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Rocketdyne J-2
The J-2, commonly known as Rocketdyne J-2, was a liquid-fuel rocket, liquid-fuel cryogenic rocket engine used on NASA's Saturn IB and Saturn V launch vehicles. Built in the United States by Rocketdyne, the J-2 burned Cryogenic fuel, cryogenic liquid hydrogen (LH2) and liquid oxygen (LOX) propellants, with each engine producing of thrust in vacuum. The engine's preliminary design dates back to recommendations of the 1959 Silverstein Committee. Rocketdyne won approval to develop the J-2 in June 1960 and the first flight, AS-201, occurred on 26 February 1966. The J-2 underwent several minor upgrades over its operational history to improve the engine's performance, with two major upgrade programs, the de Laval nozzle-type J-2S and Aerospike engine, aerospike-type J-2T, which were cancelled after the conclusion of the Apollo program. The engine produced a specific impulse (''I''sp) of in a vacuum (or at sea level) and had a mass of approximately . Five J-2 engines were used on the Sa ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Upper Stage
A multistage rocket or step rocket is a launch vehicle that uses two or more rocket ''stages'', each of which contains its own Rocket engine, engines and Rocket propellant, propellant. A ''tandem'' or ''serial'' stage is mounted on top of another stage; a ''parallel'' stage is attached alongside another stage. The result is effectively two or more rockets stacked on top of or attached next to each other. Two-stage rockets are quite common, but rockets with as many as five separate stages have been successfully launched. By jettisoning stages when they run out of propellant, the mass of the remaining rocket is decreased. Each successive stage can also be optimized for its specific operating conditions, such as decreased atmospheric pressure at higher altitudes. This ''staging'' allows the thrust of the remaining stages to Newton's First Law of Motion, more easily accelerate the rocket to its final velocity and height. In serial or tandem staging schemes, the first stage is at th ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
United States
The United States of America (USA), also known as the United States (U.S.) or America, is a country primarily located in North America. It is a federal republic of 50 U.S. state, states and a federal capital district, Washington, D.C. The 48 contiguous states border Canada to the north and Mexico to the south, with the semi-exclave of Alaska in the northwest and the archipelago of Hawaii in the Pacific Ocean. The United States asserts sovereignty over five Territories of the United States, major island territories and United States Minor Outlying Islands, various uninhabited islands in Oceania and the Caribbean. It is a megadiverse country, with the world's List of countries and dependencies by area, third-largest land area and List of countries and dependencies by population, third-largest population, exceeding 340 million. Its three Metropolitan statistical areas by population, largest metropolitan areas are New York metropolitan area, New York, Greater Los Angeles, Los Angel ... [...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] |
Earth Departure Stage
The Earth Departure Stage (EDS) was the name given to the proposed second stage of the Block 2 Space Launch System. The EDS was intended to boost the rocket's payload into a parking orbit around the Earth and from there send the payload out of low Earth orbit to its destination in a manner similar to that of the S-IVB rocket stage used on the Saturn V rockets that propelled the Apollo spacecraft to the Moon. Its development was initially put on hold until stages capable for Mars are required. It was eventually cancelled in favor of Exploration Upper Stage. Ares V Design The EDS used on the cancelled Ares V would have been propelled by a single J-2X main engine fuelled with liquid oxygen (LOX) and liquid hydrogen (LH2), and was to have been designed at NASA's Marshall Space Flight Center in Huntsville, Alabama as part of Project Constellation. Originally, the stage would have been based on the Space Shuttle's external tank, and would have used two J-2X engines, while the Ares ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
RS-25
The RS-25, also known as the Space Shuttle Main Engine (SSME), is a liquid-fuel cryogenic rocket engine that was used on NASA's Space Shuttle and is used on the Space Launch System. Designed and manufactured in the United States by Rocketdyne (later Pratt & Whitney Rocketdyne and Aerojet Rocketdyne), the RS-25 burns cryogenic (very low temperature) liquid hydrogen and liquid oxygen propellants, with each engine producing thrust at liftoff. Although RS-25 heritage traces back to the 1960s, its concerted development began in the 1970s with the first flight, STS-1, on April 12, 1981. The RS-25 has undergone upgrades over its operational history to improve the engine's thrust, reliability, safety, and maintenance load. The engine produces a specific impulse (''I''sp) of 452 seconds (4.43 kN-sec/kg) in vacuum, or 366 seconds (3.59 kN-sec/kg) at sea level, has a mass of approximately , and is capable of throttling between 67% and 109% of its rated power level in one- ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Nova (rocket)
Nova was a series of NASA's rocket designs that were proposed both before and after the Saturn V rocket used in the Apollo program. Nova was NASA's first large launcher proposed in 1958, for missions similar to what Saturn V was subsequently used for. The Nova and Saturn V designs closely mirrored each other in basic concept, power, size, and function. Differences were minor but practical, and the Saturn was ultimately selected for the Apollo program, largely because it would reuse existing facilities to a greater extent and could make it to the pad somewhat earlier. During a series of post-Apollo studies in the late 1960s, considerations for a Human mission to Mars, crewed mission to Mars revealed the need for boosters much larger than Apollo's, and a new series of designs with as many as eight Rocketdyne F-1 engines were developed under the Nova name (along with the Saturn MLV). The image of the Nova C8 is commonly used as a representative of the entire Nova series, and many ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Specific Impulse
Specific impulse (usually abbreviated ) is a measure of how efficiently a reaction mass engine, such as a rocket engine, rocket using propellant or a jet engine using fuel, generates thrust. In general, this is a ratio of the ''Impulse (physics), impulse'', i.e. change in momentum, ''per mass'' of propellant. This is equivalent to "thrust per massflow". The resulting unit is equivalent to velocity. If the engine expels mass at a constant exhaust velocity v_e then the thrust will be \mathbf = v_e \frac . If we integrate over time to get the total change in momentum, and then divide by the mass, we see that the specific impulse is equal to the exhaust velocity v_e . In practice, the specific impulse is usually lower than the actual physical exhaust velocity inefficiencies in the rocket, and thus corresponds to an "effective" exhaust velocity. That is, the specific impulse I_ in units of velocity *is defined by* : \mathbf = I_ \frac , where \mathbf is the average thrust. ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Apollo Program
The Apollo program, also known as Project Apollo, was the United States human spaceflight program led by NASA, which Moon landing, landed the first humans on the Moon in 1969. Apollo followed Project Mercury that put the first Americans in space. It was conceived in 1960 as a three-person spacecraft during President Presidency of Dwight D. Eisenhower, Dwight D. Eisenhower's administration. Apollo was later dedicated to President John F. Kennedy's national goal for the 1960s of "landing a man on the Moon and returning him safely to the Earth" in an address to United States Congress, Congress on May 25, 1961. It was the third American human spaceflight program to fly, preceded by Project Gemini conceived in 1961 to extend spaceflight capability in support of Apollo. Kennedy's goal was accomplished on the Apollo 11 mission when astronauts Neil Armstrong and Buzz Aldrin landed their Apollo Lunar Module (LM) on July 20, 1969, and walked on the lunar surface, while Michael Collins ( ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Aerospike Engine
The aerospike engine is a type of rocket engine that maintains its aerodynamic efficiency across a wide range of altitudes. It belongs to the class of altitude compensating nozzle engines. Aerospike engines were proposed for many single-stage-to-orbit (SSTO) designs. They were a contender for the Space Shuttle main engine. However, as of 2023 no such engine was in commercial production, although some large-scale aerospikes were in testing phases. The term ''aerospike'' was originally used for a truncated plug nozzle#In rockets, plug nozzle with a rough conical taper and some gas injection, forming an "air spike" to help make up for the absence of the plug tail. However, a full-length plug nozzle may also be called an aerospike. Principles The purpose of any engine bell is to direct the exhaust of a rocket engine in one direction, generating thrust in the opposite direction. The exhaust, a high-temperature mix of gases, has an effectively random momentum distribution (i.e., the ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
De Laval Nozzle
A de Laval nozzle (or convergent-divergent nozzle, CD nozzle or con-di nozzle) is a tube which is pinched in the middle, with a rapid convergence and gradual divergence. It is used to accelerate a compressible fluid to supersonic speeds in the axial (thrust) direction, by converting the thermal energy of the flow into kinetic energy. De Laval nozzles are widely used in some types of steam turbines and rocket engine nozzles. It also sees use in supersonic jet engines. Similar flow properties have been applied to jet streams within astrophysics. History Giovanni Battista Venturi designed converging-diverging tubes known as Venturi tubes for experiments on fluid pressure reduction effects when fluid flows through chokes ( Venturi effect). German engineer and inventor Ernst Körting supposedly switched to a converging-diverging nozzle in his steam jet pumps by 1878 after using convergent nozzles but these nozzles remained a company secret. Later, Swedish engineer Gustaf de Lav ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Silverstein Committee
The Saturn Vehicle Evaluation Committee, better known as the Silverstein Committee, was a US government commission assembled in 1959 to recommend specific directions that NASA could take with the Saturn rocket program. The committee was chaired by Abe Silverstein, a long-time NASA engineer, with the express intent of selecting upper stages for the Saturn after a disagreement broke out between the Air Force and Army over its development. During the meetings the Committee members outlined a number of different potential designs, including the low-risk solution von Braun was developing with existing ICBM airframes, as well as versions using entirely new upper stages developed to take full advantage of the booster stage. The advantages of using new uppers were so great that the committee won over an initially skeptical von Braun, and the future of the Saturn program changed forever. Background In 1957 the Department of Defense (DoD) released a set of requirements for a new heavy-lift ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Thrust
Thrust is a reaction force described quantitatively by Newton's third law. When a system expels or accelerates mass in one direction, the accelerated mass will cause a force of equal magnitude but opposite direction to be applied to that system. The force applied on a surface in a direction perpendicular or normal to the surface is also called thrust. Force, and thus thrust, is measured using the International System of Units (SI) in newtons (symbol: N), and represents the amount needed to accelerate 1 kilogram of mass at the rate of 1 meter per second per second. In mechanical engineering, force orthogonal to the main load (such as in parallel helical gears) is referred to as static thrust. Examples A fixed-wing aircraft propulsion system generates forward thrust when air is pushed in the direction opposite to flight. This can be done by different means such as the spinning blades of a propeller, the propelling jet of a jet engine, or by ejecting hot gases f ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
