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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.
Field propulsion is the concept of spacecraft propulsion where no propellant is necessary but instead momentum of the spacecraft is changed by an interaction of the spacecraft with external force fields, such as gravitational and magnetic fields from stars and planets.
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]
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 ...
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.
The amount of propellant could be defined either in units of mass or weight. If mass is used, specific impulse is an impulse per unit of mass, which dimensional analysis shows to be equivalent to units of speed; this interpretation is commonly labeled the effective exhaust velocity. If a force-based unit system is used, impulse is divided by ...
For example, calculations show that the Titan II first stage, launched on its own, would have a 25-to-1 ratio of fuel to vehicle hardware. [29] It has a sufficiently efficient engine to achieve orbit, but without carrying much payload.
The most commonly used propellant in this case is stabilized propylene glycol dinitrate , often referred to as "Otto fuel". A potential future use for monopropellants not directly related to propulsion is in compact, high-intensity powerplants for aquatic or exoatmospheric environments.