When it was first broadcast in 1975, there had never been a more lavishly produced science fiction TV series than Space: 1999, a British production whose budget for the first of its two seasons ran an astounding 3.25 million pounds. What keeps us fans enthralled after all these years has only partly to due with the first-rate production values, the plausibly constructed spaceship models, and expert special effects. The tone of the show is one of scientific dispassion, … mehrsetting it apart from its TV sci-fi predecessors such as Star Trek, whose mood was more convivial. Our heroes here are in dire circumstances that require cool heads as a survival trait. Those circumstances: the 311 crew members of Moonbase Alpha experience a cataclysm that causes the moon to break away from Earth's orbit and travel endlessly through space, turning our heroes into unintentional explorers. No TV series has created a more palpable feel of hard science fiction than this. This set includes the episodes "Missing Link," "Guardian of Piri," "Force of Life," "Alpha Child," "The Last Sunset," and "Voyager's Return." --Jim Gay weniger