Concept Selection Criteria

Table 5 contains a list of concept selection criteria the study team used for the Pugh concept selection approach. These criteria were considered to be broad and served only to ensure that all Pugh voters were at a common point of reference in their understanding of the criteria. This system is based on current technology expendable solid upper stages such as the transfer orbit stage (TOS) and the payload assist module (PAM) DII Solids are simple, expendable, non-restartable systems. The...

Upper Stage Production

The subsystems are structures, mechanisms, passive thermal control, active thermal control, electric power, C& DH, GN& C, reaction control system, propulsion, SRM's, liquid rocket engines, electric propulsion engine, advanced solar arrays, absorber gimbal, collector optics mechanism, nuclear rocket engine, apogee kick motors, and airborne support equipment. Each upper stage concept does not necessarily utilize all of these subsystems. NASCOM was used to compute, where feasible, first-unit...

Recommendations for Future Studies

Explore indepth the issues and technological requirements of reusable systems. A comparison could then be made between reusability and expendability for the solar thermal system, and an understanding gained of the complexities and potential cost savings of reusability. B. Study in more detail what could be done to reduce the costs further. C. Examine in more detail the tether systems. This study looked at the dynamic tether, however not enough information was available to do an indepth...

Solar Electric Propulsion Concepts Concept Description

This space-based, reusable upper-stage concept uses a solar electric rocket engine for main propulsion and is a low-thrust system. Since the operable life of the engine was assumed to exceed that of the solar arrays the arrays may degrade severely due to repeated exposure to the Van Allen Belts , this concept is limited to a total of 10 flights 9 reuses . A sketch of the concept is shown in figure 13 and weight summaries are given in tables 14 and 15. Additionally, tables 16 and 17 show the...

Design Development Test and Evaluation Cost Model

Since the AIST concepts incorporate only those technologies that are at TRL-6 or higher by the year 2005, the DDT amp E cost does not include any research and development R amp D cost to bring current 1995 pre-TRL-6 concept technologies up to TRL-6 or beyond. Subsystems costed are structures, mechanisms, passive thermal control, active thermal control, electric power, C amp DH, GN amp C, reaction control system, propulsion, SRM's, liquid rocket engines, advanced solar arrays, electric...

NASA Study Team Members

Robert Armstrong Leslie Curtis John Fikes Scott May Jim McCarter Jeff Morton Mahmoud Naderi Saroj Patel Alan Philips James Thompson Stephen Tucker Melissa Van Dyke Ron White Jim Wiser Determination of mission models Final documentation final report of study results Operations queing model program Assignment of complexity factor for all concepts All details associated with the solar thermal, solid, and hybrid concepts NASCOM costing of all concepts