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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 397 records · Page 22

Challenges in Aeropropulsion

Aeropropulsion technologies must progress to satisfy increasingly stringent global environmental requirements with economically viable air transportation systems. In this paper, key propulsion technologies to meet future needs are identified and the associated challenges are briefly discussed. Also discussed are NASA's vision, NASA's changing role in meeting today's challenge of a shrinking research budget, and propulsion technology impacts on the environment and air transport economics. Critical aeropropulsion technology drivers are identified and their impact evaluated. The aviation industry is critical to the nation's economy, job creation, and national security. NASA's advanced aeropropulsion technology programs and their relation to the aviation industry are discussed.

Campbell, Donald C.↗

The Hubble Space Telescope servicing missions: Past, present, and future operational challenges

The Hubble Space Telescope (HST) is a complex spacecraft designed to conduct leading edge scientific observations over a planned fifteen year mission lifetime. It was designed for servicing by the Space Shuttle to upgrade systems, replace failed components, and boost into a higher orbit. There are many operational challenges that must be addressed in preparing for and executing a Servicing Mission (SM) which range from both technical to managerial issues. This paper will be exploring the operational challenges faced by the HST Operations and Ground System Project in supporting the First Servicing Mission (FSM) and future Servicing Missions. We give special emphasis to those areas that helped ensure mission success. These areas include training, testing, and contingency planning.

William R Ochs↗

Systems Challenges for Hypersonic Vehicles

This paper examines the system challenges posed by fully reusable hypersonic cruise airplanes and access to space vehicles. Hydrocarbon and hydrogen fueled airplanes are considered with cruise speeds of Mach 5 and 10, respectively. The access to space matrix is examined. Airbreathing and rocket powered, single- and two-stage vehicles are considered. Reference vehicle architectures are presented. Major systems/subsystems challenges are described. Advanced, enhancing systems concepts as well as common system technologies are discussed.

Hunt, James L.↗

Systems Challenges for Hypersonic Vehicles

This paper examines the system challenges posed by fully reusable hypersonic cruise airplanes and access to space vehicles. Hydrocarbon and hydrogen fueled airplanes are considered with cruise speeds of Mach 5 and 10, respectively. The access to space matrix is examined. Airbreathing and rocket powered, single- and two-stage vehicles are considered. Reference vehicle architectures are presented. Major systems/subsystems challenges are described. Advanced, enhancing systems concepts as well as common system technologies are discussed.

James L. Hunt↗

Challenges to Laser-Based Imaging Techniques in Gas Turbine Combustor Systems for Aerospace Applications

Increasingly severe constraints on emissions, noise and fuel efficiency must be met by the next generation of commercial aircraft powerplants. At NASA Lewis Research Center (LeRC) a cooperative research effort with industry is underway to design and test combustors that will meet these requirements. To accomplish these tasks, it is necessary to gain both a detailed understanding of the combustion processes and a precise knowledge of combustor and combustor sub-component performance at close to actual conditions. To that end, researchers at LeRC are engaged in a comprehensive diagnostic investigation of high pressure reacting flowfields that duplicate conditions expected within the actual engine combustors. Unique, optically accessible flame-tubes and sector rig combustors, designed especially for these tests. afford the opportunity to probe these flowfields with the most advanced, laser-based optical diagnostic techniques. However, these same techniques, tested and proven on comparatively simple bench-top gaseous flame burners, encounter numerous restrictions and challenges when applied in these facilities. These include high pressures and temperatures, large flow rates, liquid fuels, remote testing, and carbon or other material deposits on combustor windows. Results are shown that document the success and versatility of these nonintrusive optical diagnostics despite the challenges to their implementation in realistic systems.

Locke, Randy J.↗

Mathematical and Computational Challenges in Population Biology and Ecosystems Science

Mathematical and computational approaches provide powerful tools in the study of problems in population biology and ecosystems science. The subject has a rich history intertwined with the development of statistics and dynamical systems theory, but recent analytical advances, coupled with the enhanced potential of high-speed computation, have opened up new vistas and presented new challenges. Key challenges involve ways to deal with the collective dynamics of heterogeneous ensembles of individuals, and to scale from small spatial regions to large ones. The central issues-understanding how detail at one scale makes its signature felt at other scales, and how to relate phenomena across scales-cut across scientific disciplines and go to the heart of algorithmic development of approaches to high-speed computation. Examples are given from ecology, genetics, epidemiology, and immunology.

Levin, Simon A.↗

Engine Technology Challenges for the High-Speed Civil Transport Plane

Ongoing NASA-funded and privately funded studies continue to indicate that an opportunity exists for a second generation supersonic commercial airliner, or High-Speed Civil Transport (HSCT), to become a key part of the 21 st century international air transportation system. Long distance air travel is projected to be the fastest growing segment of the air transportation market by the turn of the century with increases at about 5 percent per annum over the next two decades. This projection suggests that by the year 2015, more than 600,000 passengers per day will be traveling long distances, predominantly over water. These routes would provide the greatest potential for an HSCT to become a significant part of the international air transportation system. The potential market for an HSCT is currently projected to be anywhere from 500-1500 aircraft over the 2005-2030 time period. Such an aircraft fleet size would represent a considerable share of the potential long-range aircraft market. However, this projected HSCT fleet can become a reality only if technologies are developed which will allow an HSCT design that is (1) environmentally compatible and (2) economically viable. Simply stated, the HSCT will be a technology driven airplane. Without significant advances in airframe and propulsion technologies over the levels currently available, there will be no second generation supersonic airliner! This paper will briefly describe the propulsion technology challenges which must be met prior to any product launch decision being made by industry and the progress toward meeting these challenges through NASAs High-Speed Research (HSR) Program, a partnership between NASA and Boeing, General Electric and Pratt & Whitney.

Plencner, Robert M.↗

Technical Challenges for Next Generation Composite Duct Technology

The Access to Space Study identified the requirement for lightweight structures to achieve orbit with a single stage vehicle. The use of composite components partially fulfills that requirement. The purpose of this presentation is to review the technical challenges in the use of composite materials and processes for lines and ducts on next generation launch vehicles. This presentation will identify current requirements for space and missile system components; review the state of the art for existing system components; identify show stoppers to advancing the state of the art; identify technical issues that might limit the application of advanced materials; identify key materials that might provide a high payoff; and identify opportunities for joint partnerships to overcome these multiple technical challenges.

Ledbetter, Frank E., III↗

Design Challenges Encountered in a Propulsion-Controlled Aircraft Flight Test Program

The NASA Dryden Flight Research Center conducted flight tests of a propulsion-controlled aircraft system on an F-15 airplane. This system was designed to explore the feasibility of providing safe emergency landing capability using only the engines to provide flight control in the event of a catastrophic loss of conventional flight controls. Control laws were designed to control the flightpath and bank angle using only commands to the throttles. Although the program was highly successful, this paper highlights some of the challenges associated with using engine thrust as a control effector. These challenges include slow engine response time, poorly modeled nonlinear engine dynamics, unmodeled inlet-airframe interactions, and difficulties with ground effect and gust rejection. Flight and simulation data illustrate these difficulties.

Maine, Trindel↗

Technical Challenges for Next Generation Liquid Rocket Engine Nozzles

Next generation launch and propulsion systems face significant challenges of providing increased performance at lower cost with shorter development cycles. The use of existing materials in new application areas and the development and application of "advanced" material systems are enabling for the achievement of these aggressive goals. An area which offers substantial opportunity to decrease liquid rocket engine systems weight, and thus provide a measure of increased performance, is the nozzle. This presentation will examine the technical issues and showstoppers limiting the application of alternate materials to liquid rocket engine nozzles and identify the key material systems which have the potential for high payoff relative to the forcing functions of cost and performance (weight). Existing nozzle material development projects will be cited and opportunities for future joint partnerships to address these materials and processes challenges will be addressed. The presentation will include overviews of activities in low cost ablative nozzles, ceramic matrix composite cooled and uncooled nozzles, and advanced metallics.

Clinton, R. G., Jr.↗

HSR Aerodynamic Performance Status and Challenges

This paper describes HSR (High Speed Research) Aerodynamic Performance Status and Challenges. The topics include: 1) Aero impact on HSR; 2) Goals and Targets; 3) Progress and Status; and 4) Remaining Challenges. This paper is presented in viewgraph form.

Gilbert, William P.↗

Internet Technologies for Space-based Communications: State of the Art and Challenges

The Internet is rapidly changing the ways we communicate information around the globe today. The desire to provide Internet-based services to anyone, anywhere, anytime has brought satellite communications to the forefront to become an integral part of the Internet. In spite of the distances involved, satellite links are proving to be capable of providing Internet services based on Internet protocol (TCP/IP) stack. This development has led to the question particularly at NASA; can satellites and other space platforms become an Internet-node in space? This will allow the direct transfer of information directly from space to the users on Earth and even be able to control the spacecraft and its instruments. NASA even wants to extend the near earth space Internet to deep space applications where scientists and the public here on Earth may view space exploration in real time via the Internet. NASA's future solar system exploration will involve intensive in situ investigations of planets, moons, asteroids, and comets. While past missions typically involved a single fly-by or orbiting science spacecraft, future missions will begin to use fleets of small, highly intelligent robotic vehicles to carry out collaborative investigations. The resulting multi-spacecraft topologies will effectively create a wide area network spanning the solar system. However, this will require significant development in Internet technologies for space use. This paper provides the status'of the Internet for near earth applications and the potential extension of the Internet for use in deep space planetary exploration. The paper will discuss the overall challenges of implementing the space Internet and how the space Internet will integrate into the complex terrestrial systems those forms the Internet of today in a hybrid set of networks. Internet. We envision extending to the deep space environment such Internet concepts as a well-designed layered architecture. This effort will require an ability to develop and infuse new physical layer technology to increase network bandwidth at very low-bit error rates. In addition, we identify network technologies such as routers and switches needed to maintain standard application layer interfaces, while providing low-cost, efficient, modular networking solutions. We will describe the overall architectural approach to extending the concept of the Internet to space and highlight the important technological challenges and initiatives that will make it a reality.

Bhasin, K.↗

Chip Scale Package Implementation Challenges

The JPL-led MicrotypeBGA Consortium of enterprises representing government agencies and private companies have jointed together to pool in-kind resources for developing the quality and reliability of chip scale packages (CSPs) for a variety of projects. In the process of building the Consortium CSP test vehicles, many challenges were identified regarding various aspects of technology implementation. This paper will present our experience in the areas of technology implementation challenges, including design and building both standard and microvia boards, and assembly of two types of test vehicles. We also discuss the most current package isothermal aging to 2,000 hours at 100 C and 125 C and thermal cycling test results to 1,700 cycles in the range of -30 to 100 C.

Ghaffarian, Reza↗

Space Human Factors Engineering Challenges in Long Duration Space Flight

The focus of this panel is on identifying and discussing the critical human factors challenges facing long duration space flight. Living and working aboard the International Space Station (ISS) will build on the experience humans have had to date aboard the Shuttle and MIR. More extended missions, involving lunar and planetary missions to Mars are being planned. These missions will involve many human factors challenges regarding a number of issues on which more research is needed.

Garland, Daniel J.↗

The Challenge of Planning and Execution for Spacecraft Mobile Robots

The need for spacecraft mobile robots continues to grow. These robots offer the potential to increase the capability, productivity, and duration of space missions while decreasing mission risk and cost. Spacecraft Mobile Robots (SMRs) can serve a number of functions inside and outside of spacecraft from simpler tasks, such as performing visual diagnostics and crew support, to more complex tasks, such as performing maintenance and in-situ construction. One of the predominant challenges to deploying SMRs is to reduce the need for direct operator interaction. Teleoperation is often not practical due to the communication latencies incurred because of the distances involved and in many cases a crewmember would directly perform a task rather than teleoperate a robot to do it. By integrating a mixed-initiative constraint-based planner with an executive that supports adjustably autonomous control, we intend to demonstrate the feasibility of autonomous SMRs by deploying one inside the International Space Station (ISS) and demonstrate in simulation one that operates outside of the ISS. This paper discusses the progress made at NASA towards this end, the challenges ahead, and concludes with an invitation to the research community to participate.

Dorais, Gregory A.↗

Biological Invasions: A Challenge In Ecological Forecasting

The spread of invasive species is one of the most daunting environmental, economic, and human-health problems facing the United States and the World today. It is one of several grand challenge environmental problems being considered by NASA's Earth Science Vision for 2025. The invasive species problem is complex and presents many challenges. Developing an invasive species predictive capability could significantly advance the science and technology of ecological forecasting.

Schnase, J. L.↗

2002 Controls Design Challenge

This document is intended to provide the specifications and requirements for a flight control system design challenge. The response to the challenge will involve documenting whether the particular design has met the stated requirements through analysis and computer simulation. The response should be written in the general format of a technical publication with corresponding length limits, e.g., an approximate maximum length of 45 units, with each full-size figure and double-spaced typewritten page constituting one unit.

Hess, Ronald A.↗

A Survey of Challenges in Aerodynamic Exhaust Nozzle Technology for Aerospace Propulsion Applications

The current paper discusses aerodynamic exhaust nozzle technology challenges for aircraft and space propulsion systems. Technology advances in computational and experimental methods have led to more accurate design and analysis tools, but many major challenges continue to exist in nozzle performance, jet noise and weight reduction. New generations of aircraft and space vehicle concepts dictate that exhaust nozzles have optimum performance, low weight and acceptable noise signatures. Numerous innovative nozzle concepts have been proposed for advanced subsonic, supersonic and hypersonic vehicle configurations such as ejector, mixer-ejector, plug, single expansion ramp, altitude compensating, lobed and chevron nozzles. This paper will discuss the technology barriers that exist for exhaust nozzles as well as current research efforts in place to address the barriers.

Shyne, Rickey J.↗