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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 325 records · Page 18
All sourcesNASA NTRSDOE OSTI
NASA NTRS2011

Modeling a Transient Pressurization with Active Cooling Sizing Tool

As interest in the area of in-space zero boil-off cryogenic propellant storage develops, the need to visualize and quantify cryogen behavior during ventless tank self-pressurization and subsequent cool-down with active thermal control has become apparent. During the course of a mission, such as the launch ascent phase, there are periods that power to the active cooling system will be unavailable. In addition, because it is not feasible to install vacuum jackets on large propellant tanks, as is typically done for in-space cryogenic applications for science payloads, instances like the launch ascent heating phase are important to study. Numerous efforts have been made to characterize cryogenic tank pressurization during ventless cryogen storage without active cooling, but few tools exist to model this behavior in a user-friendly environment for general use, and none exist that quantify the marginal active cooling system size needed for power down periods to manage tank pressure response once active cooling is resumed. This paper describes the Transient pressurization with Active Cooling Tool (TACT), which is based on a ventless three-lump homogeneous thermodynamic self-pressurization model1 coupled with an active cooling system estimator. TACT has been designed to estimate the pressurization of a heated but unvented cryogenic tank, assuming an unavailable power period followed by a given cryocooler heat removal rate. By receiving input data on the tank material and geometry, propellant initial conditions, and passive and transient heating rates, a pressurization and recovery profile can be found, which establishes the time needed to return to a designated pressure. This provides the ability to understand the effect that launch ascent and unpowered mission segments have on the size of an active cooling system. A sample of the trends found show that an active cooling system sized for twice the steady state heating rate would results in a reasonable time for tank pressure recovery with ZBO of a liquid oxygen propellant tank.

Guzik, Monica C.↗
NASA NTRS1999

Interpretation of Lidar and Satellite Data Sets Using a Global Photochemical Model

A primary goal of the NASA Tropospheric Chemistry Program (TCP) is to "contribute substantially to scientific understanding of human impacts on the global troposphere". In order to analyze global or regional trends and factors of the troposphere chemistry, for example, its oxidation capacity or composition, a continuous global/regional data coverage as well as model simulations are needed. The Global Tropospheric Experiment (GTE), a major component of the TCP, provides data vital to these questions via aircraft measurement of key trace chemical species in various remote regions of the world. Another component in NASA's effort are satellite projects for exploration of tropospheric chemistry and dynamics. A unique data product is the Tropospheric Ozone Residual (TOR) utilizing global tropospheric ozone data. Another key research tool are simulation studies of atmospheric chemistry and dynamics for the theoretical understanding of the atmosphere, the extrapolation of observed trends, and for sensitivity studies assessing a changing anthropogenic impact to air chemistry and climate. In the context with model simulations, field data derived from satellites or (airborne) field missions are needed for two purposes: 1. To initialize and validate model simulations, and 2., to interpret field data by comparison to model simulation results in order to analyze global or regional trends and deviations from standard tropospheric chemistry and transport conditions as defined by the simulations. Currently, there is neither a sufficient global data coverage available nor are existing well established global circulation models. The NASA LARC CTM model is currently not yet in a state to accomplish a sufficient tropospheric chemistry simulation, so that the current research under this cooperative agreement focuses on utilizing field data products for direct interpretation. They will be also available for model testing and a later interpretation with a finally utilized model.

Zenker, Thomas↗
NASA NTRSDate not supplied

Power System Redundancy Design Trends for All-Electric eVTOL Quadrotors

Electrical vertical takeoff and landing (eVTOL) vehicles promise to enable a variety of new local and intraregional air transport missions. However, there are significant challenges that must be solved to enable their use. One challenge is the relatively low reliability of power components (e.g. motors, power electronic devices, and batteries). No clear development path to create reliable eVTOL power systems has been articulated in the literature, though it is generally assumed redundancy is part of the solution. This work proposes an analysis process to examine the redundancy design space and select mass optimal designs for eVTOL power systems. The process is applied to a six passenger quadrotor vehicle, and results are used to highlight redundancy design trends for this class of vehicle. This process and associated data can help vehicle designers more effectively develop eVTOLs that meet reliability requirements.

Electric vertical takeoff and landing↗
NASA NTRSDate not supplied

Power System Redundancy Design Trends for All-Electric eVTOL Quadrotors

Electrical vertical takeoff and landing (eVTOL) vehicles promise to enable a variety of new local and intraregional air transport missions. However, there are significant challenges that must be solved to enable their use. One challenge is the relatively low reliability of power components (e.g. motors, power electronic devices, and batteries). No clear development path to create reliable eVTOL power systems has been articulated in the literature, though it is generally assumed redundancy is part of the solution. This work proposes an analysis process to examine the redundancy design space and select mass optimal designs for eVTOL power systems. The process is applied to a six passenger quadrotor vehicle, and results are used to highlight redundancy design trends for this class of vehicle. This process and associated data can help vehicle designers more effectively develop eVTOLs that meet reliability requirements.

Electric vertical takeoff and landing↗
NASA NTRS2012

Long-Lasting Science Returns from the Apollo Heat Flow Experiments

The Apollo astronauts deployed geothermal heat flow instruments at landing sites 15 and 17 as part of the Apollo Lunar Surface Experiments Packages (ALSEP) in July 1971 and December 1972, respectively. These instruments continuously transmitted data to the Earth until September 1977. Four decades later, the data from the two Apollo sites remain the only set of in-situ heat flow measurements obtained on an extra-terrestrial body. Researchers continue to extract additional knowledge from this dataset by utilizing new analytical techniques and by synthesizing it with data from more recent lunar orbital missions such as the Lunar Reconnaissance Orbiter. In addition, lessons learned from the Apollo experiments help contemporary researchers in designing heat flow instruments for future missions to the Moon and other planetary bodies. For example, the data from both Apollo sites showed gradual warming trends in the subsurface from 1971 to 1977. The cause of this warming has been debated in recent years. It may have resulted from fluctuation in insolation associated with the 18.6-year-cycle precession of the Moon, or sudden changes in surface thermal environment/properties resulting from the installation of the instruments and the astronauts' activities. These types of reanalyses of the Apollo data have lead a panel of scientists to recommend that a heat flow probe carried on a future lunar mission reach 3 m into the subsurface, approx 0.6 m deeper than the depths reached by the Apollo 17 experiment. This presentation describes the authors current efforts for (1) restoring a part of the Apollo heat flow data that were left unprocessed by the original investigators and (2) designing a compact heat flow instrument for future robotic missions to the Moon. First, at the conclusion of the ALSEP program in 1977, heat flow data obtained at the two Apollo sites after December 1974 were left unprocessed and not properly archived through NASA. In the following decades, heat flow data from January 1975 through February 1976, as well as the metadata necessary for processing the data (the data reduction algorithm, instrument calibration data, etc.), were somehow lost. In 2010, we located 450 original master archival tapes of unprocessed data from all the ALSEP instruments for a period of April through June 1975 at the Washington National Records Center. We are currently extracting the heat flow data packets from these tapes and processing them. Second, on future lunar missions, heat flow probes will likely be deployed by a network of small robotic landers, as recommended by the latest Decadal Survey of the National Academy of Science. In such a scenario, the heat flow probe must be a compact system, and that precludes use of heavy excavation equipment such as a rotary drill for reaching the 3-m target depth. The new heat flow system under development uses a pneumatically driven penetrator. It utilizes a stem that winds out of a reel and pushes its conical tip into the regolith. Simultaneously, gas jets, emitted from the cone tip, loosen and blow away the soil. Lab experiments have demonstrated its effectiveness in lunar vacuum.

Nagihara, S.↗
NASA NTRS2004

A Comparison of Transportation Systems for Human Missions to Mars

There are many ways to send humans to Mars. Credible technical reports can be traced to the 1950's. More recently, NASA has funded major studies that depict a broad variety of trajectories, technologies, stay times, and costs. Much of this data is still valid with direct application to today's exploration planning. This paper presents results comparing these studies with particular emphasis on the in-space transportation aspects of the mission. Specifically, comparisons are made on propulsion systems used for getting the crew and mission equipment from Earth orbit to Mars orbit, descending and ascending from the surface, and returning to Earth orbit. Areas of comparison for each of these phases include crew size, mission mass, propellant mass, delta v, specific impulse, transit time, surface stay time, aero-braking, and others. Data is analyzed to demonstrate either strong trends toward particular technologies or diverging solutions.

Bipropellants↗
NASA NTRS2010

Ensuring US National Aeronautics Test Capabilities

U.S. leadership in aeronautics depends on ready access to technologically advanced, efficient, and affordable aeronautics test capabilities. These systems include major wind tunnels and propulsion test facilities and flight test capabilities. The federal government owns the majority of the major aeronautics test capabilities in the United States, primarily through the National Aeronautics and Space Administration (NASA) and the Department of Defense (DoD). However, changes in the Aerospace landscape, primarily the decrease in demand for testing over the last 20 years required an overarching strategy for management of these national assets. Therefore, NASA established the Aeronautics Test Program (ATP) as a two-pronged strategic initiative to: (1) retain and invest in NASA aeronautics test capabilities considered strategically important to the agency and the nation, and (2) establish a strong, high level partnership with the DoD. Test facility utilization is a critical factor for ATP because it relies on user occupancy fees to recover a substantial part of the operations costs for its facilities. Decreasing utilization is an indicator of excess capacity and in some cases low-risk redundancy (i.e., several facilities with basically the same capability and overall low utilization). However, low utilization does not necessarily translate to lack of strategic importance. Some facilities with relatively low utilization are nonetheless vitally important because of the unique nature of the capability and the foreseeable aeronautics testing needs. Unfortunately, since its inception, the customer base for ATP has continued to shrink. Utilization of ATP wind tunnels has declined by more than 50% from the FY 2006 levels. This significant decrease in customer usage is attributable to several factors, including the overall decline in new programs and projects in the aerospace sector; the impact of computational fluid dynamics (CFD) on the design, development, and research process; and the reductions in wind tunnel testing requirements within the largest consumer of ATP wind tunnel test time, the Aeronautics Research Mission Directorate (ARMD). Retirement of the Space Shuttle Program and recent perturbations of NASA's Constellation Program will exacerbate this downward trend. Therefore it is crucial that ATP periodically revisit and determine which of its test capabilities are strategically important, which qualify as low-risk redundancies that could be put in an inactive status or closed, and address the challenges associated with both sustainment and improvements to the test capabilities that must remain active. This presentation will provide an overview of the ATP vision, mission, and goals as well as the challenges and opportunities the program is facing both today and in the future. We will discuss the strategy ATP is taking over the next five years to address the National aeronautics test capability challenges and what the program will do to capitalize on its opportunities to ensure a ready, robust and relevant portfolio of National aeronautics test capabilities.

Marshall, Timothy J.↗
NASA NTRS1992

Space Station Freedom Environmental Health Care Program

The paper discusses the environmental planning and monitoring aspects of the Space Station Freedom (SSF) Environmental Health Care Program, which encompasses all phases of the SSF assembly and operation from the first element entry at MB-6 through the Permanent Manned Capability and beyond. Environmental planning involves the definition of acceptability limits and monitoring requirements for the radiation dose barothermal parameters and potential contaminants in the SSF air and water and on internal surfaces. Inflight monitoring will be implemented through the Environmental Health System, which consists of five subsystems: Microbiology, Toxicology, Water Quality, Radiation, and Barothermal Physiology. In addition to the environmental data interpretation and analysis conducted after each mission, the new data will be compared to archived data for statistical and long-term trend analysis and determination of risk exposures. Results of these analyses will be used to modify the acceptability limits and monitoring requirements for the future.

Richard, Elizabeth E.↗
NASA NTRS2009

An Update on Mortality in the U.S. Astronaut Corps: 1959-2009

Although it has now been over 50 years since mankind first ventured into space, the long-term health impacts of human space flight remain largely unknown. Identifying factors that affect survival and prognosis among those who participate in space flight is vitally important, as the era of commercial space flight approaches and NASA prepares for missions to Mars. The Longitudinal Study of Astronaut Health is a prospective study designed to examine trends in astronaut morbidity and mortality. The purpose of this analysis was to describe and explore predictors of overall and cause-specific mortality among individuals selected for the U.S. astronaut corps. All U.S. astronauts (n=321), regardless of flight status, were included in this analysis. Death certificate searches were conducted to ascertain vital status and cause of death through April 2009. Data were collected from medical records and lifestyle questionnaires. Multivariable Cox regression modeling was used to calculate the mortality hazard associated with embarking on space flight, adjusted for sex, race, and age at selection. Between 1959 and 2009, there were 39 (12.1%) deaths. Of these deaths, 18 (42.2%) were due to occupational accidents; 7 (17.9%) were due to other accidents; 6 (15.4%) were attributable to cancer; 6 (15.4%) resulted from cardiovascular/circulatory diseases; and 2 (5.1%) were from other causes. Participation in space flight did not significantly increase mortality hazard over time (adjusted hazard ratio=0.57; 95% confidence interval=0.26-1.26. Because our results are based on a small sample size, future research that includes payload specialists, other space flight participants, and international crew members is warranted to maximize statistical power.

Amirian, E.↗
NASA NTRS2011

Core Noise: Implications of Emerging N+3 Designs and Acoustic Technology Needs

This presentation is a summary of the core-noise implications of NASA's primary N+3 aircraft concepts. These concepts are the MIT/P&W D8.5 Double Bubble design, the Boeing/GE SUGAR Volt hybrid gas-turbine/electric engine concept, the NASA N3-X Turboelectric Distributed Propulsion aircraft, and the NASA TBW-XN Truss-Braced Wing concept. The first two are future concepts for the Boeing 737/Airbus A320 US transcontinental mission of 180 passengers and a maximum range of 3000 nm. The last two are future concepts for the Boeing 777 transpacific mission of 350 passengers and a 7500 nm range. Sections of the presentation cover: turbofan design trends on the N+1.5 time frame and the already emerging importance of core noise; the NASA N+3 concepts and associated core-noise challenges; the historical trends for the engine bypass ratio (BPR), overall pressure ratio (OPR), and combustor exit temperature; and brief discussion of a noise research roadmap being developed to address the core-noise challenges identified for the N+3 concepts. The N+3 conceptual aircraft have (i) ultra-high bypass ratios, in the rage of 18 - 30, accomplished by either having a small-size, high-power-density core, an hybrid design which allows for an increased fan size, or by utilizing a turboelectric distributed propulsion design; and (ii) very high OPR in the 50 - 70 range. These trends will elevate the overall importance of turbomachinery core noise. The N+3 conceptual designs specify the need for the development and application of advanced liners and passive and active control strategies to reduce the core noise. Current engineering prediction of core noise uses semi-empirical methods based on older turbofan engines, with (at best) updates for more recent designs. The models have not seen the same level of development and maturity as those for fan and jet noise and are grossly inadequate for the designs considered for the N+3 time frame. An aggressive program for the development of updated noise prediction tools for integrated core assemblies as well as and strategies for noise reduction and control is needed in order to meet the NASA N+3 noise goals. The NASA Fundamental Aeronautics Program has the principal objective of overcoming today's national challenges in air transportation. The SFW Reduced-Perceived-Noise Technical Challenge aims to develop concepts and technologies to dramatically reduce the perceived aircraft noise outside of airport boundaries. This reduction of aircraft noise is critical to enabling the anticipated large increase in future air traffic.

Hultgren, Lennart S.↗
NASA NTRSDate not supplied

Small Satellite-sized Hypersonic Inflatable Decelerators for Interplanetary Science Missions

To take full advantage of our increased access to space, through reduced launch costs that ridesharing opportunities present, innovative and lower cost options for interplanetary exploration are needed. Capitalizing on the technology miniaturization trends and the SmallSat class of vehicles could provide advancements for interplanetary space exploration. Presented here, are the results of a feasibility study conducted during an internship at NASA Langley Research Center that explored the use of a SmallSat-sized Hypersonic Inflatable Aerodynamic Decelerator (HIAD) to enable interplanetary orbital science missions via aerocapture.

Shelly C. Mann↗
NASA NTRSDate not supplied

Small Satellite-sized Hypersonic Inflatable Decelerators for Interplanetary Science Missions

To take full advantage of our increased access to space, through reduced launch costs that ridesharing opportunities present, innovative and lower cost options for interplanetary exploration are needed. Capitalizing on the technology miniaturization trends and the SmallSat class of vehicles could provide advancements for interplanetary space exploration. Presented here, are the results of a feasibility study conducted during an internship at NASA Langley Research Center that explored the use of a SmallSat-sized Hypersonic Inflatable Aerodynamic Decelerator (HIAD) to enable interplanetary orbital science missions via aerocapture.

Shelly C. Mann↗
NASA NTRS1997

Advanced Ion Propulsion Technology for Solar System Exploration

The use of ion propulsion for deep-space missions is becoming a reality with the flight next year of the ion propelled Ner Millenium Deep Space 1 Spacecraft. This event is already stimulating the call for improved ion propulsion technologies, a trend which is expected to continue. This paper describes the examination of advanced solar electric propulsion technologies to determine their potential benefits for projeted near and mid-term solar system exploration missions.

Ion↗
NASA NTRS2018

NASA and COTS Electronics: Past Approach and Successes - Future Considerations

NASA has a long history of using commercial grade electronics in space. In this talk, a brief history of NASAâ's trends and approaches to commercial grade electronics focusing on processing and memory systems will be presented. This will include providing summary information on the space hazards to electronics as well as NASA mission trade space. We will also discuss developing recommendations for risk management approaches to Electrical, Electronic and Electromechanical (EEE) parts and reliability in space. The final portion of the talk will discuss emerging aerospace trends and the future for Commercial Off The Shelf (COTS) usage.

LaBel, Kenneth A.↗
NASA NTRS1983

Some historical trends in the research and development of aircraft

A survey of some trends in aircraft design was made in an effort to determine the relation between research, development, test, and evaluation (RDT and E) and aircraft mission capability, requirements, and objectives. Driving forces in the history of aircraft include the quest for speed which involved design concepts incorporating jet propulsion systems and low drag features. The study of high speed design concepts promoted new experimental and analytical research techniques. These research techniques, in turn, have lead to concepts offering new performance potential. Design trends were directed toward increased speed, efficiency, productivity, and safety. Generally speaking, the research and development effort has been evolutionary in nature and, with the exception of the transition to supersonic flight, little has occurred since the origin of flight that has drastically changed the basic design fundamentals of aircraft. However, this does not preclude the possibility of dramatic changes in the future since the products of research are frequently unpredictable. Advances should be expected and sought in improved aerodynamics (reduced drag, enhanced lift, flow field exploitation); propulsion (improved engine cycles, multimode engines, alternate fuels, alternate power sources); structures (new materials, manufacturing techniques); all with a view toward increased efficiency and utility.

Spearman, M. L.↗
NASA NTRS1985

Simulation for human factors research. A central question: Fidelity

Generalized outlines are presented for simulation in human factors research. Recent trends in aeronautical simulation are given. Some criteria for effective training devices are also given. Full system/full mission simulation in aviation and in space human factors research is presented.

Nagel, D.↗
NASA NTRS1999

Spacecraft Environments Interactive: Space Radiation and Its Effects on Electronic System

The natural space environment is characterized by complex and subtle phenomena hostile to spacecraft. Effects of these phenomena impact spacecraft design, development, and operation. Space systems become increasingly susceptible to the space environment as use of composite materials and smaller, faster electronics increases. This trend makes an understanding of space radiation and its effects on electronic systems essential to accomplish overall mission objectives, especially in the current climate of smaller/better/cheaper faster. This primer outlines the radiation environments encountered in space, discusses regions and types of radiation, applies the information to effects that these environments have on electronic systems, addresses design guidelines and system reliability, and stresses the importance of early involvement of radiation specialists in mission planning, system design, and design review (part-by-part verification).

Howard, J. W., Jr.↗