Speeds higher than escape velocity retain a positive speed at infinite distance. In other words, if given escape velocity, the object will move away from the other body, continually slowing, and will asymptotically approach zero speed as the object's distance approaches infinity, never to come back.
Once escape velocity is achieved, no further impulse need be applied for it to continue in its escape. With escape velocity in a direction pointing away from the ground of a massive body, the object will move away from the body, slowing forever and approaching, but never reaching, zero speed. More generally, escape velocity is the speed at which the sum of an object's kinetic energy and its gravitational potential energy is equal to zero an object which has achieved escape velocity is neither on the surface, nor in a closed orbit (of any radius). Likewise, hindrances like air drag are also considered propulsion (only, negative), so they are not part of the escape speed calculation, but are to be taken into account later in further calculation of trajectories. Any means to provide acceleration will do ( gravity assist, solar sail, etc.). It can achieve escape at any speed, given sufficient propellant to provide new acceleration to the rocket to counter gravity's deceleration and thus maintain its speed. A rocket can escape without ever reaching escape speed, since its engines counteract gravity, continue to add kinetic energy, and thus reduce the needed speed. As evidenced by Voyager program, an object starting even at zero speed from the ground can escape, if sufficiently accelerated. On the other hand, an object already at escape speed needs slowing (negative acceleration) for it to be captured by the gravitational influence of the body. Its calculation at a given distance means that no acceleration is further needed for the object to escape: it will slow down as it travels-due to the massive body's gravity-but it will never quite slow to a stop. The escape speed is independent of the mass of the escaping object, but increases with the mass of the primary body it decreases with the distance from the primary body, thus taking into account how far the object has already traveled. Although the term "escape velocity" is common, it is more accurately described as a speed than a velocity because it is independent of direction. It is typically stated as an ideal speed, ignoring atmospheric friction. In celestial mechanics, escape velocity or escape speed is the minimum speed needed for a free, non- propelled object to escape from the gravitational influence of a primary body, thus reaching an infinite distance from it.
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