Why had we come to the moon? The thing presented itself to me as a perplexing problem. What is this spirit in man that urges him for ever to depart from happiness and security, to toil, to place himself in danger, to risk an even a reasonable certainty of death? It dawned upon me that there in the moon as a thing I ought always to have known, that man is not made to go about safe and comfortable and well fed and amused. … against his interest, against his happiness, he is constantly being driven to do unreasonable things. Some force not himself impels him, and he must go.