APOLLO: The Race to the Moon Charles Murray and Catherine Bly Cox Simon and Schuster. 506 pp. $24.95 MEN FROM EARTH By Buzz Aldrin and Malcolm McConnell Bantam. 312 pp. $19.95 JOURNEY INTO SPACE The First Three Decades of Space Exploration By Bruce Murray Norton. 381 pp. $19.95 IT IS NOW 20 YEARS since humans first set foot on the Moon. To more than half the species, that event is pure history, having taken place before they were born. And to many of the rest of us, that fact is itself incredible, because the first lunar landing was one of the seminal events of our lives. We remember following the progress of the flight on radio and television, and we recall just where we were and what we were doing when the Eagle landed and when Neil Armstrong seven hours later set his overshoe firmly on the Moon's surface. The astronauts were just the highly visible tip of a huge pyramid of people, all necessary to achieve John Kennedy's stated 1961 goal of landing a man on the moon, and returning him safely to earth before the decade was over. However, that diamond tip has through the years received almost all the attention. In Charles Murray and Catherine Bly Cox's Apollo: The Race to the Moon, the rest of the pyramid is finally seen whole. This is the amazing story of the engineers, Americans plus immigrant Germans and Canadians who, between the formation of NASA in October 1958 and the last Apollo mission in December 1972, designed and built the Mercury, Gemini and Apollo spacecraft, together with their launch vehicles and their command and control systems. Then they employed those systems to take scores of men safely to Earth orbit and a dozen men to the Moon and back. Apollo is a highly satisfying tale, rich, densely packed and beautifully told. I found it more exciting than much fiction, a book filled with cliffhangers, suspense and spine-tingling adventure. There was one tragic loss of three astronauts -- Grissom, White and Chaffee -- in the Apollo fire of Jan. 27, 1967; and the account of the events leading up to, during and after that tragedy is totally gripping. But except for that accident, the U.S. space program in the '60s might suggest to many people a continuous string of apparently effortless successes. This is far from the truth. In retrospect, the fact that all the missions brought their crews back safely to Earth seems almost miraculous -- a huge tribute to the dedication, ingenuity and nerve of thousands of people on the ground, as well as to the crews themselves. Look at the record. Apollo 6, one of the first unmanned tests of the Saturn rockets, lost two engines out of five on the second stage, and the third stage engine failed as well; yet the flight controllers were able to complete the mission. In Apollo 11, Armstrong and Aldrin's landing on the Moon was plagued by a computer overload. The ground controllers (rightly) told them to ignore the warning messages. They did, but landed with only a few seconds of fuel remaining. Apollo 12 was struck by lightning on the ascent into Earth orbit -- yet it performed its mission of the second lunar landing perfectly. No press reports mentioned the marvels of improvisation performed by the crew and the ground controllers to make everything work. Apollo 13 came closest of all to being a space disaster. On the third evening of the flight, 205,000 miles away from Earth, a major explosion blew out the command module's oxygen tanks, leaving it without power. The ground controllers moved the crew into the lunar module, juggled with inadequate power supplies and reduced the heat and water to a point where the three crew members arrived home chilled, weakened and dehydrated -- but alive, against all the odds. The whole program demanded extraordinary effort and a religious zeal from its workers. Many of the outstanding engineers now confess to having "missed the 1960s" in their preoccupation with program success. Yet most of these men of unique talent and character had no interest in publicity, and remain quite unknown to the public. Of them all, only Wernher von Braun, and to a lesser extent Chris Kraft, achieved superstar status. It is good to see the others given some of the recognition they all deserve, in chapter after chapter of compulsive reading. For they do deserve recognition, and not just for their superb engineering. Like many religions, this one demanded its sacrifices. In addition to the lives of three astronauts, the program took the mental and physical health of many workers, plus the family life and marriages of many more. But if you were to ask the survivors, today, if they have any regrets, this book suggests that they would all answer with a firm No. They were key players in one of the great adventures of this or any century. They know it, and nothing can ever take that away from them. BUZZ ALDRIN, the second man to walk on the Moon, was a central figure in that historic landing, and in the events of the 20 years that led up to it. His account of those events, Men From Earth, thus has the immediacy that comes only from someone who was there, in the middle of things, as Mercury and Gemini and Apollo were conceived, shaped and carried through. But it has more than that. Aldrin embeds his own personal saga, from Korean War jet pilot to Apollo 11 lunar module pilot, within the context of the Cold War. Space development is seen as one part of geopolitics, the pressure of both American and Soviet programs to "one up the other guy" is made very real, and activities at Tyuratam in the Soviet Union figure as largely as those in Houston and Cape Canaveral. The result is a vivid picture of a day-by-day struggle, in which both sides were continuously aware of what the other was doing, and in which to achieve rapid progress both took risks they would have otherwise avoided. If the Soviet Union now declares that it was never in a race to the Moon, Aldrin makes it clear that they are guilty of selective amnesia. The evidence also suggests that the Soviets, at Khrushchev's urging, took risks with their personnel far beyond anything NASA tolerated. Sometimes the pressure for another space spectacular produced only spectacular disaster, as in the ground explosion of a rocket in 1960, which led to the loss of scores of experienced launch technicians. The biggest disaster to the Soviet program, however, was almost certainly the death of Sergei Korolev, the mastermind of their best efforts. Men From Earth makes an unstated case for the idea that it was his death in January 1966, more than any other cause, that made the Soviet Union lose the race to the Moon. Even while the superpower struggle for space achievements occupied the pages of the world's newspapers, a more private struggle was going on in the United States. Aldrin describes, as few others have attempted to do, the importance to the astronauts of their personal roles. In public they were united, with no other thought than the success of the missions; and they did care about those missions, deeply. But in private each man also cared, more than anyone would admit, about himself: who would fly, who would be given the plum asignments, who would be left behind. "I think we were both beginning to realize just how important being the first man to set foot on the moon was. Neil hemmed and hawed for a moment and then looked away, breaking eye contact with a coolness I'd never seen in him before. 'Buzz,' he said, 'I realize the historical significance of all this . . .' "I was amazed." But I don't think Aldrin was, because he admits it mattered to him just as much as it did to Armstrong. Aldrin got his own chance to fly Gemini because of the accidental death of his friend and next-door neighbor, Charlie Bassett. Twenty years later, he still feels guilty about it. Can the decline of recent years in the U.S. space program be reversed? Aldrin suggests in his last pages several new initiatives, bright ideas for a revitalized U.S. space program. But he also knows that there is no money today to pay for them: "NASA's future plans certainly give the impression of . . . ambitious innovation . . . {but} NASA's budget simply does not provide for this scale of activity." And he ses a real danger that "we will become a second-rate space power in the next century." Maybe so. To a man who has given as much to the United States as Buzz Aldrin, and to someone who knew this country's space program in its golden and glorious youth, that prospect can only be heartbreaking. SINCE 1958, the U.S. scientific exploration of space using unmanned spacecraft has enjoyed a curious love-hate relationship with the manned space program, from Mercury, Gemini and Apollo on through to the space shuttle and the proposed space station. On the one hand, science has benefitted and still benefits from the development of powerful launch vehicles, guidance and control systems and communications equipment. On the other hand, space science often seems like the Cinderella of NASA. It makes do with a small fraction of the manned program's budget, it rarely has first call on resources, human or otherwise, and when cuts have to be made science usually feels the knife first. Bruce Murray, a professor at California Institute of Technology, former director of the Jet Propulsion Laboratory and a founder of the Planetary Society, has been at the center of this country's space science program for almost 30 years. His book recounts its major triumphs -- the Mariner Mars flybys and probes, the Mariner and Pioneer encounters with Venus and Mercury and the Viking Mars orbiter and lander. The high point of these efforts, the centerpiece of the past 20 years and one of the most extraordinary sagas of exploration ever, is surely the Voyager-1 and Voyager 2 encounters with Jupiter, Saturn and Uranus, with a climactic Neptune encounter due in August of this year. Murray makes it clear that there were many more technological cliffhangers in these efforts than the public would ever see. And in presenting the triumphs, he also throws in a liberal dose of frustration. His own views on the manned versus unmanned question are quite clear. Despite the title, Journey Into Space, this book is the story of unmanned exploration, for whom the manned program was always the bully, doing just what it liked. It was NASA's god, and dozens of valuable science projects were sacrificed on its altar -- often after extraordinary design efforts had already been completed. In some cases, notably the Giotto mission to Halley's comet and the solar polar spacecraft, international cooperation had already been promised to Europe, then withdrawn. It's hard not to feel sympathetic with Murray's point of view, even if at times one thinks of the fly on the axle of the moving chariot in Aesop's fable, looking around and remarking on the fine dust it is kicking up. For it is an undeniable fact, however distasteful, that the unmanned spacecraft of this country would not have reached their present sophistication, and most would never have existed, without the excitement and drive provided by the manned program. There is a strange irony in the way that this point is made by Murray's own writing. The technical problems he describes are always interesting, but they are not exciting. Only when he describes the events that surrounded the Challenger accident, or when he tells of Washington promises, evasions and betrayals, does the tension rise and the story become truly riveting. Murray saves his strongest criticism for the space shuttle project. He considers its inadequate design and insatiable demand for new funds, plus NASA management's decision to kill the expendable launch vehicle program in order to force all users towards the shuttle, as the twin forces that in the 1970s and 1980s crippled and almost destroyed U.S. science activities in space. Regrettably, it's hard to disagree with Murray's condemnation. In a final section, he dreams of an international cooperative exploration of the planet Mars. This is a fine vision, but the power of Murray's own analysis of the shuttle's development, added to NASA's current obsession with an ever-more-expensive space station, make such plans seem far away in an improbable future. Charles Sheffield is a novelist, physicist and past president of the American Astronautical Society.