Definition The heart of the "hard science fiction" designation is the relationship of the science content and attitude to the rest of the narrative, and (for some readers, at least) the "hardness" or rigor of the science itself. One requirement for hard SF is procedural or intentional: a story should try to be accurate, logical, credible and rigorous in its use of current scientific and technical knowledge about which technology, phenomena, scenarios and situations that are practically or theoretically possible. For example, the development of concrete proposals for spaceships, space stations, space missions, and a US space program in the 1950s and 1960s influenced a widespread proliferation of "hard" space stories. Later discoveries do not necessarily invalidate the label of hard SF, as evidenced by P. Schuyler Miller, who called Arthur C. Clarke's 1961 novel A Fall of Moondust hard SF, and the designation remains valid even though a crucial plot element, the existence of deep pockets of "moondust" in lunar craters, is now known to be incorrect.
Definition The heart of the "hard science fiction" designation is the relationship of the science content and attitude to the rest of the narrative, and (for some readers, at least) the "hardness" or rigor of the science itself. One requirement for hard SF is procedural or intentional: a story should try to be accurate, logical, credible and rigorous in its use of current scientific and technical knowledge about which technology, phenomena, scenarios and situations that are practically or theoretically possible. For example, the development of concrete proposals for spaceships, space stations, space missions, and a US space program in the 1950s and 1960s influenced a widespread proliferation of "hard" space stories. Later discoveries do not necessarily invalidate the label of hard SF, as evidenced by P. Schuyler Miller, who called Arthur C. Clarke's 1961 novel A Fall of Moondust hard SF, and the designation remains valid even though a crucial plot element, the existence of deep pockets of "moondust" in lunar craters is now known to be incorrect.