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Human scalp hair is increasingly regarded as a valuable indicator tissue for biological monitoring of environmental exposure to toxic substances. Hair provides both current and past records of exposure during prolonged periods of time. To validate hair monitoring for assessment of toxic substances in space, a unique biological model was developed. Human scalp grafts were transplanted to athymic BALB/c-nu/nu nude mice and then animals were exposed continuously over 2 months, using implanted osmotic pumps, to methylmercury (MeHg), a substance known to be incorporated into hair. Mercury concentrations in hairs were determined using X-ray fluorescence (XRF) spectrometry by segmental analysis of single strands. Blood, skin and brain concentrations of methylmercury were measured by cold vapor analysis. Human scalp hair grown in nude mice showed long-term persistence of human characteristics.

In spacecraft life support systems which are partially or fully closed, the air and water systems have sufficient interaction that contaminants in one system may become contaminants in the other. Life support system designers typically consider these media separately. In order to develop plausible and appropriate drinking water contaminant standards for longer-term NASA space missions, we performed a human health risk characterization using toxicological and exposure values typical of space operations and crew. It showed that the greatest waterborne health concern was from acute microbial infection leading to incapacitating gastrointestinal illness. While substantial data gaps exist for toxicities and exposures, ingestion exposure pathways for toxic materials yielded de minimus acute health risks unlikely to affect SEI space missions. Risks of chronic health problems from the relatively short exposures of expected space missions were within acceptable public health limits.

Investigations of iodine species distribution of various aqueous solutions of iodine disinfectants and water from equilibrated suspensions of triiodide and pentaiodide resins were done at the University of Colorado for the Center for Space Environmental Health during 1992 and 1993. Direct measurements of three individual iodine species: I-, I2 and I3-, were made. In addition three measures of total titratable iodine species were used. It has been found that I2 and I3- solutions produce a significant fraction of the non-disinfecting species iodide (I-), ranging from 50 to 80% of added iodine, respectively, at pH values of approximately 5. Correspondingly, I2 solutions produce more than twice the concentration of disinfecting iodine species per mass iodine dose than I3- solutions. Both I- and I2 species were found in aqueous extracts of pentaiodide resin, although no soluble species were detected with triiodide resin.

The reaction of iodine, a potential disinfectant for use in the treatment of recycled water during long-duration manned space missions, and several organic substrates that are expected chemical constituents in a closed-loop recycle water system, yields iodinated disinfection by-products. The reactions were studied using procedures analagous to those developed by the U. S. Environmental Protection Agency for evaluation of chlorinated disinfection by-products in water. The iodinated products formed in these studies were identified using gas chromatography with both electron capture and mass spectrometric detection. Aqueous solutions of acetic acid and of dextran produce iodinated alkyl-compounds when treated with iodine, as triiodide ion, at neutral pH. Similar treatment of phenol yields iodine-substituted phenols at appreciable concentrations.

The smallest manned spacecraft conceivable is the Extravehicular Activity Space Suit (EVA). It makes the astronaut autonomous on the space facilities, protecting him against the hostile environment and allowing the crew to provide sufficient performance and productivity. The specificity of the suit enclosure is related to the fact that it must ensure protection functions which are in conflict with the human performance function. For example, the enclosure is pressurized to protect the astronaut against the vacuum but such inner pressure rigidifies limbs and waist thus degrading mobility and working capability. The mobility is obtained through the combination of pressure tight bearings and one or two degrees of freedom (DOF) joints interfacing with a hard upper torso and hard bearings. In fact, the astronaut (motor) and the suit (passive) can be considered as two separate robots working in parallel, the performance depending on their compatibility and the level of the inner pressure.

In the frame of the development of the European EVA Suit, a complete trade-off was conducted to select the lower torso architecture. This study, performed under an ESA contract, included a formal trade-off dealing with all cost and programmatic impacts together with a technical assessment based on man rated underwater evaluations and analysis. The candidate architectures were: the European baseline including 2 hip and 2 thigh bearings, the Russian like soft ORLAN-DMA, a soft lower torso including 2 thigh bearings and another soft one including 2 calf bearings. The idea was to compare the different design performances without having necessarily developed the 4 pressurized lower torsos and then also to gain experience on predicting methods for such ergonomic/kinematic studies. The trade-off was based on the manned underwater evaluation of ergonomical suit simulators (wet suit concept), supported by the 1-g pressurized evaluation of the Russian ORLAN-DMA and CAD-CAM kinematic analysis.

The original Shuttle Extravehicular Mobility Unit (EMU) Hard Upper Torso (HUT) configuration developed in1978 by Hamilton Standard and ILC, Dover had the arm attached in such a way that the shoulder bearing outer race was integral with the HUT. This method of attachment has been termed “planar arm.” During development, this configuration proved unacceptable because some astronauts and test subjects experienced difficulty, and in some cases pain, while donning. Interference occurred when the arms transitioned from vertical to horizontal as the HUT was entered (arms over head). At the time, designers needed to quickly resolve this issue and certify the EMU for the first Shuttle flight. The solution - pivot sockets - allowed the shoulder bearing to pivot relative to the HUT for donning purposes and then pivot back to allow for optimum arm performance. The pivoted HUT configuration has been very successful and is one of the design features that allows arm mobility and range in the EMU.

During Extravehicular Activities (EVA) an astronaut has to be protected against various external factors ranging from mechanical hazards to solar radiation and micrometeoroids. An important element in this external protection is the outermost fabric layer. It has to ensure the mechanical protection of the pressure retention bladder and at the same time - by its thermooptical properties - plays an important role in the thermal control of the space suit. New weaving and knitting technologies enable the fabrication of so-called 3-D fabrics with interconnected layers and local variation of properties in one manufacturing step. By this a tailored design of protection properties is possible. A study has been performed to define concepts adapted for use on a European Space Suit. Different fabric samples were manufactured and tested, amongst others, for strength, flexibility, puncture and wear resistance, UV stability, flammability, out/offgassing and micrometeoroid protection effctiveness.

The success of astronauts performing extravehicular activity (EVA) on orbit is highly dependent upon the performance of their spacesuit gloves. A study has recently been conducted to advance the development and manufacture of spacesuit gloves. The process replaces the manual techniques of spacesuit glove manufacture by utilizing emerging technologies such as laser scanning, Computer Aided Design (CAD), computer generated two-dimensional patterns from three-dimensional surfaces, rapid prototyping technology, and laser cutting of materials, to manufacture the new gloves. Results of the program indicate that the baseline process will not increase the cost of the gloves as compared to existing styles, and in production, may reduce the cost of the gloves. Perhaps the most important outcome of the Laserscan process is that greater accuracy and design control can be realized.

The construction and operation of the Space Station Freedom will require longer stays in space and extended re-use of the Liquid Cooling and Ventilation Garment (LCVG) and the Space Suit Assembly (SSA) bladder. Since these conditions require redefinition of microbial control procedures, a program was undertaken to identify an undergarment, an antimicrobial finish, and cleaning protocols for various space suit components. Using standard microbiological techniques and researching earlier American space program experience, a baseline microbial control procedure was established and a series of manned SSA tests undertaken to determine the validity of the procedure. The results suggest that the use of an undergarment with an antimicrobial finish improved the hygiene of the LCVG, and the use of a disinfectant effectively kills bacterial on the SSA bladder. In addition, forced air focused on selected areas of the suit significantly reduces microbial viability.

McDonnell Douglas Aerospace has developed an innovative piccolo tube system approach to fire detection and suppression (FDS) in Space Station Freedom Node 2. In a gravity environment, smoke travels by natural convection and triggers an alarm; however, in a microgravity environment there is no mechanism for smoke to move from a remote distance to the sensor without assistance. In addition, the Space Station nodes contain closed-out, odd-shaped regions that have surprisingly large free air volumes in which smoke can “hide.” We have overcome these problems by drawing the smoke to the alarm sensors through piccolo tubes that sample all regions of the node. Similarly, we release fire suppressant through piccolo tubes to ensure an even distribution throughout the fire area. This paper will first give an overview of the Node 2 architecture. The middle section will describe the detection and suppression systems, including the avionics architecture and operations.

One of the primary safety concerns for Space Station Freedom pressurized modules is fire. Some Freedom modules are unattended for long periods of time. In other cases, enclosed, pressurized volumes are not open to crew monitoring. As a result, a fire detection system is required to continuously monitor all modules for combustion. This paper briefly reviews the overall design for the Freedom fire detection system, and the design of the two basic types of detectors: smoke and flame. The smoke detectors monitor particulates in small open areas, stand-offs, end-cones, and racks. The flame detectors survey open areas for radiation at wavelengths and intensities characteristic of combustion. Responses from detectors are evaluated by Freedom's data management system to determine the presence of combustion and to recommend appropriate action.

The Space Station Temperature and Humidity Control Condensing Heat Exchangers will be utilized to collect and remove atmospheric water vapor generated by the metabolic and hygienic activity of crew members. The porous hydrophilic coating within the heat exchangers will always be wet. Cabin air will continuously flow through the heat exchangers during system operation which makes them a potential site for microbial colonization. This paper summarizes the findings from an ongoing study which evaluates biofilm formation on wet hydrophilic coated panels compared to panels to which microbial control measures have been applied. The control measures evaluated are an antimicrobial agent within the coating and periodic drying.

Boeing is responsible for Space Station Freedom (Work Package (WP) 01) which includes the Habitat and U.S. Laboratory modules, which includes the integration of the Environmental Control and Life Support System (ECLSS). Included as part of the ECLSS is the Atmosphere Revitalization (AR) subsystem. The AR subsystem provides for removal of metabolic carbon dioxide, removal of trace contaminants, and continuous monitoring of the cabin atmosphere major constituent composition during the Manned Tended Configuration (MTC) phase of station operations. The focus of this paper is on the Carbon Dioxide Removal Assembly (CDRA) flight design aspects of the Space Station Freedom (SSF) AR subsystem. A Four Bed Molecular Sieve (4BMS) has been selected by Boeing as the CDRA for SSF. The CDRA removes carbon dioxide from an air slip stream pulled from the Cabin Air Temperature & Humidity Control (THC) assembly.

The wing of the Learjet Model 60 was tailored for improved aerodynamic characteristics using the TRANAIR transonic full-potential CFD code. A root leading edge glove and wing tip fairing were shaped to reduce shock strength, improve cruise drag and extend the buffet limit. The aerodynamic design was validated by wind tunnel test and flight test data.

Hovering flight is a critical skill that must be acquired by neophyte helicopter pilots prior to learning other flight maneuvers. Hover training in the aircraft is potentially dangerous given the tendency for neophytes to overcontrol the helicopter near the ground. It is also expensive. The Army uses the UH-1 helicopter for Primary Phase hover training at a cost of approximately $700.00 per hour with a hover training requirement of approximately 10-14 hours per student. The Automated Hover Trainer (AHT) was designed to provide ab initio pilots with safe, low-cost training in the basic hovering maneuvers: stationary hover, hover taxi, hovering turns, and takeoff to and land from a hover. Research was performed to assess the effectiveness of the AHT by measuring the Transfer of Training (TOT) from the AHT simulator to the helicopter using Army flight students as research subjects. Significant positive TOT was demonstrated for all five hovering maneuvers.

This paper presents an application of artificial neural networks in adaptive helicopter hover training of novice student pilots. The design of the adaptive trainer utilizes the hypothesis that novices can be trained to fly a helicopter system automatically (with no human interaction) if the helicopter system adapts to the learning curve of the student. Two different techniques based on the above approach are presented. In the first technique, the helicopter system actively enforces optimality by augmenting the novice's control inputs by amounts necessary to satisfy desired performance criteria. The second technique uses relaxed performance criteria that are not initially optimal, but approach optimality in a graded fashion, based on the learning curve of the student. Adaptive neuro-controllers, together with a critic model, are used to implement the adaptive helicopter system.

This paper discusses the creation of the aerodynamic analysis module of a PC-based aircraft design program called “RDS”, using the time-honored aerodynamic methods found in classical textbooks and the USAF DATCOM. Using this program, reasonably realistic aerodynamic results can be calculated in less than an hour given the geometric inputs which define an aircraft, such as component wetted areas, wing geometry, and cross-section areas. Aerodynamics analysis in RDS includes parasite drag (subsonic and supersonic), drag due to lift, lift curve slope, and maximum lift. Comparisons to T-38 data show good results.

Predictions of the aerodynamic coefficients for a two-slot circulation control airfoil are made by solving the two-dimensional, compressible, mass-averaged, Navier-Stokes equations. Numerical solutions are obtained by using the Beam-Warming implicit approximate factorization technique and the Baldwin-Lomax turbulence model with a curvature correction. Predictions using different combinations of blowing momentum coefficients with each of the two slots are discussed and compared with previous single-slot numerical results.