Designing for Annual Spacelift Performance

This paper presents a methodology for approaching space launch system design from a total architectural point of view. This different approach to conceptual design is contrasted with traditional approaches that focus on a single set of metrics for flight system performance, i.e., payload lift per flight, vehicle mass, specific impulse, etc. The approach presented works with a larger set of metrics, including annual system lift, or "spacelift" performance. Spacelift performance is more inclusive of the flight production capability of the total architecture, i.e., the flight and ground systems working together as a whole to produce flights on a repeated basis. In the proposed methodology, spacelift performance becomes an important design-for-support parameter for flight system concepts and truly advanced spaceport architectures of the future. The paper covers examples of existing system spacelift performance as benchmarks, points out specific attributes of space transportation systems that must be greatly improved over these existing designs, and outlines current activity in this area

Adapting New Space System Designs into Existing Ground Infrastructure

As routine space operations extend beyond earth orbit, the ability for ground infrastructures to take on new launch vehicle systems and a more complex suite of spacecraft and payloads has become a new challenge. The U.S. Vision for Space Exploration and its Constellation Program provides opportunities for our space operations community to meet this challenge. Presently, as new flight and ground systems add to the overall groundbased and space-based capabilities for NASA and its international partners, specific choices are being made as to what to abandon, what to retain, as well as what to build new. The total ground and space-based infrastructure must support a long-term, sustainable operation after it is all constructed, deployed, and activated. This paper addresses key areas of engineering concern during conceptual design, development, and routine operations, with a particular focus on: (1) legacy system reusability, (2) system supportability attributes and operations characteristics, (3) ground systems design trades and criteria, and (4) technology application survey. Each key area explored weighs the merits of reusability of the infrastructure in terms of: engineering analysis methods and techniques; top-level facility, systems, and equipment design criteria; and some suggested methods for making the operational system attributes (the "-ilities") highly visible to the design teams and decisionmakers throughout the design process

Independent Space Operators: Gaining a Voice in Design for Operability

Affordable and sustainable space exploration remains an elusive goal. We explore the competitive advantages of evolving towards independent operators for space transportation in our economy. We consider the pros and cons of evolving business organizations that operate and maintain space transportation system assets independently from flight system manufacturers and from host spaceports. The case is made that a more competitive business climate for creating inherently operable, dependable, and supportable space transportation systems can evolve out of today's traditional vertical business model-a model within which the voice of the operator is often heard, but rarely acted upon during crucial design commitments and critical design processes. Thus new business models may be required, driven less by hardware consumption and more by space system utilization

Space Transportation System Availability Requirement and Its Influencing Attributes Relationships

It is important that engineering and management accept the need for an availability requirement that is derived with its influencing attributes. It is the intent of this paper to provide the visibility of relationships of these major attribute drivers (variables) to each other and the resultant system inherent availability. Also important to provide bounds of the variables providing engineering the insight required to control the system's engineering solution, e.g., these influencing attributes become design requirements also. These variables will drive the need to provide integration of similar discipline functions or technology selection to allow control of the total parts count. The relationship of selecting a reliability requirement will place a constraint on parts count to achieve a given availability requirement or if allowed to increase the parts count will drive the system reliability requirement higher. They also provide the understanding for the relationship of mean repair time (or mean down time) to maintainability, e.g., accessibility for repair, and both the mean time between failure, e.g., reliability of hardware and availability. The concerns and importance of achieving a strong availability requirement is driven by the need for affordability, the choice of using the two launch solution for the single space application, or the need to control the spare parts count needed to support the long stay in either orbit or on the surface of the moon. Understanding the requirements before starting the architectural design concept will avoid considerable time and money required to iterate the design to meet the redesign and assessment process required to achieve the results required of the customer's space transportation system. In fact the impact to the schedule to being able to deliver the system that meets the customer's needs, goals, and objectives may cause the customer to compromise his desired operational goal and objectives resulting in considerable increased life cycle cost of the fielded space transportation system

Paper Session I-A - Space Shuttle to Reusable Launch Vehicle

The National Space Transportation Policy establishes national policy, guidelines, and implementing actions for the conduct of National space transportation programs that will sustain and revitalize U.S. space transportation capabilities... . The direction to the National Aeronautics and Space Administration (NASA) is to provide for the improvement of the Space Shuttle system focusing on reliability, safety, and cost effectiveness. as well as be the lead agency for technology development and demonstration for next generation reusable space transportation systems, such as the single-stage-to-orbit concept. With this vision, NASA has initiated Cooperative Agreement Notices between NASA and the private sector for X-33 (Reusable Launch Vehicle-Advanced Technology Demonstrator) and X-34 (Reusable Launch Vehicle-Small Reusable Booster) which would provide insight to a decision by December 1996 to proceed with sub-scale flight demonstration to prove the single-stage-to-orbit (SSTO) concept. This paper deals with operational issues which must be dealt with in order to achieve SSTO goals of reliable low cost space transportation and order of magnitude reductions in operating costs

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