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This document provides standalone information for the Lightning Strike Protection (LSP) Composite Substrate Test Bed Design. A six-sheet drawing set is reproduced for reference, as is some additional descriptive information on suitable sensors and use of the test bed.
Engineering drawings and the detailed mechanical and electrical design of a horizontal-axis wind turbine designed for DOE at the NASA Lewis Research Center and installed in Clayton, New Mexico are discussed. The drawings show the hub, pitch change mechanism, drive train, nacelle equipment, yaw drive system, tower, foundation, electrical power systems, and the control and safety systems.
The program theory used to obtain the software package, MAIL LOG, developed for the Scout Project Automatic Data System, SPADS, is described. The program is written in FORTRAN for the PRIME 300 computer system. The MAIL LOG data base consists of three main subfiles: (1) incoming and outgoing mail correspondence; (2) design information releases and reports; and (3) drawings and engineering orders. All subroutine descriptions, flowcharts, and MAIL LOG outputs are given and the data base design is described.
This report documents the capabilities of the EDICT tools for error modeling and error propagation analysis when operating with models defined in the Architecture Analysis & Design Language (AADL). We discuss our experience using the EDICT error analysis capabilities on a model of the Scalable Processor-Independent Design for Enhanced Reliability (SPIDER) architecture that uses the Reliable Optical Bus (ROBUS). Based on these experiences we draw some initial conclusions about model based design techniques for error modeling and analysis of highly reliable computing architectures.
The history of major Space Station designs over the last twenty-five years is reviewed. The evolution of design concepts is analyzed with respect to the changing functions of Space Stations; and available or anticipated technology capabilities. Emphasis is given to the current NASA Space Station reference configuration, the 'power tower'. Detailed schematic drawings of the different Space Station designs are provided.
The Solid Rocket Motors (SRM) used by NASA to propel the Space Shuttle employ gimballing nozzles as a means for vehicular guidance during launch and ascent. Gimballing a nozzle renders the pressure field of the exhaust gases nonaxisymmetric. This has two effects: (1) it exerts a torque and side load on the nozzle; and (2) the exhaust gases flow circumferentially in the aft-dome region, thermally loading the flexible boot, case-to-nozzle joint, and casing insulation. The use of CFD models to simulate such flows is imperative in order to assess SRM design. The grids for these problems were constructed by obtaining information from drawings and tabulated coordinates. The 2D axisymmetric grids were designed and generated using the EZ-Surf and GEN2D surface and grid generation codes. These 2D grids were solved using codes such as FDNS, GASP, and MINT. These axisymmetric grids were rotated around the center-line to form 3D nongimballed grids. These were then gimballed around the pivot point and the gaps or overlaps resurfaced to obtain the final domains, which contained approximately 366,000 grid points. The 2D solutions were then rotated and manipulated as appropriate for geometry and used as initial guesses in the final solution. The analyses were used in answering questions about flight criteria.
Gregorian, Cassegrain, and single reflector systems were analyzed in configuration studies for communications satellite receive antennas. Parametric design and performance curves were generated. A preliminary design of each reflector/feed system was derived including radiating elements, beam-former network, beamsteering system, and MMIC module architecture. Performance estimates and component requirements were developed for each design. A recommended design was selected for both the scanning beam and the fixed beam case. Detailed design and performance analysis results are presented for the selected Cassegrain configurations. The final design point is characterized in detail and performance measures evaluated in terms of gain, sidelobe level, noise figure, carrier-to-interference ratio, prime power, and beamsteering. The effects of mutual coupling and excitation errors (including phase and amplitude quantization errors) are evaluated. Mechanical assembly drawings are given for the final design point. Thermal design requirements are addressed in the mechanical design.
The aviation industry is gradually moving toward the use of integrated modular avionics (IMA) for civilian transport aircraft. An important concern for IMA is ensuring that applications are safely partitioned so they cannot interfere with one another. We have investigated the problem of ensuring safe partitioning and logical non-interference among separate applications running on a shared Avionics Computer Resource (ACR). This research was performed in the context of ongoing standardization efforts, in particular, the work of RTCA committee SC-182, and the recently completed ARINC 653 application executive (APEX) interface standard. We have developed a formal model of partitioning suitable for evaluating the design of an ACR. The model draws from the mathematical modeling techniques developed by the computer security community. This report presents a formulation of partitioning requirements expressed first using conventional mathematical notation, then formalized using the language of SRI'S Prototype Verification System (PVS). The approach is demonstrated on three candidate designs, each an abstraction of features found in real systems.
Broadband scanning radiometers have been used extensively on earth-orbiting satellites to measure the Earth's outgoing radiation. The resulting estimates of longwave and shortwave fluxes have played an important role in helping to understand the Earth's radiant energy balance or budget. The Clouds and the Earth Radiant Energy System (CERES) experiment is expected to include instruments with three broadband scanning radiometers. The design of the CERES instrument will draw heavily from the flight-proven Earth Radiation Budget Experiment (ERBE) scanner instrument technology and will benefit from the several years of ERBE experience in mission operations and data processing. The discussion starts with a description of the scientific objectives of ERBE and CERES. The design and operational characteristics of the ERBE and CERES instrument are compared and the two ground-based data processing systems are compared. Finally, aspects of the CERES data processing which might be performed in near real-time aboard a spacecraft platform are discussed, and the types of algorithms and input data requirements for the onboard processing system are identified.
Engineers in the Integrated Design and Analysis Division (EV30) use a variety of different tools to aid in the design and analysis of the Ares I vehicle. One primary tool in use is Pro-Engineer. Pro-Engineer is a computer-aided design (CAD) software that allows designers to create computer generated structural models of vehicle structures. For the Upper State thrust cone, Pro-Engineer was used to assist in the design of a layout for two camera housings. These cameras observe the separation between the first and second stage of the Ares I vehicle. For the Ares I-X, one standard speed camera was used. The Ares I design calls for two separate housings, three cameras, and a lighting system. With previous design concepts and verification strategies in mind, a new layout for the two camera design concept was developed with members of the EV32 team. With the new design, Pro-Engineer was used to draw the layout to observe how the two camera housings fit with the thrust cone assembly. Future analysis of the camera housing design will verify the stability and clearance of the camera with other hardware present on the thrust cone.
The assembly of flanges, seals, and pipes are used to carry cryogenic fluid from a storage tank to the vehicle at launch sites. However, after a certain amount of cycles these raised face flanges with glass-filled Teflon gaskets have been found to have torque relaxation and are as a result susceptible to cryogenic fluid leakage if not re-torqued. The intent of this project is to identify alternate combinations of flanges and seals which may improve thermal cycle performance and decrease re-torque requirements. The general approach is to design a test fixture to evaluate leak characteristics between spiral and concentric serrations and to test alternate flange and seal combinations. Due to insufficient time, it was not possible to evaluate these different types of combinations for the combination that improved thermal cycle performance the most. However, the necessary drawings for the test fixture were designed and assembled along with the collection of the necessary parts.
The development of satellite solar power stations is described with attention given to station design and assembly in space. Problems associated with conversion of solar energy into microwaves and with getting the station into orbit are considered. The use of a solar propulsion system for pushing the station to high orbit is discussed along with questions of station lifetime (estimated to be about thirty years). The paper is copiously illustrated with drawings projecting various aspects of station design and utilization.
Pandora Operation and Analysis Software controls the Pandora Sun- and sky-pointing optical head and built-in filter wheels (neutral density, UV bandpass, polarization filters, and opaque). The software also controls the attached spectrometer exposure time and thermoelectric cooler to maintain the spectrometer temperature to within 1 C. All functions are available through a GUI so as to be easily accessible by the user. The data are automatically stored on a miniature computer (netbook) for automatic download to a designated server at user defined intervals (once per day, once per week, etc.), or to a USB external device. An additional software component reduces the raw data (spectrometer counts) to preliminary scientific products for quick-view purposes. The Pandora systems are built from off-the-shelf commercial parts and from mechanical parts machined using electronic machine shop drawings. The Pandora spectrometer system is designed to look at the Sun (tracking to within 0.1 ), or to look at the sky at any zenith or azimuth angle, to gather information about the amount of trace gases or aerosols that are present.
Identification breakdown chart that lists the component parts required for any specific end item is used to identify rapidly and accurately, from numerous drawings, all the component parts of a complex design assembly. Cylindrical and complex configurations are depicted as continuous flat surfaces for ready identification.
Report contains performance specifications and detailed drawings for two instruments: (1) differential controller, and (2) temperature monitor, for solar-powered water-heating systems. Included in package are schematics, wiring diagrams, test procedures, and parts list.
A computer program, the Multi-Adaptive Drawings, Renderings and Similitudes (MADRAS) program, is discussed. The modeling program, written for a desktop computer system (the Hewlett-Packard 9845/C), is written in BASIC and uses modular construction of objects while generating both wire-frame and hidden-line drawings from any viewpoint. The dimensions and placement of objects are user definable. Once the hidden-line calculations are made for a particular viewpoint, the viewpoint may be rotated in pan, tilt, and roll without further hidden-line calculations. The use and results of this program are discussed.
The cylindrical shell combustor with T-bar supports in the 8-foot HTST at the NASA-Langley Research Center encountered vibratory fatigue cracking over a period of 50-250 tunnel tests within a limited range of the required operating envelope. A preliminary design study provided several suitable thermal protection system designs for the combustor, one of which was a two-pass regenerative type air-cooled omega-shaped segment liner. A final design layout of the omega segment liner was prepared and analyzed for steady-state and transient conditions. The design of a support system for the fuel spray bar assembly was also included. Detail drawings suitable for fabrication purposes were also prepared. Liner design problems defined during the preliminary study included (1) the ingress of gas into the attachment bulb section of the omega segment, (2) the large thermal gradient along the leg of the omega bulb attachment section and, (3) the local peak metal temperature at the radius between the liner ID and the leg of the bulb attachment. These were resolved during the final design task. Analyses of the final design of the omega segment liner indicated that all design goals were met and the design provided the capability of operating over the required test envelope with a life expectancy substantially above the goal of 1500 cycles.
A new method of introducing the OXONE (Registered Trademark) Monopersulfate Compound for urine pretreat into a two-phase urine/air flow stream has been successfully tested and evaluated. The feasibility of this innovative method has been established for purposes of providing a simple, convenient, and safe method of handling a chemical pretreat required for urine processing in a microgravity space environment. Also, the Oxone portion of the urine pretreat has demonstrated the following advantages during real time collection of 750 pounds of urine in a Space Station design two-phase urine Fan/Separator: Eliminated urine precipitate buildup on internal hardware and plumbing; Minimized odor from collected urine; and Virtually eliminated airborne bacteria. The urine pretreat, as presently defined for the Space Station program for proper downstream processing of urine, is a two-part chemical treatment of 5.0 grams of Oxone and 2.3 ml of H2SO4 per liter of urine. This study program and test demonstrated only the addition of the proper ratio of Oxone into the urine collection system upstream of the Fan/Separator. This program was divided into the following three major tasks: (1) A trade study, to define and recommend the type of Oxone injection method to pursue further; (2) The design and fabrication of the selected method; and (3) A test program using high fidelity hardware and fresh urine to demonstrate the method feasibility. The trade study was conducted which included defining several methods for injecting Oxone in different forms into a urine system. Oxone was considered in a liquid, solid, paste and powered form. The trade study and the resulting recommendation were presented at a trade study review held at Hamilton Standard on 24-25 October 94. An agreement was reached at the meeting to continue the solid tablet in a bag concept which included a series of tablets suspended in the urine/air flow stream. These Oxone tablets would slowly dissolve at a controlled rate providing the proper concentration in the collected urine. To implement the solid tablet in a bag approach, a design concept was completed with prototype drawings of the complete urine pretreat prefilter assembly. A successful fabrication technique was developed for retaining the Oxone tablets in a fabric casing attached to the end of the existing Space Station Waste Collection System urine prefilter assembly. The final pretreat prefilter configuration held sufficient Oxone in a tablet form to allow normal scheduled daily (or twice daily) change out of the urine filter depending on the use rate of the Space Station urine collection system. The actual tests to prove the concept were conducted using the Urine Fan/Separator assembly that was originally used in the STS-52 Design Test Objective (DTO) urinal assembly. Other related tests were conducted to demonstrate the actual minimum ratio of Oxone to urine that will control microbial growth.