National Geographic : 1964 Nov
THE MOON WILL NEVER seem the same. For scientist and romanticist alike, its enigmatic face is altered. It's our fault, and we're delighted. We've taken the first close look at our space mate, and if fantasies have faded, facts have replaced them. And the facts suggest that we can set down a manned spacecraft on the lunar land scape without unreasonable risk. Earth's Satellite Brought Nearer Ever since man became man, and so learned to wonder, the moon has seized his emotions and teased his curiosity. Millenni ums of myth and mystery brought him no closer to an understanding of the eternal traveler of the night skies than was his low browed ancestor, watching naked on the Afri can plains. Then, an instant ago in the time span of the planets, an Italian named Galileo made a telescope and at once saw many wonderful things. In that moment our knowledge of our place in space leapt forward. The moon took form and revealed its features. A period of great astronomical discovery began. By July 31, 1964, when the spacecraft Ranger 7 hit the moon, we had gone about as far as we could in discerning lunar topograph ic features with earth-based optics. Our best telescopes had brought us visually to within 400 miles of the moon's surface. But they could do no more. The protective atmosphere that shields us from the blaze and bombard ment of the universe also shields its secrets from us; our vision is blurred. No lunar detail less than 800 feet across had been distin guished from our planet. Still, we had inherited many basic facts about the moon. We knew its diameter: one quarter that of the earth; its mass: 11/4 percent of earth's; its orbital and rotational periods: both 271/3 days, keeping the same face always toward us. And we had learned much that was new, as befits a nation on the verge of space travel. We had measured variations in the brightness of the moon's reflected light. We had charted its features, all the way down to those of one mile or less across. We had worked out the layering of its surface, and so learned the se quence of major events in its history. We had even bounced radar off it to determine its exact orbit. And yet, the face of the moon raised more questions than it answered. We could only guess at its exact topography and the rough ness of its surface-matters of particular in 692 terest to an astronaut bound for the moon. We needed a breakthrough greater than Galileo's glass, of a kind never before achiev able. The Jet Propulsion Laboratory of the California Institute of Technology at Pasa dena had spent five years and $200,000,000 trying to deliver just that to the National Aer onautics and Space Administration. Through its Ranger program, JPL sought to provide future manned and unmanned lunar landing projects with vitally needed information about the surface of the moon.* A series of Ranger spacecraft had been sent out to get it. None had succeeded. But Ranger 6 proved beyond question the ex cellence of the Ranger design by a flawless if scientifically unproductive flight. Ranger 6 sent home no photographs; its cameras were knocked out by an accident shortly after launch. But now JPL proposed again, with Ranger 7, to provide man with distant eyes, positioned perfectly in space, through which to see what nature had made invisible to him. Scientists Compile Moon Portrait As JPL's research progressed, my organi zation, the Astrogeology Branch of the United States Geological Survey, focused its instru ments and intellects on the moon. We, too, were set up to support NASA's programs. We mapped the Ranger target areas not only by observation but by applying such astronomical techniques as photometry to geological procedures. With the data ob tained, we assisted in the selection of sites for Ranger photographic coverage, hoping through its pictures to discover areas smooth enough for a manned landing. Ranger 7's target was a promising site. A plainlike region about 400 miles south of the great crater of Copernicus, it appeared to be one of the smoothest in its part of the moon. And at the end of July, 1964, it would be well lighted for Ranger photography. When Ranger 7 was launched, I was at JPL, closeted with other scientists responsible for choosing impact areas and interpreting pictures. In the control room, Pat Rygh, the space flight operations director, sent the messages that guided the little blue-winged, six-eyed spacecraft into a precise trajectory for a moon landing. It would have to fly through a 10-mile-wide "window" 120 miles *See, in NATIONAL GEOGRAPHIC, "Exploring Our Neighbor World, the Moon," by Donald H. Menzel, February, 1958, and "Robots to the Moon," by Frank Sartwell, October, 1962.