What is the name for the minimum speed needed to escape a planet's gravitational pull?

Escape velocity is the minimum speed needed for an object to escape a planet’s gravitational pull without further propulsion. More precisely, it is the speed required to reach infinitely far away with zero remaining speed, assuming no atmospheric drag or additional forces.

For a spherical body, escape velocity depends on its mass and radius, not on the mass of the escaping object. It is calculated with v = √(2GM/r), where G is the gravitational constant, M is the body’s mass, and r is the distance from its center. This means a more massive or more compact world has a higher escape velocity.

Earth’s escape velocity at the surface is about 11.2 kilometers per second, or 25,000 miles per hour. The Moon’s is only about 2.38 km/s, which is why lunar launches require much less speed. At a black hole’s event horizon, the classical escape-velocity idea reaches the speed of light, though modern explanations use general relativity rather than Newtonian mechanics.

Escape velocity does not mean an object must instantly travel at that speed in every launch scenario; rockets can continue thrusting and follow efficient trajectories.