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A reactionless drive is a hypothetical device producing motion without the exhaust of a propellant.A propellantless drive is not necessarily reactionless when it constitutes an open system interacting with external fields; but a reactionless drive is a particular case of a propellantless drive that is a closed system, presumably in contradiction with the law of conservation of momentum.
For example, a 1-tonne spaceship traveling at 1/10 of the speed of light carries a kinetic energy of 4.5 × 10 17 joules, equal to 5 kg according to the mass–energy equivalence. This means that for accelerating to such speed, no matter how this is achieved, the spaceship must have converted at least 5 kg of mass/energy into momentum ...
All designs for electromagnetic propulsion operate on the principle of reaction mass. A hypothetical drive which did not expel propellant in order to produce a reaction force, providing thrust while being a closed system with no external interaction, would be a reactionless drive, violating the conservation of momentum and Newton's third law. [17]
Electric propulsion methods like mass drivers are systems where energy does not come from the propellant itself. (This contrasts with chemical rockets where propulsive efficiency varies with the ratio of exhaust velocity to vehicle velocity at the time, but near maximum obtainable specific impulse tends to be a design goal when corresponding to ...
Atmosphere-breathing electric propulsion, or air-breathing electric propulsion, shortly ABEP, [1] 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 ...
"We’re just college students who have homework and dishes and groceries to do, and we just sent a rocket to space. We broke the world record and sent a rocket higher than any [amateur] ever has.”
A cold gas thruster (or a cold gas propulsion system) is a type of rocket engine which uses the expansion of a (typically inert) pressurized gas to generate thrust.As opposed to traditional rocket engines, a cold gas thruster does not house any combustion and therefore has lower thrust and efficiency compared to conventional monopropellant and bipropellant rocket engines.
For example, LH 2 /LO 2 bipropellant produces higher I sp (due to higher chemical energy and lower exhaust molecular mass) but lower thrust than RP-1/LO 2 (due to higher density and propellant flow). In many cases, propulsion systems with very high specific impulse—some ion thrusters reach 25x-35x better I sp than chemical engines—produce ...