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The thermo-optical properties of optical solar reflectors (OSRs) can be modified by thin films. Development activity has produced a mirror with a solar absorptance of 0.04. The UV reflector has also been combined with a conductive layer for electrostatic discharge resistance, and functions over a range of solar flux incidence angles. This paper will provide an update on work that has been carried out.

A centrifugal pump concept was elaborated for a multiple application in future spacecrafts. Based on this concept a prototype of a small centrifugal pump was manufactured and comprehensively tested. The model pump has been approved in different test series with the fluids liquid ammonia and demineralized water. The design of the model pump was driven by the strict requirements of COLUMBUS, namely long life, noiseless operation, minimum mass and low energy consumption. Because of its modular design and as a result of selected materials of multiple compatibility, this pump is suited for the delivery of various further fluids, such as freons, hydrocarbons, propellants (hydrazine) etc.. It is also capable of pumping corrosive or toxic fluids for laboratory processes in space. The wide speed range from about 1,000 to 20,000 rpm which corresponds to a flow from about 1 to 20 l/min, permits an energy saving adaption and flow control.

For the determination of the solar absorptance αs and the thermal emittance ε preferably optical methods are utilized. To these methods belong spectral reflectance αs and ε measurements and / or emission measurements (only ε), whereby for αs must be measured in the common range 0,3 μm to 2,5 μm and ε in the range 5 μm to 35 μm with an essentially better resolution than 10 nm. Besides so-called integrated reflectance measurements are known, for which special detectors are used, in the above indicated spectral ranges. These optical measuring procedures are relatively exact. They deliver also information about a perhaps spectral selective behavior of surfaces, however, special measuring equipment is required.

Integral black anodizing and gold plating on Mg-Li alloys were developed for spacecraft thermal control applications. The influence of various process conditions have been investigated to optimise the process. The deposits were characterized by morphological studies, adhesion test, thickness measurement, microhardness evaluation and porosity inspection. The space worthiness of the coatings has been evaluated by humidity, thermal cycling, and thermovacuum tests and measurement of optical properties. The high solar absorptance and infrared emittance (αs = 0.95, εIR = 0.93) value of black anodic film showed that these can be effectively utilized to improve heat radiation characteristics. The gold coating on the other hand provides the infrared emittance as low as 0.03, is extremely suitable in minimising the radiative coupling with other components within the spacecraft.

The MELISSA (Microbial Ecological Life Support System Alternative) project, conceived as a microorganism based ecosystem, is an early simplified model of a future biological life support system for manned space missions. The driving element is the recovery of edible biomass from waste, CO2 and minerals with direct use of light as a source of energy for photosynthesis. MELISSA is composed of four axenic compartments colonised by microorganisms and of a fifth compartment that is the crew on board the craft. This paper reports on the solution of mass balances over the entire MELISSA loop. The compartments within MELISSA are first analysed separately, each compartment being described by one or more stoichiometric equations derived from knowledge of the cells metabolic pathways. For each stoichiometric equation a key substrate entering a compartment is assumed to be completely exhausted at the outlet; process kinetics such as rates of biological reactions and mass transfer are ignored.

The NASA Controlled Ecological Life Support System (CELSS) Program has the goal of developing life support systems for humans in space based on the use of higher plants. The program has supported research at universities with a primary focus of increasing the productivity of candidate crop plants. To understand the effects of the space environment on plant productivity, the CELSS Test Facility (CTF) has been developed as an instrument that will permit the evaluation of plant productivity on Space Station Freedom. The CTF will maintain specific environmental conditions and collect data on gas exchange rates and biomass accumulation over the growth period of several crop plants grown sequentially from seed to harvest. To better understand the systems needed to support plants and maintain the environmental conditions required by CTF, an Engineering Development Unit (EDU) is being constructed at NASA Ames Research Center in the Advanced Life Support Division.

This paper describes a newly designed, 2.7 Kg (6 pound) capacity, laundry machine called the Single Phase Space Laundry (SPSL). The machine was designed to wash and dry crew clothing in a micro-gravity environment. A prototype unit was fabricated for NASA-JSC under a Small Business Innovative Research (SBIR) contract extending from September 1990 to January 1993. The unit employs liquid jet agitation, microwave vacuum drying, and air jet tumbling, which was perfected by KC-135 zero-g flight testing. Operation is completely automated except for loading and unloading clothes. The unit uses about 20 percent less power than a conventional household appliance.

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.