The idea of space exploration can be traced back at least to the second century a.d. when the Greek satirist, Lucian, described an imaginary lunar voyage. Others have described space travel in fiction. In modern times the theoretical basis of space navigation was developed by R.H. Goddard in America, H.J. Oberth in Germany, and K.E. Tsiolkovsky in Russia. After World War II the early work on rockets carried out in Germany was continued in the USA and the USSR. In 1961 Yuri Gagarin was the first man in space, and the Russians triumphantly announced that he found no sign of God in the sky. In 1969, when Americans were the first men on the moon, Neil Armstrong and Edwin Aldrin read the Bible back to earth and partook together of the Lord's Supper on the surface of the moon. Space exploration and its kindred developments inevitably raise some questions of Christian concern: (1) Do they merit expenditure of so much money and resources when there is so much need on earth? (2) Do they bring nearer the concept of the superstate as prophesied (cf. Rev. 13, assuming the futurist interpretation)? (3) Has God made other intelligent creatures? Are they sinful? If so, by what means does He redeem them, since Christ died once only for sin? These questions are, of course, unanswerable in view of our ignorance. Man is beginning to realize, nevertheless, how vast is God's universe-so vast as to suggest that man's extraterrestrial investigation is circumscribed in God's comprehensive plan.