Escape Velocity Equation Derivation. An object can escape a celestial body of mass m only when its kinetic energy is equal to its gravitational potential energy. Escape velocity is derived by considering the product of orbital velocity and the square root of 2.

First, calculate the velocity, which is needed to escape the gravitational field of the sun from a stationary earth. The escape velocity at the earth’s surface is 11.2 km/sec.