|
Ion Thruster
An ion thruster, ion drive, or ion engine is a form of electric propulsion used for spacecraft propulsion. An ion thruster creates a cloud of positive ions from a neutral gas by ionizing it to extract some electrons from its atoms. The ions are then accelerated using electricity to create thrust. Ion thrusters are categorized as either electrostatic or electromagnetic. Electrostatic thruster ions are accelerated by the Coulomb force along the electric field direction. Temporarily stored electrons are reinjected by a ''neutralizer'' in the cloud of ions after it has passed through the electrostatic grid, so the gas becomes neutral again and can freely disperse in space without any further electrical interaction with the thruster. By contrast, electromagnetic thruster ions are accelerated by the Lorentz force to accelerate all species (free electrons as well as positive and negative ions) in the same direction whatever their electric charge, and are specifically refer ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Ion Engine Test Firing - GPN-2000-000482
An ion () is an atom or molecule with a net electrical charge. The charge of an electron is considered to be negative by convention and this charge is equal and opposite to the charge of a proton, which is considered to be positive by convention. The net charge of an ion is not zero because its total number of electrons is unequal to its total number of protons. A cation is a positively charged ion with fewer electrons than protons (e.g. K+ (potassium ion)) while an anion is a negatively charged ion with more electrons than protons (e.g. Cl− (chloride ion) and OH− (hydroxide ion)). Opposite electric charges are pulled towards one another by electrostatic force, so cations and anions attract each other and readily form ionic compounds. Ions consisting of only a single atom are termed ''monatomic ions'', ''atomic ions'' or ''simple ions'', while ions consisting of two or more atoms are termed polyatomic ions or ''molecular ions''. If only a + or − is present, it indicates ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Plasma Propulsion Engine
A plasma propulsion engine is a type of electric propulsion that generates thrust from a quasi-neutral Plasma (physics), plasma. This is in contrast with ion thruster engines, which generate thrust through extracting an ion current from the Plasma (physics), plasma source, which is then accelerated to high velocities using grids of anodes. These exist in many forms (see electric propulsion). However, in the scientific literature, the term "plasma thruster" sometimes encompasses thrusters usually designated as "Ion thruster, ion engines". Plasma thrusters do not typically use high voltage grids or anodes/cathodes to accelerate the charged particles in the plasma, but rather use currents and potentials that are generated internally to accelerate the ions, resulting in a lower exhaust velocity given the lack of high accelerating voltages. This type of thruster has a number of advantages. The lack of high voltage grids of anodes removes a possible limiting element as a result of ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Atmosphere-breathing Electric Propulsion
Atmosphere-breathing electric propulsion, or air-breathing electric propulsion, shortly ABEP, is a propulsion technology for spacecraft, which could allow thrust generation in low orbits without the need of on-board propellant, by using residual gases in the atmosphere as propellant. Atmosphere-breathing electric propulsion could make a new class of long-lived, low-orbiting missions feasible. The concept is currently being investigated by the European Space Agency (ESA), the EU-funded BREATHE project at Sant'Anna School of Advanced Studies in Pisa and the EU-funded DISCOVERER project. Current state-of-the-art conventional electric thrusters cannot maintain flight at low altitudes for any times longer than about 2 years, because of the limitation in propellant storage and in the amount of thrust generated, which force the spacecraft's orbit to decay. The ESA officially announced the first successful RAM-EP prototype on-ground demonstration in March 2018. Principle of operation ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Tiangong Space Station
Tiangong (), officially the ''Tiangong'' space station (), is a permanently crewed space station constructed by China and operated by China Manned Space Agency. Tiangong is a modular design, with modules docked together while in low Earth orbit, between above the surface. It is China's first long-term space station, part of the Tiangong program and the core of the "Third Step" of the China Manned Space Program; it has a pressurised volume of 340 m3 (12,000 cu ft), slightly over one third the size of the International Space Station. The space station aims to provide opportunities for space-based experiments and a platform for building capacity for scientific and technological innovation. The construction of the station is based on the experience gained from its precursors, Tiangong-1 and Tiangong-2. The first module, the ''Tianhe core module, Tianhe'' ("Harmony of the Heavens") core module, was launched on 29 April 2021. This was followed by multiple crewed and uncrewed miss ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Space Station
A space station (or orbital station) is a spacecraft which remains orbital spaceflight, in orbit and human spaceflight, hosts humans for extended periods of time. It therefore is an artificial satellite featuring space habitat (facility), habitation facilities. The purpose of maintaining a space station varies depending on the program. Most often space stations have been research stations, but they have also served militarization of space, military or commercialization of space, commercial uses, such as hosting space tourism, space tourists. Space stations have been hosting the only continuous human presence in space, presence of humans in space. The first space station was Salyut 1 (1971), hosting the first crew, of the ill-fated Soyuz 11. Consecutively space stations have been operated since Skylab (1973) and occupied since 1987 with the Salyut program, Salyut successor Mir. Uninterrupted human presence in orbital space through space stations have been sustained since the operat ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Crewed Spacecraft
This is a list of all crewed spacecraft types that have flown into space, including sub-orbital flights above 80 km, space stations that have been visited by at least one crew member, and spacecraft currently planned to operate with crews in the future. It does not contain spacecraft that have only flown uncrewed and have retired from service, even if they were designed for crewed flight, such as Buran, or crewed flights by spacecraft below 80 km. There is some debate concerning the height at which space is reached (the Karman Line): the Fédération Aéronautique Internationale (FAI) recognizes 100 km, while NASA and the USAF recognize this as 50 miles (approx 80 km). Since the first crewed spaceflight of Vostok 1 in 1961 there have been 13 types of spacecraft that have made crewed flights into space – nine American, three Russian, and one Chinese. There are currently five operational crewed spacecraft, which form the first part of the list below; the ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Satellite
A satellite or an artificial satellite is an object, typically a spacecraft, placed into orbit around a celestial body. They have a variety of uses, including communication relay, weather forecasting, navigation ( GPS), broadcasting, scientific research, and Earth observation. Additional military uses are reconnaissance, early warning, signals intelligence and, potentially, weapon delivery. Other satellites include the final rocket stages that place satellites in orbit and formerly useful satellites that later become defunct. Except for passive satellites, most satellites have an electricity generation system for equipment on board, such as solar panels or radioisotope thermoelectric generators (RTGs). Most satellites also have a method of communication to ground stations, called transponders. Many satellites use a standardized bus to save cost and work, the most popular of which are small CubeSats. Similar satellites can work together as groups, forming constellatio ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Delta-v
Delta-''v'' (also known as "change in velocity"), symbolized as and pronounced , as used in spacecraft flight dynamics, is a measure of the impulse per unit of spacecraft mass that is needed to perform a maneuver such as launching from or landing on a planet or moon, or an in-space orbital maneuver. It is a scalar that has the units of speed. As used in this context, it is not the same as the physical change in velocity of said spacecraft. A simple example might be the case of a conventional rocket-propelled spacecraft, which achieves thrust by burning fuel. Such a spacecraft's delta-''v'', then, would be the change in velocity that spacecraft can achieve by burning its entire fuel load. Delta-''v'' is produced by reaction engines, such as rocket engines, and is proportional to the thrust per unit mass and the burn time. It is used to determine the mass of propellant required for the given maneuver through the Tsiolkovsky rocket equation. For multiple maneuvers, delta ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Dawn (spacecraft)
''Dawn'' is a retired space probe that was launched by NASA in September 2007 with the mission of studying two of the three known protoplanets of the asteroid belt: Vesta and Ceres. In the fulfillment of that mission—the ninth in NASA's Discovery Program—''Dawn'' entered orbit around Vesta on July 16, 2011, and completed a 14-month survey mission before leaving for Ceres in late 2012. It entered orbit around Ceres on March 6, 2015. In 2017, NASA announced that the planned nine-year mission would be extended until the probe's hydrazine fuel supply was depleted. On November 1, 2018, NASA announced that ''Dawn'' had depleted its hydrazine, and the mission was ended. The derelict probe remains in a stable orbit around Ceres. ''Dawn'' is the first spacecraft to have orbited two extraterrestrial bodies, the first spacecraft to have visited either Vesta or Ceres, and the first to have orbited a dwarf planet. The ''Dawn'' mission was managed by NASA's Jet Propulsion Laboratory, ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Xenon
Xenon is a chemical element; it has symbol Xe and atomic number 54. It is a dense, colorless, odorless noble gas found in Earth's atmosphere in trace amounts. Although generally unreactive, it can undergo a few chemical reactions such as the formation of xenon hexafluoroplatinate, the first noble gas compound to be synthesized. Xenon is used in flash lamps and arc lamps, and as a general anesthetic. The first excimer laser design used a xenon dimer molecule (Xe2) as the lasing medium, and the earliest laser designs used xenon flash lamps as pumps. Xenon is also used to search for hypothetical weakly interacting massive particles and as a propellant for ion thrusters in spacecraft. Naturally occurring xenon consists of seven stable isotopes and two long-lived radioactive isotopes. More than 40 unstable xenon isotopes undergo radioactive decay, and the isotope ratios of xenon are an important tool for studying the early history of the Solar System. Radioactive xe ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Deep Space 1
''Deep Space 1'' (DS1) was a NASA technology demonstration spacecraft which flew by an asteroid and a comet. It was part of the New Millennium Program, dedicated to testing advanced technologies. Launched on 24 October 1998, the ''Deep Space 1'' spacecraft carried out a flyby of asteroid 9969 Braille, which was its primary science target. The mission was extended twice to include an encounter with comet 19P/Borrelly and further engineering testing. Problems during its initial stages and with its star tracker led to repeated changes in mission configuration. While the flyby of the asteroid was only a partial success, the encounter with the comet retrieved valuable information. The Deep Space series was continued by the '' Deep Space 2'' probes, which were launched in January 1999 piggybacked on the Mars Polar Lander and were intended to strike the surface of Mars (though contact was lost and the mission failed). ''Deep Space 1'' was the first NASA spacecraft to use ion propu ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Propulsive Efficiency
In aerospace engineering, concerning aircraft, rocket and spacecraft design, overall propulsion system efficiency \eta is the efficiency with which the energy contained in a vehicle's fuel is converted into kinetic energy of the vehicle, to accelerate it, or to replace losses due to aerodynamic drag or gravity. Mathematically, it is represented as \eta = \eta_\mathrm \eta_\mathrm, where \eta_\mathrm is the cycle efficiency and \eta_\mathrm is the propulsive efficiency. The cycle efficiency is expressed as the percentage of the heat energy in the fuel that is converted to mechanical energy in the engine, and the propulsive efficiency is expressed as the proportion of the mechanical energy actually used to propel the aircraft. The propulsive efficiency is always less than one, because conservation of momentum requires that the exhaust have some of the kinetic energy, and the propulsive mechanism (whether propeller, jet exhaust, or ducted fan) is never perfectly efficient. It is great ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
