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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 1,063 records · Page 59
All sourcesNASA NTRSDOE OSTI
NASA NTRS1976

The charge spectrum of positive ions in a hydrogen aurora

An auroral ion charge spectrometer was flown into a hydrogen aurora on a Javelin sounding rocket launched from Churchill, Manitoba. The instrument contained an electrostatic analyzer which selected particles with incident energy per unit charge up to 20 keV/charge and an 80-kV power supply which accelerated these ions onto an array of solid state detectors. Ions tentatively identified as H(+), He(+2), and O(+) were detected from 225 to 820 km in altitude. The experiment did not discriminate between H(+) and He(+), or between O(+), N(+), and C(+). Upper limits of highly charged heavy ion abundances have been set at 20% of the He(+2) and 0.15% of the H(+). It is concluded that both terrestrial and solar wind sources play significant roles in auroral ion precipitation.

Lynch, J.↗
NASA NTRS1976

Mineral and nitrogen balance study observations - The second manned Skylab mission

A metabolic study of important body elements, particularly those of the musculoskeletal system, was carried out on the astronauts of the Skylab 3 mission during the preflight, inflight, and postflight phases. An elevation in the level of urinary calcium similar to that observed in the 28-d Skylab flight continued throughout the flight. Significant nitrogen and phosphorus losses, apparently associated with muscle tissue loss, occurred in spite of inflight exercise programs. On the basis of these results it is predicted that capable musculoskeletal function is likely to occur in flights longer than about 9 months in duration.

Whedon, G. D.↗
NASA NTRS1976

Metabolic and endocrine studies - The second manned Skylab mission

Complete metabolic collections were performed on the Skylab 3 crew in the preflight, inflight, and postflight phases of the mission. Changes in fluid and electrolyte balance have been correlated with weight loss, changes in the excretion of aldosterone, vasopressin, and fluid compartments. The initial changes observed were consistent with an increase in thoractic blood volume upon transition to a zero gravity environment, producing a net fluid loss. Compensatory mechanisms reestablished positive water balance. The indicators investigated returned to thin preflight levels during the recovery period postflight

Leach, C. S.↗
NASA NTRS1976

Changes in glucose, insulin, and growth hormone levels associated with bedrest

Changes in plasma glucose, insulin, and growth hormone (HGH) resulting from exposure to 56 d of bedrest were determined in five healthy young male subjects. Changes in the daily levels of these factors for each subject were expressed as the mean of six blood samples per 24-h period. The level of HGH dropped after 10 d of bedrest, then showed a 1.5-fold increase at 20 d and subsequently decreased gradually reaching levels of 2.5 mg/ml/24 h, well below pre-bedrest controls of 4.2 mg/ml/24 h, by the 54th d. In spite of a marked increase in the daily plasma insulin levels during the first 30 d of bedrest, glucose levels remained unchanged. Beyond 30 d of bedrest, insulin began decreasing toward pre-bedrest levels and glucose followed with a similar reduction to below the control levels of 75 mg/100 ml/24 h on day 54. The daily mean changes reflect a change in the amplitude of the diurnal variation. The daily peak in plasma insulin shifted progressively to the late evening during the bedrest period.

Vernikos-Danellis, J.↗
NASA NTRS1976

Mars - Wind friction speeds for particle movement

Wind friction threshold speeds for particle movement were determined in a low pressure boundary layer wind tunnel at an atmospheric pressure of 5.3 mb. The results imply that for comparable pressures on Mars, the minimum wind friction threshold speed is about 2.5 m/sec, which would require free-stream winds of 50 to 135 m/sec, depending on the character of the surface and the atmospheric conditions. The corresponding wind speeds at the height of the Viking lander meteorology instrument would be about a factor of two less than the free-stream wind speed. The particle size most easily moved by winds on Mars is about 160 microns; particles both larger and smaller than this (at least down to about 5 microns) require stronger winds to initiate movement.

Greeley, R.↗
NASA NTRS1976

Deployable radiators for waste heat dissipation from Shuttle payloads

Thermal control of Shuttle instruments will require the use of a pumped fluid space radiator system to reject large quantities of waste heat. Many payloads, however, will have insufficient vehicle surface area available for radiators to reject this waste heat and will, therefore, require the use of deployed panels. It is desirable to utilize modularized, deployable radiator systems which have a high degree of configuration and component commonality to minimize the design, development, and fabrication costs. Prototypes of two radiator systems which meet these criteria are currently under development for Shuttle payload utilization: a 'rigid' radiator system which utilizes aluminum honeycomb panels of the Shuttle Orbiter configuration that are deployed by an Apollo Telescope Mount type scissors mechanism; and two 'flexible' radiator systems which use panels constructed from flexible metal/dielectric composite materials that are deployed by 'unrolling' or 'extending' in orbit. Detailed descriptions of these deployable radiator systems, along with design and performance features, are presented.

Cox, R. L.↗
NASA NTRS1976

Space motion sickness medications - Interference with biomedical parameters

The possibility that drugs administered to Skylab 3 and 4 crewmen for space motion sickness may have interfered with their biomedical evaluation in space is investigated. The mixture of scopolamine and dextroamphetamine produced changes which allow a more valid interpretation of the early biomedical changes ocurring in weightlessness. There is no doubt that the dramatic increase in aldosterone excretion is not attributable to the drug, while the drug could have contributed to the in-flight changes observed in cortisol, epinephrine, heart rate and possibly urine volume.

Vernikos-Danellis, J.↗
NASA NTRS1977

Mineral and nitrogen metabolic studies, experiment M071

The similarity between bed rest test and space flight effects on human mineral and nitrogen metabolisms indicates impairment of capable musculoskeletal functions. A pattern of urinary calcium increases and total calcium shifts suggests that calcium losses continue with time. Significant losses of nitrogen and phosphorus are associated with reduction in muscle tissue. It is concluded that capable musculoskeletal function is likely to be impaired during space flights of 1 1/2 to 3 years duration.

Whedon, G. D.↗
NASA NTRS1977

Biochemical responses of the Skylab crewmen: An overview

Continuous metabolic and endocrinic monitoring of Skylab crewmen established significant biochemical changes that varied in magnitude and direction but disappeared shortly after return to earth. These changes indicate adaptation by the body to the combined stresses of weightlessness. Transient changes in fluid and electrolyte metabolisms lead to the conclusion that a homeostasis condition had been achieved. Unstable states persisted in the metabolisms of bone mineral, protein, and carbohydrates.

Leach, C. S.↗
NASA NTRS1976

Deployable radiators for waste heat dissipation from Shuttle payloads

Prototypes of two types of modularized, deployable radiator systems with a high degree of configuration and component commonality to minimize design, development and fabrication costs are currently under development for Shuttle payloads with high waste heat: a rigid radiator system which utilizes aluminum honeycomb panels that are deployed by a scissors mechanism; and two 'flexible' radiator systems which use panels constructed from flexible metal/dielectric composite materials that are deployed by 'unrolling' or 'extending' in orbit. Detail descriptions of these deployable radiator systems along with design and performance features are presented.

Cox, R. L.↗
NASA NTRS1976

Mineral and nitrogen metabolic studies on Skylab flights and comparison with effects of earth long-term recumbency

A metabolic study of the effects of space flight on various chemical elements, particularly those with special relevance to the musculo-skeletal system, was carried out on the nine astronauts who participated in the three Skylab flights of 28, 59 and 84 days in 1973-1974. The study required of the cooperating crewmen constant dietary intake, continuous 24-hour urine collections and total fecal collections for 21-31 days before each flight, throughout each flight and for 17-18 days post-flight. Increases in urinary calcium and negative calcium balances during space flight were generally similar to those found in previous immobilization and bedrest studies. The persistence of these alterations in calcium metabolism throughout the flights suggested that calcium losses would continue in weightlessness for a very long time. Significant losses of nitrogen and phosphorus occurred, associated with observed reduction in muscle tissue. Both mineral and muscle losses occurred despite rigorous exercise regimens in flight. It was concluded that unless protective measures can be developed, capable musculo-skeletal function is likely to be impaired in space flights, ultimately to be conducted to Mars, of 1-1/2 to 3 years duration.

Whedon, G. D.↗
NASA NTRS1977

Flexible deployable-retractable space radiators

A lightweight flexible radiator system for on-orbit cooling of space payloads is described. The radiator is packaged as a compact unit which can be attached to a vehicle structure or hatch prior to or after launch. On-orbit, it is deployed to provide the radiating surface needed for a specific experiment. The unit is being independently developed and qualified as a heat rejection system which will be ready for any spacecraft or experiment, and which will not require significant structural and systems accommodation. Design details and thermal vacuum test results are presented.

Leach, J. W.↗
NASA NTRS1977

Prolonged weightlessness effect on postflight plasma thyroid hormones

Blood drawn before and after spaceflight from the nine Skylab astronauts showed a statistically significant increase in mean plasma thyroxine (T-4) of 1.4 micro g/dl and in thyroid-stimulating hormone (TSH) of 4 microunits ml. Concurrent triiodothyronine (T-3) levels decreased 27 ng/dl indicating inhibited conversion of T-4 to T-3. The T-3 decrease is postulated to be a result of the increased cortisol levels noted during and following each mission. These results confirm the thyroidal changes noted after the shorter Apollo flights and show that thyroid hormone levels change during spaceflight.

Leach, C. S.↗
NASA NTRS1977

Dust storms on Mars: Considerations and simulations

Aeolian processes are important in modifying the surface of Mars at present, and appear to have been significant in the geological past. Aeolian activity includes local and global dust storms, the formation of erosional features such as yardangs and depositional features such as sand dunes, and the erosion of rock and soil. As a means of understanding aeolian processes on Mars, an investigation is in progress that includes laboratory simulations, field studies of earth analogs, and interpretation of spacecraft data. This report describes the Martian Surface Wind Tunnel, an experimental facility established at NASA-Ames Research Center, and presents some results of the general investigation. Experiments dealing with wind speeds and other conditions required for the initiation of particle movement on Mars are described and considerations are given to the resulting effectiveness of aeolian erosion.

Greeley, R.↗
NASA NTRS1977

Metabolic energy requirements during manned orbital Skylab missions

The metabolic balance of nine Skylab astronauts was studied during the course of 28-, 59-, and 84-day flights. Control periods of at least three weeks preceding each flight and at least 18 days following each flight were included in the metabolic studies. Results of the investigation indicated that all members lost mass in flight without experiencing an increase in body density. Analysis of bone density, blood and urinary nitrogen levels, and overall calcium and nitrogen balances suggested that lean body mass declined through loss of protein. It thus appeared that despite adequate energy intake, the crew members did not reach equilibrium with the weightless environment within the time periods studied.

Rambaut, P. C.↗
NASA NTRS1977

Observations in energy balance in man during spaceflight

An investigation was undertaken of the changes in metabolic energy balance which occur in weightlessness. Daily energy intake was determined each day throughout the 28-, 59-, and 84-day flights for each of the nine Skylab astronauts. The energy content of the urine and feces was also measured. Changes in body composition were inferred from measurements of weight, volume, water, and total exchangeable potassium before and after flight. During flight, changes were followed by a daily measurement of body mass and by metabolic balance. Examination of the data reveal losses in body weight during the 1st and 2nd months of flight, a loss in body water and protein during the 1st month and a loss of fat during the 1st, 2nd, and 3rd months of flight. The energy input was about 41.7 kcal/kg per day on the ground, and 43.7 kcal/kg per day after 3 months in space. The increase in net energy input of about 1.6% per month is significant (P less than 0.05). When the net energy input is expressed on the basis of total body potassium, the increase in the resulting normalized net energy input of about 3.7% per month is also significant (P less than 0.05).

Rambaut, P. C.↗
NASA NTRS1978

Hormonal indices of tolerance to +Gz acceleration in female subjects

As a possible predictive test for screening Space Shuttle passengers, the secretions of the pituitary adrenal system and the adrenal medulla have been studied in conjunction with exposure to gravitational acceleration three times the normal level. The 12 female subjects in the test were divided into ambulatory and bedrest groups. Before bedrest, a high tolerance to centrifugation appeared to be linked to increases in plasma ACTH and cortisol. This relationship did not hold after bedrest. The correlation between tolerance to centrifugation and 24-hour urinary epinephrine-to-norepinephrine ratios was not significant.

Vernikos-Danellis, J.↗
NASA NTRS1978

Measurements of X-ray source positions by the scanning modulation collimator on HEAO 1

This paper reports preliminary results on the positions of X-ray sources obtained with the modulation collimator on the first NASA High Energy Astronomy Observatory, HEAO 1. Calibration on Sco X-1 establishes the experiment capabilities to be within 7 sec as limited by aspect errors. For the reported X-ray sources certain ambiguities in their positions are resolved and the previous optical identifications of four sources are confirmed, two of which are X-ray bursters and one of which is the black hole candidate Cir X-1. An accurate position for a new transient source is also presented.

Gursky, H.↗