Space Exploration: The Full Picture from Mars

Mariner IV, the agile U.S. spacecraft designed to take the measure of Mars, has lived up to every expectation. At Caltech's Jet Propulsion Laboratory last week, the last worries vanished; there was no longer any concern that the ship's tape recorder might have gone haywire during part of its historic pass at the red planet. As soon as the eleventh picture came through, JPL monitors knew that all was well. Mariner got all the 21 pictures it went after—plus a bonus: 22 lines of a 22nd picture, which might show the dark edge of Mars.

Although the first three pictures...