1.0 INTRODUCTION

1.1 Purpose

The purpose of this document is to provide the Reusable Launch Vehicle (RLV) Technology Development and Demonstration (RLVTD&D) Program with an synthesized operations concept and set of criteria for measuring operability characteristics of proposed technologies and vehicle concepts. The concept and criteria will provide the relative measure of return on investment of proposed RLV technologies and concepts with respect to reduction in operations cost or increase in operability.

1.2 Scope

This document provides driving requirements for the RLVTD&D Program. This document is not a traditional vehicle operations concept document. Appendix B provides a strawman outline for the subjects which would be included in such a vehicle operations concept defining the support required of a selected architectural approach.

The RLV program has not progressed to a maturity of concept selection. Vehicle design concepts and operations concepts must be developed in conjunction with one another including the necessary tradeoffs and analyses to ensure a desirable architecture will result.

This document defines the attributes of an operational system which should result in achievement of the RLV Program goals and requirements. All proposed technologies and vehicle configurations will be assessed for compliance with and application of the concepts and criteria herein. Technologies and vehicle configurations which do not promote an increase in operability as measured against the content of this document will not be recommended for further study, development or demonstration.

1.3 Documentation

1.3.1 Applicable Documents

National Space Transportation Policy, The White House, Office of Science and Technology Policy (OSTP), August 5, 1994

Reusable Launch Vehicle (RLV) Technology Development and Demonstration Program Plan, National Aeronautics and Space Administration (NASA), Space Access and Technology Office, Draft 2.0, August 18.1994

1.3.2 Reference Documents

Access to Space Study, Advanced Technology Team (Option 3), Final Report, Volume I: Executive Summary, and, Volume IV: Operations Plan, July 1993

1.4 Program Level Requirements

This section is a compilation of the requirements, goals, ground rules and assumptions which have been agreed to as the basis of the RLVTD&D Program. The RLVTD&D Program is a technology program not a launch vehicle program. There is, however, a vehicle definition framework within which these technologies must be applicable. For this reason, a presupposed set of RLV program definition requirements, goals, ground rules, and assumptions serves as this framework for the RLVTD&D Program technology evaluation. All operability criteria and requirements contained in this document are constrained only by the content of this section.

1.4.1 RLV Technology Development and Demonstration (RLVTD&D) Program Requirements and Goals

The overall goal of the RLVTD&D Program is to bring the technologies required for next generation reusable launch system to a demonstration in relevant environments. All technologies are being demonstrated with the objective of dramatically reducing the operations cost of future launch vehicles. NASA's technology requirements as derived form the National Space Transportation Policy are:

NASA's technology program as derived from the National Space Transportation Policy is:

1.4.2 RLV Program Requirements

This section is a compilation of previously defined RLV Level I Requirements. These vehicle program requirements preceded the National Space Transportation Policy release, and as such, have been evaluated for applicability to the RLVTD&D Program as defined by this policy.

The RLV Level I Program Requirements as agreed to by the MSFC RLV Study Team and presented to Industry in April 1994 were rewritten and presented to the combined RLVTD&D Program Synergy Teams at Ames Research Center (ARC) in August 1994. The following captures the content of these Level I Requirements

1.4.3 RLV Program Goals, Ground Rules and Assumptions

Many RLV Program goals, assumptions and ground rules have been formulated and proposed by various teams and working groups. In some cases these statements are in conflict with the requirements stated above and in many instances are in conflict with each other. In fairness to the authors, many of these goals, ground rules and assumptions were derived prior to the release of the National Space Transportation Policy and without insight into the definition processes taking place within the other working groups and synergy teams.

In any case, since many of these statements drove to further refine the top level program requirements above, they also necessarily narrowed the concept definitions which could meet the requirements. Many of these proposed goals, ground rules and assumptions could be categorized as: 1) Functional Requirements; 2) Attributes; 3) Constraints, or; 4) Design Solutions.

To eliminate further specification of any resulting design concept, we have chosen to not repeat any of these statements here. We have chosen instead, to provide a "visionary" framework within which to evaluate proposed vehicle concepts through analysis of derived and potential operations approaches and concepts. Vehicle and operations concepts which reach farther toward this vision can ultimately be supported with significantly reduced costs.

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Edgar Zapata, NASA Kennedy Space Center

Shuttle Process Engineering Directorate, Fluid Systems Division