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NASA NTRS2003

Initial SVS Integrated Technology Evaluation Flight Test Requirements and Hardware Architecture

This document presents the flight test requirements for the Initial Synthetic Vision Systems Integrated Technology Evaluation flight Test to be flown aboard NASA Langley's ARIES aircraft and the final hardware architecture implemented to meet these requirements. Part I of this document contains the hardware, software, simulator, and flight operations requirements for this light test as they were defined in August 2002. The contents of this section are the actual requirements document that was signed for this flight test. Part II of this document contains information pertaining to the hardware architecture that was realized to meet these requirements as presented to and approved by a Critical Design Review Panel prior to installation on the B-757 Airborne Research Integrated Experiments Systems (ARIES) airplane. This information includes a description of the equipment, block diagrams of the architecture, layouts of the workstations, and pictures of the actual installations.

Harrison, Stella V.↗

NASA NTRS2003

Structural Evaluation of Exo-Skeletal Engine Fan Blades

The available computational simulation capability is used to demonstrate the structural viability of composite fan blades of innovative Exo-Skeletal Engine (ESE) developed at NASA Glenn Research Center for a subsonic mission. Full structural analysis and progressive damage evaluation of ESE composite fan blade is conducted through the NASA in-house computational simulation software system EST/BEST. The results of structural assessment indicate that longitudinal stresses acting on the blade are in compression. At a design speed of 2000 rpm, pressure and suction surface outer most ply stresses in longitudinal, transverse and shear direction are much lower than the corresponding composite ply strengths. Damage is initiated at 4870 rpm and blade fracture takes place at rotor speed of 7735 rpm. Damage volume is 51 percent. The progressive damage, buckling, stress and strength results indicate that the design at hand is very sound because of the factor of safety, damage tolerance, and buckling load of 6811 rpm.

Kuguoglu, Latife↗

NASA NTRS2003

Manufacturing Process Simulation of Large-Scale Cryotanks

NASA's Space Launch Initiative (SLI) is an effort to research and develop the technologies needed to build a second-generation reusable launch vehicle. It is required that this new launch vehicle be 100 times safer and 10 times cheaper to operate than current launch vehicles. Part of the SLI includes the development of reusable composite and metallic cryotanks. The size of these reusable tanks is far greater than anything ever developed and exceeds the design limits of current manufacturing tools. Several design and manufacturing approaches have been formulated, but many factors must be weighed during the selection process. Among these factors are tooling reachability, cycle times, feasibility, and facility impacts. The manufacturing process simulation capabilities available at NASA.s Marshall Space Flight Center have played a key role in down selecting between the various manufacturing approaches. By creating 3-D manufacturing process simulations, the varying approaches can be analyzed in a virtual world before any hardware or infrastructure is built. This analysis can detect and eliminate costly flaws in the various manufacturing approaches. The simulations check for collisions between devices, verify that design limits on joints are not exceeded, and provide cycle times which aide in the development of an optimized process flow. In addition, new ideas and concerns are often raised after seeing the visual representation of a manufacturing process flow. The output of the manufacturing process simulations allows for cost and safety comparisons to be performed between the various manufacturing approaches. This output helps determine which manufacturing process options reach the safety and cost goals of the SLI. As part of the SLI, The Boeing Company was awarded a basic period contract to research and propose options for both a metallic and a composite cryotank. Boeing then entered into a task agreement with the Marshall Space Flight Center to provide manufacturing simulation support. This paper highlights the accomplishments of this task agreement, while also introducing the capabilities of simulation software.

Babai, Majid↗

NASA NTRS2003

Colossal Tooling Design: 3D Simulation for Ergonomic Analysis

The application of high-level 3D simulation software to the design phase of colossal mandrel tooling for composite aerospace fuel tanks was accomplished to discover and resolve safety and human engineering problems. The analyses were conducted to determine safety, ergonomic and human engineering aspects of the disassembly process of the fuel tank composite shell mandrel. Three-dimensional graphics high-level software, incorporating various ergonomic analysis algorithms, was utilized to determine if the process was within safety and health boundaries for the workers carrying out these tasks. In addition, the graphical software was extremely helpful in the identification of material handling equipment and devices for the mandrel tooling assembly/disassembly process.

Hunter, Steve L.↗

NASA NTRS2003

A Design for Composing and Extending Vehicle Models

The Systems Development Branch (SDB) at NASA Langley Research Center (LaRC) creates simulation software products for research. Each product consists of an aircraft model with experiment extensions. SDB treats its aircraft models as reusable components, upon which experiments can be built. SDB has evolved aircraft model design with the following goals: 1. Avoid polluting the aircraft model with experiment code. 2. Discourage the copy and tailor method of reuse. The current evolution of that architecture accomplishes these goals by reducing experiment creation to extend and compose. The architecture mechanizes the operational concerns of the model's subsystems and encapsulates them in an interface inherited by all subsystems. Generic operational code exercises the subsystems through the shared interface. An experiment is thus defined by the collection of subsystems that it creates ("compose"). Teams can modify the aircraft subsystems for the experiment using inheritance and polymorphism to create variants ("extend").

Madden, Michael M.↗

NASA NTRS2005

Matlab GUI for a Fluid Mixer

The Test and Engineering Directorate at NASA John C. Stennis Space Center developed an interest to study the modeling, evaluation, and control of a liquid hydrogen (LH2) and gas hydrogen (GH2) mixer subsystem of a ground test facility. This facility carries out comprehensive ground-based testing and certification of liquid rocket engines including the Space Shuttle Main engine. A software simulation environment developed in MATLAB/SIMULINK (M/S) will allow NASA engineers to test rocket engine systems at relatively no cost. In the progress report submitted in February 2004, we described the development of two foundation programs, a reverse look-up application using various interpolation algorithms, a variety of search and return methods, and self-checking methods to reduce the error in returned search results to increase the functionality of the program. The results showed that these efforts were successful. To transfer this technology to engineers who are not familiar with the M/S environment, a four-module GUI was implemented allowing the user to evaluate the mixer model under open-loop and closed-loop conditions. The progress report was based on an udergraduate Honors Thesis by Ms. Jamie Granger Austin in the Department of Electrical Engineering and Computer Science at Tulane University, during January-May 2003, and her continued efforts during August-December 2003. In collaboration with Dr. Hanz Richter and Dr. Fernando Figueroa we published these results in a NASA Tech Brief due to appear this year. Although the original proposal in 2003 did not address other components of the test facility, we decided in the last few months to extend our research and consider a related pressurization tank component as well. This report summarizes the results obtained towards a Graphical User Interface (GUI) for the evaluation and control of the hydrogen mixer subsystem model and for the pressurization tank each taken individually. Further research would combine the two components - mixer and tank, for a more realistic simulation tool.

Barbieri, Enrique↗

NASA NTRS2004

Digital communication constraints in prior space missions

Digital communication is crucial for space endeavors. Jt transmits scientific and command data between earth stations and the spacecraft crew. It facilitates communications between astronauts, and provides live coverage during all phases of the mission. Digital communications provide ground stations and spacecraft crew precise data on the spacecraft position throughout the entire mission. Lessons learned from prior space missions are valuable for our new lunar and Mars missions set by our president s speech. These data will save our agency time and money, and set course our current developing technologies. Limitations on digital communications equipment pertaining mass, volume, data rate, frequency, antenna type and size, modulation, format, and power in the passed space missions are of particular interest. This activity is in support of ongoing communication architectural studies pertaining to robotic and human lunar exploration. The design capabilities and functionalities will depend on the space and power allocated for digital communication equipment. My contribution will be gathering these data, write a report, and present it to Communications Technology Division Staff. Antenna design is very carefully studied for each mission scenario. Currently, Phased array antennas are being developed for the lunar mission. Phased array antennas use little power, and electronically steer a beam instead of DC motors. There are 615 patches in the phased array antenna. These patches have to be modified to have high yield. 50 patches were created for testing. My part is to assist in the characterization of these patch antennas, and determine whether or not certain modifications to quartz micro-strip patch radiators result in a significant yield to warrant proceeding with repairs to the prototype 19 GHz ferroelectric reflect-array antenna. This work requires learning how to calibrate an automatic network, and mounting and testing antennas in coaxial fixtures. The purpose of this activity is to assist in the set-up of phase noise instrumentation, assist in the process of automated wire bonding, assist in the design and optimization of tunable microwave components, especially phase shifters, based on thin ferroelectric films, and learn how to use commercial electromagnetic simulation software.

Yassine, Nathan K.↗

NASA NTRS1999

Reconfigurable Data Communications Packet-Switch Emulation Test Bed Demonstrated

The Communications Technology Division at the NASA Lewis Research Center has an ongoing program to develop advanced switching and routing technology concepts for future satellite onboard processing systems. Through a university grant as a part of this research, the Cleveland State University is using a flexible reconfigurable data communications packet switch emulation test bed to investigate packet switching techniques. Because of the switching speed and protocol complexity, implementing a data communications network is a tremendous task. Various alternatives should be carefully studied and evaluated in the development stage so that the optimal system configuration can be obtained and implemented later. Therefore, it is desirable to predict the performance of the network before it is actually constructed. This is especially true in the case of satellite systems. In the past, theoretical analysis, software simulation, and prototyping were used to evaluate performance. However, each method has its drawback. There are basic tradeoffs among accuracy, cost, and required evaluation time. No method is completely satisfactory.

Chu, Pong P.↗

NASA NTRS2005

Integration of Launch Vehicle Simulation/Analysis Tools and Lunar Cargo Lander Design

Simulation and analysis of vehicle performance is essential for design of a new launch vehicle system. It is more and more demand to have an integrated, highly efficient, robust simulation tool with graphical user interface (GUI) for vehicle performance and simulations. The objectives of this project are to integrate and develop launch vehicle simulation and analysis tools in MATLAB/Simulink under PC Platform, to develop a vehicle capable of being launched on a Delta-IV Heavy Launch Vehicle which can land on the moon with the goal of pre-implanting cargo for a new lunar mission, also with the capability of selecting other launch vehicles that are capable of inserting a payload into Trans-Lunar Injection (TLI). The vehicle flight simulation software, MAVERIC-II (Marshall Aerospace VEhicle Representation In 'C'), developed by Marshall Space Flight Center was selected as a starting point for integration of simulation/analysis tools. The goals are to convert MAVERIC-II from UNIX to PC platform and build input/output GUI s in the MATLAB environment, and then integrate them under MATLAB/Simulink with other modules. Currently, MAVERIC-II has been successfully converted from UNIX to PC using Microsoft Services for UNIX subsystem on PC. Input/Output GUI's have been done for some key input/output files. Calling MAVERIC-II from Simulink has been tested. Details regarding Lunar Cargo Lander Design are described in Part 2/2 of the paper on page X-1.

Shiue, Yeu-Sheng Paul↗

NASA NTRS2005

Computational Simulations and the Scientific Method

As scientific simulation software becomes more complicated, the scientific-software implementor's need for component tests from new model developers becomes more crucial. The community's ability to follow the basic premise of the Scientific Method requires independently repeatable experiments, and model innovators are in the best position to create these test fixtures. Scientific software developers also need to quickly judge the value of the new model, i.e., its cost-to-benefit ratio in terms of gains provided by the new model and implementation risks such as cost, time, and quality. This paper asks two questions. The first is whether other scientific software developers would find published component tests useful, and the second is whether model innovators think publishing test fixtures is a feasible approach.

Kleb, Bil↗

NASA NTRS1996

Asynchronous Message Passing in the JPL Flight System Testbed

The flight mission simulation software in the Jet Propulsion Laboratory's Flight System Testbed (FST) is a heterogeneous, distributed system that is built on an interprocess communication model of asynchronous message passing rather than remote procedure calls (RPCs). The reasoning behind this design decision is discussed; the mechanism used to implement it (.

message passing RPC interprocess communication dis↗

NASA NTRS2004

A practical six-degree of freedom solar sail dynamics model for optimizing solar sail trajectories with torque constraints

Controlled flight of a solar sail-propelled spacecraft ('sailcraft') is a six-degree-of-freedom dynamics problem. Current state-of-the-art tools that simulate and optimize the trajectories flown by sailcraft do not treat the full kinetic (i.e. force and torque-constrained) motion, instead treating a discrete history of commanded sail attitudes, and either neglecting the sail attitude motion over an integration timestep, or treating the attitude evolution kinematically with a spline or similar treatment. The present paper discusses an aspect of developing a next generation sailcraf trajectory designing optimization tool JPL, for NASA's Solar Sail Spaceflight Simulation Software (SS). The aspect discussed in an experimental approach to modeling full six-degree-of-freedom kinetic motion of a solar sail in a trajectory propagator. Early results from implementing this approach in a new trajectory propagation tool are given.

six-degree-of-freedom↗

NASA NTRS2007

Comparing the Robustness of High-Frequency Traveling-Wave Tube Slow-Wave Circuits

A three-dimensional electromagnetic field simulation software package was used to compute the cold-test parameters, phase velocity, on-axis interaction impedance, and attenuation, for several high-frequency traveling-wave tube slow-wave circuit geometries. This research effort determined the effects of variations in circuit dimensions on cold-test performance. The parameter variations were based on the tolerances of conventional micromachining techniques.

Chevalier, Christine T.↗

NASA NTRS2008

IceVal DatAssistant: An Interactive, Automated Icing Data Management System

As with any scientific endeavor, the foundation of icing research at the NASA Glenn Research Center (GRC) is the data acquired during experimental testing. In the case of the GRC Icing Branch, an important part of this data consists of ice tracings taken following tests carried out in the GRC Icing Research Tunnel (IRT), as well as the associated operational and environmental conditions during those tests. Over the years, the large number of experimental runs completed has served to emphasize the need for a consistent strategy to manage the resulting data. To address this situation, the Icing Branch has recently elected to implement the IceVal DatAssistant automated data management system. With the release of this system, all publicly available IRT-generated experimental ice shapes with complete and verifiable conditions have now been compiled into one electronically-searchable database; and simulation software results for the equivalent conditions, generated using the latest version of the LEWICE ice shape prediction code, are likewise included and linked to the corresponding experimental runs. In addition to this comprehensive database, the IceVal system also includes a graphically-oriented database access utility, which provides reliable and easy access to all data contained in the database. In this paper, the issues surrounding historical icing data management practices are discussed, as well as the anticipated benefits to be achieved as a result of migrating to the new system. A detailed description of the software system features and database content is also provided; and, finally, known issues and plans for future work are presented.

Levinson, Laurie H.↗

NASA NTRS2008

IceVal DatAssistant: An Interactive, Automated Icing Data Management System

As with any scientific endeavor, the foundation of icing research at the NASA Glenn Research Center (GRC) is the data acquired during experimental testing. In the case of the GRC Icing Branch, an important part of this data consists of ice tracings taken following tests carried out in the GRC Icing Research Tunnel (IRT), as well as the associated operational and environmental conditions documented during these tests. Over the years, the large number of experimental runs completed has served to emphasize the need for a consistent strategy for managing this data. To address the situation, the Icing Branch has recently elected to implement the IceVal DatAssistant automated data management system. With the release of this system, all publicly available IRT-generated experimental ice shapes with complete and verifiable conditions have now been compiled into one electronically-searchable database. Simulation software results for the equivalent conditions, generated using the latest version of the LEWICE ice shape prediction code, are likewise included and are linked to the corresponding experimental runs. In addition to this comprehensive database, the IceVal system also includes a graphically-oriented database access utility, which provides reliable and easy access to all data contained in the database. In this paper, the issues surrounding historical icing data management practices are discussed, as well as the anticipated benefits to be achieved as a result of migrating to the new system. A detailed description of the software system features and database content is also provided; and, finally, known issues and plans for future work are presented.

Levinson, Laurie H.↗

NASA NTRS2008

Reconfigurable HIL Testing of Earth Satellites

In recent years, hardware-in-the-loop (HIL) testing has carved a strong niche in several industries, such as automotive, aerospace, telecomm, and consumer electronics. As desktop computers have realized gains in speed, memory size, and data storage capacity, hardware/software platforms have evolved into high performance, deterministic HIL platforms, capable of hosting the most demanding applications for testing components and subsystems. Using simulation software to emulate the digital and analog I/O signals of system components, engineers of all disciplines can now test new systems in realistic environments to evaluate their function and performance prior to field deployment. Within the Aerospace industry, space-borne satellite systems are arguably some of the most demanding in terms of their requirement for custom engineering and testing. Typically, spacecraft are built one or few at a time to fulfill a space science or defense mission. In contrast to other industries that can amortize the cost of HIL systems over thousands, even millions of units, spacecraft HIL systems have been built as one-of-a-kind solutions, expensive in terms of schedule, cost, and risk, to assure satellite and spacecraft systems reliability. The focus of this paper is to present a new approach to HIL testing for spacecraft systems that takes advantage of a highly flexible hardware/software architecture based on National Instruments PXI reconfigurable hardware and virtual instruments developed using LabVIEW. This new approach to HIL is based on a multistage/multimode spacecraft bus emulation development model called Reconfigurable Hardware In-the-Loop or RHIL.

Source record↗

NASA NTRS2008

Attitude and Translation Control of a Solar Sail Vehicle

A report discusses the ability to control the attitude and translation degrees-of-freedom of a solar sail vehicle by changing its center of gravity. A movement of the spacecraft s center of mass causes solar-pressure force to apply a torque to the vehicle. At the compact core of the solar-sail vehicle lies the spacecraft bus which is a large fraction of the total vehicle mass. In this concept, the bus is attached to the spacecraft by two single degree-of-freedom linear tracks. This allows relative movement of the bus in the sail plane. At the null position, the resulting solar pressure applies no torque to the vehicle. But any deviation of the bus from the null creates an offset between the spacecraft center of mass and center of solar radiation pressure, resulting in a solar-pressure torque on the vehicle which changes the vehicle attitude. Two of the three vehicle degrees of freedom can be actively controlled in this manner. The third, the roll about the sunline, requires a low-authority vane/propulsive subsystem. Translation control of the vehicle is achieved by directing the solar-pressure-induced force in the proper inertial direction. This requires attitude control. Attitude and translation degrees-of-freedom are therefore coupled. A guidance law is proposed, which allows the vehicle to stationkeep at an appropriate point on the inertially-rotating Sun-Earth line. Power requirements for moving the bus are minimal. Extensive software simulations have been performed to demonstrate the feasibility of this concept.

Singh, Gurkirpal↗

NASA NTRS2009

[A Handling Qualities Metric for Damaged Aircraft]

In recent flight tests of F-15 Intelligent Flight Control System (IFCS), software simulated aircraft control surface failures were inserted to evaluate the IFCS adaptive systems. The failure commanded the left stabilator to a fixed position. The adaptive system uses a neural network that is designed to change control law gains, in the event of damage (real or simulated), that allows the aircraft to fly as it had before the damage. The performance of the adaptive system was assessed in terms of its ability to re-establish good onboard model tracking and its ability to decouple roll and pitch response.

Cogan, Bruce↗