A rocket stage is part of a multi-stage rocket . It drives the entire rocket for a certain period of time and is disconnected after it has burned out to reduce its overall mass. Each stage is basically a rocket with a fuel supply and rocket engine .
Rockets that are to enter Earth orbit must at least reach first cosmic speed . The basic rocket equation describes the dependence of the maximum speed of a rocket on the exhaust speed of the engine gases and the ratio of take-off mass to empty mass plus payload. Since the outflow speed of the engine gases is limited by the fuels used and the payload is specified, the only option left is to keep the empty weight correspondingly low. Therefore, rocket stages that no longer have enough fuel are cut off in flight.
Rocket stages can be stacked on top of each other or attached to the outside of the rocket as a booster . They are used in space launch vehicles, ICBMs, and in some cases sounding missiles . The releasable main tank of the space shuttle was not a rocket stage, as he had no drive of its own.
Small, attached directly to the payload additional stages will also kick stage ( English kick stage called). Examples are the Fregat stage of the Soyuz rocket, the Curie of the Electron and the versatile Star 48 . After the first start phase, these stages take on the task of an apogee motor by slowly and finely dosed raising the orbit of the payload to the target height.