JOURNEY TO THE STARS Space Exploration--Tomorrow and Beyond <i> by Robert Jastrow (Bantam: $9.95, illustrated) </i>

As the author is the former director of NASA’s Institute for Space Studies, it’s hardly surprising that “Journey� has a gung-ho tone reminiscent of the science- advocacy tracts of the late ‘50s, when the United States was struggling to overcome the initial successes of the Soviet Union in the “space race.� Robert Jastrow presents some interesting, basic material on the formation of the solar system and the early days of the U.S. space program, but his more speculative chapters, including trips to the various planets, are a bit silly. Twenty-one years after the first moon landing, the space program that once galvanized the nation has lost its appeal, but Jastrow fails to explain why the enthusiasm faded, and the resulting book is really a scientific sermon for the converted.