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General Purpose Heat Source
The general-purpose heat source is a U.S. DOE-designed radioactive heat source for radioisotope thermoelectric generators (RTG) or Stirling radioisotope generators (SRG). It is meant for space applications and is packaged as a stackable module. Characteristics GPHSs are fueled with plutonium-238 dioxide. Each module has a temperature of over 600 degrees Celsius and delivers 250 watts at the time of manufacture. They measure 9.948 cm wide x 9.32 cm deep x 5.82 cm high and weigh no more than 1.44 kg each. Safety GPHSs are designed with safety in mind and employ iridium-clad plutonium-238 dioxide pellets. The generated alpha particles are blocked by the cladding, thus no further radiation shielding is necessary. The pellets are encased within nested layers of carbon-based material and placed within an aeroshell housing to comprise the complete module. The modules can withstand extreme conditions including a launch-pad explosion or a high-speed reentry. Overheati ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
General Purpose Heat Source - Exploded View With English Labels
A general officer is an Officer (armed forces), officer of highest military ranks, high rank in the army, armies, and in some nations' air forces, space forces, and marines or naval infantry. In some usages the term "general officer" refers to a rank above colonel."general, adj. and n.". OED Online. March 2021. Oxford University Press. https://www.oed.com/view/Entry/77489?rskey=dCKrg4&result=1 (accessed May 11, 2021) The term ''general'' is used in two ways: as the generic title for all grades of general officer and as a specific rank. It originates in the Tudor period, 16th century, as a shortening of ''captain general'', which rank was taken from Middle French ''capitaine général''. The adjective ''general'' had been affixed to officer designations since the late Middle Ages, late medieval period to indicate relative superiority or an extended jurisdiction. Today, the title of ''general'' is known in some countries as a four-star rank. However, different countries use di ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
United States Department Of Energy
The United States Department of Energy (DOE) is an executive department of the U.S. federal government that oversees U.S. national energy policy and manages the research and development of nuclear power and nuclear weapons in the United States. The DOE oversees the U.S. nuclear weapons program, nuclear reactor production for the United States Navy, energy-related research, and domestic energy production and energy conservation. The DOE was created in 1977 in the aftermath of the 1973 oil crisis. It sponsors more physical science research than any other U.S. federal agency, the majority of which is conducted through its system of National Laboratories. The DOE also directs research in genomics, with the Human Genome Project originating from a DOE initiative. The department is headed by the Secretary of Energy, who reports directly to the president of the United States and is a member of the Cabinet. The current Secretary of Energy is Jennifer Granholm, who has served ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Radioisotope Thermoelectric Generator
A radioisotope thermoelectric generator (RTG, RITEG), sometimes referred to as a radioisotope power system (RPS), is a type of nuclear battery that uses an array of thermocouples to convert the heat released by the decay of a suitable radioactive material into electricity by the Seebeck effect. This type of generator has no moving parts. RTGs have been used as power sources in satellites, space probes, and uncrewed remote facilities such as a series of lighthouses built by the Soviet Union inside the Arctic Circle. RTGs are usually the most desirable power source for unmaintained situations that need a few hundred watts (or less) of power for durations too long for fuel cells, batteries, or generators to provide economically, and in places where solar cells are not practical. Safe use of RTGs requires containment of the radioisotopes long after the productive life of the unit. The expense of RTGs tends to limit their use to niche applications in rare or special situations. Beca ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Stirling Radioisotope Generator
Radioisotope power systems (RPS) are an enabling technology for challenging solar system exploration missions by NASA to destinations where solar energy is weak or intermittent, or where environmental conditions such as dust can limit the ability of a mission to achieve its scientific or operational goals. RPS use the heat generated by the natural radioactive decay of plutonium-238 (Pu-238), in the form of plutonium dioxide. All past RPS used in space have been radioisotope thermoelectric generators (RTGs), which use metallic thermocouples to transform the heat from their nuclear fuel into electrical power, using no moving parts. The currently available RPS, the Multi-Mission Radioisotope Thermoelectric Generator (MMRTG), operates with a beginning-of-life conversion efficiency of about 6.3 percent. Dynamic RPS that utilize heat-engines have the potential to be three times more efficient than RTGs, which would allow RPS to use about one-third of the quantity of Pu-238 to produce a si ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Plutonium-238
Plutonium-238 (238Pu or Pu-238) is a fissile, radioactive isotope of plutonium that has a half-life of 87.7 years. Plutonium-238 is a very powerful alpha emitter; as alpha particles are easily blocked, this makes the plutonium-238 isotope suitable for usage in radioisotope thermoelectric generators (RTGs) and radioisotope heater units. The density of plutonium-238 at room temperature is about 19.8 g/cc. The material will generate about 0.57 watts/gram of 238Pu. The bare sphere critical mass of metallic plutonium-238 is not precisely known, but its calculated range is between 9.04 and 10.07 kilograms. History Initial production Plutonium-238 was the first isotope of plutonium to be discovered. It was synthesized by Glenn Seaborg and associates in December 1940 by bombarding uranium-238 with deuterons, creating neptunium-238. The subsequent decay via β− decay creates Plutonium-238. + → + 2 The neptunium isotope then undergoes β− decay to plutonium- ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Iridium
Iridium is a chemical element with the symbol Ir and atomic number 77. A very hard, brittle, silvery-white transition metal of the platinum group, it is considered the second-densest naturally occurring metal (after osmium) with a density of as defined by experimental X-ray crystallography. It is one of the most corrosion-resistant metals, even at temperatures as high as . However, corrosion-resistance is not quantifiable in absolute terms; although only certain molten salts and halogens are corrosive to solid iridium, finely divided iridium dust is much more reactive and can be flammable, whereas gold dust is not flammable but can be attacked by substances that iridium resists, such as aqua regia. Iridium was discovered in 1803 among insoluble impurities in natural platinum. Smithson Tennant, the primary discoverer, named it after the Greek goddess Iris, personification of the rainbow, because of the striking and diverse colors of its salts. Iridium is one of the rarest ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
OSTI
The Office of Scientific and Technical Information (OSTI) is a component of the Office of Science within the U.S. Department of Energy (DOE). The '' Energy Policy Act'' PL 109–58, Section 982, called out the responsibility of OSTI: "The Secretary, through the Office of Scientific and Technical Information, shall maintain with the Department publicly available collections of scientific and technical information resulting from research, development, demonstration, and commercial applications activities supported by the Department." Resources OSTI provides access to energy, science, and technology information through publicly available web-based systems, with supporting tools and technologies to enable information search, retrieval and re-use. Science information resources freely available for public use *OSTI.GOV - The primary search tool for DOE science, technology, and engineering R&D results and the organizational hub for information about DOE OSTI ; *DOE PAGES ( ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
GPHS-RTG
GPHS-RTG or general-purpose heat source — radioisotope thermoelectric generator, is a specific design of the radioisotope thermoelectric generator (RTG) used on US space missions. The GPHS-RTG was used on ''Ulysses'' (1), ''Galileo'' (2), '' Cassini-Huygens'' (3), and '' New Horizons'' (1). The GPHS-RTG has an overall diameter of 0.422 m and a length of 1.14 m. Each GPHS-RTG has a mass of about 57 kg and generates about 300 watts of electrical power at the start of mission (5.2 We/kg), using about 7.8 kg of Pu-238 which produces about 4,400 watts of thermal power.G. L. BennettSpace Nuclear Power: Opening the Final Frontier AIAA 2006-4191, 4th International Energy Conversion Engineering Conference and Exhibit (IECEC), 26–29 June 2006, San Diego, California The plutonium oxide fuel is in 18 GPHSs. Note that the GPHS are cuboid although they contain cylindrical plutonium based pellets. The GPHS-RTG units used on spacecraft were not created by NASA. They were ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
New Horizons
''New Horizons'' is an Interplanetary spaceflight, interplanetary space probe that was launched as a part of NASA's New Frontiers program. Engineered by the Johns Hopkins University Applied Physics Laboratory (APL) and the Southwest Research Institute (SwRI), with a team led by Alan Stern, the spacecraft was launched in 2006 with the primary mission to perform a Planetary flyby, flyby study of the Pluto system in 2015, and a secondary mission to fly by and study one or more other Kuiper belt objects (KBOs) in the decade to follow, which became a mission to 486958 Arrokoth. It is the List of artificial objects leaving the Solar System, fifth space probe to achieve the escape velocity needed to leave the Solar System. On January 19, 2006, ''New Horizons'' was launched from Cape Canaveral Space Force Station by an Atlas V rocket directly into an Earth-and-solar Escape velocity, escape trajectory with a speed of about . It was the fastest (average speed with respect to Earth) man ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Galileo Probe
''Galileo'' was an American robotic space probe that studied the planet Jupiter and its moons, as well as the asteroids Gaspra and Ida. Named after the Italian astronomer Galileo Galilei, it consisted of an orbiter and an entry probe. It was delivered into Earth orbit on October 18, 1989, by , during STS-34. ''Galileo'' arrived at Jupiter on December 7, 1995, after gravitational assist flybys of Venus and Earth, and became the first spacecraft to orbit an outer planet. The Jet Propulsion Laboratory built the ''Galileo'' spacecraft and managed the ''Galileo'' program for NASA. West Germany Messerschmitt-Bölkow-Blohm supplied the propulsion module. NASA's Ames Research Center managed the atmospheric probe, which was built by Hughes Aircraft Company. At launch, the orbiter and probe together had a mass of and stood tall. Spacecraft are normally stabilized either by spinning around a fixed axis or by maintaining a fixed orientation with reference to the Sun and a star. ''Ga ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Ulysses Probe
''Ulysses'' ( , ) was a robotic space probe whose primary mission was to orbit the Sun and study it at all latitudes. It was launched in 1990 and made three "fast latitude scans" of the Sun in 1994/1995, 2000/2001, and 2007/2008. In addition, the probe studied several comets. ''Ulysses'' was a joint venture of the European Space Agency (ESA) and the United States' National Aeronautics and Space Administration (NASA), under leadership of ESA with participation from Canada's National Research Council. The last day for mission operations on ''Ulysses'' was 30 June 2009. To study the Sun at all latitudes, the probe needed to change its orbital inclination and leave the plane of the Solar System. To change the orbital inclination of a spacecraft to about 80° requires a large change in heliocentric velocity, the energy to achieve which far exceeded the capabilities of any launch vehicle. To reach the desired orbit around the Sun, the mission's planners chose a gravity assist mane ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
