Mistaken Identity

As scientists to date had found four planets of Earth type, all within our own galaxy. Close enough to be visited with our new ionic drive, that can enter super-space. There was unfortunately a slight mistake, when the young lady working the computer put in H. Potter, instead of Harold Potter. The computer sent out a telegram to Henry Potter. The space ship Aurora left Earth with the wrong commander. During the space-journey it proved to be an advantage to have Henry instead of Harold. They, because of Henry escaped from some space pirates, and found the planet that had sent the flying saucers, and the E.T.