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Escape velocity of Earth
Beginner
Approximately 11.2 km/s.
v_e ≈ 11.2 km/sAbout 11.2 km/s (40,300 km/h). Rockets don't need this at launch; they climb gradually and need more energy over time.
Moon missions need less than full escape energy.
Applies to a projectile with no further propulsion.
In more detail
Earth's escape velocity is about 11.2 km/s from the surface. Its value follows from Earth's mass and radius, and it is much lower than the speed needed to leave the solar system.
Real-world uses
- Launch vehicles aim to exceed about 11 km/s to leave Earth entirely.
- Interplanetary missions need additional speed beyond escape velocity.
- Space agencies quote the escape speed of 11.2 km/s when planning launches from Earth's surface.
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Frequently asked questions
Is Earth's escape speed the same as orbital speed?
No. Orbital speed near the surface is about 7.9 km/s, which is lower.
Why do we need 11 km/s to leave Earth?
It is the speed needed to get far enough from Earth to avoid being pulled back by its gravity.
Does escape speed depend on the mass of the rocket?
No. It depends only on the planet's mass and radius, so a light and a heavy rocket need the same speed.
Related topics in Gravitation & Orbits
Field of a spherical shell · Field inside a uniform sphere · Escape velocity · Orbital velocity · Satellite energy · Orbital period