SCIENTIFIC AND TECHNICAL AEROSPACE REPORTS

A Biweekly Publication of the National Aeronautics and Space Administration
VOLUME 44, ISSUE 12 - JUNE 20, 2006

20 SPACECRAFT PROPULSION AND POWER
Includes main propulsion systems and components, e.g., rocket engines; and spacecraft auxiliary power sources.

For related information see also 07 Aircraft Propulsion and Power, 28 Propellants and Fuels, 15 Launch Vehicles and Launch Operations, and 44 Energy Production and Conversion.

20060014015 NASA Stennis Space Center, Stennis Space Center, MS, USA

Development of a Work Control System for Propulsion Testing at NASA Stennis

Messer, Elizabeth A.; [2005]; 10 pp.; In English; AIAA Aerodynamic Measurement Technology and Ground Testing Conference, 1-31 Jan. 2005, Portland, OR, USA; Original contains color and black and white illustrations Report No.(s): SSTI-8080-0003-EPLEX; AIAA Paper 2005-1130; No Copyright; Avail.: CASI: A02, Hardcopy

In 1996 Stennis Space Center was given management authority for all Propulsion Testing for NASA. Over the next few years several research and development (R&D) test facilities were completed and brought up to full operation in what is known as the E-Complex Test Facility at Stennis Space Center. To construct, activate and operate these test facilities, a manual paper-based work control system was created. After utilizing this paper-based work control system for approximately three years, it became apparent that the research and development test area needed a better method to execute, monitor, and report on tasks required to further propulsion testing. The paper based system did not provide the engineers adequate visibility into work tasks or the tracking of testing or hardware discrepancies. This system also restricted the engineer s ability to utilize and access past knowledge and experiences given the severe schedule limitations for most R&D propulsion testing projects. Therefore a system was developed to meet the growing need of Test Operations called the Propulsion Test Directorate (PTD) Work Control System. This system is used to plan, perform, and track tasks that support testing and also to capture lessons learned while doing so. Author

Propulsion; Test Facilities; Engineers.

20060014316 Air Force Research Lab., Wright-Patterson AFB, OH USA

Propulsion Directorate/Control and Engine Health Management (CEHM): Real-Time Turbofan Engine Simulation

Behbahani, Al; Curry, Tramone; Sep 2005; 14 pp.; In English Contract(s)/Grant(s): Proj-306 39 Report No.(s): AD-A441884; AFRL-PR-WP-TP-2005-209; No Copyright; ONLINE: http://hdl.handle.net/100.2/ADA441884; Avail.: Defense Technical Information Center (DTIC)

As the interest in intelligent engine technology increases so does the demand for advanced methods of engine model simulation. Undoubtedly, this element is very cost effective, in that, it can decrease test and experimentation hours significantly. In order to extract more meaningful information for analysis, model simulation must be conducted in a real-time environment. The Modular Aero-Propulsion System Simulation (MAPSS) is a generic turbofan engine simulation derived from FORTRAN-based coding developed at NASA Glenn Research Center. It is a non-real time, multi-rate system composed of the Controller and Actuator Dynamics (CAD) and Component Level Model (CLM) modules, representing the digital controller and engine, respectively. This paper discusses the implementation and simulation of the MAPSS model in a real-time nvironment. The controller and engine are loaded on two separate simulators with data transfer between the two systems via a set of electrical cables. This analysis platform encompasses all of the aspects of a real-time environment with plant and sensor noise.

The real-time implementation is validated against the non-real time simulation through transient and steady-state conditions.Key parameters of comparison are the three states of the engine, low pressure spool speed (XNL), high pressure spool speed (XNH), and core metal temperature (TMPC), and burner fuel flow (WF36) and net thrust (FN). It is observed with each parameter that the average percent error is less than 1%. Thus, a successful real-time implementation is achieved while maintaining a high degree of accuracy. The model's behavior now approximates a real gas turbine and provides an ideal test bed for observing faults and failures, engine parameter variations, and degradation over time. This in turn provides a valuable tool in observing the symptoms of failure, developing diagnostic DTIC

Computerized Simulation; Gas Turbines; Health; Propulsion; Propulsion System Configurations; Propulsion System Performance; Turbofan Engines

20060015378 McMillion (L. Glen), Reno, NV USA

A Simple Method for Predicting RF Attenuation Through a Rocket Exhaust Plume

McMillion, L G; Sep 5, 1997; 19 pp.; In English Contract(s)/Grant(s): DAAL03-91-C-0034 Report No.(s): AD-A443181; No Copyright; ONLINE: http://hdl.handle.net/100.2/ADA443181; Avail.: CASI: A03, Hardcopy

A simple method for predicting radio frequency signal attenuation through a rocket exhaust plume has been developed. A theoretical model development suitable for a writing a computer code to predict line-of-sight RF signal attenuation is presented. The model consists of seven calculation steps: 1. Nozzle exhaust conditions. 2. Correction for non-optimal nozzle expansion. 3. Plume inviscid core flow field. 4. Plume mixing/afterburning region flow field. 5. Plume electron and neutral body density field. 6. Electron-neutral body collision frequency. 7. Radio frequency transmission loss. The model uses many simplifying assumptions and represents the least complex approach available. The model is appropriate only for static-fired motors or low altitude, low Mach number flight profiles. DTIC

Exhaust Gases; Plumes; Predictions; Radio Frequencies; Rocket Exhaust

20060016358 NASA Marshall Space Flight Center, Huntsville, AL, USA

Nondestructive Evaluation of the Gimbal Joint Flowliner Slots in the Space Shuttle Main Propulsion System Hydrogen Feedline

Suits, Michael W.; Bryson, Craig C.; [2006]; 1 pp.; In English; American Society of Nondestructive Testing Research Symposium, 13-17 Mar. 2006, Orlando, FL, USA; No Copyright; Avail.: Other Sources; Abstract Only

Fatigue cracks were discovered in the STS-112 Liquid Hydrogen Feedline flowliners in 2002. This led to a development program aimed at providing nondestructive evaluation methods and techniques to verify the existence of these types of cracks in oval shaped slots cut into the ends of the feedlines above the bellows joints. These slots were used to improve flow dynamics and to facilitate cleaning in the bellow joint region. These types of fatigue cracks posed a possible metal debris ingestion threat for the Space Shuttle Main Engines, which attached to these particular joints. Results of this program produced three reliable inspection techniques utilizing the imaging of replisets with a Scanning Electron microscope, eddy current, and ultrasound. The program developed unique probes and fixtures and in the case of eddy current and ultrasound, provided qualification and certification of the particular techniques by various Design of Experiments and Probability of Detection studies utilizing multiple inspectors. Author

Gimbals; Nondestructive Tests; Slots; Space Shuttle Main Engine; Feed Systems; Liquid Hydrogen; Joints (Junctions); Propulsion System Configurations

Source: NASA