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Tripropellant Rocket
A tripropellant rocket is a rocket that uses three propellants, as opposed to the more common bipropellant rocket or monopropellant rocket designs, which use two or one propellants, respectively. Tripropellant systems can be designed to have high specific impulse and have been investigated for single-stage-to-orbit designs. While tripropellant engines have been tested by Rocketdyne and Energomash, no tripropellant rocket has been flown. There are two different kinds of tripropellant rockets. One is a rocket engine which mixes three separate streams of propellants, burning all three propellants simultaneously. The other kind of tripropellant rocket is one that uses one oxidizer but two fuels, burning the two fuels in sequence during the flight. Simultaneous burn Simultaneous tripropellant systems often involve the use of a high energy density metal additive, like beryllium or lithium, with existing bipropellant systems. In these motors, the burning of the fuel with the oxidizer p ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Rocket
A rocket (from it, rocchetto, , bobbin/spool) is a vehicle that uses jet propulsion to accelerate without using the surrounding air. A rocket engine produces thrust by reaction to exhaust expelled at high speed. Rocket engines work entirely from propellant carried within the vehicle; therefore a rocket can fly in the vacuum of space. Rockets work more efficiently in a vacuum and incur a loss of thrust due to the opposing pressure of the atmosphere. Multistage rockets are capable of attaining escape velocity from Earth and therefore can achieve unlimited maximum altitude. Compared with airbreathing engines, rockets are lightweight and powerful and capable of generating large accelerations. To control their flight, rockets rely on momentum, airfoils, auxiliary reaction engines, gimballed thrust, momentum wheels, deflection of the exhaust stream, propellant flow, spin, or gravity. Rockets for military and recreational uses date back to at least 13th-century China. Signific ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Kerosene
Kerosene, paraffin, or lamp oil is a combustible hydrocarbon liquid which is derived from petroleum. It is widely used as a fuel in aviation as well as households. Its name derives from el, κηρός (''keros'') meaning "wax", and was registered as a trademark by Canadian geologist and inventor Abraham Gesner in 1854 before evolving into a generic trademark. It is sometimes spelled kerosine in scientific and industrial usage. The term kerosene is common in much of Argentina, Australia, Canada, India, New Zealand, Nigeria, and the United States, while the term paraffin (or a closely related variant) is used in Chile, eastern Africa, South Africa, Norway, and in the United Kingdom. The term lamp oil, or the equivalent in the local languages, is common in the majority of Asia and the Southeastern United States. Liquid paraffin (called mineral oil in the US) is a more viscous and highly refined product which is used as a laxative. Paraffin wax is a waxy solid extracted from pet ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Plug Nozzle
The plug nozzle is a type of nozzle which includes a centerbody or plug around which the working fluid flows. Plug nozzles have applications in aircraft, rockets, and numerous other fluid flow devices. Hoses Common garden hose trigger nozzles are a simple example of the plug nozzle and its method of operation. In this example the nozzle consists of a conical or bell shaped opening with a plug on a movable rod positioned in front of the nozzle. The plug looks similar to a poppet valve. The stem of the valve runs back through the body of the nozzle body to a "trigger", normally a long lever running down the back of the nozzle assembly. A spring keeps the valve pressed against the opening under normal use, thereby providing a failsafe cut-off that stops the flow of water when the nozzle is dropped. When water is supplied to the hose, it flows through the nozzle body to the opening, where it would normally flow straight forward in a stream. Just after leaving the opening it encounter ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Propellant Mass Fraction
In aerospace engineering, the propellant mass fraction is the portion of a vehicle's mass which does not reach the destination, usually used as a measure of the vehicle's performance. In other words, the propellant mass fraction is the ratio between the propellant mass and the initial mass of the vehicle. In a spacecraft, the destination is usually an orbit, while for aircraft it is their landing location. A higher mass fraction represents less weight in a design. Another related measure is the payload fraction, which is the fraction of initial weight that is payload. It can be applied to a vehicle, a stage of a vehicle or to a rocket propulsion system. Formulation The propellant mass fraction is given by: \begin \zeta &= \frac \\ pt &= \frac = \frac \\ &= 1 - \frac \end where: *\zeta is the propellant mass fraction *m_0 = m_\text + m_\text is the initial mass of the vehicle *m_\text is the propellant mass *m_\text is the final mass of the vehicle Significance ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Single-stage-to-orbit
A single-stage-to-orbit (SSTO) vehicle reaches orbit from the surface of a body using only propellants and fluids and without expending tanks, engines, or other major hardware. The term usually, but not exclusively, refers to reusable vehicles. To date, no Earth-launched SSTO launch vehicles have ever been flown; orbital launches from Earth have been performed by either fully or partially expendable multi-stage rockets. The main projected advantage of the SSTO concept is elimination of the hardware replacement inherent in expendable launch systems. However, the non-recurring costs associated with design, development, research and engineering (DDR&E) of reusable SSTO systems are much higher than expendable systems due to the substantial technical challenges of SSTO, assuming that those technical issues can in fact be solved. SSTO vehicles may also require a significantly higher degree of regular maintenance. It is considered to be marginally possible to launch a single-stage- ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Space Shuttle
The Space Shuttle is a retired, partially 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 Space Transportation System (STS), taken from a 1969 plan 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 with Russia, and participated in construction and servicing of the International Space Station (ISS). ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
RP-1
RP-1 (alternatively, Rocket Propellant-1 or Refined Petroleum-1) is a highly refined form of kerosene outwardly similar to jet fuel, used as rocket fuel. RP-1 provides a lower specific impulse than liquid hydrogen (LH2), but is cheaper, is stable at room temperature, and presents a lower explosion hazard. RP-1 is far denser than LH2, giving it a higher energy density (though its specific energy is lower). RP-1 also has a fraction of the toxicity and carcinogenic hazards of hydrazine, another room-temperature liquid fuel. Usage and history RP-1 is a fuel in the first-stage boosters of the Electron, Soyuz, Zenit, Delta I-III, Atlas, Falcon, Antares, and Tronador II rockets. It also powered the first stages of the Energia, Titan I, Saturn I and IB, and Saturn V. The Indian Space Research Organization (ISRO) is also developing an RP-1 fueled engine for its future rockets. Development During and immediately after World War II, alcohols (primarily ethanol, occasionally metha ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Saturn V
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, with multistage rocket, three stages, and powered with liquid-propellant rocket, liquid fuel. It was 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 carry humans beyond low Earth orbit (LEO). Saturn V holds records for the heaviest payload launched and largest payload capacity to low Earth orbit: , which included the third stage and 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 contractor ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Gravity Drag
In astrodynamics and rocketry, gravity loss is a measure of the loss in the net performance of a rocket while it is thrusting in a gravitational field. In other words, it is the cost of having to hold the rocket up in a gravity field. Gravity losses depend on the time over which thrust is applied as well the direction the thrust is applied in. Gravity losses as a proportion of delta-v are minimised if maximum thrust is applied for a short time, or if thrust is applied in a direction perpendicular to the local gravitational field. During the launch and ascent phase, however, thrust must be applied over a long period with a major component of thrust in the opposite direction to gravity, so gravity losses become significant. For example, to reach a speed of 7.8 km/s in low Earth orbit requires a delta-v of between 9 and 10 km/s. The additional 1.5 to 2 km/s delta-v is due to gravity losses, steering losses and atmospheric drag. Example Consider the simplified case of ... [...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 from a rocket ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Atmospheric Drag
In fluid dynamics, drag (sometimes called air resistance, a type of friction, or fluid resistance, another type of friction or fluid friction) is a force acting opposite to the relative motion of any object moving with respect to a surrounding fluid. This can exist between two fluid layers (or surfaces) or between a fluid and a solid surface. Unlike other resistive forces, such as dry friction, which are nearly independent of velocity, the drag force depends on velocity. Drag force is proportional to the velocity for low-speed flow and the squared velocity for high speed flow, where the distinction between low and high speed is measured by the Reynolds number. Even though the ultimate cause of drag is viscous friction, turbulent drag is independent of viscosity. Drag forces always tend to decrease fluid velocity relative to the solid object in the fluid's path. Examples Examples of drag include the component of the net aerodynamic or hydrodynamic force acting opposite to the dire ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
RS-68
The Aerojet Rocketdyne RS-68 (Rocket System 68) is a liquid-fuel rocket engine that uses liquid hydrogen (LH2) and liquid oxygen (LOX) as propellants in a gas-generator power cycle. It is the largest hydrogen-fueled rocket engine ever flown. Its development started in the 1990s with the goal of producing a simpler, less-costly, heavy-lift engine for the Delta IV launch system. Two versions of the engine have been produced: the original RS-68 and the improved RS-68A. A third version, the RS-68B, was planned for the National Aeronautics and Space Administration's (NASA) Ares V rocket before cancellation of the rocket and the Constellation Program altogether. Design and development One of the main goals of the RS-68 program was to produce a simple engine that would be cost-effective when used for a single launch. To achieve this, the RS-68 has 80% fewer parts than the multi-launch Space Shuttle Main Engine (SSME). [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
