Summary and Conclusions

The intent of this report is a dynamic document providing a framework which will be updated as more data is gathered, improvements are implemented in current systems and new systems are developed and demonstrated.

This document is focused on the HRST study - "to identify innovative new systems concepts that can achieve Earth-to-orbit (ETO) transportation at costs of $100-$200 per pound payload". These costs are now approximately $5,000-$8,000. With few exceptions the features and the priority order presented in this report are also very applicable to any new space transportation system and to the Shuttle program and any future upgrades it may implement. The identification of concepts and associated technologies that hold the greatest promise of achieving very low recurring costs in space transportation results in critical up front investment decisions. Understanding how system choices relate to eventual recurring costs is a critical part of any up front planning.

The SPST challenges the technical community developing new systems to compare the features of their systems to the features, especially the design features, contained in this guide. The same basic questions apply to a system or an entire concept.

• Are many of the first 10 design features being improved upon?
• Are many of the first 20 design features being improved upon?
• Is a design responsive to the most important programmatics but not the most important design features?
• Is an effort focused on functional performance or is a balanced approach being used which addresses the design features as well as programmatics?
• Have other disciplines been directly involved early on in determining the direction of a technology development - what should be developed and focused on? Has manufacturing been involved early on well before implementation? Have operators been involved in setting a development focus?

Even if the prior questions are not easily answered (such as assessing a concepts improvement against the design features) is the general thrust or direction of a concept responsive to many of the top design features?

This document may be used by designers or program managers in terms of general thrust or direction even if a full assessment against the recommended improvements in order of priority is not immediately possible. The emphasis here is strategic.

Various conclusions are possible at this point:

1. The questions contained in each of this guides design features (how many toxic fluids, how much potential for BIT/BITE and so forth) must be well understood and quantified. Being non-traditional information at early decision making stages does not alter this need. This information has been determined to be key to understanding the total costs of a space transportation system. It is important that any HRST, reusable being the focus, quantify and understand the relationship of certain design features to eventual life cycle costs - development, acquisition and especially operation.
2. The need to quantify, predict and optimize recurring costs as well as other attributes of a concept such as launch on time or operability requires further efforts such as in modeling development. The ability to answer the question "how often can it launch and how many people are required" leads directly to "how much will it cost to operate". In order to enable successful decision making connected to long term goals information is required to formulate benchmarks that allow predicting the eventual operating costs of potential designs and architectures. This information which establishes a resource that is a result of a design would allow improvements focused on the costs of access to space to be well anchored and therefore more likely to actually succeed in achieving market growth through greater overall affordability.
3. A significant few top features have been determined here based on diverse sets and levels of information and team member backgrounds. Tentatively, it can be derived that an understanding of the complex inter-relationships of these top criteria is key to any strategy for improvement in space transportation affordability. A "cascade" effect for these criteria should be sought for improvements at the component, subsystems, and architecture levels. The intent is to have a ripple through as many of the important, prioritized criteria as possible. This is similar to the approach used in cascading weights to achieve performance gains.

Return to KSC Next Gen Site

Edgar Zapata, NASA Kennedy Space Center

Shuttle Process Engineering Directorate, Fluid Systems Division