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Search indexed NASA NTRS and DOE OSTI research on propulsion, heat transfer, battery materials and energy systems. Follow report and document links to the original sources.

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At least 253 records · Page 14
All sourcesNASA NTRSDOE OSTI
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 NTRSDate not supplied

Video Analysis for Surveillance of Spacecraft Parachute Systems

The Commercial Crew Program (CCP) has established a surveillance methodology to ensure the reliability of spacecraft parachute systems. The implemented methodology relies on an interconnected framework consisting of imagery analysis, hardware inspections, and vehicle data analysis. Imagery analysis serves as a foundation for these core activities which provide a robust approach to the surveillance of spacecraft parachute systems. As the surveillance framework has been developed, the role of imagery has become more prominent, and therefore imagery requirements have changed. To complete photogrammetric analysis, careful consideration must be made to the role of imagery, required data, imagery requirements, the analysis process, and mission planning. The role of imagery will drive the required data, which will in turn drive imagery requirements. Imagery requirements are likely to drive mission planning through consideration to camera selection and placement. If onboard imagery is required, the camera and data system must be implemented prior to launch. If external imagery is required, the photography package must be implemented such that it can be positioned for a return and free of potential debris fields. For these reasons, an integrated approach must be used to build an imagery package around the required analysis with careful coordination with mission planners.

parachutes↗
NASA NTRSDate not supplied

Video Analysis for Surveillance of Spacecraft Parachute Systems

The Commercial Crew Program (CCP) has established a surveillance methodology to ensure the reliability of spacecraft parachute systems. The implemented methodology relies on an interconnected framework consisting of imagery analysis, hardware inspections, and vehicle data analysis. Imagery analysis serves as a foundation for these core activities which provide a robust approach to the surveillance of spacecraft parachute systems. As the surveillance framework has been developed, the role of imagery has become more prominent, and therefore imagery requirements have changed. To complete photogrammetric analysis, careful consideration must be made to the role of imagery, required data, imagery requirements, the analysis process, and mission planning. The role of imagery will drive the required data, which will in turn drive imagery requirements. Imagery requirements are likely to drive mission planning through consideration to camera selection and placement. If onboard imagery is required, the camera and data system must be implemented prior to launch. If external imagery is required, the photography package must be implemented such that it can be positioned for a return and free of potential debris fields. For these reasons, an integrated approach must be used to build an imagery package around the required analysis with careful coordination with mission planners.

parachutes↗
NASA NTRS2008

Integrated Vehicle Ground Vibration Testing in Support of Launch Vehicle Loads and Controls Analysis

All structural systems possess a basic set of physical characteristics unique to that system. These unique physical characteristics include items such as mass distribution and damping. When specified, they allow engineers to understand and predict how a structural system behaves under given loading conditions and different methods of control. These physical properties of launch vehicles may be predicted by analysis or measured by certain types of tests. Generally, these properties are predicted by analysis during the design phase of a launch vehicle and then verified by testing before the vehicle becomes operational. A ground vibration test (GVT) is intended to measure by test the fundamental dynamic characteristics of launch vehicles during various phases of flight. During the series of tests, properties such as natural frequencies, mode shapes, and transfer functions are measured directly. These data will then be used to calibrate loads and control systems analysis models for verifying analyses of the launch vehicle. NASA manned launch vehicles have undergone ground vibration testing leading to the development of successful launch vehicles. A GVT was not performed on the inaugural launch of the unmanned Delta III which was lost during launch. Subsequent analyses indicated had a GVT been performed, it would have identified instability issues avoiding loss of the vehicle. This discussion will address GVT planning, set-up, execution and analyses, for the Saturn and Shuttle programs, and will also focus on the current and on-going planning for the Ares I and V Integrated Vehicle Ground Vibration Test (IVGVT).

Askins, Bruce R.↗
NASA NTRS1979

Verification and validation of the NASA Terminal Configured Vehicle's /TCV/ Wind Analysis program using real-time digital simulation

NASA's Terminal Configured Vehicle (TCV) program has been established to develop and evaluate aircraft and flight management technology that will benefit conventional takeoff and landing operations in the terminal area. To this end, a process whereby estimates of longitudinal, lateral, and vertical winds are obtained using the present complement of sensors onboard the TCV aircraft (B737-100) is developed. The results of the simulation experiment to verify and validate the TCV B737 Data Merging and Wind Analysis program have shown that the wind analysis algorithms are correct and that very satisfactory estimates of all three wind components are obtained even in the presence of adverse atmospheric conditions and realistic measurement noise. In realistic worst case conditions, wind component errors of the order of + or - 2.0 knots longitudinally, + or - 0.5 knot laterally, and + or - 1.0 knot vertically are to be expected.

Dieudonne, J. E.↗
NASA NTRS1991

Integrated trajectory and control analysis for generic hypersonic vehicles

A tool which supports integrated assessment of air-breathing hypersonic vehicle trajectory management and control strategy has been developed by Hattis and Malchow (1991). Using a two-point boundary value problem solution technique, the tool can construct an entire near-minimum-fuel trajectory and desired control strategy from takeoff to orbit, while satisfying physically derived inequality constraints and while achieving efficient propulsive mode phasing. A strategy is also formulated to construct preliminary trajectory and control history representations with less computational burden than required for the overall flight profile assessment. A tabulated example hypersonic vehicle model has been used to demonstrate the integrated analysis methodology. To assure good numerical behavior when the algorithm uses tabulated model data, a multidimensional cubic spline curve smoothing routine has been developed. A dynamic-pressure-constrained, near-fuel-optimal trajectory was computed to provide examples of information that the methodology can provide. Previously unspecified propulsive discontinuities were located, flight regimes demanding rapid attitude changes were identified, available and closed-loop controller authority was ascertained, and inadequacies in vehicle and specific subsystem model representations were determined.

Hattis, Philip D.↗
NASA NTRSDate not supplied

Mars Ascent Vehicle Flight Test Mission Design, Analysis, and Instrumentation

The Mars Ascent Vehicle (MAV) will be the first rocket ever to launch off the surface of Mars, inserting Martian regolith samples into orbit. Since the MAV vehicle is a two-stage all-solid rocket with no thrust termination system, orbit in-sertion accuracy is heavily dependent on pre-flight predictions of the motor per-formance and dynamics of the spin-stabilized upper stage (MAV2). Therefore, a flight test of the MAV2 as the final stage on a Black Brant IX sounding rocket from Wallops Flight Facility (WFF) is planned. This paper discusses the mission design, post flight reconstruction approach, and instrumentation package pro-posed to meet the relevant flight test objectives.

MAV↗
NASA NTRSDate not supplied

Mars Ascent Vehicle Flight Test Mission Design, Analysis, and Instrumentation

The Mars Ascent Vehicle (MAV) will be the first rocket ever to launch off the surface of Mars, inserting Martian regolith samples into orbit. Since the MAV vehicle is a two-stage all-solid rocket with no thrust termination system, orbit in-sertion accuracy is heavily dependent on pre-flight predictions of the motor per-formance and dynamics of the spin-stabilized upper stage (MAV2). Therefore, a flight test of the MAV2 as the final stage on a Black Brant IX sounding rocket from Wallops Flight Facility (WFF) is planned. This paper discusses the mission design, post flight reconstruction approach, and instrumentation package pro-posed to meet the relevant flight test objectives.

MAV↗
NASA NTRS2005

Identifying Contingency Requirements using Obstacle Analysis on an Unpiloted Aerial Vehicle

This paper describes experience using Obstacle Analysis to identify contingency requirements on an unpiloted aerial vehicle. A contingency is an operational anomaly, and may or may not involve component failure. The challenges to this effort were: ( I ) rapid evolution of the system while operational, (2) incremental autonomy as capabilities were transferred from ground control to software control and (3) the eventual safety-criticality of such systems as they begin to fly over populated areas. The results reported here are preliminary but show that Obstacle Analysis helped (1) identify new contingencies that appeared as autonomy increased; (2) identify new alternatives for handling both previously known and new contingencies; and (3) investigate the continued validity of existing software requirements for contingency handling. Since many mobile, intelligent systems are built using a development process that poses the same challenges, the results appear to have applicability to other similar systems.

fault protection↗
NASA NTRS1973

Unsteady aerodynamic analysis of space shuttle vehicles. Part 2: Steady and unsteady aerodynamics of sharp-edged delta wings

An analysis of the steady and unsteady aerodynamics of sharp-edged slender wings has been performed. The results show that slender wing theory can be modified to give the potential flow static and dynamic characteristics in incompressible flow. A semiempirical approximation is developed for the vortex-induced loads, and it is shown that the analytic approximation for sharp-edged slender wings gives good prediction of experimentally determined steady and unsteady aerodynamics at M = 0 and M = 1. The predictions are good not only for delta wings but also for so-called arrow and diamond wings. The results indicate that the effects of delta planform lifting surfaces can be included in a simple manner when determining elastic launch vehicle dynamic characteristics. For Part 1 see (N73-32763).

Ericsson, L. E.↗
NASA NTRS2010

Ares Launch Vehicle Transonic Buffet Testing and Analysis Techniques

It is necessary to define the launch vehicle buffet loads to ensure that structural components and vehicle subsystems possess adequate strength, stress, and fatigue margins when the vehicle structural dynamic response to buffet forcing functions are considered. In order to obtain these forcing functions, the accepted method is to perform wind-tunnel testing of a rigid model instrumented with hundreds of unsteady pressure transducers designed to measure the buffet environment across the desired frequency range. The buffet wind-tunnel test program for the Ares Crew Launch Vehicle employed 3.5 percent scale rigid models of the Ares I and Ares I-X launch vehicles instrumented with 256 unsteady pressure transducers each. These models were tested at transonic conditions at the Transonic Dynamics Tunnel at NASA Langley Research Center. The ultimate deliverable of the Ares buffet test program are buffet forcing functions (BFFs) derived from integrating the measured fluctuating pressures on the rigid wind-tunnel models. These BFFs are then used as input to a multi-mode structural analysis to determine the vehicle response to buffet and the resulting buffet loads and accelerations. This paper discusses the development of the Ares I and I-X rigid buffet model test programs from the standpoint of model design, instrumentation system design, test implementation, data analysis techniques to yield final products, and presents normalized sectional buffet forcing function root-mean-squared levels.

Piatak, David J.↗
NASA NTRS1996

Computational Study of a McDonnell Douglas Single-Stage-to-Orbit Vehicle Concept for Aerodynamic Analysis

This paper presents the results of a computational flow analysis of the McDonnell Douglas single-stage-to-orbit vehicle concept designated as the 24U. This study was made to determine the aerodynamic characteristics of the vehicle with and without body flaps over an angle of attack range of 20-40 deg. Computations were made at a flight Mach number of 20 at 200,000 ft. altitude with equilibrium air, and a Mach number of 6 with CF4 gas. The software package FELISA (Finite Element Langley imperial College Sawansea Ames) was used for all the computations. The FELISA software consists of unstructured surface and volume grid generators, and inviscid flow solvers with (1) perfect gas option for subsonic, transonic, and low supersonic speeds, and (2) perfect gas, equilibrium air, and CF4 options for hypersonic speeds. The hypersonic flow solvers with equilibrium air and CF4 options were used in the present studies. Results are compared with other computational results and hypersonic CF4 tunnel test data.

Prabhu, Ramadas K.↗