How much is the minimum Escape Velocity of a Rocket to be launched in Space ?

Answer 1

Escape velocity = 11.2 km/s

Answer 2

11.2km/sec is known as escape velocity because a body travelling up at this speed at the earth's surface will keep going up without any further force being applied; the reverse argument (that you must reach escape velocity to keep going up) does not follow, but anything travelling more slowly will need a bit of a push on the way up.