
The first astronauts took pictures out their little portholes. They were great documentary photos, but about as useful for science as the snapshots I've taken through airliner windows
Before we went into the depth of learning about the space, science fiction stories treated space travel as a new form of air or sea travel. Nobody thought the real space program would be like riding a giant wheel—we get on, go in circles, then come down, and while we're up there we look mostly down at the ground. But the real payoff of space, for Earth science and for every other human endeavor, has been the new vantage point we get to look at Earth itself.
The biggest Earth-watching satellite program is probably the Earth Observing System (EOS) program. Check out the Earth Observatory to see the scope of this enterprise, which is much bigger than I have space to review. Among other things, there is a thorough treatment of satellite imagery, as good as a full-fledged seminar on the subject.
James Irwin, USA: One of the famous astronauts who have gone into space had said about it in this way “The Earth reminded us of a Christmas tree ornament hanging in the blackness of space. As we got farther and farther away it diminished in size. Finally it shrank to the size of a marble, the most beautiful marble you can imagine. That beautiful, warm, living object looked so fragile, so delicate, that if you touched it with a finger it would crumble and fall apart. Seeing this has to change a man, has to make a man appreciate the creation of God and the love of God.”