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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 361 records · Page 20
All sourcesNASA NTRSDOE OSTI
NASA NTRS1997

Altered vestibular function in fetal and newborn rats gestated in space

Researchers evaluated vestibular development and function in rat pups flown during gestation on the NASA-NIH R1 and R2 missions. Fetal and postnatal vestibular function were examined. Altered vestibular-mediated responses in the experimental fetal pups are attributed to either direct effect of gravity on the vestibular system or indirect effects of microgravity transduced through the mother. The postnatal tests confirmed the hypothesis that the vestibular system continually adapts and responds to tonic stimulation.

Non-NASA Center↗
NASA NTRS1996

[Investigation of tibial bones of the rats exposed on board "Spacelab-2":histomorphometric analysis]

Proximal metaphyses of tibial bones from the Sprague-Dowly rats exposed in US dedicated space life sciences laboratory SLS-2 for 13-14 days and sacrificed on day 13 in microgravity and within 5 hours and 14 days following recovery were the subject of histological, histochemical, and histomorphometric analyses. After the 13-day flight of SLS-2 the rats showed initial signs of osteopenia in the spongy tissue of tibial bones, secondary spongiosis affected first. Resorption of the secondary spongiosis was consequent to enhanced resorption and inhibition of osteogenesis. In rats sacrificed within 5 hours of recovery manifestations of tibial osteopenia were more evident than in rats sacrificed during the flight. Spaceflight-induced changes in tibial spongiosis were reverse by character the amount of spongy bone was fully compensated and following 14 days of readaptation to the terrestrial gravity.

NASA Experiment Number 178194 2/2↗
NASA NTRS1990

Cosmos 1887: morphology, histochemistry, and vasculature of the growing rat tibia

Light microscopy, electron microscopy, and enzyme histochemistry were used to study the effects of spaceflight on metaphyseal and cortical bone of the rat tibia. Cortical cross-sectional area and perimeter were not altered by a 12.5-day spaceflight in 3-month-old male rats. The endosteal osteoblast population and the vasculature near the periosteal surface in flight rats compared with ground controls showed more pronounced changes in cortical bone than in metaphyseal bone. The osteoblasts demonstrated greater numbers of transitional Golgi vesicles, possibly caused by a decreased cellular metabolic energy source, but no difference in the large Golgi saccules or the cell membrane-associated alkaline phosphatase activity. The periosteal vasculature in the diaphysis of flight rats often showed lipid accumulations within the lumen of the vessels, occasional degeneration of the vascular wall, and degeneration of osteocytes adjacent to vessels containing intraluminal deposits. These changes were not found in the metaphyseal region of flight animals. The focal vascular changes may be due to ischemia of bone or a developing fragility of the vessel walls as a result of spaceflight.

Non-NASA Center↗
NASA NTRS1997

Rat pregnancy and parturition survive spaceflight challenge: new considerations of developmental consequences

Results of the NASA-NIH.R1 and NASA-NIH.R2 pregnant rat studies are reported and compared with results of Cosmos-1514 study. Similarities and differences between the Cosmos and STS flights are reviewed. STS rats were videotaped so that in-flight and post-flight behavior could be observed. Rats were observed during readaptation to 1-g and labor and delivery. Results indicate that pregnancy can proceed after exposure to microgravity and that vaginal delivery can occur despite readaptation to 1-g. Analysis of videotape revealed that flight dams experienced almost twice as many labor contractions as controls.

short duration↗
NASA NTRS1988

The tethered satellite electrodynamics experiment project

NASA and Italy's PSN have undertaken the Tethered Satellite Electrodynamics Experiment, in which two tethered bodies will be equipped with data-collecting scientific instruments, as the first stage of the development of the Tethered Satellite System that can be deployed by the Space Shuttle. The experiment will give attention to the electromagnetic interaction between the satellite/tether/orbiter system and the ambient space plasma, and should demonstrate the operation of both satellite- and Shuttle-borne electrodynamic instruments with a conductive tether.

Price, John M.↗
NASA NTRS1992

Signal processing for airborne doppler radar detection of hazardous wind shear as applied to NASA 1991 radar flight experiment data

Radar data collected during the 1991 NASA flight tests have been selectively analyzed to support research directed at developing both improved as well as new algorithms for detecting hazardous low-altitude windshear. Analysis of aircraft attitude data from several flights indicated that platform stability bandwidths were small compared to the data rate bandwidths which should support an assumption that radar returns can be treated as short time stationary. Various approaches at detection of weather returns in the presence of ground clutter are being investigated. Non-coventional clutter rejection through spectrum mode tracking and classification algorithms is a subject of continuing research. Based upon autoregressive modeling of the radar return time sequence, this approach may offer an alternative to overcome errors in conventional pulse-pair estimates. Adaptive filtering is being evaluated as a means of rejecting clutter with emphasis on low signal-to-clutter ratio situations, particularly in the presence of discrete clutter interference. An analysis of out-of-range clutter returns is included to illustrate effects of ground clutter interference due to range aliasing for aircraft on final approach. Data are presented to indicate how aircraft groundspeed might be corrected from the radar data as well as point to an observed problem of groundspeed estimate bias variation with radar antenna scan angle. A description of how recorded clutter return data are mixed with simulated weather returns is included. This enables the researcher to run controlled experiments to test signal processing algorithms. In the summary research efforts involving improved modelling of radar ground clutter returns and a Bayesian approach at hazard factor estimation are mentioned.

Baxa, Ernest G., Jr.↗
NASA NTRS1975

Pressure contact sounding data for NASA's Atmospheric Variability Experiment (AVE 2)

The basic rawinsonde data are described at each pressure contact from the surface to sounding termination for the 54 stations participating in the AVE 2 pilot experiment. Soundings were taken at three-hour intervals from stations within the United States east of about 105 degrees west longitude. Methods of data reduction and estimates of data accuracy are discussed. Examples of the data records produced are shown. The AVE 2 pilot experiment was conducted as part of NASA's program to better understand and establish the extent of applications for meteorological satellite sensor data through correlative ground truth experiments and to provide basic experimental data for use in studies of atmospheric scales-of-motion interrelationships.

Fuelberg, H. E.↗
NASA NTRS1995

Lessons Learned From the Flight of the NASA In-Step Cryo System Experiment

The Cryo System Experiment (CSE), a NASA In-Space Technology Experiments Program (IN- STEP) Flight Experiment, was developed by Hughes Aircraft Company under contract to the Jet Propulsion Laboratory (JPL) to validate in near zero-g space a 65 K cryogenic system for focal planes, optics, instruments, or other equipment (gamma-ray spectrometers, and infrared and submillimeter imaging instruments) that require continuous cryogenic cooling.

NASA↗
NASA NTRS1994

Lessons Learned During the Integration Phase of the NASA IN-STEP Cryo System Experiment

The Cryo System Experiment (CSE), a NASA In-Space Technology Experiments Proram (IN-STEP) Class D Flight Experiment, was developed by Hughes Aircraft Company (Hughes) to validate in zero-g space a 65 K cryogenic system for focal planes, optics, instruments, or other equipment (gramma-ray spectrometers and infrared and submillimeter imaging instruments) that require continuous cryogenic cooling.

cryogenic launch-vibration restraints thermal stra↗
NASA NTRS2014

NASA Bioculture System: From Experiment Definition to Flight Payload

Starting in 2015, the NASA Bioculture System will be available to the science community to conduct cell biology and microbiology experiments on ISS. The Bioculture System carries ten environmentally independent Cassettes, which house the experiments. The closed loop fluids flow path subsystem in each Cassette provides a perfusion-based method for maintain specimen cultures in a shear-free environment by using a biochamber based on porous hollow fiber bioreactor technology. Each Cassette contains an incubator and separate insulated refrigerator compartment for storage of media, samples, nutrients and additives. The hardware is capable of fully automated or manual specimen culturing and processing, including in-flight experiment initiation, sampling and fixation, up to BSL-2 specimen culturing, and the ability to up to 10 independent cultures in parallel for statistical analysis. The incubation and culturing of specimens in the Bioculture System is a departure from standard laboratory culturing methods. Therefore, it is critical that the PI has an understanding the pre-flight test required for successfully using the Bioculture System to conduct an on-orbit experiment. Overall, the PI will conduct a series of ground tests to define flight experiment and on-orbit implementation requirements, verify biocompatibility, and determine base bioreactor conditions. The ground test processes for the utilization of the Bioculture System, from experiment selection to flight, will be reviewed. Also, pre-flight test schedules and use of COTS ground test equipment (CellMax and FiberCell systems) and the Bioculture System will be discussed.

Bioculture System↗
NASA NTRSDate not supplied

Fire on the Moon: Solid Fuel Combustion Experiments

As NASA plans to return people to the Moon for extended durations, we present an experiment concept to understand fire and material flammability there. A small combustion chamber would be used to conduct the first-ever combustion tests on another world. Multiple fuel samples are to be individually burned in Lunar gravity, with cameras and other sensors recording flame characteristics. The main hypothesis is that some materials burning in Lunar-g are more flammable than on Earth. The reason is that buoyant flow has two counteracting effects on material flammability. Increasing gravity level permits more fresh oxygen to be supplied to the flame, but if the buoyant speed is too high, combustion chemistry and increased cooling hinder combustion. This has important implications for the current 1-g material screening method used by NASA. Oxygen limits for upward and downward spread on the Moon will be compared to 1-g values. Earth-based partial gravity facilities (drop towers, aircraft, and sounding rockets) will be used to refine the experiment and provide some limited-duration data. Measured flame characteristics in 1-g and Lunar-g will be compared to a detailed model. These will refine pressure-gravity scaling relations that will then be applied to other g-levels. The work directly addresses knowledge gaps in flammability and crew safety as defined in several NASA strategic documents.

Fire↗
NASA NTRS2002

Space radiation absorbed dose distribution in a human phantom

The radiation risk to astronauts has always been based on measurements using passive thermoluminescent dosimeters (TLDs). The skin dose is converted to dose equivalent using an average radiation quality factor based on model calculations. The radiological risk estimates, however, are based on organ and tissue doses. This paper describes results from the first space flight (STS-91, 51.65 degrees inclination and approximately 380 km altitude) of a fully instrumented Alderson Rando phantom torso (with head) to relate the skin dose to organ doses. Spatial distributions of absorbed dose in 34 1-inch-thick sections measured using TLDs are described. There is about a 30% change in dose as one moves from the front to the back of the phantom body. Small active dosimeters were developed specifically to provide time-resolved measurements of absorbed dose rates and quality factors at five organ locations (brain, thyroid, heart/lung, stomach and colon) inside the phantom. Using these dosimeters, it was possible to separate the trapped-proton and the galactic cosmic radiation components of the doses. A tissue-equivalent proportional counter (TEPC) and a charged-particle directional spectrometer (CPDS) were flown next to the phantom torso to provide data on the incident internal radiation environment. Accurate models of the shielding distributions at the site of the TEPC, the CPDS and a scalable Computerized Anatomical Male (CAM) model of the phantom torso were developed. These measurements provided a comprehensive data set to map the dose distribution inside a human phantom, and to assess the accuracy and validity of radiation transport models throughout the human body. The results show that for the conditions in the International Space Station (ISS) orbit during periods near the solar minimum, the ratio of the blood-forming organ dose rate to the skin absorbed dose rate is about 80%, and the ratio of the dose equivalents is almost one. The results show that the GCR model dose-rate predictions are 20% lower than the observations. Assuming that the trapped-belt models lead to a correct orbit-averaged energy spectrum, the measurements of dose rates inside the phantom cannot be fully understood. Passive measurements using 6Li- and 7Li-based detectors on the astronauts and inside the brain and thyroid of the phantom show the presence of a significant contribution due to thermal neutrons, an area requiring additional study.

STS-91 Shuttle Project↗
NASA NTRS1997

Radiation dosimetry measurements with real time radiation monitoring device (RRMD)-II in Space Shuttle STS-79

The real-time measurement of radiation environment was made with an improved real-time radiation monitoring device (RRMD)-II onboard Space Shuttle STS-79 (S/MM#4: 4th Shuttle MIR Mission, at an inclination angle of 51.6 degrees and an altitude of 250-400km) for 199 h during 17-25 September, 1996. The observation of the detector covered the linear energy transfer (LET) range of 3.5-6000 keV/micrometer. The Shuttle orbital profile in this mission was equivalent to that of the currently planned Space Station, and provided an opportunity to investigate variations in count rate and dose equivalent rate depending on altitude, longitude, and latitude in detail. Particle count rate and dose equivalent rate were mapped geographically during the mission. Based on the map of count rate, an analysis was made by dividing whole region into three regions: South Atlantic Anomaly (SAA) region, high latitude region and other regions. The averaged absorbed dose rate during the mission was 39.3 microGy/day for a LET range of 3.5-6000 keV/micrometer. The corresponding average dose equivalent rates during the mission are estimated to be 293 microSv/day with quality factors from International Commission on Radiological Protection (ICRP)-Pub. 60 and 270 microSv/day with quality factors from ICRP-Pub. 26. The effective quality factors for ICRP-Pub. 60 and 26 are 7.45 and 6.88, respectively. From the present data for particles of LET > 3.5keV/micrometer, we conclude that the average dose equivalent rate is dominated by the contribution of galactic cosmic ray (GCR) particles. The dose-detector depth dependence was also investigated.

manned↗
NASA NTRS1999

Effects of spaceflight conditions on fertilization and embryogenesis in the sea urchin Lytechinus pictus

Calcium loss and muscle atrophy are two of the main metabolic changes experienced by astronauts and crew members during exposure to microgravity in space. Calcium and cytoskeletal events were investigated within sea urchin embryos which were cultured in space under both microgravity and 1 g conditions. Embryos were fixed at time-points ranging from 3 h to 8 days after fertilization. Investigative emphasis was placed upon: (1) sperm-induced calcium-dependent exocytosis and cortical granule secretion, (2) membrane fusion of cortical granule and plasma membranes; (3) microfilament polymerization and microvilli elongation; and (5) embryonic development into morula, blastula, gastrula, and pluteus stages. For embryos cultured under microgravity conditions, the processes of cortical granule discharge, fusion of cortical granule membranes with the plasma membrane, elongation of microvilli and elevation of the fertilization coat were reduced in comparison with embryos cultured at 1 g in space and under normal conditions on Earth. Also, 4% of all cells undergoing division in microgravity showed abnormalities in the centrosome-centriole complex. These abnormalities were not observed within the 1 g flight and ground control specimens, indicating that significant alterations in sea urchin development processes occur under microgravity conditions. Copyright 1999 Academic Press.

STS-77 Shuttle Project↗
NASA NTRS1999

Wrist actigraphic measures of sleep in space

STUDY OBJECTIVES: To determine whether wrist actigraphy is useful as a tool for space-based sleep research. Specifically, to determine whether bedtimes and waketimes can be identified from the actigraphic record, and whether actigraphic measures of sleep in space are related to polysomnographic (PSG) ones. DESIGN AND SETTING: Actigraphy, sleep diary, and Polysomnographic (PSG) measures of sleep were obtained from four subjects in two 72h measurement blocks occurring 2d and 12d into a 17d Space Shuttle mission in orbiting the earth in microgravity. PATIENTS: Four healthy male astronauts aged 38y - 47y. INTERVENTIONS: NA. MEASUREMENTS AND RESULTS: Sleep onset and offset at "night" could be quite clearly identified from the actigraphic record and were better estimated by actigraph than by diary. There was a high correlation between actigraphic and PSG estimates of sleep duration (r = 0.96) and sleep efficiency (r = 0.88), and a similarity in the mean estimates obtained. On a minute-by-minute basis, there was a good correlation between sleep stage and actigraphic movement counts, with a higher level of counts per minute recorded in epochs with lighter PSG sleep stages. There was also a high correlation (r = 0.90) between minutes of stage 0 (wake) occurring between bedtime and wake time, and number of non-zero actigraph epochs during the same interval. CONCLUSIONS: Actigraphy worked well in space both as a way of detecting bedtimes and waketimes, and as an indicant of sleep restlessness.

NASA Discipline Regulatory Physiology↗
NASA NTRS1992

Precursor Space Station Freedom experiments

The NASA Office of Aeronautics and Space Technology uses the In-Space Technology Experiments Program (IN-STEP) as the primary management vehicle to pursue innovative and potentially high payoff space technology experiments. The purpose of this presentation is to provide an overview of the IN-STEP approach in developing precursor Space Station experiments; identify those experiments now in the program; review the key points of the IN-STEP 1992 Announcement of Opportunity; and describe the OAST in-space technology experiments development process.

Breckenridge, Roger A.↗