The future space program of the United States is linked to the near-term deployment of the Space Transportation System (STS), or Space Shuttle. The Space Shuttle will provide routine access to the space environment at a cost that will be greatly reduced over that of previous booster systems. The STS features reliance on reusable components to cut transportation costs. Once the Shuttle is success-fully deployed, a series of scientific and technical missions will be flown which will greatly expand the role of space technology in creating a positive future for all humanity. Shuttle missions will be concerned with resource monitoring, pollution abatement, crop, ocean and forestry surveying, communications, improved weather forecasting, space processing, life sciences, and a host of other basic and applied investigations which will greatly advance the frontiers of human knowledge (1).