Tektite - Experience with an underwater analog of future space operations
Tektite II program of underwater research as future manned space flight operations model, discussing mission structure, crew selection and communications
Miller, J. W.↗
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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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Mathematical model analysis of underwater simulation of astronaut extravehicular activities in weightless conditions
Mathematical model for underwater simulation of astronaut extravehicular activities in weightless conditions, using computer program
Pao, Y. C.↗
Operation and testing of Mark 10 Mod 3 underwater breathing apparatus
Performance tests on a closed circuit, mixed gas underwater breathing apparatus are reported. The equipment is designed to provide a minimum diving duration of four hours at 1500 ft below sea surface; it senses oxygen partial pressure in the breathing gas mix and controls oxygen content of the breathing gas within narrow limits about a preset value. The breathing circuit subsystem provides respirable gas to the diver and removes carbon dioxide and moisture from the expired gas. Test results indicate undesirable variations in oxygen partial pressure with oxygen addition and insufficient carbon dioxide absorption.
Milwee, W. I., Jr.↗
Laboratory and field evaluation of an underwater sand height gage
An underwater sand height gage was investigated. This instrument consisted of two transducers, one screened and one unscreened. Laboratory experimentation included static and dynamic tests with three test sands--fine, medium, and coarse. Field tests were conducted at Rudee Inlet, Virginia Beach, Virginia. Test results showed a linear response to up to 10 inches of sand loading. Deviation observed in identical tests appeared to be due to variation in the density of sand. Density differences reflected varying packing styles which, in turn, were a consequence of grain size and flow regime. Further evaluations of the sand height gage reflect this instrument's potential.
Swift, D. J. P.↗
Underwater space suit pressure control regulator
A device is reported for regulating the pneumatic pressure in a ventilated space suit relative to the pressure imposed on the suit when being worn by a person underwater to simulate space environment for testing and experimentation. A box unit located on the chest area of the suit comprises connections for suit air supply and return lines and carries a regulator valve that stabilizes the air pressure differential between the inside and outside of the suit. The valve and suit pressure is controlled by the suit occupant and the valve includes a mechanism for quickly dumping the suit pressure in case of emergency. Pressure monitoring and relief devices are also included in the box unit.
Aldrich, B. R.↗
Cardiorespiratory responses to exercise in air and underwater.
Respiratory gas exchange, end-tidal gas tensions, alveolar ventilation, respiratory frequency, cardiac output, and pulse rate were measured in four healthy adult males at rest and during mild and moderate exercise in air at 18-22 C and underwater at 35.0-35.5 C. Immersion was associated with a 10% increase in pulse rate and cardiac output at all levels of exercise. There were no changes in end-tidal CO2 tension or alveolar ventilation. It is concluded that horizontal subjects breathing at eupneic pressures and working against mild and moderate loads in warm water show the same responses to exercise as in air.-
Denison, D. M.↗
Ejectable underwater sound source recovery assembly
An underwater sound source is described that may be ejectably mounted on any mobile device that travels over water, to facilitate in the location and recovery of the device when submerged. A length of flexible line maintains a connection between the mobile device and the sound source. During recovery, the sound source is located be particularly useful in the recovery of spent rocket motors that bury in the ocean floor upon impact.
Irick, S. C.↗
Underwater probing with laser radar
Recent advances in laser and electro optics technology have greatly enhanced the feasibility of active optical probing techniques aimed at the remote sensing of water parameters. This paper describes a LIDAR (laser radar) that has been designed and constructed for underwater probing. The influence of the optical properties of water on the general design parameters of a LIDAR system is considered. Discussion of the specific details in the choice of the constructed LIDAR is given. This system utilizes a cavity dumped argon ion laser transmitter capable of 50 watt peak powers, 10 nanosecond pulses and megahertz pulse repetition rates at 10 different wavelengths in the blue green region of the spectrum. The performance of the system, in proving various types of water, is demonstrated by summarizing the results of initial laboratory and field experiments.
Carswell, A. I.↗
An overview of underwater remotely manned Systems and sub-systems
A current overview of how the underwater facet of remotely manned systems has progressed since 1972 is presented. The current approaches being pursued and the success of American and foreign technology is assessed.
Rechnitzer, A., B.↗
Underwater seismic source
Apparatus for generating a substantially oscillation-free seismic signal for use in underwater petroleum exploration, including a bag with walls that are flexible but substantially inelastic, and a pressured gas supply for rapidly expanding the bag to its fully expanded condition is described. The inelasticity of the bag permits the application of high pressure gas to rapidly expand it to full size, without requiring a venting mechanism to decrease the pressure as the bag approaches a predetermined size to avoid breaking of the bag.
Yang, L. C.↗
Fabricating Underwater Electroacoustic Transducers
Use of retainer ring instead of adhesives simplifies assembly and disassembly. Underwater electroacoustical transducer assembly uses precast silicone rubber compressed between ceramic crystal and metal container. Removable retainer ring holds assembly in place. Method provides proper stress loading, speed and ease of assembly, and way of removing transducer without damaging crystal.
Ferguson, R. L.↗
Modular detector for deep underwater registration of muons and muon groups
Registration and identification of muons and muon groups penetrating into the ocean depth, can be performed using a modular multilayer detector with high resolution bidimensional readout - deep underwater calorimeter (project NADIR). Laboratory testing of a prototype sensor cell with liquid scintillator in light-tight casing, testifies to the practicability of the full-scale experiment within reasonable expences.
Demianov, A. I.↗
Application of NASTRAN/COSMIC in the analysis of ship structures to underwater explosion shock
The application of NASTRAN/COSMIC in predicting the transient motion of ship structures to underwater, non-contact explosions is discussed. Examples illustrate the finite element models, mathematical formulations of loading functions and, where available, comparisons between analytical and experimental results.
Fallon, D. J.↗
Experimental studies on the tripping behavior of narrow T-stiffened flat plates subjected to hydrostatic pressure and underwater shock
An experimental investigation was conducted to determine the static and dynamic responses of a specific stiffened flat plate design. The air-backed rectangular flat plates of 6061-T6 aluminum with an externally machined longitudinal narrow-flanged T-stiffener and clamped boundary conditions were subjected to static loading by water hydropump pressure and shock loading from an eight pound TNT charge detonated underwater. The dynamic test plate was instrumented to measure transient strains and free field pressure. The static test plate was instrumented to measure transient strains, plate deflection, and pressure. Emphasis was placed upon forcing static and dynamic stiffener tripping, obtaining relevant strain and pressure data, and studying the associated plate-stiffener behavior.
Budweg, H. L.↗
The use of underwater dynamometry to evaluate two space suits
Four Astronauts were instrumented and donned one of three extravehicular activity (EVA) suits: the currently in use shuttle suit (STS), the Mark III (MK3), and the AX5. The STS was used as the comparison suit because of approved status. Each subject performed ten different exercises in each suit in three different manners (static, dynamic and fatigue) in two different environments, WETF and KC-135 (KC-135 not completed as of this report). Data were recorded from a flight qualified underwater dynamometer (Cybex power head) with a TEAC multichannel recorder/tape and downloaded into the VAX computer system for analysis. Also direct hard copy strip chart recordings were made for backup comparisons. Data were analyzed using the ANOVA procedure and results were graphed and reported without interpretation to the NASA/JSC ABL manager.
Squires, W. G.↗
A mission executor for an autonomous underwater vehicle
The Naval Postgraduate School has been conducting research into the design and testing of an Autonomous Underwater Vehicle (AUV). One facet of this research is to incrementally design a software architecture and implement it in an advanced testbed, the AUV II. As part of the high level architecture, a Mission Executor is being constructed using CLIPS (C Language Integrated Production System) version 5.0. The Mission Executor is an expert system designed to oversee progress from the AUV launch point to a goal area and back to the origin. It is expected that the executor will make informed decisions about the mission, taking into account the navigational path, the vehicle subsystem health, and the sea environment, as well as the specific mission profile which is downloaded from an offboard mission planner. Heuristics for maneuvering, avoidance of uncharted obstacles, waypoint navigation, and reaction to emergencies (essentially the expert knowledge of a submarine captain) are required. Many of the vehicle subsystems are modeled as objects using the CLIPS Object Oriented Language (COOL) embedded in CLIPS 5.0. Also, truth maintenance is applied to the knowledge base to keep configurations updated.
Lee, Yuh-Jeng↗
Early SEI milestones - Underwater habitats and Antarctic research outposts as analogs for long duration spaceflight and lunar and Mars outposts
The use of analog environments for space research is considered focusing on underwater habitats and Antarctic research sites as analogous settings to long-duration space flight. It is pointed out that the use of these earth analogs can provide engineers, scientists, and future crew members with critical 'mission' experience at a relatively low cost.
Rummel, John D.↗
Chemical Sensing of Unexploded Ordnance with the Mobile Underwater Survey System (MUDSS)
The ability to sense explosives residues in the marine environment is a critical tool for identification and classification of underwater unexploded ordnance (UXO). Trace explosives signatures of TNT and DNT have been extracted from multiple sediment samples adjacent to unexploded undersea ordnance at Halifax Harbor, Canada. The ordnance was hurled into the harbor during a massive explosion fifty years earlier, in 1945 after World War II had ended. Laboratory sediment extractions were made using the solid-phase microextraction (SPME) method in seawater, and detection using the Reversal Electron Attachment Detection (READ) technique and, in the case of DNT, a commercial gas-chromatography/mass spectrometer (GC/MS). Results show that, after more than 50 years in the environment, ordnance which appeared to be physically intact gave good explosives signatures at the parts-per-billion level, whereas ordnance which had been cracked open during the explosion gave no signatures at the 10 parts-per-trillion sensitivity level. These measurements appear to provide the first reported data of explosives signatures from undersea UXOs.
Darrach, M. R.↗