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Payload Fraction
In aerospace engineering, payload fraction is a common term used to characterize the efficiency of a particular design. The payload fraction is the quotient of the payload mass and the total vehicle mass at the start of its journey. It is a function of specific impulse, propellant mass fraction and the structural coefficient. In aircraft, loading less than full fuel for shorter trips is standard practice to reduce weight and fuel consumption. For this reason, the useful load fraction calculates a similar number, but it is based on the combined weight of the payload and fuel together in relation to the total weight. Propeller-driven airliners had useful load fractions on the order of 25–35%. Modern jet airliners have considerably higher useful load fractions, on the order of 45–55%. For orbital rockets the payload fraction is between 1% and 5%, while the useful load fraction is perhaps 90%. Examples For payload fractions and fuel fractions in aviation, see Fuel Fract ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Aerospace Engineering
Aerospace engineering is the primary field of engineering concerned with the development of aircraft and spacecraft. It has two major and overlapping branches: aeronautical engineering and astronautical engineering. Avionics engineering is similar, but deals with the electronics side of aerospace engineering. "Aeronautical engineering" was the original term for the field. As flight technology advanced to include vehicles operating in outer space, the broader term "aerospace engineering" has come into use. Aerospace engineering, particularly the astronautics branch, is often colloquially referred to as "rocket science". Overview Flight vehicles are subjected to demanding conditions such as those caused by changes in atmospheric pressure and temperature, with structural loads applied upon vehicle components. Consequently, they are usually the products of various technological and engineering disciplines including aerodynamics, air propulsion, avionics, materials science, st ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Soyuz-2
Soyuz2 (; GRAU index: 14A14) is a Russian expendable medium-lift launch vehicle and the seventh major iteration of the Soyuz rocket family. Compared to its predecessors, Soyuz-2 features significant upgrades, including improved engines and a digital flight control system that enables launches from fixed platforms and supports larger payload fairings. Developed by the Progress Rocket Space Centre (RKTs Progress) in Samara, Soyuz-2 is used to place payloads into low Earth orbit in standard configuration but can also support missions to higher orbits using an additional upper stage, most commonly the Fregat, though the smaller Volga is available as a less expensive option. Since its introduction in 2004, Soyuz-2 has gradually replaced earlier Soyuz variants and is launched from the facilities of its R-7 derived predecessors: Site 31/6 at the Baikonur Cosmodrome in Kazakhstan and Sites 43/3 and 43/4 at the Plesetsk Cosmodrome in northwestern Russia, and, since 2016, Site ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Tsiolkovsky Rocket Equation
The classical rocket equation, or ideal rocket equation is a mathematical equation that describes the motion of vehicles that follow the basic principle of a rocket: a device that can apply acceleration to itself using thrust by expelling part of its mass with high velocity and can thereby move due to the conservation of momentum. It is credited to Konstantin Tsiolkovsky, who independently derived it and published it in 1903,К. Ціолковскій, Изслѣдованіе мировыхъ пространствъ реактивными приборами, 1903 (available onlinhere in a RAR (file format), RARed PDF) although it had been independently derived and published by William Moore (British mathematician), William Moore in 1810, and later published in a separate book in 1813. Robert Goddard also developed it independently in 1912, and Hermann Oberth derived it independently about 1920. The maximum change of velocity of the vehicle, \Delta v (with no external forces act ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Fuel Fraction
In aerospace engineering, an aircraft's fuel fraction, fuel weight fraction, or a spacecraft's propellant fraction, is the weight of the fuel or propellant divided by the gross take-off weight of the craft (including propellant): :\ \zeta = \frac The fractional result of this mathematical division is often expressed as a percent. For aircraft with external drop tanks, the term internal fuel fraction is used to exclude the weight of external tanks and fuel. Fuel fraction is a key parameter in determining an aircraft's range, the Range (aircraft), distance it can fly without refueling. Louis Charles Breguet, Breguet’s aircraft range (aircraft), range equation describes the relationship of range with airspeed, lift-to-drag ratio, Thrust specific fuel consumption, specific fuel consumption, and the part of the total fuel fraction available for cruise, also known as the cruise fuel fraction, or cruise fuel weight fraction. In this context, the Breguet range is proportional to - ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Sub-orbital Spaceflight
A sub-orbital spaceflight is a spaceflight in which the spacecraft reaches outer space, but its trajectory intersects the surface of the primary (astronomy), gravitating body from which it was launched. Hence, it will not complete one orbital revolution, will not become an artificial satellite nor will it reach escape velocity. For example, the path of an object launched from Earth that reaches the Kármán line (about – above sea level), and then falls back to Earth, is considered a sub-orbital spaceflight. Some sub-orbital flights have been undertaken to test spacecraft and launch vehicles later intended for orbital spaceflight. Other vehicles are specifically designed only for sub-orbital flight; examples include crewed vehicles, such as the North American X-15, X-15 and SpaceShipTwo, and uncrewed ones, such as intercontinental ballistic missile, ICBMs and sounding rockets. Flights which attain sufficient velocity to go into low Earth orbit, and then de-orbit before com ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
V-2 Rocket
The V2 (), with the technical name ''Aggregat (rocket family), Aggregat-4'' (A4), was the world's first long-range missile guidance, guided ballistic missile. The missile, powered by a liquid-propellant rocket engine, was developed during the Second World War in Nazi Germany as a "V-weapons, vengeance weapon" and assigned to attack Allies of World War II, Allied cities as retaliation for the Strategic bombing during World War II#The British later in the war, Allied bombings of German cities. The rocket also became the first artificial object to travel into space by crossing the Kármán line (edge of space) with the vertical launch of MW 18014 on 20 June 1944. Research of military use of long-range rockets began when the graduate studies of Wernher von Braun were noticed by the German Army. A series of prototypes culminated in the A4, which went to war as the . Beginning in September 1944, more than 3,000 were launched by the Wehrmacht against Allied targets, first London and ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Moon
The Moon is Earth's only natural satellite. It Orbit of the Moon, orbits around Earth at Lunar distance, an average distance of (; about 30 times Earth diameter, Earth's diameter). The Moon rotation, rotates, with a rotation period (lunar day) that is synchronized to its orbital period (Lunar month#Synodic month, lunar month) of 29.5 Earth days. This is the product of Earth's gravitation having tidal forces, tidally pulled on the Moon until one part of it stopped rotating away from the near side of the Moon, near side, making always the same lunar surface face Earth. Conversley, the gravitational pull of the Moon, on Earth, is the main driver of Earth's tides. In geophysical definition of planet, geophysical terms, the Moon is a planetary-mass object or satellite planet. Its mass is 1.2% that of the Earth, and its diameter is , roughly one-quarter of Earth's (about as wide as the contiguous United States). Within the Solar System, it is the List of Solar System objects by ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Lunar Orbit
In astronomy and spaceflight, a lunar orbit (also known as a selenocentric orbit) is an orbit by an object around Earth's Moon. In general these orbits are not circular. When farthest from the Moon (at apoapsis) a spacecraft is said to be at apolune, apocynthion, or aposelene. When closest to the Moon (at periapsis) it is said to be at perilune, pericynthion, or periselene. These derive from names or epithets of the moon goddess. Lunar orbit insertion (LOI) is an orbit insertion maneuver used to achieve lunar orbit. Low lunar orbit (LLO) is an orbit below altitude. These have a period of about 2 hours. They are of particular interest in the exploration of the Moon, but suffer from gravitational perturbations that make most unstable, and leave only a few orbital trajectories possible for indefinite '' frozen orbits''. These would be useful for long-term stays in LLO. Perturbation effects and low orbits Most lunar low orbits below 100 km (60 mi) are unstable. Gravitationa ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Lunar Module
The Apollo Lunar Module (LM ), originally designated the Lunar Excursion Module (LEM), was the lunar lander spacecraft that was flown between lunar orbit and the Moon's surface during the United States' Apollo program. It was the first crewed spacecraft to operate exclusively in the airless vacuum of space, and remains the only crewed vehicle to land anywhere beyond Earth. Structurally and aerodynamically incapable of flight through Earth's atmosphere, the two-stage Lunar Module was ferried to lunar orbit attached to the Apollo command and service module (CSM), about twice its mass. Its crew of two flew the Lunar Module from lunar orbit to the Moon's surface. During takeoff, the spent descent stage was used as a launch pad for the ascent stage which then flew back to the command module, after which it was also discarded. Overseen by Grumman, the LM's development was plagued with problems that delayed its first uncrewed flight by about ten months and its first crewed flight by ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Trans-lunar Injection
A trans-lunar injection (TLI) is a propulsive maneuver, which is used to send a spacecraft to the Moon. Typical lunar transfer trajectories approximate Hohmann transfers, although low-energy transfers have also been used in some cases, as with the Hiten probe. For short duration missions without significant perturbations from sources outside the Earth-Moon system, a fast Hohmann transfer is typically more practical. A spacecraft performs TLI to begin a lunar transfer from a low circular parking orbit around Earth. The large TLI burn, usually performed by a chemical rocket engine, increases the spacecraft's velocity, changing its orbit from a circular low Earth orbit to a highly eccentric orbit. As the spacecraft begins coasting on the lunar transfer arc, its trajectory approximates an elliptical orbit about the Earth with an apogee near to the radius of the Moon's orbit. The TLI burn is sized and timed to precisely target the Moon as it revolves around the Earth. The bu ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Saturn V
The Saturn V is a retired American super heavy-lift launch vehicle developed by NASA under the Apollo program for human exploration of the Moon. The rocket was human-rated, had multistage rocket, three stages, and was powered by liquid-propellant rocket, liquid fuel. Flown from 1967 to 1973, it was used for nine crewed flights to the Moon, and to launch Skylab, the first American space station. the Saturn V remains the only launch vehicle to have carried humans beyond low Earth orbit (LEO). The Saturn V holds the record for the largest payload capacity to low Earth orbit, , which included unburned propellant needed to send the Apollo command and service module and Apollo Lunar Module, Lunar Module to the Moon. The largest production model of the Saturn (rocket family), Saturn family of rockets, the Saturn V was designed under the direction of Wernher von Braun at the Marshall Space Flight Center in Huntsville, Alabama; the lead contractors for construction of the rocket were ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Space Shuttle
The Space Shuttle is a retired, partially reusable launch system, reusable low Earth orbital spacecraft system operated from 1981 to 2011 by the U.S. National Aeronautics and Space Administration (NASA) as part of the Space Shuttle program. Its official program name was the Space Transportation System (STS), taken from the 1969 plan led by U.S. vice president Spiro Agnew for a system of reusable spacecraft where it was the only item funded for development. The first (STS-1) of four orbital test flights occurred in 1981, leading to operational flights (STS-5) beginning in 1982. Five complete Space Shuttle orbiter vehicles were built and flown on a total of 135 missions from 1981 to 2011. They launched from the Kennedy Space Center (KSC) in Florida. Operational missions launched numerous satellites, interplanetary probes, and the Hubble Space Telescope (HST), conducted science experiments in orbit, participated in the Shuttle–Mir program, Shuttle-''Mir'' program with Russia, ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
