Fact-laden novel on space program; Space, by James A. Michener. New York: Random House. 640 pp. $17.95.

In all his previous work James A. Michener's point of origin is the beginning of things. Whether his subject is Hawaii, the American West, or Chesapeake Bay, he lays out a virgin land and through a sometimes labored process of accretion fills it with people, customs, and objects.

Locale, therefore, dominates the action of his story and the development of character, a tendency indicated by the titles of his major novels. There is a brooding presence of landscape, a Hardyesque sense of determinism subjecting even the strongest of his people to a fate beyond their control.

So he might have opened this novel with a picture of planets and suns hurling through a million miles of emptiness. That would have given us a familiar Michener beginning. Instead, he moves to the last days of World War II and the men who had the early vision and professional promise to shape the American program in space.

The crucial decision to get into the action right away tells us something about this book that's different from other Michener novels. His focus here is not on the land and traditions of a given region, but rather on the people - the husbands, wives, and children - who were most affected by the space effort.

Four families dominate the reader's attention. One is a dedicated researcher who sacrifices everything for space exploration. Another is a US Senator serving on the powerful Space Committee. A third is a young athlete who becomes one of America's first straight-arrow astronauts.

The best-drawn of these families are a scientist and his wife who come to the US with Wernher von Braun. He is an untutored mechanic with a genius for designing and directing the V-2 rocket program in Germany. She had been a plain farm girl of peasant origin, but through determination to survive she saves her husband and herself from sure execution by the Nazis.

Lost and bewildered in their new country, the couple settle in Huntsville, Ala., with their young son and begin to adjust to their new lives. They face not only hostile neighbors, but also shifting scientific demands and expectations.

Choices facing the space pioneers were not always thrilling and dramatic. Many were simply administrative: Should the program be civilian or military, aimed at pure science, or used as a defense tool? How should it be financed, and to what extent should its limits be taken? Where should the brains come from? How should the astronauts be chosen?

In addition to these nuts-and-bolts issues, the scientists were divided among themselves by a philosophic question: Should the space program be satisfied with a spectacular, short-range trip to the moon, or should it take a longer course and aim for the planets beyond? This dilemma, which forms a major motif throughout the novel, provides the necessary intellectual tension between sets of characters.

Michener's familiar use of counterpoint is used here in a series of effective ways. He compares German civilization to American crassness and political expediency. Washington politicians are pitted against West Coast scientists, educated technicians against charlatans and pretenders. The scope of history is long and the canvas wide.

What is lacking is depth, a fault in all of Michener's work. For some it may be a virtue. He makes no great demands on the reader, spells out no spiritual or moral dilemma, claims nothing in the way of final truths.

Fiction of this kind becomes a matter of precise detail, an overload of information and fact. In many ways it is antifiction. But ''Space'' is readable, even in its prodigious length, and if that's the first test of a novel, then Michener has once again made the grade.