Summary: The "average cost per flight" for the space shuttle, which the National Aeronautics and Space Administration (NASA) pegged at $413.5 million in fiscal year 1993, includes most costs for shuttle operations but omits about $30.2 billion spent through fiscal year 1992 to develop the shuttle as well as more than $1 billion that will be needed annually for future shuttle upgrades and for improvements like the advanced solid rocket motor. For fiscal year 1993, NASA estimated the marginal costs savings associated with deleting a single flight at $44.4 million. Marginal cost includes consumable hardware and materials, along with personnel, that can be added or removed with temporary adjustments in the flight rate. It does not include any of the fixed costs required if NASA is to maintain the capability to fly the shuttle eight or nine times per year. NASA says that these fixed costs account for about 90 percent of the total operations cost of a flight. Although no single criterion is generally accepted for determining which costs to include when attributing shuttle transportation costs to payloads, GAO believes that the average cost per flight would better reflect the cost of transportation for payloads that are frequent shuttle users. Because the Space Station Freedom program will be the main user of shuttle services in fiscal years 1997 to 1999, it should be allocated a proportionate share of the shuttle's fixed operating costs when calculating transportation costs during those years.
