National Security Requirements. Drive Shuttle Design

When NASA in its September 30, 1970, budget proposal to the Office of Management and Budget OMB) characterized the space shuttle as “cost- effective,” it was responding to pressure from the budget office to demon­strate that the combination of the costs of developing and operating the reusable shuttle would, over the period of shuttle use, produce a cost savings over the use of existing or new expendable launch vehicles to launch the same missions. This requirement was unprecedented; in the 12 years since NASA had begun operations, it had never been required to show that one of its programs could be justified in economic terms. The NASA leadership, once it had decided to defer the space station and to justify the shuttle as a general – purpose launch system, concluded that it had no alternative but to accede to the cost-effectiveness requirement. NASA quickly recognized that meeting this requirement would require the shuttle being used to launch essentially all U. S. payloads. In particular, military and intelligence satellites launched by the national security community comprised almost half of the U. S. demand for space launches, and there was no way that the shuttle could be cost effec­tive unless that community abandoned its own launch vehicles and commit­ted to use the shuttle once its feasibility had been demonstrated.

This put the national security community in a strong bargaining position. Knowing that NASA needed its commitment to use the shuttle, the com­munity could both set out a demanding set of performance requirements for the shuttle to meet and refuse to share in the cost of shuttle development, claiming it already had perfectly adequate launch capability. This was the path that was followed from early 1969 to the final approval of the shuttle. While NASA if it had not had to respond to national security requirements might well have chosen another shuttle design, its leaders decided that they had no choice but to meet those requirements. Throughout the shuttle study process, and particularly in the critical year of 1971, it was the ability of the shuttle to launch all or almost all national security as well as NASA payloads that defined the shuttle design NASA would advocate.

National security requirements defined three shuttle performance char­acteristics:

1. Payload bay dimensions: The shuttle would carry its cargo in a “payload bay.” The width and length of the payload bay would determine the size of the cargo that could be carried.

2. Payload weight: The lifting power of the shuttle was usually expressed in how many pounds of payload it could launch to various orbits. The weight of payloads that the shuttle could take to various orbits was in turn linked to how many future missions could be launched by the shuttle. The heavi­est payloads anticipated for the shuttle were national security missions.

3. Cross range: This was the ability of the shuttle to maneuver sideways from a “straight ahead” path as it returned to Earth. There were a variety of speculative national security missions for the shuttle that required cross range of over 1,100 nautical miles (nm).

This chapter gives only minimal attention to the detailed technical issues involved in defining a space shuttle design that would meet these national security requirements; those issues have been treated in several other studies.1