[on his historic flight orbiting the earth] The engines started.I could feel them light off as the capsule vibrated from their ignition. And I could hear the roar. While the engines built to their proper thrust, the booster remained on the pad, and then the big hold-down clamps dropped away and I could feel us go. I had always thought that it would seem slow, even smooth, like an elevator rising. Well, it wasn't like that at all. It was a solid and exhilarating surge of up and away.