Engineering topics

Moore, A. A.

Publications and source records attributed to Moore, A. A..

3 records

NASA NTRS1996

Use of the Collaborative Optimization Architecture for Launch Vehicle Design

Collaborative optimization is a new design architecture specifically created for large-scale distributed-analysis applications. In this approach, problem is decomposed into a user-defined number of subspace optimization problems that are driven towards interdisciplinary compatibility and the appropriate solution by a system-level coordination process. This decentralized design strategy allows domain-specific issues to be accommodated by disciplinary analysts, while requiring interdisciplinary decisions to be reached by consensus. The present investigation focuses on application of the collaborative optimization architecture to the multidisciplinary design of a single-stage-to-orbit launch vehicle. Vehicle design, trajectory, and cost issues are directly modeled. Posed to suit the collaborative architecture, the design problem is characterized by 5 design variables and 16 constraints. Numerous collaborative solutions are obtained. Comparison of these solutions demonstrates the influence which an priori ascent-abort criterion has on development cost. Similarly, objective-function selection is discussed, demonstrating the difference between minimum weight and minimum cost concepts. The operational advantages of the collaborative optimization

Braun, R. D.↗

NASA NTRS1995

Optimal technology investment strategies for a reusable launch vehicle

Within the present budgetary environment, developing the technology that leads to an operationally efficient space transportation system with the required performance is a challenge. The present research focuses on a methodology to determine high payoff technology investment strategies. Research has been conducted at Langley Research Center in which design codes for the conceptual analysis of space transportation systems have been integrated in a multidisciplinary design optimization approach. The current study integrates trajectory, propulsion, weights and sizing, and cost disciplines where the effect of technology maturation on the development cost of a single stage to orbit reusable launch vehicle is examined. Results show that the technology investment prior to full-scale development has a significant economic payoff. The design optimization process is used to determine strategic allocations of limited technology funding to maximize the economic payoff.

Moore, A. A.↗

NASA NTRS1986

The relationship of intravascular bubbles to bends at altitude

In response to recent findings attesting to a correlation between intravehicular bubbling and decompression sickness at intermediate altitudes, an attempt was made to define a minimum pressure for a pressure suit which would obviate the need for prebreathing 100 percent oxygen prior to extravehicular activity (EVA). Fifty-seven male subjects were exposed to altitudes ranging from 16,000 to 30,000 ft in two separate protocols. The first was designed to determine a pressure at which no bends occurred if a crewmember were decompressed from a sea level space station pressure just prior to EVA without prebreathing 100 percent oxygen. The other study was designed to define an altitude and exercise regimen at which bends-susceptible and bends-resistant crewmembers could be separated. It is shown that the close association which exists between severe bubbling and bends at a pressure altitude of 4.3 psia (30,000 ft) decreases as pressure is increased and essentially disappears at pressures less than or equal to 7.8 psia (16,000 ft).

Krutz, R. W.↗