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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 145 records · Page 8
All sourcesNASA NTRSDOE OSTI
NASA NTRS1972

In-flight aeroacoustic environments on prospective space shuttle vehicles

The problem of in-flight aerodynamic noise has been studied by reliable estimates of full scale surface-pressure fluctuations from scale model tests in wind tunnels. Scaling relationships have been verified, and many details of the fluctuating pressure characteristics such as spatial correlation and convection velocities are understood. The effects of the wind tunnel environmental turbulence and noise have also been investigated sufficiently so that threshold levels of usable data are known.

Dods, J. B., Jr.↗
NASA NTRS1997

Development of an Antimicrobial Susceptibility Testing Method Suitable for Performing During Space Flight

Very little is known regarding the affects of the microgravity environment of space flight upon the action of antimicrobial agents on bacterial pathogens. This study was undertaken to develop a simple method for conducting antibacterial susceptibility tests during a Space Shuttle mission. Specially prepared susceptibility test research cards (bioMerieux Vitek, Hazelwood, MO) were designed to include 6-11 serial two-fold dilutions of 14 antimicrobial agents, including penicillins, cephalosporins, a Beta-lactamase inhibitor, vancomycin, erythromycin, tetracycline, gentamicin, ciprofloxacin, and trimethoprim/sulfamethoxazole. Minimal inhibitory concentrations (MICS) of the drugs were determined by visual reading of color endpoints in the Vitek research cards made possible by incorporation of a colorimetric growth indicator (alamarBlue(Trademark), Accumed International, Westlake, OH). This study has demonstrated reproducible susceptibility results when testing isolates of Staphylococcus aurezis, Group A Streptococcus, Enterococcusfaecalis, Escherichia coli (beta-lactamase positive and negative strains), Klebsiella pneumoniae, Enterobacter cloacae, and Pseudomoiias aeruginosa. In some instances, the MICs were comparable to those determined using a standard broth microdilution method, while in some cases the unique test media and format yielded slightly different values, that were themselves reproducible. The proposed in-flight experiment will include inoculation of the Vitek cards on the ground prior to launch of the Space Shuttle, storage of inoculated cards at refrigeration temperature aboard the Space Shuttle until experiment initiation, then incubation of the cards for 18-48 h prior to visual interpretation of MICs by the mission's astronauts. Ground-based studies have shown reproducible MICs following storage of inoculated cards for 7 days at 4-8 C to accommodate the mission's time schedule and the astronauts' activities. For comparison, ground-based control (normal gravity) MIC values will be generated by simultaneous inoculation and incubation of a second set of test cards in a laboratory at the launch site. This procedure can provide a safe and compact experiment that should yield new information on the affects of microgravity on the biological activities of various classes of antibiotics.

Jorgensen, James H.↗
NASA NTRS1995

A study of the radiation environment on board the space shuttle flight STS-57

A joint NASA-Russian study of the radiation environment inside a SPACEHAB 2 locker on space shuttle flight STS-57 was conducted. The shuttle flew in a nearly circular orbit of 28.5 deg inclination and 462 km altitude. The locker carried a charged particle spectrometer, a tissue equivalent proportional counter (TEPC), and two area passive detectors consisting of combined NASA plastic nuclear track detectors (PNTD's) and thermoluminescent detectors (TLD's), and Russian nuclear emulsions, PNTD's, and TLD's. All the detector systems were shielded by the same shuttle mass distribution. This makes possible a direct comparison of the various dose measurement techniques. In addition, measurements of the neutron energy spectrum were made using the proton recoil technique. The results show good agreement between the integral LET spectrum of the combined galactic and trapped particles using the tissue equivalent proportional counter and track detectors between about 15 keV/micron and 200 keV/micron. The LET spectrum determined from nuclear emulsions was systematically lower by about 50%, possibly due to emulsion fading. The results show that the TEPC measured an absorbed dose 20% higher than TLD's, due primarily to an increased TEPC response to neutrons and a low sensitivity of TLD's to high LET particles under normal processing techniques. There is a significant flux of high energy neutrons that is currently not taken into consideration in dose equivalent calculations. The results of the analysis of the spectrometer data will be reported separately.

Badhwar, G. D.↗
NASA NTRS2000

Vision Aspects of Space Flight

Vision, being one of our most important senses, is critically important in the unique working environment of space flight. Critical evaluation of the astronauts visual system begins with pre-selection examinations resulting in an average of 65% of all medical disqualification's caused by ocular findings. With an average age of 42, approximately 60% of the astronaut corps requires vision correction. Further demands of the unique training and working environment of microgravity, variable lighting from very poor to extreme brightness of sunlight and exposure to extremes of electromagnetic energy results in unique eyewear and contact lens applications. This presentation will describe some of those unique eyewear and contact lens applications used in space flight and training environments. Additionally, ocular findings from 26 shuttle and 5 MIR mission post-flight examinations will be presented.

Manuel, Keith↗
NASA NTRS2014

The Impact of Apollo-Era Microbiology on Human Space Flight

The microbiota of crewmembers and the spacecraft environment contributes significant risk to crew health during space flight missions. NASA reduces microbial risk with various mitigation methods that originated during the Apollo Program and continued to evolve through subsequent programs: Skylab, Shuttle, and International Space Station (ISS). A quarantine of the crew and lunar surface samples, within the Lunar Receiving Laboratory following return from the Moon, was used to prevent contamination with unknown extraterrestrial organisms. The quarantine durations for the crew and lunar samples were 21 days and 50 days, respectively. A series of infections among Apollo crewmembers resulted in a quarantine before launch to limit exposure to infectious organisms. This Health Stabilization Program isolated the crew for 21 days before flight and was effective in reducing crew illness. After the program developed water recovery hardware for Apollo spacecraft, the 1967 National Academy of Science Space Science Board recommended the monitoring of potable water. NASA implemented acceptability limits of 10 colony forming units (CFU) per mL and the absence of viable E. coli, anaerobes, yeasts, and molds in three separate 150 mL aliquots. Microbiological investigations of the crew and spacecraft environment were conducted during the Apollo program, including the Apollo-Soyuz Test Project and Skylab. Subsequent space programs implemented microbial screening of the crew for pathogens and acceptability limits on spacecraft surfaces and air. Microbiology risk mitigation methods have evolved since the Apollo program. NASA cancelled the quarantine of the crew after return from the lunar surface, reduced the duration of the Health Stabilization Program; and implemented acceptability limits for spacecraft surfaces and air. While microbial risks were not a main focus of the early Mercury and Gemini programs, the extended duration of Apollo flights resulted in the increased scrutiny of impact of the space flight environment on crew health. The lessons learned during that era of space flight continue to impact microbiology risk mitigation in space programs today.

Elliott, T. F↗
NASA NTRS2010

The Value of Biomedical Simulation Environments to Future Human Space Flight Missions

With the ambitious goals to send manned missions to asteroids and onto Mars, substantial work will be required to ensure the well being of the men and women who will undertake these difficult missions. Unlike current International Space Station or Shuttle missions, astronauts will be required to endure long-term exposure to higher levels of radiation, isolation and reduced gravity. These new operation conditions will pose health risks that are currently not well understood and perhaps unanticipated. Therefore, it is essential to develop and apply advanced tools to predict, assess and mitigate potential hazards to astronaut health. NASA s Digital Astronaut Project (DAP) is working to develop and apply computational models of physiologic response to space flight operation conditions over various time periods and environmental circumstances. The collective application and integration of well vetted models assessing the physiology, biomechanics and anatomy is referred to as the Digital Astronaut. The Digital Astronaut simulation environment will serve as a practical working tool for use by NASA in operational activities such as the prediction of biomedical risks and functional capabilities of astronauts. In additional to space flight operation conditions, DAP s work has direct applicability to terrestrial biomedical research by providing virtual environments for hypothesis testing, experiment design, and to reduce animal/human testing. A practical application of the DA to assess pre and post flight responses to exercise is illustrated and the difficulty in matching true physiological responses is discussed.

Mulugeta, Lealem↗
NASA NTRS2011

The Value of Biomedical Simulation Environments to Future Human Space Flight Missions

Mars and NEO missions will expose astronaut to extended durations of reduced reduced gravity, isolation and higher radiation. These new operation conditions pose health risks that are not well understood and perhaps unanticipated. Advanced computational simulation environments can beneficially augment research to predict, assess and mitigate potential hazards to astronaut health. The NASA Digital Astronaut Project (DAP), within the NASA Human Research Program, strives to achieve this goal.

Mulugeta,Lealem↗
NASA NTRS2011

End-of-Life Optical Property Predictions of White Conductive Thermal Control Coatings through Analysis of On-Orbit and Ground Based Testing Data

New system requirements pertaining to thermal optical properties and coating electrical properties are commonly specified on non-low earth orbit missions. An increasing number of projects are specifying coatings with a surface resistivity of less than lE-9 ohm/square to mitigate electrostatic charge buildup events over a range of operational temperatures. There are a limited number of coatings that. meet these electrical property requirements while having flight derived optical properties in representative environments. Goddard Space Flight Center Code 546, Contamination and Thermal Coatings Group has recently explored the variety of electrically conductive white coatings available through domestic vendors to evaluate properties to meet project requirements in a geostationary orbit. The lack of significant flight data in representative environments required the careful selection of samples in ground based tests to establish end of life thermal properties. Attention must be given to the origin and pedigree of samples used on past on-orbit experiments to insure that the present formulations for the materials are similar and will react in similar manner.

Hasegawa, Mark↗
NASA NTRS1983

Development of space shuttle ignition overpressure environment and correlation with flight data

The Space Transportation (STS) launch vehicles are more complex than other launch vehicles. A comprehensive analysis of the lift-off event is required so that the responses of the vehicle and payloads can be predicted. The transient overpressure induced by ignition of the solid rocket motors (SRM's) is one of the critical design factors assessed for lift-off. The STS-1 ignition overpressure design environment was developed from 6.4-percent scale-model tests in which the Tomahawk solid rocket motors were used to simulate the start-up process of the SRM's. The overpressures measured during STS-1 lift-off were much more severe than predicted. The reasons for this anomaly are discussed in this paper. The 6.4-percent scale model was redesigned and used as a tool to develop an effective ignition overpressure suppression system for STS-2 and subsequent flights. Also presented are advancements in subscale-model simulation and theoretical understanding of this transient overpressure phenomenon that led to the successful development of the fix.

Lai, S.↗
NASA NTRS1965

Manned space flight.

Monograph on manned space flight, discussing environment, crew, spacecraft, navigation, guidance, control, communications, etc

MANNED SPACE FLIGHT↗
NASA NTRS2012

Electrodynamic Dust Shields on the International Space Station: Exposure to the Space Environment

Electrodynamic Dust Shields (EDS) have been in development at NASA as a dust mitigation method for lunar and Martian missions. An active dust mitigation strategy. such as that provided by the EDS, that can remove dust from surfaces, is of crucial importance to the planetary exploration program. We report on the development of a night experiment to fully ex pose four EDS panels to the space environment. This flight experiment is part of the Materials International Space Station experiment X(MISSE-X). an external platform on the International Space Station that will expose materials to the space environment.

Calle, C. I.↗
NASA NTRS1993

Visual Earth observation performance in the space environment. Human performance measurement 4: Flight experiments

A wide variety of secondary payloads have flown on the Space Transportation System (STS) since its first flight in the 1980's. These experiments have typically addressed specific issues unique to the zero-gravity environment. Additionally, the experiments use the experience and skills of the mission and payload specialist crew members to facilitate data collection and ensure successful completion. This paper presents the results of the Terra Scout experiment, which flew aboard STS-44 in November 1991. This unique Earth Observation experiment specifically required a career imagery analyst to operate the Spaceborne Direct-View Optical System (SpaDVOS), a folded optical path telescope system designed to mount inside the shuttle on the overhead aft flight deck windows. Binoculars and a small telescope were used as backup optics. Using his imagery background, coupled with extensive target and equipment training, the payload specialist was tasked with documenting the following: (1) the utility of the equipment; (2) his ability to acquire and track ground targets; (3) the level of detail he could discern; (4) the atmospheric conditions; and (5) other in-situ elements which contributed to or detracted from his ability to analyze targets. Special emphasis was placed on the utility of a manned platform for research and development of future spaceborne sensors. The results and lessons learned from Terra Scout will be addressed including human performance and equipment design issues.

Huth, John F.↗
NASA NTRS2005

A Summary of Meteorological Parameters During Space Shuttle Pad Exposure Periods

During the 113 missions of the Space Transportation System (STS), the Space Shuffle fleet has been exposed to the elements on the launch pad for a total of 4195 days. The Natural Environments Branch at Marshall Space Flight Center archives atmospheric environments to which the Space Shuttle vehicles are exposed. This paper provides a summary of the historical record of the meteorological conditions encountered by the Space Shuttle fleet during the pad exposure period. Sources of the surface parameters, including temperature, dew point temperature, relative humidity, wind speed, wind direction, sea level pressure and precipitation are presented. Data is provided from the first launch of the STS in 1981 through the launch of STS-107 in 2003.

Overbey, Glenn↗
NASA NTRS2005

Space Shuttle Pad Exposure Period Meteorological Parameters STS-1 Through STS-107

During the 113 missions of the Space Transportation System (STS) to date, the Space Shuttle fleet has been exposed to the elements on the launch pad for approx. 4,195 days. The Natural Environments Branch at Marshall Space Flight Center archives atmospheric environments to which the Space Shuttle vehicles are exposed. This Technical Memorandum (TM) provides a summary of the historical record of the meteorological conditions encountered by the Space Shuttle fleet during the pad exposure period. Parameters included in this TM are temperature, relative humidity, wind speed, wind direction, sea level pressure, and precipitation. Extremes for each of these parameters for each mission are also summarized. Sources for the data include meteorological towers and hourly surface observations. Data are provided from the first launch of the STS in 1981 through the launch of STS-107 in 2003.

Overbey, B. G.↗
NASA NTRS1983

An assessment of the Space Shuttle Orbiter thermal environment using flight data

A unified analysis of the Shuttle Orbiter aerothermodynamic environment and thermal protection system performance is presented using the Space Transportation System development flight data. Comparisons of predicted and measured temperatures and heating rates along the Orbiter lower windward fuselage centerline and lower wing 50 percent and 80 percent semi-spans are discussed. The results of this study indicate lower than predicted heating on windward fuselage surface but higher heating on the nose cap and 50 percent semi-span wing panels.

Williams, S. D.↗
NASA NTRS2004

Inducer Hydrodynamic Forces in a Cavitating Environment

Marshall Space Flight Center has developed and demonstrated a measurement device for sensing and resolving the hydrodynamic loads on fluid machinery. The device - a derivative of the six-component wind tunnel balance - senses the forces and moments on the rotating device through a weakened shaft section instrumented with a series of strain gauges. This rotating balance was designed to directly measure the steady and unsteady hydrodynamic loads on an inducer, thereby defining the amplitude and frequency content associated with operating in various cavitation modes. The rotating balance was calibrated statically using a dead-weight load system in order to generate the 6 x 12 calibration matrix later used to convert measured voltages to engineering units. Structural modeling suggested that the rotating assembly first bending mode would be significantly reduced with the balance s inclusion. This reduction in structural stiffness was later confirmed experimentally with a hammer-impact test. This effect, coupled with the relatively large damping associated with the rotating balance waterproofing material, limited the device s bandwidth to approximately 50 Hertz Other pre-test validations included sensing the test article rotating assembly built-in imbalance for two configurations and directly measuring the assembly mass and buoyancy while submerged under water. Both tests matched predictions and confirmed the device s sensitivity while stationary and rotating. The rotating balance was then demonstrated in a water test of a full-scale Space Shuttle Main Engine high-pressure liquid oxygen pump inducer. Experimental data was collected a scaled operating conditions at three flow coefficients across a range of cavitation numbers for the single inducer geometry and radial clearance. Two distinct cavitation modes were observed symmetric tip vortex cavitation and alternate-blade cavitation. Although previous experimental tests on the same inducer demonstrated two additional cavitation modes at lower inlet pressures, these conditions proved unreachable with the rotating balance installed due to the intense dynamic environment. The sensed radial load was less influenced by flow coefficient than by cavitation number or cavitation mode although the flow coefficient range was relatively narrow. Transition from symmetric tip vortex to alternate-blade cavitation corresponded to changes in both radial load magnitude and radial load orientation relative to the inducer. Sensed moments indicated that the effective load center moved downstream during this change in cavitation mode. An occurrence of "higher+rdex cavitation" was also detected in both the stationary pressures and the rotating balance data although the frequency of the phenomena was well above the reliable bandwidth of the rotating balance. In summary the experimental tests proved both the concept and device s capability despite the limitations and confirmed that hydrodynamically-induced forces and moments develop in response to the unbalanced pressure field, which is, in turn, a product of the cavitation environment.

Skelley, Stephen E.↗