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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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All sourcesNASA NTRSDOE OSTI
DOE OSTI2025

The Dynamic Tripolar Strategic Balance: A Net Assessment (Workshop Summary)

On December 9-10, the Center for Global Security Research (CGSR) at Lawrence Livermore National Laboratory (LLNL) hosted a workshop titled “The Dynamic Tripolar Strategic Balance: A Net Assessment.” The discussion was guided by the following key questions: • By what metrics should the strategic balance be assessed? • How dynamic is the balance? How fragile? • Is the United States gaining strategic advantage, losing it, or holding steady, overall? • In order to gain new advantages or re-gain advantages lost, can or should the United States prioritize some domains and accept more risk in others? If so, which ones?

45 MILITARY TECHNOLOGY, WEAPONRY, AND NATIONAL DEF↗
DOE OSTI2026

Technical Justifications for Outdoor Bulk Gaseous Hydrogen Storage Setback Distances

Setback distances define a prescribed distance between a potentially hazardous system and different types of other systems, people, buildings, or materials that may be exposed to that hazard. Riskinformed separation distances are not meant to completely eliminate risk, but rather to limit the risk to an acceptable level. A sensitivity study of risk suggested that a leak size of 3% of the pipe cross-sectional area would be a conservative but reasonable basis. Calculation of the setback distances for gaseous hydrogen was done in a deterministic manner, using a selected leak size and harm criteria for each group of exposures. Harm criteria have been updated to better reflect the exposure types under consideration, and to be consistent with setback distances for liquid hydrogen. The resulting setback distance values are primarily driven by radiative heat flux values for all exposure groups. For the typical pipe sizes, the setback distances slightly increase compared to the previous version of NFPA 2.

08 HYDROGEN↗
NASA NTRS1972

Solid rocket motors for the Space Shuttle booster.

The evolution of the space shuttle booster system is reviewed from its initial concepts based on liquid-propellant reusable boosters to the final selection of recoverable, solid-fuel rocket motors. The rationale associated with each of the several major decisions in the evolution process is discussed. It is shown that the external tank orbiter configuration emerging from the latest studies takes maximum advantage of the solid rocket motor development experience and promises to be the optimum configuration for fulfilling the paramount shuttle program requirements of minimum total development risk within acceptable costs.

Odom, J. B.↗
NASA NTRS1978

Energy efficient engine: Preliminary design and integration studies

A mixed exhaust, direct drive fan turbofan configuration was selected from four candidates. This choice was based on its ability to exceed study goals of 12% lower thrust specific fuel consumption and 5% lower direct operating cost by the 1990's with commercially acceptable technical risk and relative mechanical simplicity. The evaluation leading to configuration selection is discussed. Necessary technology advancements are identified and related to the goals.

Gray, D. E.↗
NASA NTRS1983

Aeroassisted orbit transfer window opens on missions

Studies of aeroassisted spacecraft orbit transfer conducted over the last two decades have produced an extensive literature and a well developed technology base, which suggest the obtainability of substantial performance improvements over all-propulsive spacecraft maneuvers. In such cases as that of multipass aerobraking, in which the vehicle is transferred from its approach velocity to a highly elliptic orbit about the planet by means of a rocket burn, followed by the circularization of the orbit through many high altitude atmospheric passes, the technology appears to be ready for application. In most other areas of aeroassisted orbit transfer, further work is required to reduce design risks to acceptable levels.

Walberg, G. D.↗
NASA NTRS1985

Satellite voice broadcast. Volume 1: Executive summary

An Executive Summary of the Satellite Voice Broadcast System Study designs are synthesized for direct sound broadcast satellite systems for HF-, VHF-, and Ku-bands. Methods are developed and used to predict satellite weight, volume, and RF performance for the various concepts considered. Cost and schedule risk assessments are performed to predict time and cost required to implement selected concepts. Technology assessments and tradeoffs are made to identify critical enabling technologies that require development to bring technical risk to acceptable levels for full scale development.

Bachtell, E. E.↗
NASA NTRS1985

Satellite voice broadcast. Volume 2: System study

The Technical Volume of the Satellite Broadcast System Study is presented. Designs are synthesized for direct sound broadcast satellite systems for HF-, VHF-, L-, and Ku-bands. Methods are developed and used to predict satellite weight, volume, and RF performance for the various concepts considered. Cost and schedule risk assessments are performed to predict time and cost required to implement selected concepts. Technology assessments and tradeoffs are made to identify critical enabling technologies that require development to bring technical risk to acceptable levels for full scale development.

Bachtell, E. E.↗
NASA NTRS1989

Liquid Rocket Booster (LRB) for the Space Transportation System (STS) systems study. Volume 1: Executive summary

The feasibility of replacing the Space Transportation System (STS) Solid Rocket Boosters (SRBs) with Liquid Rocket Boosters (LRBs) was studied. Feasibility required acceptable technical risk, program costs, and a program plan which supports STS requirements. Three major goals were identified to direct booster design and operation: increased STS safety and reliability; STS/LRB integration with minimum impact; and increased STS performance. Two booster engine designs were studied. The first engine design was a turbopump-fed engine with state-of-the-art design, and the second was a pressure-fed engine which might provide a lower cost alternative to the pump-fed concept. Both booster concepts were carried through to completion of conceptual design and all system impacts and program costs were identified. Applications for LRB use in the Advanced Launch System (ALS) program were studied using the pump-fed LRB baseline concept and variations on the baseline concept. Support for the Pressure-Fed Booster Test Bed (PFBTB) included test program planning and costs and technical support.

Source record↗
NASA NTRS2000

NASA's Integrated Space Transportation Plan

Improvements in the safety, reliability and affordability of current and future space transportation systems must be achieved if NASA is to perform its mission and if the U.S. space industry is to reach its full commercial potential. In response to Presidential Policy in 1994, NASA, working with our industrial partners, initiated several efforts including the X-33, X-34, X-37 and Advanced Space Transportation programs with the goal of demonstrating the technologies that could enable these goals. We have learned that emerging technologies will enable the needed advancements but that more development along multiple, competing paths is needed. We have learned that developing requirements diligently and in partnership with industry will allow us to better converge with commercial capabilities. We have learned that commercial markets are not growing as fast as projected earlier, but there are still possibilities in the near-term to pursue alternate paths that can make access to space more robust. The goal of transitioning NASA's space transportation needs to commercial launch vehicles remains the key aim of our efforts and will require additional investment to reduce business and technical risks to acceptable levels.

Cook, Stephen A.↗
NASA NTRS1999

A Summary fo Solar Sail Technology Developments and Proposed Demonstration Missions

NASA's drive to reduce mission costs and accept the risk of incorporating innovative, high payoff technologies into it's missions while simultaneously undertaking ever more difficult missions has sparked a greatly renewed interest in solar sails. From virtually no technology or flight mission studies activity three years ago solar sails are now included in NOAA, NASA, DOD, DLR, ESA and ESTEC technology development programs and technology roadmaps. NASA programs include activities at Langley Research Center, Jet Propulsion Laboratory, Marshall Space Flight Center, Goddard Space Flight Center, and the NASA Institute for Advanced Concepts; NOAA has received funding for a proposed solar sail mission; DLR is designing and fabricating a 20-m laboratory model sail, there are four demonstration missions under study at industry, NASA, DOD and Europe, two new text books on solar sailing were recently published and one new test book is planned. This paper summarizes these on-going developments in solar sails.

Garner, Charles↗
NASA NTRS2003

PEM-INST-001: Instructions for Plastic Encapsulated Microcircuit (PEM) Selection, Screening, and Qualification

Potential users of plastic encapsulated microcircuits (PEMs) need to be reminded that unlike the military system of producing robust high-reliability microcircuits that are designed to perform acceptably in a variety of harsh environments, PEMs are primarily designed for use in benign environments where equipment is easily accessed for repair or replacement. The methods of analysis applied to military products to demonstrate high reliability cannot always be applied to PEMs. This makes it difficult for users to characterize PEMs for two reasons: 1. Due to the major differences in design and construction, the standard test practices used to ensure that military devices are robust and have high reliability often cannot be applied to PEMs that have a smaller operating temperature range and are typically more frail and susceptible to moisture absorption. In contrast, high-reliability military microcircuits usually utilize large, robust, high-temperature packages that are hermetically sealed. 2. Unlike the military high-reliability system, users of PEMs have little visibility into commercial manufacturers proprietary design, materials, die traceability, and production processes and procedures. There is no central authority that monitors PEM commercial product for quality, and there are no controls in place that can be imposed across all commercial manufacturers to provide confidence to high-reliability users that a common acceptable level of quality exists for all PEMs manufacturers. Consequently, there is no guaranteed control over the type of reliability that is built into commercial product, and there is no guarantee that different lots from the same manufacturer are equally acceptable. And regarding application, there is no guarantee that commercial products intended for use in benign environments will provide acceptable performance and reliability in harsh space environments. The qualification and screening processes contained in this document are intended to detect poor-quality lots and screen out early random failures from use in space flight hardware. However, since it cannot be guaranteed that quality was designed and built into PEMs that are appropriate for space applications, users cannot screen in quality that may not exist. It must be understood that due to the variety of materials, processes, and technologies used to design and produce PEMs, this test process may not accelerate and detect all failure mechanisms. While the tests herein will increase user confidence that PEMs with otherwise unknown reliability can be used in space environments, such testing may not guarantee the same level of reliability offered by military microcircuits. PEMs should only be used where due to performance needs there are no alternatives in the military high-reliability market, and projects are willing to accept higher risk.

Teverovsky, Alexander↗
NASA NTRS1999

Preparing for Mars: the physiologic and medical challenges

As the twentieth century closes, retrospectives cite the Apollo moon missions as one of the important events of the past 100 years. A trip to Mars, however, would be even more challenging and significant. A round-trip Mars journey would require nearly three years away from Earth, a significant leap in complexity compared to the two week long Moon trips or the record-breaking fourteen-month flight on Mir. What would be the physiologic and medical challenges of a Mars flight? Two key areas of physiology present the greatest potential problems--calcium metabolism and radiation exposure. Data from Mir missions show that bone loss continues in space despite an aggressive countermeasure program. Average losses were 0.35% per month, but some load bearing areas lost >1% per month. A 1% loss rate, if it continued unabated for 30 months, could produce osteoporosis. Smaller losses could still increase fracture risk. Some bone loss can be well tolerated, particularly if the bone can be regained after the mission. But the effectiveness of post-flight rehabilitation to restore the density and quality of bone after spaceflight is not well known. Bone loss estimates are based on continuous weightlessness exposure, but this is not a requirement for a Mars trip. Most of the time on a Mars trip will be spent in the 1/3 Earth's gravity environment on Mars, and either intermittent or continuous artificial gravity can be provided for the transit between planets (although at an engineering cost). The dosing of the gravity exposure (e.g. the level and duration), however, has not been established. Radiation protection also requires a balance between engineering cost and human health. Excessive shielding could add billions of dollars to the cost of a mission. Trips in interplanetary space, however, expose the crew to heavy high-energy particles from cosmic rays (HZE particles), which have a high linear energy transfer. This high energy leads to significant biological damage (e.g. chromosomal aberrations, cancer induction). A recent report from the Committee on Space Biology and Medicine notes that only one systematic study of cancer induction from high-energy particles has been conducted (using the mouse Harderian gland). Predictions of cancer risk and acceptable radiation exposure in space are extrapolated from minimal data. Other areas of physiology also present problems, such as muscle loss, cardiovascular deconditioning, and vestibular adaptation. Despite all the issues, however, a focussed, aggressive research program that uses the resources of the International Space Station should pave the way for mankind's greatest adventure--a trip to Mars.

STS-90 Shuttle Project↗
NASA NTRS2007

Implementation of Leak Test Methods for the International Space Station (ISS) Elements, Systems and Components

The International Space Station (ISS has Qualification and Acceptance Environmental Test Requirements document, SSP 41172 that includes many environmental tests such as Thermal vacuum & Cycling, Depress/Repress, Sinusoidal, Random, and Acoustic Vibration, Pyro Shock, Acceleration, Humidity, Pressure, Electromatic Interference (EMI)/Electromagnetic Compatibility (EMCO), etc. This document also includes (13) leak test methods for Pressure Integrity Verification of the ISS Elements, Systems, and Components. These leak test methods are well known, however, the test procedure for specific leak test method shall be written and implemented paying attention to the important procedural steps/details that, if omitted or deviated, could impact the quality of the final product and affect the crew safety. Such procedural steps/details for different methods include, but not limited to: - Sequence of testing, f or example, pressurization and submersion steps for Method I (Immersion); - Stabilization of the mass spectrometer leak detector outputs fo r Method II (vacuum Chamber or Bell jar); - Proper data processing an d taking a conservative approach while making predictions for on-orbit leakage rate for Method III(Pressure Change); - Proper Calibration o f the mass spectrometer leak detector for all the tracer gas (mostly Helium) Methods such as Method V (Detector Probe), Method VI (Hood), Method VII (Tracer Probe), Method VIII(Accumulation); - Usage of visibl ility aides for Method I (Immersion), Method IV (Chemical Indicator), Method XII (Foam/Liquid Application), and Method XIII (Hydrostatic/Visual Inspection); While some methods could be used for the total leaka ge (either internal-to-external or external-to-internal) rate requirement verification (Vacuum Chamber, Pressure Decay, Hood, Accumulation), other methods shall be used only as a pass/fail test for individual joints (e.g., welds, fittings, and plugs) or for troubleshooting purposes (Chemical Indicator, Detector Probe, Tracer Probe, Local Vacuum Chamber, Foam/Liquid Application, and Hydrostatic/Visual Inspection). Any isolation of SSP 41172 requirements have led to either retesting of hardware or accepting a risk associated with the potential system or component pressure integrity problem during flight.

Underwood, Steve↗
NASA NTRS2005

Probabilistic Reasoning for Plan Robustness

A planning system must reason about the uncertainty of continuous variables in order to accurately project the possible system state over time. A method is devised for directly reasoning about the uncertainty in continuous activity duration and resource usage for planning problems. By representing random variables as parametric distributions, computing projected system state can be simplified in some cases. Common approximation and novel methods are compared for over-constrained and lightly constrained domains. The system compares a few common approximation methods for an iterative repair planner. Results show improvements in robustness over the conventional non-probabilistic representation by reducing the number of constraint violations witnessed by execution. The improvement is more significant for larger problems and problems with higher resource subscription levels but diminishes as the system is allowed to accept higher risk levels.

autonomous planning↗
NASA NTRS2009

Occupant Protection during Orion Crew Exploration Vehicle Landings

The constellation program is evaluating current vehicle design capabilities for nominal water landings and contingency land landings of the Orion Crew Exploration vehicle. The Orion Landing Strategy tiger team was formed to lead the technical effort for which associated activities include the current vehicle design, susceptibility to roll control and tip over, reviewing methods for assessing occupant injury during ascent / aborts /landings, developing an alternate seat/attenuation design solution which improves occupant protection and operability, and testing the seat/attenuation system designs to ensure valid results. The EVA physiology, systems and Performance (EPSP) project is leading the effort under the authority of the Tiger Team Steering committee to develop, verify, validate and accredit biodynamics models using a variety of crash and injury databases including NASCAR, Indy Car and military aircraft. The validated biodynamics models will be used by the Constellation program to evaluate a variety of vehicle, seat and restraint designs in the context of multiple nominal and off-nominal landing scenarios. The models will be used in conjunction with Acceptable Injury Risk definitions to provide new occupant protection requirements for the Constellation Program.

Gernhardt, Michael L.↗
NASA NTRS2011

Constellation Program: Lessons Learned: Executive Summary - Volume 1

This document (Volume I) provides an executive summary of the lessons learned from the Constellation Program. A companion Volume II provides more detailed analyses for those seeking further insight and information. In this volume, Section 1.0 introduces the approach in preparing and organizing the content to enable rapid assimilation of the lessons. Section 2.0 describes the contextual framework in which the Constellation Program was formulated and functioned that is necessary to understand most of the lessons. Context of a former program may seem irrelevant in the heady days of new program formulation. However, readers should take some time to understand the context. Many of the lessons would be different in a different context, so the reader should reflect on the similarities and differences in his or her current circumstances. Section 3.0 summarizes key findings developed from the significant lessons learned at the program level that appear in Section 4.0. Readers can use the key findings in Section 3.0 to peruse for particular topics, and will find more supporting detail and analyses in Section 4.0 in a topical format. Appendix A contains a white paper describing the Constellation Program formulation that may be of use to readers wanting more context or background information. The reader will no doubt recognize some very similar themes from previous lessons learned, blue-ribbon committee reviews, National Academy reviews, and advisory panel reviews for this and other large-scale human spaceflight programs; including Apollo, Space Shuttle, Shuttle/Mir, and the ISS. This could represent an inability to learn lessons from previous generations; however, it is more likely that similar challenges persist in the Agency structure and approach to program formulation, budget advocacy, and management. Perhaps the greatest value of these Constellation lessons learned can be found in viewing them in context with these previous efforts to guide and advise the Agency and its stakeholders.

Constellation Program↗
NASA NTRS2012

Benchmarking Evaluation Results for Prototype Extravehicular Activity Gloves

The Space Suit Assembly (SSA) Development Team at NASA Johnson Space Center has invested heavily in the advancement of rear-entry planetary exploration suit design but largely deferred development of extravehicular activity (EVA) glove designs, and accepted the risk of using the current flight gloves, Phase VI, for unique mission scenarios outside the Space Shuttle and International Space Station (ISS) Program realm of experience. However, as design reference missions mature, the risks of using heritage hardware have highlighted the need for developing robust new glove technologies. To address the technology gap, the NASA Game-Changing Technology group provided start-up funding for the High Performance EVA Glove (HPEG) Project in the spring of 2012. The overarching goal of the HPEG Project is to develop a robust glove design that increases human performance during EVA and creates pathway for future implementation of emergent technologies, with specific aims of increasing pressurized mobility to 60% of barehanded capability, increasing the durability by 100%, and decreasing the potential of gloves to cause injury during use. The HPEG Project focused initial efforts on identifying potential new technologies and benchmarking the performance of current state of the art gloves to identify trends in design and fit leading to establish standards and metrics against which emerging technologies can be assessed at both the component and assembly levels. The first of the benchmarking tests evaluated the quantitative mobility performance and subjective fit of four prototype gloves developed by Flagsuit LLC, Final Frontier Designs, LLC Dover, and David Clark Company as compared to the Phase VI. All of the companies were asked to design and fabricate gloves to the same set of NASA provided hand measurements (which corresponded to a single size of Phase Vi glove) and focus their efforts on improving mobility in the metacarpal phalangeal and carpometacarpal joints. Four test subjects representing the design ]to hand anthropometry completed range of motion, grip/pinch strength, dexterity, and fit evaluations for each glove design in both the unpressurized and pressurized conditions. This paper provides a comparison of the test results along with a detailed description of hardware and test methodologies used.

Aitchison, Lindsay↗