the RBS business case does not account for new entrant commercial providers, in that the business case is based on a comparison of the RBS concept to an extrapolation of recent Evolved Expendable Launch Vehicle (EELV) costs. Given the significant number of commercial entities pursuing novel approaches towards achieving launch capabilities, the future of space lift may look very different from that employed today. With global competition to reduce launch costs, it is anticipated that recent EELV costs may not be the proper baseline for cost comparisons.

Second, the RBS business case does not address the impacts of single source providers. So, while the business case assumes that RBS captures the complete Air Force launch manifest and is developed with a single source provider, the cost risks associated with using a single source are not adequately addressed. Said another way, the cost benefits associated with retaining competition in vehicle development were not included in the business case. Since the commercial launch market is rapidly changing and will be driven by cost considerations, neglecting an assessment of the role of competition is viewed as a weakness in the current RBS business case.

Third, the RBS business case assumed full capture of the Air Force launch manifest, but the Air Force maintains a requirement for independent launch capabilities for mission assurance needs. With this need for development and/or maintenance of a second launch system capability, the RBS business case model is overly optimistic in its assumption regarding full capture of the Air Force launch manifest.

The end result of these factors is that the uncertainties associated with the RBS business case are sufficiently large that the business case cannot be considered to be closed at the present time.

Finding 3: Reusability remains an option for achieving significant new full-spectrum launch capabilities at lower cost and greater launch flexibility.

The Air Force Space Command has identified a long-term science and technology objective for achieving full-spectrum launch capabilities at significantly reduced costs, and reusability remains a potential option for realizing this objective. In concert with reduced costs, development of a robust reusable system might have additional benefits that may be realized, including replenishment of satellites on need; deployment of distributed constellations; rapid deployment of capabilities; robust launch operations from multiple, defendable launch sites; and operations by Air Force personnel.

Finding 4: For RBS to significantly impact Air Force launch operations, it would have to be more responsive than current expendable launch systems. However, no requirement for RBS responsiveness has been identified that would drive technology development.

The current business case for RBS is built on satisfying the current EELV launch manifest with a launch-on-schedule assumption to operations. With this assumption and the lack of an operability requirement for RBS, the technologies necessary to significantly enhance operability and reduce operations costs will not be emphasized. It is through development of design features and technologies, and the resulting changes to Air Force operations that the true value of a reusable system lays.

Finding 5: Technology areas have been identified in which continued applied research and advanced development are required before proceeding to large-scale development. These areas include reusable ORSC hydrocarbon-fueled engines, rocketback return-to-launch-site (RTLS) operation, vehicle health management systems, and adaptive guidance and control capabilities.

Finding 6: Given the uncertainties in the business case and the yet-to-be mitigated technology risks, it is premature for Air Force Space Command to program significant investments associated with the development of a RBS capability.

While the committee found that the RBS business case cannot be closed at this time, and it is premature to begin large-scale RBS development activities, the committee does strongly endorse the continued research and



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