Even at an altitude of 200 kilometers, the Space Shuttle is still inside the outer reaches of the Earth's atmosphere. To really leave the atmosphere it probably has to get to a distance of 27,000 miles near the 'geosynchronous' limit is reached where it orbits once every 24 hours. The velocity at the Earth's surface that it needs is practically the same as the Earth escape velocity of 11.2 kilometers per second, or 25,805 miles per hour. The speed of sound is 33 meters per second or 760 miles per hour, so its escape velocity is about Mach 30.