Solar System Escape Velocity

Solar System Escape Velocity 

the minimum initial speed that must be imparted to a body at the earth’s surface for the body to overcome the earth’s and then the sun’s gravitational attraction and leave the solar system forever. The solar system escape velocity is approximately 16.6 km/sec for a launch at an altitude of 200 km above the earth’s surface. This escape velocity is determined by the condition that the body, upon reaching the boundary of the earth’s sphere of influence, has a parabolic velocity relative to the sun. Since the parabolic velocity at the distance of the earth’s orbit is 42.10 km/sec, the minimum speed that the body must have at the boundary of the earth’s sphere of influence is 12.33 km/sec (the direction of the body’s motion must coincide with the direction of the earth’s orbital motion, the mean speed of which is 29.77 km/sec).