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Apollo Expeditions to the Moon



The military rockets developed in the 1950s provided a basic tool with which it became possible to send rudimentary spacecraft to the Moon. Both the Army and the Air Force were quick to initiate efforts to be the first to the Moon with a manmade object. (The Russians, as it proved, were equally quick, or quicker.) These first U.S. projects, which were transferred in 1958 to the newly formed National Aeronautics and Space Administration, consisted of four Air Force Thor-Able rockets, and two Army Juno II rockets, each with tiny payloads, designed to measure radiation and magnetic fields near the Moon and, in some cases, to obtain rudimentary pictures. NASA and the Air Force then added three Atlas-Abie rockets, which could carry heavier payloads, in an attempt to bolster these early high-risk efforts. Of these nine early missions launched between August 1958 and December 1960, none really succeeded. Two Thor-Able and all three Atlas-Able vehicles were destroyed during launch. One Thor-Able and one of the Juno II's did not attain sufficient velocity to reach the Moon and fell back to Earth. Two rockets were left.

Mankind's first glimpse of the far side of the Moon came in October 1959, provided by the Soviet spacecraft Luna 3. Although crude compared with later views, its pictures showed a number of lunar features for the first time. One of these was the crater Tsiolkovsky, named for the famed Russian mathematician, which appears here in the lower right as a small sea with an island in it. The images from Luna 3 indicated that the Moon's far side lacked the large mare areas an the side facing Earth.

The Soviets were also having problems. But on January 4, 1959, Luna 1, the first space vehicle to reach escape velocity, passed the Moon within about 3700 miles and went into orbit about the Sun. Two months later the United States repeated the feat with the last Juno II, although its miss distance was 37,300 miles. A year later the last Thor-Able payload flew past the Moon, but like its predecessors it yielded no new information about the surface. On October 7, 1959, the Soviet Luna 3 became the first spacecraft to photograph another celestial body, radioing to Earth crude pictures of the previously unseen far side of the Moon. The Moon was not a "billboard in the sky" with slatted back and props. Its far side was found to be cratered, as might be expected, but unlike the front there were no large mare basins. The primitive imagery that Luna 3 returned was the first milepost in automated scientific exploration of other celestial bodies.

A sophisticated craft for its day, the 800-lb Ranger or its launch vehicle failed in its first six tries. Then it behaved beautifully, returning thousands of pictures in its last three flights, most of them far superior to the best that could be obtained from telescopes on Earth. Rangers crashed on the Moon at nonsurvivable velocity; their work was done in the few short moments from camera turn-on to impact.

Heading in toward Alphonsus, a lunar crater of high scientific interest, Ranger IX sent back 5814 pictures of the surface before it crashed. The one at left, taken several score miles away, shows part of the crater floor and slumped wall of Alphonsus, a rille structure, and a varied population of craters. Ranger pictures were exciting in the wholly new details of the Moon that they provided.

The last instant before it srnashed, Ranger IX radioed back this historic image, taken at a spacecraft altitude of one-third mile about a quarter of a second before impact. The area pictured is about 200 by 240 feet, and details about one foot in size are shown. The Ranger pictures revealed nothing that discouraged Apollo planners, although they did indicate that choosing an ideally smooth site for a manned landing was not going to be an easy task.

Undaunted by initial failures, and certainly spurred on by Soviet efforts, a NASA team began to plan a long-term program of lunar exploration that would embody all necessary ingredients for success. The National Academy of Sciences was enlisted to help draw the university community into the effort. The Jet Propulsion Laboratory, a California Institute of Technology affiliate that had been transferred from the Army to NASA in 1958, was selected to carry out the program. JPL was already experienced in rocketry and had participated in the Explorer and Pioneer IV projects.