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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 613 records · Page 34

Nutritional criteria for closed-loop space food systems

The nutritional requirements for Skylab crews are summarized as a data base for long duration spaceflight nutrient requirements. Statistically significant increases in energy consumption were detected after three months, along with CO2/O2 exhalation during exercise and thyroxine level increases. Linoleic acid amounting to 3-4 g/day was found to fulfill all fat requirements, and carbohydrate and protein (amino acid) necessities are discussed, noting that vigorous exercise programs avoid deconditioning which enhances nitrogen loss. Urinary calcium losses continued at a rate 100% above a baseline figure, a condition which ingestion of vitamin D2 did not correct. Projections are given that spaceflights lasting more than eight years will necessitate recycling of human waste for nutrient growth, which can be processed into highly efficient space food with a variety of tastes.

Rambaut, P. C.↗

Low-speed wind-tunnel study of the high-angle-of-attack stability and control characteristics of a cranked-arrow-wing fighter configuration

The low-speed, high-angle-of-attack stability and control characteristics of a fighter configuration incorporating a cranked arrow wing were investigated in the Langley 30- by 60-foot tunnel as part of a NASA/General Dynamics cooperative research program to investigate the application of advanced wing designs to combat aircraft. Tests were conducted on a baseline configuration and on several modified configurations. The results show that the baseline configuration exhibited a high level of maximum lift but displayed undesirable longitudinal and lateral-directional stability characteristics at high angles of attack. Various wing modifications were made which improved the longitudinal and lateral-directional stability characteristics of the configuration at high angles of attack. However, most of the modifications were detrimental to maximum lift.

Grafton, S. B.↗

Advanced OTV engines and issues

The propulsion system requirements of orbit transfer vehicles (OTV). A baseline expander cycle engine which will meet those requirements was defined. The principal characteristics of a baseline engine and some options which are available to accommodate OTV system optimization studies was discussed. Engine program issues which are dependent on the mission scenario and the vehicle system configuration are shown. The rationale for a new cryogenic OTV engine is summarized.

Brown, J. R.↗

Summary of studies to reduce wing-mounted propfan installation drag on an M = 0.8 transport

Powerplant installation losses for an advanced, high-speed, turboprop transport have been investigated in the Ames Research Center Transonic Wind Tunnels as a part of the NASA Advanced Turboprop Program (ATP). Force and pressure tests have been completed at Mach numbers from 0.6 to 0.82 on baseline and modified powered-model configurations to determine the magnitude of the losses and to what extent current design tools could be used to optimize the installed performance of turboprop propulsion systems designed to cruise at M = 0.8. Results of the tests indicate a large reduction in installed drag for the modified configuration. The wing-mounted power plant caused destabilizing pitching moments and a negative shift in the zero-lift pitching moment.

Smith, Ronald C.↗

Considerations for spacecraft design for MSAT

The paper describes the system design considerations and design activities performed at Spar Aerospace in the last 18 months in support of the development of a Canadian Mobile Communication Satellite (MSAT). Recent evolving international agreements and events of importance to MSAT are the emergence of the U.S. Operator and the Mobile WARC 1987. Their impacts on the system requirements and system design are discussed. Solutions to these new requirements are implemented into the 9 Beam baseline design. The system design and the parallel technology development permit the support of a commercial flight program.

Hing, Kunvana↗

Space Station Freedom growth power requirements

Options and scenarios for the evolution of Space Station Freedom beyond the current baseline have been established and analyzed at NASA Langley Research Center to identify growth requirements for the program's Preliminary Requirements Review (PRR). Time-phase requirements for electrical power and other critical resources were determined based upon the future needs of the science, technology and commercial users. In addition, impacts and resource growth were determined for the utilization of station as a transportation node in support of human exploration initiatives to the moon and/or Mars. The set of requirements chosen for the PRR were selected on the basis of their adequacy in accommodating each of the evolution options and scenarios within each option, thereby maximizing future flexibility. In the case of electrical power, growth to 275 kW (average) was determined to be adequate for evolutionary missions and station housekeeping growth, given projections of future earth-to-orbit transportation capabilities.

Meredith, B. D.↗

Supersonic jet noise - Its generation, prediction and effects on people and structures

This paper presents the results of a study aimed at quantifying the effects of jet source noise reduction, increases in aircraft lift, and reduced aircraft thrust on the take-off noise associated with supersonic civil transports. Supersonic jet noise sources are first described, and their frequency and directivity dependence are defined. The study utilizes NASA's Aircraft Noise Prediction Program in a parametric study to weigh the relative benefits of several approaches to low noise. The baseline aircraft concept used in these predictions is the AST-205-1 powered by GE21/J11-B14A scaled engines. Noise assessment is presented in terms of effective perceived noise levels at the FAA's centerline and sideline measuring locations for current subsonic aircraft, and in terms of audiologically perceived sound of people and other indirect effects. The results show that significant noise benefit can be achieved through proper understanding and utilization of all available approaches.

Preisser, J. S.↗

Status of frequency and time support for NASA systems

NASA has frequency and timing systems at many facilities and centers. Timing systems with specifications tighter than several microseconds are covered. These ground based systems support scientific experiments and spacecraft tracking for the following programs; NASA Satellite Laser Ranging (NSLR); Network Mission Operations Support (NMOS); Kennedy Space Center (KSC); Very Long Baseline Interferometry (VLBI); Tracking Data Relay Satellite System (TDRSS) Ground Terminal Network; and the Deep Space Network (DSN). Major equipment assemblies, specifications, performance, and requirements, both present and future, are presented.

Kuhnle, Paul F.↗

AVHRR-Based Polar Pathfinder Products: Evaluation, Enhancement, and Transition to MODIS

The AVHRR-Based Polar Pathfinder (APP) products include calibrated AVHRR channel data, surface temperatures, albedo, satellite scan and solar geometries, and a cloud mask composited into twice- per-day images, and daily averaged fields of sea ice motion, for regions poleward of 50 deg. latitude. Our goals under this grant, in general, are four-fold: 1. To quantify the APP accuracy and sources of error by comparing Pathfinder products with field measurements. 2. To determine the consistency of mean fields and trends in comparison with longer time series of available station data and forecast model output. 3. To investigate the consistency of the products between the different AVHRR instruments over the 1982-present period of the NOAA program. 4. To compare an annual cycle of the AVHRR Pathfinder products with MODIS to establish a baseline for extending Pathfinder-type products into the new ESE period. Year One tasks include intercomparisons of the Pathfinder products with field measurements, testing of algorithm assumptions, collection of field data, and further validation and possible improvement of the multi-sensor ice motion fields. Achievements for these tasks are summarized below.

Fowler, Charles↗

Study of a High-Energy Upper Stage for Future Shuttle Missions

Space Shuttle Orbiters are likely to remain in service to 2020 or beyond for servicing the International Space Station and for launching very high value spacecraft. There is a need for a new STS-deployable upper stage that can boost certain Orbiter payloads to higher energy orbits, up to and including Earth-escape trajectories. The inventory of solid rocket motor Inertial Upper Stages has been depleted, and it is unlikely that a LOX/LH2-fueled upper stage can fly on Shuttle due to safety concerns. This paper summarizes the results of a study that investigated a low cost, low risk approach to quickly developing a new large upper stage optimized to fly on the existing Shuttle fleet. Two design reference missions (DRMs) were specified: the James Webb Space Telescope (JWST) and the Space Interferometry Mission (SIM). Two categories of upper stage propellants were examined in detail: a storable liquid propellant and a storable gel propellant. Stage subsystems 'other than propulsion were based largely on heritage hardware to minimize cost, risk and development schedule span. The paper presents the ground rules and guidelines for conducting the study, the preliminary conceptual designs margins, assessments of technology readiness/risk, potential synergy with other programs, and preliminary estimates of development and production costs and schedule spans. Although the Orbiter Columbia was baselined for the study, discussion is provided to show how the results apply to the remaining STS Orbiter fleet.

Dressler, Gordon A.↗

The ASPRS Remote Sensing Industry Forecast: Phase II & III - Digital Sensor Compilation

In August 1999, ASPRS and NASA's (then) Commercial Remote Sensing Program (CRSP) entered into a 5-year Space Act Agreement (SAA), combining resources and expertise to: (a) Baseline the Remote Sensing Industry (RSI) based on GEIA Model; (b) Develop a 10-Year RSI market forecast and attendant processes; and (c) Provide improved information for decision makers.

Mondello, Charles↗

Damage Tolerance Comparison of IM7/8552 and T1100/3960 Carbon Fiber/Epoxy Sandwich Structure in Support of the Space Launch System Payload Adapter Fitting

As technology evolves and improves within the science of composite materials, new fiber/ resin systems are being developed for improved properties given certain loading and environmental scenarios. Improving the room temperature damage tolerance capabilities has long been one of the goals in the carbon fiber/polymer composite industry. Recently a new fiber/epoxy system has been introduced that is claimed to have superior damage tolerance capabilities. To examine if this new carbon fiber/epoxy composite material would be of benefit to a program to manufacture a Payload Adapter Fitting (PAF) for NASA’s Space Launch System (SLS) rocket, the question was asked as to just how much damage tolerance could be realized if this new system were used. Compression after impact (CAI) strength of sandwich structure is one of the leading metrics being used to evaluate materials for the PAF program. As a result, a comparison of this new fiber/resin system with a very common (and planned baseline) fiber/resin system with respect to CAI was considered in this study. While it was already known that the older, baseline carbon fiber structure would not have as good damage tolerance characteristics as the newer carbon fiber system, the quantitative difference in damage tolerance was sought in this study since no other CAI data could be found in open literature on sandwich structures made with this new fiber/resin system.

A.T. Nettles↗

Quantifying Operational Drivers of Multimodal Biometric Verification in Aerial Surveillance

Multimodal biometric verification is increasingly applied across operational contexts ranging from close-range security cameras and building-mounted surveillance to long-range ground sensors and unmanned aerial system (UAS) imagery. Variations in acquisition conditions—such as image resolution, viewing geometry, and motion artifacts—pose significant challenges for cross-domain algorithmic generalization. This study evaluates two independent multimodal biometric verification systems developed under the Intelligence Advanced Research Projects Activity (IARPA) Biometric Recognition and Identification at Altitude and Range (BRIAR) program, comparing performance on close-range and aerial datasets. Close-range video served as a baseline to quantify the decline in verification performance on aerial footage. The dataset included six UAS platforms, spanning small quadcopters at 10m altitude to medium-sized fixed-wing aircraft at 360m. Mixed-effects logistic regression identified image resolution (head and body pixel counts), head height, sensor characteristics, and algorithm selection as primary determinants of verification success, whereas demographic attributes and mission gait were not significant predictors. Activity type and collection site influenced performance in close-range data but had negligible impact on UAS imagery. These results clarify modality-specific strengths and limitations and highlight opportunities to enhance cross-domain biometric verification.

Peluso, Alina [ORNL] (ORCID:0000000328950406)↗

A very-long-baseline interferometer system for geodetic applications

A very-long-baseline interferometer system was designed and built for geodetic applications. Each interferometer terminal records a 360-kHz spectral band of noise from a compact extragalactic radio source. The center frequency of the spectral band can be selected to sample sequentially bands covering a much wider frequency range to obtain subnanosecond accuracy in group-delay measurements. A tunnel-diode pulse generator is used to calibrate the delays in the receiver. The necessary sets of algorithms and computer programs have been developed to analyze the data and have allowed the system to be employed to make accurate determinations of vector baselines, radio-source positions, polar motion, and universal time.

Whitney, A. R.↗

Analytical and experimental studies of a short compact subsonic diffuser for a two-dimensional supersonic inlet

An experimental study of a two-dimensional supersonic inlet with a short compact subsonic diffuser, length to exit diameter (dl/d) ratio of 1.25, was conducted to investigate the impact of the short diffuser on inlet performance at low speeds and to assess the diffuser subsonic performance for a simulated diffuser flow corresponding to high-speed inlet conditions near the design flight Mach number of 2.2. For the low-speed testing, a drooped lip was employed to improve the inlet performance at a high angle of attack. For the simulated high-speed testing, air was blown through slots or discrete nozzles as an active boundary-layer control. The results from the low-speed performance test were compared with the results from a previous test program on the same inlet with a long subsonic diffuser (dl/d = 4.5). The comparison indicates that inlet recovery was not affected by the use of the short diffuser for either the baseline (no droop) or the drooped cowl lip configuration. However, the inlet baseline distortion for the short diffuser configuration was substantially higher than for the long diffuser. A comparison of the two configurations with a 70 deg drooped lip showed no significant difference in distortion. For the portion of the experimental program in which diffuser conditions for high-speed flight were simulated, diffuser-induced flow separation occurred. This separation was predicted from an analytical study that used the Hess potential flow panel method and the Herring two-dimensional boundary-layer analysis computer codes. The flow separated mainly on the diffuser ramp. Subsequent tests in which boundary-control systems were utilized showed that blowing with either slots or discrete nozzles could suppress the flow separation in the short subsonic diffuser, thereby substantially improving the diffuser performance.

Iek, Chanthy↗

Integrated Technology Assessment Center (ITAC) Update

The Integrated Technology Assessment Center (ITAC) has developed a flexible systems analysis framework to identify long-term technology needs, quantify payoffs for technology investments, and assess the progress of ASTP-sponsored technology programs in the hypersonics area. For this, ITAC has assembled an experienced team representing a broad sector of the aerospace community and developed a systematic assessment process complete with supporting tools. Concepts for transportation systems are selected based on relevance to the ASTP and integrated concept models (ICM) of these concepts are developed. Key technologies of interest are identified and projections are made of their characteristics with respect to their impacts on key aspects of the specific concepts of interest. Both the models and technology projections are then fed into the ITAC's probabilistic systems analysis framework in ModelCenter. This framework permits rapid sensitivity analysis, single point design assessment, and a full probabilistic assessment of each concept with respect to both embedded and enhancing technologies. Probabilistic outputs are weighed against metrics of interest to ASTP using a multivariate decision making process to provide inputs for technology prioritization within the ASTP. ITAC program is currently finishing the assessment of a two-stage-to-orbit (TSTO), rocket-based combined cycle (RBCC) concept and a TSTO turbine-based combined cycle (TBCC) concept developed by the team with inputs from NASA. A baseline all rocket TSTO concept is also being developed for comparison. Boeing has recently submitted a performance model for their Flexible Aerospace System Solution for Tomorrow (FASST) concept and the ISAT program will provide inputs for a single-stage-to-orbit (SSTO) TBCC based concept in the near-term. Both of these latter concepts will be analyzed within the ITAC framework over the summer. This paper provides a status update of the ITAC program.

Taylor, J. L.↗

Design of test specimens and procedures for generating material properties of Douglas fir/epoxy laminated wood composite material: With the generation of baseline data at two environmental conditions

In support of the design of wind turbine generator airfoils/blades utilizing Douglas Fir/West System Epoxy laminated composite material, a program was undertaken to define pertinent material properties utilizing small scale test specimens. Task 1 was the development of suitable monotonic tension, compression, short beam shear and full reversed cyclic specimen designs and the companion grips and testing procedures. Task 2 was the generation of the material properties at two environmental conditions utilizing the specimens and procedures developed in Task 1. The monotonic specimens and procedures generated results which compare favorably with other investigators while the cyclic results appear somewhat conservative. Adding moisture and heat or scarf joints degraded the monotonic performance but had a more nebulus effect with cyclic loading.

Johnson, Paul E.↗