SEARCH · Engineering Papers
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.
Quote a phrase for an exact phrase match. Source license links do not imply unrestricted reuse.
Optimization for zero gravity experiment on solution growth of gallium arsenide and design of experiment package for melt growth of indium antimonide crystals
Orbital fatigue tester for Skylab program - test and design of titanium alloy and aluminum alloy specimens having various sizes
Computer simulation model for experimental data in post-Skylab space station design
Statistical considerations in designing sterilization experiments are discussed in terms of the basic design, pooling of runs, and process assessment.
A preliminary study has been completed to begin development of a flight experiment to measure spacecraft control/flexible structure interaction. The work reported consists of two phases: identification of appropriate structural parameters which can be associated with flexibility phenomena, and suggestions for the development of an experiment for a satellite configuration typical of near-future vehicles which are sensitive to such effects. Recommendations are made with respect to the type of data to be collected and instrumentation associated with these data. The approach consists of developing the equations of motion for a vehicle possessing a flexible solar array, then linearizing about some nominal motion of the craft. A set of solutions are assumed for array deflection using a continuous normal mode method and important parameters are exposed. Inflight and ground based measurements are distinguished. Interrelationships between these parameters, measurement techniques, and input requirements are discussed which assure minimization of special vehicle maneuvers and optimization of data to be obtained during the normal flight sequence.
A set of field experiments and advanced modeling studies which provide a strategy for a program of global tropospheric experiments was identified. An expanded effort to develop space applications for trospheric air quality monitoring and studies was recommended. The tropospheric ozone, carbon, nitrogen, and sulfur cycles are addressed. Stratospheric-tropospheric exchange is discussed. Fast photochemical processes in the free troposphere are considered.
Major advances in photovoltaic (PV) Power Conditioning (PC) with respect to performance and low-cost potential have been made. Solutions have been obtained to interface and control problems related to adapting available inverter designs to the grid-connected, residential photovoltaic experiments. A description is presented to contributing research and development activities. Attention is given to aspects of residential systems experience, conceptual design studies, questions of optimum topology development, and promising advanced designs for residential PV provided by development efforts of the private sector.
Lessons learned from the Alaskan North Slope construction camps and the Western Regional Undersea Laboratory are analyzed with respect to possible improvements for space station interior space utilization and living areas. The human factors engineering aspects have a direct bearing on the condition of crew and occupants.
Laser induced fluorescence (LIF) provides a noncontact method for measuring high temperature properties. It is used with aerodynamic and/or electromagnetic levitation, and electromagnetic and/or CW CO2 laser heating to develop new methods for containerless high temperature property measurements and process control. The capabilities and limitations of Earth-based experiments are demonstrated and the information necessary to design improved experiments in space is obtained. The LIF methods were developed to measure temperature and component activities, which will be applied to containerless property measurements on liquids and to process control in synthesis experiments. Component activities will be obtained from relative LIF intensities over a compound and its components at the same temperature.
AAE 451 is the capstone course required of all senior undergraduates in the School of Aeronautics and Astronautics at Purdue University. During the past year the first steps of a long evolutionary process were taken to change the content and expectations of this course. These changes are the result of the availability of advanced computational capabilities and sophisticated electronic media availability at Purdue. This presentation will describe both the long range objectives and this year's experience using the High Speed Commercial Transport (HSCT) design, the AIAA Long Duration Aircraft design and a Remotely Piloted Vehicle (RPV) design proposal as project objectives. The central goal of these efforts was to provide a user-friendly, computer-software-based, environment to supplement traditional design course methodology. The Purdue University Computer Center (PUCC), the Engineering Computer Network (ECN), and stand-alone PC's were used for this development. This year's accomplishments centered primarily on aerodynamics software obtained from the NASA Langley Research Center and its integration into the classroom. Word processor capability for oral and written work and computer graphics were also blended into the course. A total of 10 HSCT designs were generated, ranging from twin-fuselage and forward-swept wing aircraft, to the more traditional delta and double-delta wing aircraft. Four Long Duration Aircraft designs were submitted, together with one RPV design tailored for photographic surveillance. Supporting these activities were three video satellite lectures beamed from NASA/Langley to Purdue. These lectures covered diverse areas such as an overview of HSCT design, supersonic-aircraft stability and control, and optimization of aircraft performance. Plans for next year's effort will be reviewed, including dedicated computer workstation utilization, remote satellite lectures, and university/industrial cooperative efforts.
The Control-B simulation experiment was designed to improve on the Control-A experiment performed with the GMASS model. This experiment addressed several inadequacies with the first smooth terrain numerical simulation by including: (1) increased nested-grid resolution to better define the simulated gravity waves, (2) increased horizontal diffusion to remove outflow boundary condition noise, and (3) the use of reanalyzed rawinsonde data and surface observations in the initial state to increase the definition of the observed jet streak as well as other low-level features. A smoothed-terrain dry simulation with the nested-grid GMASS model has revealed many important aspects of the processes which resulted in the generation of gravity waves in the region and time when and where they were observed. However, the vertical structure, number, and characteristics of the waves are still quite different from observed waves as diagnosed thus necessitating future improved simulations. However, this control simulation has produced substantial insight into processes which occur on many spatial scales over a 30 hour time period thus allowing one to draw promising inferences as to the mechanisms for the complex process which occurred in nature during the CCOPE case study. The theoretical aspects of the project have focus on understanding the nature of the ageostrophic circulations which are produced in idealized models of the atmosphere in which the troposphere is modeled in one of two ways. The first model assumes that the lower atmosphere can be represented as a single layer of homogeneous fluid whose upper surface is free to exhibit vertical displacement. Two-dimensional internal convergence (divergence) occurring during the adjustment to an asymptotic equilibrium state from an ageostrophic initial state whose momentum structure is representative of a midlatitude localized zonal wind anomaly will cause the free upper surface of the homogeneous atmosphere to rise (fall), and therefore the response can be viewed as being physically three-dimensional. The second model assumes that the troposphere can be represented by an unbounded continuously stratified Boussinesq fluid of constant Brunt-Vaisala frequency N, where the vertical gradient of the basic state potential temperature profile allows for the existence of vertically propagating internal inertia-gravity waves.
The Radiative Heating Experiment, RHE, aboard the Aeroassist Flight Experiment, AFE, (now cancelled) was to make in-situ measurements of the stagnation region shock layer radiation during an aerobraking maneuver from geosynchronous to low earth orbit. The measurements were to provide a data base to help develop and validate aerothermodynamic computational models. Although cancelled, much work was done to develop the science requirements and to successfully meet RHE technical challenges. This paper discusses the RHE scientific objectives and expected science performance of a small sapphire window for the RHE radiometers. The spectral range required was from 170 to 900 nm. The window size was based on radiometer sensitivity requirements including capability of on-orbit solar calibration.
The report describes a method for performing optimization of a system whose analysis is so expensive that it is impractical to let the optimization code invoke it directly because excessive computational cost and elapsed time might result. In such situation it is imperative to have user control the number of times the analysis is invoked. The reported method achieves that by two techniques in the Design of Experiment category: a uniform dispersal of the trial design points over a n-dimensional hypersphere and a response surface fitting, and the technique of krigging. Analyses of all the trial designs whose number may be set by the user are performed before activation of the optimization code and the results are stored as a data base. That code is then executed and referred to the above data base. Two applications, one of the airborne laser system, and one of an aircraft optimization illustrate the method application.
NASA and NOAA earth observing satellite programs are flying a number of sophisticated scientific instruments which collect data on many phenomena and parameters of the earth's environment. The NASA Earth Observing System (EOS) Program originated the EOS Common Bus approach, which featured two spacecraft (Aqua and Aura) of virtually identical design but with completely different instruments. Significant savings were obtained by the Common Bus approach and these lessons learned are presented as information for future program requiring multiple busses for new diversified instruments with increased capabilities for acquiring earth environmental data volume, accuracy, and type.
Portable hybrid rocket motors and test stands can be seen in many papers but none have been reported on the design or instrumentation at such a small magnitude. The design of this hybrid rocket and test stand is to be small and portable (suitcase size). This basic apparatus will be used for demonstrations in rocket propulsion. The design had to include all of the needed hardware to operate the hybrid rocket unit (with the exception of the external Oxygen tank). The design of this project includes making the correlation between the rocket's thrust and its size, the appropriate transducers (physical size, resolution, range, and cost), compatability with a laptop analog card, the ease of setup, and its portability.
There is an increasing demand to provide OSSE support when seeking funding for new atmospheric observing instruments. Various individuals and groups are running or developing OSSEs with little experience in OSSEs in particular or DA in general. In this presentation we will describe some key issues that are often neglected and some of the poor practices to be avoided. These include issues regarding NR and OSSE validation, consideration of instrument, observation operator, and forecast model error, relationships between observations and synoptic conditions, and conflicts of interest.
An experiment to test a new method was designed, using backscattered radiation from a laser beam to measure oceanographic parameters in a fraction of a second. Tyndall, Rayleigh, Brillouin, and Raman scattering all are utilized to evaluate the parameters. A beam from a continuous argon ion laser is used together with an interferometer and interference filters to gather the information. The results are checked by direct measurements. Future shipboard and airborne experiments are described.
Spacelab-J was an international Spacelab mission with numerous innovative Japanese and American materials and life science experiments. Two of the Spacelab-J experiments were designed over a period of more than a decade by a team from NASA-Ames Research Center. The Frog Embryology Experiment investigated and is helping to resolve a century-long quandary on the effects of gravity on amphibian development. The Autogenic Feedback Training Experiment, flown on Spacelab-J as part of a multi-mission investigation, studied the effects of Autogenic Feedback Therapy on limiting the effects of Space Motion Sickness on astronauts. Both experiments employed the use of a wide variety of specially designed hardware to achieve the experiment objectives. This paper reviews the development of both experiments, from the initial announcement of opportunity in 1978, through selection on Spacelab-J and subsequent hardware and science procedures development, culminating in the highly successful Spacelab-J flight in September 1992.