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A rocket's required mass ratio as a function of effective exhaust velocity ratio. 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 ...
An example of rocket sled launch assist: NASA's Maglifter proposal for giving a 500+ ton rocket initial velocity from a mountain. A rocket sled launch, also known as ground-based launch assist, catapult launch assist, and sky-ramp launch, is a proposed method for launching space vehicles. With this concept the launch vehicle is supported by an ...
If the direction upward is taken as positive (the normal cartesian convention) then positive g-force (an acceleration vector that points upward) produces a force/weight on any mass, that acts downward (an example is positive-g acceleration of a rocket launch, producing downward weight).
Including gravity, launch acceleration was only 1 + 1 ⁄ 4 g, i.e., the astronauts felt 1 + 1 ⁄ 4 g while the rocket accelerated vertically at 1 ⁄ 4 g. As the rocket rapidly lost mass, total acceleration including gravity increased to nearly 4 g at T+135 seconds.
To reach orbit, the rocket must impart to the payload a delta-v of about 9.3–10 km/s. This figure is mainly (~7.8 km/s) for horizontal acceleration needed to reach orbital speed, but allows for atmospheric drag (approximately 300 m/s with the ballistic coefficient of a 20 m long dense fueled vehicle), gravity losses (depending on burn time ...
A gravity turn is commonly used with rocket powered vehicles that launch vertically, like the Space Shuttle. The rocket begins by flying straight up, gaining both vertical speed and altitude. During this portion of the launch, gravity acts directly against the thrust of the rocket, lowering its vertical acceleration.
Each rocket has a characteristic thrust-to-weight curve, or acceleration curve, not just a scalar quantity. The thrust-to-weight ratio of an engine is greater than that of the complete launch vehicle, but is nonetheless useful because it determines the maximum acceleration that any vehicle using that engine could theoretically achieve with ...
As a result, launch costs are a large percentage of the cost of all space endeavors. If launch can be made cheaper, the total cost of space missions will be reduced. Due to the exponential nature of the rocket equation, providing even a small amount of the velocity to LEO by other means has the potential of greatly reducing the cost of getting ...