Engineering topics

Benfield, Michael P. J.

Publications and source records attributed to Benfield, Michael P. J..

6 records

NASA NTRS2011

Teaching the Next Generation of Scientists and Engineers the NASA Design Process

The Integrated Product Team (IPT) program, led by The University of Alabama in Huntsville (UAH), is a multidisciplinary, multi-university, multi-level program whose goal is to provide opportunities for high school and undergraduate scientists and engineers to translate stakeholder needs and requirements into viable engineering design solutions via a distributed multidisciplinary team environment. The current program supports three projects. The core of the program is the two-semester senior design experience where science, engineering, and liberal arts undergraduate students from UAH, the College of Charleston, Southern University at Baton Rouge, and Ecole Suprieure des Techniques Aronautiques et de Construction Automobile (ESTACA) in Paris, France form multidisciplinary competitive teams to develop system concepts of interest to the local aerospace community. External review boards form to provide guidance and feedback throughout the semester and to ultimately choose a winner from the competing teams. The other two projects, the Innovative Student Project for the Increased Recruitment of Engineering and Science Students (InSPIRESS) Level I and Level II focus exclusively on high school students. InSPIRESS Level I allows high schools to develop a payload to be accommodated on the system being developed by senior design experience teams. InSPIRESS Level II provides local high school students first-hand experience in the senior design experience by allowing them to develop a subsystem or component of the UAH-led system over the two semesters. This program provides a model for NASA centers to engage the local community to become more involved in design projects.

Caruso, Pamela W.↗

NASA NTRS2005

Simulation Analysis of Computer-Controlled pressurization for Mixture Ratio Control

A procedural code (C++) simulation was developed to investigate potentials for mixture ratio control of pressure-fed spacecraft rocket propulsion systems by measuring propellant flows, tank liquid quantities, or both, and using feedback from these measurements to adjust propellant tank pressures to set the correct operating mixture ratio for minimum propellant residuals. The pressurization system eliminated mechanical regulators in favor of a computer-controlled, servo- driven throttling valve. We found that a quasi-steady state simulation (pressure and flow transients in the pressurization systems resulting from changes in flow control valve position are ignored) is adequate for this purpose. Monte-Carlo methods are used to obtain simulated statistics on propellant depletion. Mixture ratio control algorithms based on proportional-integral-differential (PID) controller methods were developed. These algorithms actually set target tank pressures; the tank pressures are controlled by another PID controller. Simulation indicates this approach can provide reductions in residual propellants.

Alexander, Leslie A.↗

NASA NTRS2005

Manned Lunar Missions: An Exercise in Propulsion Trades and Sensitivities

A recent study performed for the In-Space Propulsion Technology Office at the Marshall Space Flight Center investigated the effects of using different propellant types on the different stages required to perform a manned lunar mission. The original study included investigations into propellant type, propellant storage technology options and sensitivities to specific impulse variations for a lunar orbit rendezvous mission. The initial mission characteristics were based on previous work led by Langley Research Center. Outlined in this paper are the results of that study and the work that followed. A lunar direct return architecture was added to the analysis. Since both architectures required assembly of the various propulsive stages in low Earth orbit and multiple launches to deliver those stages, investigations of launch sequence and scheduling sensitivities were also included. Results show that lunar direct return architectures require more mass to complete missions when compared to lunar orbit rendezvous missions. Within the given architectures, trends in the results tended to be very similar with the architectures indicating very little sensitivity to launch sequence and specific impulse variations and indicating more sensitivity to the propellant choice made for each stage and the time between launches. Even though this study investigates a small subset of the possible lunar architecture trade space, it does begin to outline some of the issues that must be investigated and the characteristics of the mission and the mission elements that are of most importance to a full architecture assessment.

Percy, Thomas K.↗

NASA NTRS2004

Modeling of Spacecraft Advanced Chemical Propulsion Systems

This paper outlines the development of the Advanced Chemical Propulsion System (ACPS) model for Earth and Space Storable propellants. This model was developed by the System Technology Operation of SAIC-Huntsville for the NASA MSFC In-Space Propulsion Project Office. Each subsystem of the model is described. Selected model results will also be shown to demonstrate the model's ability to evaluate technology changes in chemical propulsion systems.

Benfield, Michael P. J.↗

NASA NTRS2004

In-Space Chemical Propulsion System Model

Multiple, new technologies for chemical systems are becoming available and include high temperature rockets, very light propellant tanks and structures, new bipropellant and monopropellant options, lower mass propellant control components, and zero boil off subsystems. Such technologies offer promise of increasing the performance of in-space chemical propulsion for energetic space missions. A mass model for pressure-fed, Earth and space-storable, advanced chemical propulsion systems (ACPS) was developed in support of the NASA MSFC In-Space Propulsion Program. Data from flight systems and studies defined baseline system architectures and subsystems and analyses were formulated for parametric scaling relationships for all ACPS subsystem. The paper will first provide summary descriptions of the approaches used for the systems and the subsystems and then present selected analyses to illustrate use of the model for missions with characteristics of current interest.

Byers, David C.↗

NASA NTRS2004

Modeling of Spacecraft Advanced Chemical Propulsion Systems

Benfield, Michael P. J.↗