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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 271 records · Page 15
All sourcesNASA NTRSDOE OSTI
NASA NTRS1983

A mobile work station concept for mechanically aided astronaut assembly of large space trusses

This report presents results of a series of truss assembly tests conducted to evaluate a mobile work station concept intended to mechanically assist astronaut manual assembly of erectable space trusses. The tests involved assembly of a tetrahedral truss beam by a pair of test subjects with and without pressure (space) suits, both in Earth gravity and in simulated zero gravity (neutral buoyancy in water). The beam was assembled from 38 identical graphite-epoxy nestable struts, 5.4 m in length with aluminum quick-attachment structural joints. Struts and joints were designed to closely simulate flight hardware. The assembled beam was approximately 16.5 m long and 4.5 m on each of the four sides of its diamond-shaped cross section. The results show that average in-space assembly rates of approximately 38 seconds per strut can be expected for struts of comparable size. This result is virtually independent of the overall size of the structure being assembled. The mobile work station concept would improve astronaut efficiency for on-orbit manual assembly of truss structures, and also this assembly-line method is highly competitive with other construction methods being considered for large space structures.

Heard, W. L., Jr.↗
NASA NTRS1985

Swing-arm beam erector (SABER) concept for single astronaut assembly of space structure

Results are presented of tests conducted to evaluate a mobile work station/assembly fixture concept that would mechanically assist an astronaut in the on-orbit manual assembly of erectable truss-beams. The concept eliminates astronaut manual translation by use of a motorized work platform with foot restraints. The tests involved assembly of a tetrahedral truss-beam by a test subject in simulated zero gravity (neutral bouyancy in water). A three-bay truss-beam was assembled from 30 aluminum struts with quick-attachment structural joints. The results show that average on-orbit assembly rates of 2.1 struts per minute can be expected for struts of the size employed in these tests.

Watson, J. J.↗
NASA NTRS1988

An investigation of conformable antennas for the astronaut backpack communication system

During periods of extravehicular activity it is obviously important that communication and telemetry systems continue to function independently of the astronaut. A system of antennas must therefore be designed that will provide the necessary isotropic coverage using circular polarization over both the transmit and receive frequency bands. To avoid the inherent physical limitations to motion that would be incurred with any sort of protruding antenna, it is necessary that the radiator be essentially flush-mounted or conformable to the structure on which it is attached. Several individual antenna elements are needed for the desired coverage. Both the particular elements chosen and their location determine the ultimate radiation pattern of the overall system. For these reasons a two-fold research plan was undertaken. First, individual elements were investigated and designed. Then various mounting locations were considered and the radiation patterns were predicted taking into account the effects of the astronaut's backpack.

Long, Stuart A.↗
NASA NTRS1987

Space processing viewed by a scientist-astronaut

An account is given of NASA astronaut T. G. Wang's 1985 experiences with Spacelab-borne containerless processing experiment equipment handling and experimental management. The mission in question was marred by the initial malfunction of the zero-gravity materials-processing experiment package; Wang's first task was accordingly to attempt repairs, and led to his living inside the experiment package for 2.5 days in order to operate the system as well as possible, on a 16-hr workday basis, with the assistance of two other astronauts.

Wang, Taylor G.↗
NASA NTRS1989

Astronaut tool development: An orbital replaceable unit-portable handhold

A tool to be used during astronaut Extra-Vehicular Activity (EVA) replacement of spent or defective electrical/electronic component boxes is described. The generation of requirements and design philosophies are detailed, as well as specifics relating to mechanical development, interface verifications, testing, and astronaut feedback. Findings are presented in the form of: (1) a design which is universally applicable to spacecraft component replacement, and (2) guidelines that the designer of orbital replacement units might incorporate to enhance spacecraft on-orbit maintainability and EVA mission safety.

Redmon, John W., Jr.↗
NASA NTRS1989

The flights before the flight - An overview of shuttle astronaut training

Space shuttle astronaut training is centered at NASA's Johnson Space Center in Houston, Texas. Each astronaut receives many different types of training from many sources. This training includes simulator training in the Shuttle Mission Simulator, in-flight simulator training in the Shuttle Training Aircraft, Extravehicular Activity training in the Weightless Environment Training Facility and a variety of lectures and briefings. Once the training program is completed each shuttle flight crew is well-prepared to perform the normal operations required for their flight and deal with any shuttle system malfunctions that might occur.

Sims, John T.↗
NASA NTRS1989

Exercise-training protocols for astronauts in microgravity

Based on physical working requirements for astronauts during intra- and extravehicular activity and on the findings from bed-rest studies that utilized exercise training as a countermeasure for the reduction of aerobic power, deterioration of muscular strength and endurance, decrements in mood and cognitive performance, and possibly for bone loss, two exercise protocols are proposed. One assumes that, during microgravity, astronaut exercise physiological functions should be maintained at 100 percent of ground-based levels. The other assumes that maximal aerobic power in flight can be reduced by 10 percent of the ground-based level.

Greenleaf, J. E.↗
NASA NTRS1991

Six-degree-of-freedom simulation of an astronaut detumble system

The problem of stabilizing the attitude of an untethered astronaut in a three-axis tumble is addressed. A simple six thruster detumbling system mounted on the astronaut's Portable Life Support System backpack is analyzed as a possible solution. A six-degree-of-freedom dynamical model is constructed using the Clohessy-Wiltshire equations, Euler's moment equations, and quaternions. The six thruster system produces both moments and forces when activated. However, it is shown that the thrust forces acting on the body during detumbling do not significantly affect the translational motion.

Fowler, W. T.↗
NASA NTRS1991

The astronaut science advisor: Ground testing during SLS-1

The objective of the Astronaut Science Advisor (ASA) is the improvement of the scientific return of experiments performed in space. This is accomplished through the use of expert systems technology to encode the domain and experiment knowledge commanded by the principal investigator (PI) and make it available to the astronaut experimenters. The principal functions of the ASA include the following: capture, reduce, and archive experimental data; monitor data quality and help diagnose problems with equipment when experimental data is erratic or poor; identify and permit investigation of interesting data; and suggest protocol changes that would result in better utilization of remaining time.

Compton, Michael M.↗
NASA NTRS1991

Design of a reusable kinetic energy absorber for an astronaut safety tether to be used during extravehicular activities on the Space Station

The goal of this project is to design a reusable safety device for a waist tether which will absorb the kinetic energy of an astronaut drifting away from the Space Station. The safety device must limit the tension of the tether line in order to prevent damage to the astronaut's space suit or to the structure of the spacecraft. The tether currently used on shuttle missions must be replaced after the safety feature has been developed. A reusable tether for the Space Station would eliminate the need for replacement tethers, conserving space and mass. This report presents background information, scope and limitations, methods of research and development, alternative designs, a final design solution and its evaluation, and recommendations for further work.

Borthwick, Dawn E.↗
NASA NTRS1991

Metabolic changes observed in astronauts

Results of medical experiments with astronauts reveal rapid loss of volume (2 l) from the legs and a transient early increase in left ventricular volume index. These findings indicate that, during space flight, fluid is redistributed from the legs toward the head. In about 2 days, total body water decreases 2 to 3 percent. Increased levels of plasma renin activity and antidiuretic hormone while blood sodium and plasma volume are reduced suggest that space flight-associated factors are influencing the regulatory systems. In addition to fluid and electrolyte loss, Skylab astronauts lost an estimated 0.3 kg of protein. Endocrine factors, including increased cortisol and thyroxine and decreased insulin, are favorable for protein catabolism. The body appears to adapt to weightlessness at some physiologic cost. Readaptation to earth's gravity at landing becomes another physiologic challenge.

Leach, Carolyn S.↗
NASA NTRS1992

Astronaut observations of the Persian (Arabian) Gulf during STS-45

As a result of the 1991 Persian Gulf war, between mid-January and June 1991, the Persian Gulf was contaminated with an estimated 4 to 6 million barrels of crude oil, released directly into the Gulf from refinement facilities, transhipment terminals, and moored tankers along the coast of Kuwait, and precipitated from oil fire smoke plumes. To assess the environmental impact of the oil, an international team of marine scientists representing 14 nations was assembled under the auspices of the United Nations International Oceanic Commission and the Regional Organization for Protection of the Marine Environment to conduct detailed surveys of the Persian Gulf, the Strait of Hormuz, and the Gulf of Oman, including hydrographic, chemical, and biological measurements. To supplement the field surveys and to serve as an aid in data interpretation, astronauts aboard the Space Shuttle Atlantis photographed water features and coastal habitats in the Persian Gulf during mission STS-45 (24 March to 02 April 1992). The astronauts collected 111 hand-held, color photographs of the Gulf (72 70-mm photographs and 39 5-inch photographs) from an altitude of 296 km (160 n.mi.). The photographs reveal distributions in water turbidity associated with outflow from the Shatt-al-Arab and water circulation along the entire coast of Iran and the Strait of Hormuz, coastal wetlands and shallow-water habitats, and sticks appearing in the sunglint pattern, which appear to be oil.

Ackleson, Steven G.↗
NASA NTRS1993

Conceptual design of an astronaut hand anthropometry device

In a microgravity environment, fluid equalizes throughout the body, causing the upper body to swell. This causes the hands to swell which can cause problems for astronauts trying to do work in pressurized EVA (extravehicular activity) gloves. To better design these gloves, accurate measurements of the astronauts swollen hands are needed. Five concepts were developed in this report from an original field of 972 possible concepts. These five concepts were based on mold impression, ultrasound, laser topography, white light photography, and video imaging. From a decision matrix based on nine weighted criteria, the video imaging technique was found to be the best design to pursue.

Mcmahan, Robert↗
NASA NTRS1994

PI in the sky: The astronaut science advisor on SLS-2

The Astronaut Science Advisor (ASA, also known as Principal-Investigator-in-a-Box) is an advanced engineering effort to apply expert systems technology to experiment monitoring and control. Its goal is to increase the scientific value of information returned from experiments on manned space missions. The first in-space test of the system will be in conjunction with Professor Larry Young's (MIT) vestibulo-ocular 'Rotating Dome' experiment on the Spacelab Life Sciences 2 mission (STS-58) in the Fall of 1993. In a cost-saving effort, off-the-shelf equipment was employed wherever possible. Several modifications were necessary in order to make the system flight-worthy. The software consists of three interlocking modules. A real-time data acquisition system digitizes and stores all experiment data and then characterizes the signals in symbolic form; a rule-based expert system uses the symbolic signal characteristics to make decisions concerning the experiment; and a highly graphic user interface requiring a minimum of user intervention presents information to the astronaut operator. Much has been learned about the design of software and user interfaces for interactive computing in space. In addition, we gained a great deal of knowledge about building relatively inexpensive hardware and software for use in space. New technologies are being assessed to make the system a much more powerful ally in future scientific research in space and on the ground.

Hazelton, Lyman R.↗
NASA NTRS1993

Assessments of astronaut effectiveness

This study examined the reliability and convergent validity of three methods of peer and supervisory ratings of the effectiveness of individual NASA astronauts and their relationships with flight assignments. These two techniques were found to be reliable and relatively convergent. Seniority and a peer-rated Performance and Competence factor proved to be most closely associated with flight assignments, while supervisor ratings and a peer-rated Group Living and Personality factor were found to be unrelated. Results have implications for the selection and training of astronauts.

Rose, Robert M.↗
NASA NTRS1995

Computer Analysis of Electromagnetic Field Exposure Hazard for Space Station Astronauts during Extravehicular Activity

In order to estimate the RF radiation hazards to astronauts and electronics equipment due to various Space Station transmitters, the electric fields around the various Space Station antennas are computed using the rigorous Computational Electromagnetics (CEM) techniques. The Method of Moments (MoM) was applied to the UHF and S-band low gain antennas. The Aperture Integration (AI) method and the Geometrical Theory of Diffraction (GTD) method were used to compute the electric field intensities for the S- and Ku-band high gain antennas. As a result of this study, The regions in which the electric fields exceed the specified exposure levels for the Extravehicular Mobility Unit (EMU) electronics equipment and Extravehicular Activity (EVA) astronaut are identified for various Space Station transmitters.

Hwu, Shian U.↗
NASA NTRS1999

Validation of Land Cover Maps Utilizing Astronaut Acquired Imagery

This report is produced in accordance with the requirements outlined in the NASA Research Grant NAG9-1032 titled "Validation of Land Cover Maps Utilizing Astronaut Acquired Imagery". This grant funds the Remote Sensing Research Unit of the University of California, Santa Barbara. This document summarizes the research progress and accomplishments to date and describes current on-going research activities. Even though this grant has technically expired, in a contractual sense, work continues on this project. Therefore, this summary will include all work done through and 5 May 1999. The principal goal of this effort is to test the accuracy of a sub-regional portion of an AVHRR-based land cover product. Land cover mapped to three different classification systems, in the southwestern United States, have been subjected to two specific accuracy assessments. One assessment utilizing astronaut acquired photography, and a second assessment employing Landsat Thematic Mapper imagery, augmented in some cases, high aerial photography. Validation of these three land cover products has proceeded using a stratified sampling methodology. We believe this research will provide an important initial test of the potential use of imagery acquired from Shuttle and ultimately the International Space Station (ISS) for the operational validation of the Moderate Resolution Imaging Spectrometer (MODIS) land cover products.

Estes, John E.↗
NASA NTRS1999

Measuring Astronaut Performance in Microgravity: Loads and Modeling

Quantitative analysis of human performance in microgravity is important for both scientific investigations and spacecraft engineering design. By collecting and evaluating the kinematics and kinetics data of astronauts in space, it becomes possible to characterize human motor strategies, postural behavior in weightlessness, improve the design of orbital modules, help maintain a quiescent microgravity for acceleration-sensitive material science and life science experiments (NASA JSC, 1996), and optimize the human operative capabilities during long-duration space missions. Hence, there is a need for a precise measurement of the forces and moments exerted by the astronauts on the space station and their postures and movements.

Newman, D.↗