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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 685 records · Page 38
All sourcesNASA NTRSDOE OSTI
NASA NTRS1990

Engine costs for reusability

The advanced Launch System (ALS) program goals demand an order-of-magnitude reduction in costs over existing launch vehicle propulsion systems. Studies suggest that reusable engines provide cost advantages over expendable propulsion systems. Early studies are quantifying operations costs, and cost sensitivities to engine production and operations variables. ALS production and operations philosophies enhance the potential of an affordable, operationally flexible launch vehicle propulsion system. The assumptions made and criteria set during the initial planning for the operations phase of the ALS highlight the changes for implementing such a system.

Schindler, Carla M.↗
NASA NTRS1990

A small missions program for investigation of near-earth asteroids

Current studies are examining the feasibility and possible content of the Discovery Program, a series of 'Explorer-class' missions to planetary targets. Organized as a multi-layer program with constant funding, the Discovery Program would support lower cost exploration opportunities that are missed in the new start procedure for larger missions. One approach to such a program is to focus on rendezvous missions to several near-Earth asteroids to characterize basic properties of this group of objects. A sample program is presented that visits six different targets over twelve years, using direct low energy trajectories; some of these are newly identified. Each flight in the program delivers a payload capable of addressing science objectives within the expected budget and programmatic constraints of small planetary missions. The key to satisfying the constraints is a disciplined program management philosophy, consistently applied over the entire program, that makes extensive use of hardware designs developed for other programs.

Stancati, M. L.↗
NASA NTRS1990

Crew workload strategies in advanced cockpits

Many methods of measuring and predicting operator workload have been developed that provide useful information in the design, evaluation, and operation of complex systems and which aid in developing models of human attention and performance. However, the relationships between such measures, imposed task demands, and measures of performance remain complex and even contradictory. It appears that we have ignored an important factor: people do not passively translate task demands into performance. Rather, they actively manage their time, resources, and effort to achieve an acceptable level of performance while maintaining a comfortable level of workload. While such adaptive, creative, and strategic behaviors are the primary reason that human operators remain an essential component of all advanced man-machine systems, they also result in individual differences in the way people respond to the same task demands and inconsistent relationships among measures. Finally, we are able to measure workload and performance, but interpreting such measures remains difficult; it is still not clear how much workload is too much or too little nor the consequences of suboptimal workload on system performance and the mental, physical, and emotional well-being of the human operators. The rationale and philosophy of a program of research developed to address these issues will be reviewed and contrasted to traditional methods of defining, measuring, and predicting human operator workload. Viewgraphs are given.

Hart, Sandra G.↗
NASA NTRS1989

Hybrid Propulsion Technology Program, phase 1. Volume 1: Executive summary

The study program was contracted to evaluate concepts of hybrid propulsion, select the most optimum, and prepare a conceptual design package. Further, this study required preparation of a technology definition package to identify hybrid propulsion enabling technologies and planning to acquire that technology in Phase 2 and demonstrate that technology in Phase 3. Researchers evaluated two design philosophies for Hybrid Rocket Booster (HRB) selection. The first is an ASRM modified hybrid wherein as many components/designs as possible were used from the present Advanced Solid Rocket Motor (ASRM) design. The second was an entirely new hybrid optimized booster using ASRM criteria as a point of departure, i.e., diameter, thrust time curve, launch facilities, and external tank attach points. Researchers selected the new design based on the logic of optimizing a hybrid booster to provide NASA with a next generation vehicle in lieu of an interim advancement over the ASRM. The enabling technologies for hybrid propulsion are applicable to either and vehicle design may be selected at a downstream point (Phase 3) at NASA's discretion. The completion of these studies resulted in ranking the various concepts of boosters from the RSRM to a turbopump fed (TF) hybrid. The scoring resulting from the Figure of Merit (FOM) scoring system clearly shows a natural growth path where the turbopump fed solid liquid staged combustion hybrid provides maximized payload and the highest safety, reliability, and low life cycle costing.

Source record↗
NASA NTRS1990

General Rotorcraft Aeromechanical Stability Program (GRASP): Theory manual

The general rotorcraft aeromechanical stability program (GRASP) was developed to calculate aeroelastic stability for rotorcraft in hovering flight, vertical flight, and ground contact conditions. GRASP is described in terms of its capabilities and its philosophy of modeling. The equations of motion that govern the physical system are described, as well as the analytical approximations used to derive them. The equations include the kinematical equation, the element equations, and the constraint equations. In addition, the solution procedures used by GRASP are described. GRASP is capable of treating the nonlinear static and linearized dynamic behavior of structures represented by arbitrary collections of rigid-body and beam elements. These elements may be connected in an arbitrary fashion, and are permitted to have large relative motions. The main limitation of this analysis is that periodic coefficient effects are not treated, restricting rotorcraft flight conditions to hover, axial flight, and ground contact. Instead of following the methods employed in other rotorcraft programs. GRASP is designed to be a hybrid of the finite-element method and the multibody methods used in spacecraft analysis. GRASP differs from traditional finite-element programs by allowing multiple levels of substructure in which the substructures can move and/or rotate relative to others with no small-angle approximations. This capability facilitates the modeling of rotorcraft structures, including the rotating/nonrotating interface and the details of the blade/root kinematics for various types. GRASP differs from traditional multibody programs by considering aeroelastic effects, including inflow dynamics (simple unsteady aerodynamics) and nonlinear aerodynamic coefficients.

Hodges, Dewey H.↗
NASA NTRS1990

A comparison of fatigue life prediction methodologies for rotorcraft

Because of the current U.S. Army requirement that all new rotorcraft be designed to a 'six nines' reliability on fatigue life, this study was undertaken to assess the accuracy of the current safe life philosophy using the nominal stress Palmgrem-Miner linear cumulative damage rule to predict the fatigue life of rotorcraft dynamic components. It has been shown that this methodology can predict fatigue lives that differ from test lives by more than two orders of magnitude. A further objective of this work was to compare the accuracy of this methodology to another safe life method called the local strain approach as well as to a method which predicts fatigue life based solely on crack growth data. Spectrum fatigue tests were run on notched (k(sub t) = 3.2) specimens made of 4340 steel using the Felix/28 tests fairly well, being slightly on the unconservative side of the test data. The crack growth method, which is based on 'small crack' crack growth data and a crack-closure model, also predicted the fatigue lives very well with the predicted lives being slightly longer that the mean test lives but within the experimental scatter band. The crack growth model was also able to predict the change in test lives produced by the rainflow reconstructed spectra.

Everett, R. A., Jr.↗
NASA NTRS1990

Spacelab D-1 mission

The Spacelab D-1 (Deutchland Eins) Mission is discussed from the points of view of safety, materials handling, and toxic materials; the laboratory and equipment used; and some of the different philosophies utilized on this flight. How to enhance scientific return at the same time as being safe was examined.

Dunbar, Bonnie J.↗
NASA NTRS1991

Engines and Innovation: Lewis Laboratory and American Propulsion Technology

This book is an institutional history of the NASA Lewis Research Center, located in Cleveland, Ohio, from 1940, when Congress authorized funding for a third laboratory for the National Advisory Committee for Aeronautics, through the 1980s. The history of the laboratory is discussed in relation to the development of American propulsion technology, with particular focus on the transition in the 1940s from the use of piston engines in airplanes to jet propulsion and that from air-breathing engines to rocket technology when the National Aeronautics and Space Administration was established in 1958. The personalities and research philosophies of the people who shaped the history of the laboratory are discussed, as is the relationship of Lewis Research Center to the Case Institute of Technology.

Dawson, Virginia Parker↗
NASA NTRS1991

Aviation safety and automation technology for subsonic transports

Discussed here are aviation safety human factors and air traffic control (ATC) automation research conducted at the NASA Ames Research Center. Research results are given in the areas of flight deck and ATC automations, displays and warning systems, crew coordination, and crew fatigue and jet lag. Accident investigation and an incident reporting system that is used to guide the human factors research is discussed. A design philosophy for human-centered automation is given, along with an evaluation of automation on advanced technology transports. Intelligent error tolerant systems such as electronic checklists are discussed along with design guidelines for reducing procedure errors. The data on evaluation of Crew Resource Management (CRM) training indicates highly significant positive changes in appropriate flight deck behavior and more effective use of available resources for crew members receiving the training.

Albers, James A.↗
NASA NTRS1990

Assured crew return capability Crew Emergency Return Vehicle (CERV) avionics

The Crew Emergency Return Vehicle (CERV) is being defined to provide Assured Crew Return Capability (ACRC) for Space Station Freedom. The CERV, in providing the standby lifeboat capability, would remain in a dormat mode over long periods of time as would a lifeboat on a ship at sea. The vehicle must be simple, reliable, and constantly available to assure the crew's safety. The CERV must also provide this capability in a cost effective and affordable manner. The CERV Project philosophy of a simple vehicle is to maximize its useability by a physically deconditioned crew. The vehicle reliability goes unquestioned since, when needed, it is the vehicle of last resort. Therefore, its systems and subsystems must be simple, proven, state-of-the-art technology with sufficient redundancy to make it available for use as required for the life of the program. The CERV Project Phase 1'/2 Request for Proposal (RFP) is currently scheduled for release on October 2, 1989. The Phase 1'/2 effort will affirm the existing project requirements or amend and modify them based on a thorough evaluation of the contractor(s) recommendations. The system definition phase, Phase 2, will serve to define CERV systems and subsystems. The current CERV Project schedule has Phase 2 scheduled to begin October 1990. Since a firm CERV avionics design is not in place at this time, the treatment of the CERV avionics complement for the reference configuration is not intended to express a preference with regard to a system or subsystem.

Myers, Harvey Dean↗
NASA NTRS1991

The Langley Research Center CSI phase-0 evolutionary model testbed-design and experimental results

A testbed for the development of Controls Structures Interaction (CSI) technology is described. The design philosophy, capabilities, and early experimental results are presented to introduce some of the ongoing CSI research at NASA-Langley. The testbed, referred to as the Phase 0 version of the CSI Evolutionary model (CEM), is the first stage of model complexity designed to show the benefits of CSI technology and to identify weaknesses in current capabilities. Early closed loop test results have shown non-model based controllers can provide an order of magnitude increase in damping in the first few flexible vibration modes. Model based controllers for higher performance will need to be robust to model uncertainty as verified by System ID tests. Data are presented that show finite element model predictions of frequency differ from those obtained from tests. Plans are also presented for evolution of the CEM to study integrated controller and structure design as well as multiple payload dynamics.

Belvin, W. K.↗
NASA NTRS1991

The Legacy of the X-15

The X-15 established such widespread confidence in aerodynamic, thermal, and structural areas that new designs for operation aircraft for any speed regime could be expected to be successfully achieved if good use was made of all pertinent test facilities and analytical methods. This philosophy guided design of the space shuttle and is the real legacy of the X-15. The accomplishments and contributions attributable to the research and development work on the X-15 that influenced the formative years of the Space Shuttle Program are presented.

Donlan, Charles J.↗
NASA NTRS1990

Orbital maneuvering vehicle remote piloting operations

The remote piloting of spacecraft is discussed using the orbital maneuvering vehicle (OMV) as a case in point. Some challenges to remotely piloted operations are listed. Approaches to solving operation problems are discussed for the two major participants in the loop tasks involved. These tasks are the remotely piloted docking task, and the task of ensuring that the rendezvous is successfully completed. Resulting changes to the OMV system are outlined. The outcome of these changes and the approaches taken in the OMV program are presented. Comparisons are drawn between philosophies and techniques used for Space Transportation System rendezvous and proximity operations, and those currently envisioned for OMV. Finally, a few of the lessons learned are summarized.

Veres, Michael L.↗
NASA NTRS1991

Operations with the special purpose dextrous manipulator on Space Station Freedom

SPAR Canada is actively participating in the Space Station Freedom Program by contributing the Mobile Servicing System (MSS) which will be involved in assembly, maintenance and servicing of both the Space Station and the MSS itself. Part of the MSS is the Special Purpose Dextrous Manipulator (SPDM), a two armed dextrous robot with advanced vision and manipulative capabilities. In addition to Space Station and payload servicing activities the SPDM will be designed to perform self maintenance on the MSS itself. The majority of Space Station equipment will be on orbit for the anticipated 30 year lifespan and the maintenance philosophy will be to repair by the exchange of Orbit Replacement Units or ORUs. The present concept, configuration, and operation of the SPDM and the detailed simulations associated with the maintenance of part of the MSS are described. The Design Reference Mission is the replacement of a Joint Drive Module on the Canadian large payload manipulator, the Space Station Remote Manipulator System. Other Design Reference Missions that were investigated are briefly described, and future operations activity to support the definition of SPDM requirements are discussed.

Cox, B.↗
NASA NTRS1991

NAVSPASUR orbital processing for satellite break-up events

Satellite breakups via explosion or collision can instantly increase the trackable orbiting population by up to several hundred objects, temporarily perturbing the routine space surveillance operations at U.S. Space Command (USSPACWCOM) and the Naval Space Surveillance Center (NAVSPASUR). This paper is a survey of some of the procedures and techniques used by NAVSPASUR to respond to such events. First, the overall data flow at NAVSPASUR is described highlighting the places at which human analysts may intervene with special processing. So-called manual intervention is required in a variety of non-nominal situations, including breakups. Second, a description is given of some of the orbital analysis and other software tools available to NAVSPASUR analysts. These tools were developed in-house over the past thirty years and can be employed in a highly flexible manner. The basic design philosophy for these tools was to implement simple concepts as efficiently as possible and to allow the analyst maximum use of his personal expertise. Finally, several historical breakup scenarios are discussed briefly. These scenarios provide examples of the types of questions that are fairly easy to answer in the present operational environment, as well as examples of questions that are very difficult to answer.

Schumacher, Paul W., Jr.↗
NASA NTRS1990

Comparison of super-high-energy-propulsion-systems based on metallic hydrogen propellant for ES to LEO space transportation

The application is studied of metallic H2 as a rocket propellant, which contains a specific energy of about 52 kcal/g in theory yielding a maximum specific impulse of 1700 s. With the convincing advantage of having a density 14 times that of conventional liquid H2/liquid O2 propellants, metallic H2 could satisfy the demands of advanced launch vehicle propulsion for the next millennium. Provided that there is an atomic metallic state of H2, and that this state is metastable at ambient pressure, which still is not proven, the results are given of the study of some important areas, which concern the production of metallic H2, the combustion, chamber cooling, and storage. The results show that the use of metallic H2 as rocket propellant could lead to revolutionary changes in space vehicle philosophy toward small size, small weight, and high performance single stage to orbit systems. The use of high metallic H2 mass fractions results in a dramatic reduction of required propellant volume, while gas temperatures in the combustion chamber exceed 5000 K. Furthermore, it follows, that H2 (liquid or slush) is the most favorable candidate as working fluid. Jet generated noise due to high exhaust velocities could be a problem.

Thierschmann, M.↗
NASA NTRS1991

Intelligent computer-aided training and tutoring

Specific autonomous training systems based on artificial intelligence technology for use by NASA astronauts, flight controllers, and ground-based support personnel that demonstrate an alternative to current training systems are described. In addition to these specific systems, the evolution of a general architecture for autonomous intelligent training systems that integrates many of the features of traditional training programs with artificial intelligence techniques is presented. These Intelligent Computer-Aided Training (ICAT) systems would provide, for the trainee, much of the same experience that could be gained from the best on-the-job training. By integrating domain expertise with a knowledge of appropriate training methods, an ICAT session should duplicate, as closely as possible, the trainee undergoing on-the-job training in the task environment, benefitting from the full attention of a task expert who is also an expert trainer. Thus, the philosophy of the ICAT system is to emulate the behavior of an experienced individual devoting his full time and attention to the training of a novice - proposing challenging training scenarios, monitoring and evaluating the actions of the trainee, providing meaningful comments in response to trainee errors, responding to trainee requests for information, giving hints (if appropriate), and remembering the strengths and weaknesses displayed by the trainee so that appropriate future exercises can be designed.

Loftin, R. Bowen↗
NASA NTRS1990

Variable Sweep Transition Flight Experiment (VSTFE): Unified Stability System (USS). Description and Users' Manual

NASA initiated the Variable Sweep Transition Flight Experiment (VSTFE) to establish a boundary layer transition database for laminar flow wing design. For this experiment, full-span upper surface gloves were fitted to a variable sweep F-14 aircraft. The development of an improved laminar boundary layer stability analysis system called the Unified Stability System (USS) is documented and results of its use on the VSTFE flight data are shown. The USS consists of eight computer codes. The theoretical background of the system is described, as is the input, output, and usage hints. The USS is capable of analyzing boundary layer stability over a wide range of disturbance frequencies and orientations, making it possible to use different philosophies in calculating the growth of disturbances on sweptwings.

Rozendaal, Rodger A.↗