The Space Shuttle reduces operational space costs and makes space accessible to more personnel. Mission objectives dictate how occupant safety is achieved. High standards of occupant safety in a space vehicle's hazardous environment, in turn, greatly influence design. Protection from some hazards, like fire, explosion, depressurization, toxicity, control loss, and radiation are controlled similarly to past space programs but with some deviations from aircraft practices. Man is another hazard source which is controlled primarily by training and proper procedures.