the optimal performance and success of the mission because if a component is subjected to temperatures which are too high or too low, it could be damaged or its performance could be severely affected. Thermal control is also necessary to keep specific ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
MESSENGER 04pd1465
Messenger, Messengers, The Messenger or The Messengers may refer to: People * Courier, a person or company that delivers messages, packages, or mail * Messenger (surname) * Bicycle messenger, a bicyclist who transports packages through cities * Messenger-at-arms, an officer of the Scottish Court of Session * Messenger of the Court, a court officer responsible for carrying communications and executing other orders * Prophets and messengers in Islam * Muhammad and other prophets in Islam, who were known as Messengers of Allah (God) Science and technology Biology and chemistry * Chemical messenger, such as a hormone or neurotransmitter, a molecule used for cellular signalling * Messenger RNA (mRNA), RNA that carries information from DNA to the ribosome sites of protein synthesis in a cell Electronics and computing *Instant messenger, a tool for online text communication **Facebook Messenger, an instant messaging service by Meta (Facebook) **Microsoft Messenger service, an instant ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Geostationary Orbit
A geostationary orbit, also referred to as a geosynchronous equatorial orbit''Geostationary orbit'' and ''Geosynchronous (equatorial) orbit'' are used somewhat interchangeably in sources. (GEO), is a circular orbit, circular geosynchronous orbit in altitude above Earth's equator, in radius from Earth's center, and following the retrograde and prograde motion, direction of Earth's rotation. An object in such an orbit has an orbital period equal to Earth's rotational period, one sidereal time, sidereal day, and so to ground observers it appears motionless, in a fixed position in the sky. The concept of a geostationary orbit was popularised by the science fiction writer Arthur C. Clarke in the 1940s as a way to revolutionise telecommunications, and the first satellite to be placed in this kind of orbit was launched in 1963. Communications satellites are often placed in a geostationary orbit so that Earth-based satellite dish, satellite antennas do not have to rotate to track t ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Plutonium Dioxide
Plutonium(IV) oxide, or plutonia, is a chemical compound with the chemical formula, formula plutonium, Puoxygen, O2. This high melting-point solid is a principal compound of plutonium. It can vary in color from yellow to olive green, depending on the particle size, temperature and method of production. Structure PuO2 crystallizes in the fluorite motif, with the Pu4+ centers organized in a face-centered cubic array and oxide ions occupying tetrahedral holes. PuO2 owes its utility as a nuclear fuel to the fact that vacancies in the octahedral holes allows room for fission products. In nuclear fission, one atom of plutonium splits into two. The vacancy of the octahedral holes provides room for the new product and allows the PuO2 monolith to retain its structural integrity. At high temperatures PuO2 tends to lose oxygen, becoming sub-stoichiometric PuO2−x, with the introduction of lower valence Pu3+. This continues into the molten liquid state where the local Pu-O coordination numbe ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Cartridge Heater
A cartridge heater is a tube-shaped, heavy-duty, industrial Joule heating element used in the process heating industry, usually custom manufactured to a specific watt density, based on its intended application. Compact designs are capable of reaching a watt density of up to 50W/cm² while some specialty high temperature designs can reach 100w/cm². Applications Cartridge heaters are found useful in many applications, such as: * Seal bars *Torpedo heaters for injection molding * Injection molding manifolds * Mass spectrometry * Rubber molding * Food production * Immersion tank heating * HVAC compressors * Fuel cells * Semiconductors * Medical devices * Sensor measurement devices * Extrusion * Die casting * Hot melt adhesives * Heat staking / hole punch * Plastic welding * Fluid heating * 3D Printers File:Cartridge-heater-cold.jpg, Cold cartridge heater File:Cartridge-heater-hot.jpg, Hot cartridge heater Construction Construction of a cartridge heater may be divided in 7 mai ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Kapton
file:Kaptonpads.jpg, Kapton insulating pads for mounting electronic parts on a heat sink Kapton is a polyimide film used in flexible printed circuits (flexible electronics) and space blankets, which are used on spacecraft, satellites, and various space instruments. Invented by the DuPont (1802-2017), DuPont Corporation in the 1960s, Kapton remains stable across a wide range of temperatures, from . Kapton is used in electronics manufacturing and space applications, with x-ray equipment, and in 3D printing applications. Its favorable thermal properties and outgassing characteristics result in its regular use in Cryogenics, cryogenic applications and in high vacuum environments. History Kapton was invented by DuPont in the 1960s. Kapton remains manufactured by DuPont to this day. The name ''Kapton'' is a registered trademark of E. I. du Pont de Nemours and Company. Chemistry and variants Kapton synthesis is an example of the use of a wikt:dianhydride, dianhydride in step pol ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Panels And Radiators On ISS After STS-120
Panel may refer to: Arts and media Visual arts *Panel painting, in art, a painting on a wood panel (as opposed to canvas, a wall etc) *Panel (comics), a single image in a comic book, comic strip or cartoon; also, a comic strip containing one such image *Groupings of rock art, pictographs or petroglyphs Television * ''The Panel'' (Australian TV series), an Australian talk show * ''The Panel'' (Irish TV series), an Irish talk show * Panel game, a form of game show involving a group of celebrities Law * Judicial panel, set of judges who sit to hear a cause of action * Jury panel, body of people convened to render a judicial verdict * ''Panel'', or ''pannel'', in Scotland, formal term in solemn proceedings for an accused person; see Indictment People * Brice Panel (born 1983), French sprinter * Caroline Giron-Panel (born 1979), French historian and musicologist Science and technology Electrical devices *Breaker panel, a flat area containing electrical circuit breakers ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Polyethylene Terephthalate
Polyethylene terephthalate (or poly(ethylene terephthalate), PET, PETE, or the obsolete PETP or PET-P), is the most common thermoplastic polymer resin of the polyester family and is used in synthetic fibre, fibres for clothing, packaging, containers for liquids and foods, and thermoforming for manufacturing, and in combination with glass fibre for engineering resins. In 2016, annual production of PET was 56 million tons. The biggest application is in fibres (in excess of 60%), with bottle production accounting for about 30% of global demand. In the context of textile applications, PET is referred to by its common name, polyester, whereas the acronym ''PET'' is generally used in relation to packaging. PET used in non-fiber applications (i.e. for packaging) makes up about 6% of world polymer production by mass. Accounting for the >60% fraction of polyethylene terephthalate produced for use as polyester fibers, PET is the fourth-most-produced polymer after polyethylene (PE), polypr ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Mylar
BoPET (biaxially oriented polyethylene terephthalate) is a polyester film made from stretched polyethylene terephthalate (PET) and is used for its high tensile strength, chemical stability, dimensional stability, transparency reflectivity, and electrical insulation. When metallized, it has gas and moisture barrier properties. The film is "biaxially oriented", which means that the polymer chains are oriented parallel to the plane of the film, and therefore oriented over two axes. 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, Lumirror and Hostaphan. It was the first biaxially oriented polymer to be manufactured on a mass commercial scale. 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 ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Fluorinated Ethylene Propylene
Fluorinated ethylene propylene (FEP) is a copolymer of hexafluoropropylene and tetrafluoroethylene. It differs from the polytetrafluoroethylene (PTFE) resins in that it is melt-processable using conventional injection molding and Plastic extrusion, screw extrusion techniques. Fluorinated ethylene propylene was invented by DuPont and is sold under the brandname Teflon FEP. Other brandnames are Neoflon FEP from Daikin or Dyneon FEP from Dyneon/3M. FEP is very similar in composition to the fluoropolymers polytetrafluoroethylene, PTFE (polytetrafluoroethylene) and Perfluoroalkoxy polymer resin, PFA (perfluoroalkoxy polymer resin). FEP and PFA both share PTFE's useful properties of low friction and non-reactivity, but are more easily formable. FEP is softer than PTFE and melts at 260 °C; it is highly transparent and resistant to sunlight. Production FEP is produced by free-radical polymerization of mixtures of tetrafluoroethylene and hexafluoropropylene. The mixture is biased to ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Nomex
Nomex is a trademarked term for an inherently flame-resistant fabric with meta-aramid chemistry widely used for industrial applications and fire protection equipment. It was developed in the early 1960s by DuPont and first marketed in 1967. The fabric is often combined with Kevlar to increase its resistance for breakage or tear. Properties Nomex and related aramid polymers are related to nylon, but have aromatic backbones, and hence are more rigid and more durable. Nomex is an example of a '' meta'' variant of the aramids (Kevlar is a '' para'' aramid). Unlike Kevlar, Nomex strands cannot align during filament polymerization and have less strength: its ultimate tensile strength is . However, it has excellent thermal, chemical, and radiation resistance for a polymer material. It can withstand temperatures of up to . Production Nomex is produced by condensation reaction from the monomers ''m''-phenylenediamine and isophthaloyl chloride. It is sold in both fiber and s ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Polyvinyl Fluoride
Polyvinyl fluoride (PVF) or –(CH2CHF)n– is a polymer material mainly used in the flammability-lowering coatings of airplane interiors and photovoltaic module backsheets. It is also used in raincoats and metal sheeting. Polyvinyl fluoride is a thermoplastic fluoropolymer with a repeating vinyl fluoride unit, and it is structurally very similar to polyvinyl chloride. History The PVF-based film was first commercialised in 1961 by DuPont under the name Tedlar. Polymerization The most widely used polymerizations of VF are in aqueous suspensions or emulsions. High pressures are required because of the VF volatility. The high electronegativity of fluorine makes the polymerization more difficult when compared to other vinyl halides. The polymerization temperatures range from 50 °C to 150 °C and can affect the crystallinity, melting point and branching of the product. Initiation is done by peroxides or azo compounds. The resonance stabilization of the propagating intermed ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
