National Geographic : 1964 Nov
above the earth at 24,470 miles per hour, with an allowable error of only 16 miles per hour. To the Goldstone tracking station in Cali fornia's Mojave Desert (page 695) came cryp tic signals acknowledging commands and reporting their execution. For more than 68 hours Ranger 7 sped on. Then, 17 minutes before impact, its cameras raised their war bling voices. Images formed in their TV tubes were being translated into electrical impulses and transmitted back for photographic and tape recording. The voice on the hot line from Goldstone told us, "... 10 seconds... we're receiving pictures to the end ... impact... impact!" Suddenly, silence. Then shouts and hand shakes all through JPL hailed America's first successful photographic mission to the moon. Craft Hits Six Miles From Mark Afterward Project Manager Harris Schur meier said, "We did it, and we're going to be able to do it again. Not every time perhaps, but there'll be other flights as perfect as this one. "We're learning," he added. "With Ranger 6 we missed our predicted target by 18 miles. This time we missed by about six." In its final minutes of flight, Ranger 7's cameras transmitted more than 4,300 photo graphs. The last was recorded at Goldstone just 1.49 seconds after the shutter clicked in the spacecraft. I scanned the photos a few hours later with my colleagues in the Ranger program, Dr. Gerard P. Kuiper (the principal investigator) and Ewen A. Whitaker, both of the University of Arizona, and Raymond L. Heacock, of JPL (page 703). To us these unlovely rectangles of mottled gray were beautiful. They were nearly unbe lievable. No one had ever seen details like these. Resolution in the last photograph taken Its television eyes focused on a 300,000 square-mile segment of the moon, shown as overlapping rectangles, Ranger 7 flies the angled approach that allows unhindered vision from the camera window. Here 1,300 miles up, solar panels face the sun. Moon's ravaged face reflects its explosive history. Lighter rays around the crater Co pernicus (upper center) contain clusters of secondary craters that reach near to point of impact (red circle). Some of the lighter splotches in the camera view are debris from the cataclysmic collision that created the vast Mare Imbrium, Sea of Rains, which ranges over the horizon at upper right. Most mountains are remnants of crater rims. PAINTING BY PIERRE MION; LUNAR SURFACE BASED ON LICK OBSERVATORYPHOTOGRAPH,COURTESYOF LUNAR AND PLANETARY 696 LABORATORYOF THE UNIVERSITY OF ARIZONA © N..S.