Keywords: fluid dynamics analysis; static culture system; computational fluid dynamics; fluid mechanics
Abstract: This report is a documentation of a fluid dynamic analysis of the proposed Automated Static Culture System cell module mixing protocol. The report consists of a review of some basic fluid dynamics principles appropriate for the mixing of a patch of high oxygen content media into the surrounding media which is initially depleted of oxygen, followed by a computational fluid dynamics study of this process for the proposed protocol over a range of the governing parameters. The time histories of oxygen concentration distributions and mechanical shear levels generated are used to characterize the mixing process for different parameter values.
Keywords: sustainability, resources, environment, climate change, energy, waste, energy sources, solar energy, ozone, deforestation, EPA, food chain, photovoltaics, landfills
Abstract: Key environmental issues are affecting our lives more and more every day. Resources are threatened in various ways and we produce increasing amounts of waste. Spaceship Earth must address similar challenges to life support systems on extended-duration spacecraft, but on a much different scale. Issues such as declining biodiversity, ozone depletion, and climate change show us that the Earth’s natural reserves are not infinite either. Our choice of energy sources is expected to be one of the most important decisions that global society will make over the next half century. While the concept is not new, there is a renewed realization that our business practices and our lifestyles must be sustainable in order to last. Simply put, sustainability is development that meets the needs of present generations without compromising the ability of future generations to meet their own needs.NASA scientists and many others are contributing to the growing knowledge of our Earth and its ecosystems. Satellites measure sea level rise, and changes in vegetation and air pollutants that travel between countries and continents. The U.S. federal government seeks to be a leader in environmental sustainability efforts through various Executive Orders and policies that save energy, reduce waste, and encourage less reliance on oil as an energy source. NASA, as an agency that is by nature focused on the future, has much to contribute to these efforts. Pollution prevention, affirmative procurement and sustainable design are all programs that are under way at NASA. But more can be done. By sharing ideas and learning from other organizations as well as from the talented workforce we are a part of, JSC can improve its sustainability performance and spread the benefits to our community.
Keywords: mechanisms, deployment, tribology, actuators, optical, Rover,
Abstract: The Aerospace Mechanisms Symposium (AMS) provides a unique forum for those active in the design, production and use of aerospace mechanisms. A major focus is reporting problems and solutions associated with the development and flight certification of new mechanisms. Organized by the Mechanisms Education Association, NASA and Lockheed Martin Space Systems Company (LMSSC) share the responsibility for hosting the AMS. Now in its 37th symposium, the AMS continues to be well attended, attracting participants from both the U.S. and abroad. The 37th AMS, hosted by the Johnson Space Center (JSC) in Galveston, Texas, was held May 19, 20 and 21, 2004. During these three days, 34 papers were presented. Topics included deployment mechanisms, tribology, actuators, pointing and optical mechanisms, Space Station and Mars Rover mechanisms, release mechanisms, and test equipment. Hardware displays during the supplier exhibit gave attendees an opportunity to meet with developers of current and future mechanism components.
Keywords: metric, budget, equivalent system mass,
Abstract: This document provides the official calculation of the Advanced Life Support (ALS) Research and Technology Development Metric (the Metric) for Fiscal Year 2003. As such, the values herein are primarily based on Systems Integration, Modeling, and Analysis (SIMA) Element approved software tools or reviewed and approved reference documents.The Metric is one of several measures employed by the National Aeronautics and Space Administration (NASA) to assess the Agency’s progress as mandated by the United States Congress and the Office of Management and Budget. Because any measure must have a reference point, whether explicitly defined or implied, the Metric is a comparison between a selected ALS Project life support system and an equivalently detailed life support system using technology from the Environmental Control and Life Support System (ECLSS) for the International Space Station (ISS). More specifically, the Metric is the ratio defined by the equivalent system mass (ESM) of a life support system for a specific mission using the ISS ECLSS technologies divided by the ESM for an equivalent life support system using the “best” ALS technologies.As defined, the Metric should increase in value as the ALS technologies become lighter, less power intensive, and require less volume. For Fiscal Year 2003, the Advanced Life Support Research and Technology Development Metric value is 1.47 for an Orbiting Research Facility and 1.36 for an Independent Exploration Mission.
Keywords: contamination; lunar rocks; lunar programs; manned space flight; Apollo 11; lunar receiving laboratory; test facilities; laboratory equipment; decontamination
Abstract: As early as 1959, the Working Group on Lunar Exploration within NASA advocated that "one of the prime objectives of the first lunar landing mission should be the collection of samples for return to Earth, where they could be subjected to detailed study and analysis." Within NASA, neither this group nor any other scientists working with the Agency were concerned about back contamination issues. Outside of NASA, back contamination concerns had been raised as early as 1960. Although NASA did not seem to pay any attention to the concerns at that time, the scientific community continued to be interested in the topic. In 1962 and again in 1963, as the Apollo Program loomed large, further discussions were held. These early discussions of back contamination did not make their way into NASA's administration, however, and when Manned Spacecraft Center personnel began to articulate early concepts for the Lunar Receiving Laboratory (LRL), the back contamination issue was not considered. Once this concern became a major focus, however, the LRL's development became increasingly complex. This is the history of that development.
Keywords: extravehicular activity, EVA, space suit
Abstract: This report documents the results of a study carried out as part of NASA’s Revolutionary Aerospace Systems Concepts Program examining the future technology needs of extravehicular activities (EVAs). The intent of this study is to produce a comprehensive report that identifies various design concepts for human-related advanced EVA systems necessary to achieve the goals of supporting future space exploration and development customers in free space and on planetary surfaces for space missions in the post-2020 timeframe. The design concepts studied and evaluated are not limited to anthropomorphic space suits, but include a wide range of human-enhancing EVA technologies as well as consideration of coordination and integration with advanced robotics. The goal of the study effort is to establish a baseline technology "road map" that identifies and describes an investment and technical development strategy, including recommendations that will lead to future enhanced synergistic human/robot EVA operations. The eventual use of this study effort is to focus evolving performance capabilities of various EVA system elements toward the goal of providing high-performance human operational capabilities for a multitude of future space applications and destinations.The data collected for this study indicate a rich and diverse history of systems that have been developed to perform a variety of EVA tasks, indicating what is possible. However, the data gathered for this study also indicate a paucity of new concepts and technologies for advanced EVA missions - at least any that researchers are willing to discuss in this type of forum.
Keywords: exercise, thermal, heat production, resistive exercise, resting metabolism, aerobic exercise, interval, exercise protocol, exercise countermeasures
Abstract: This investigation’s purpose was to determine the amount of heat produced when performing aerobic and resistance exercises planned as part of the exercise countermeasures prescription for the ISS. These data will be used to determine thermal control requirements of the Node 1 and other modules where exercise hardware might reside. To determine heat production during resistive exercise, 6 subjects using the iRED performed 5 resistance exercises which form the core exercises of the current ISS resistive exercise countermeasures. Each exerciser performed a warm-up set at 50% effort, then 3 sets of increasing resistance. We measured oxygen consumption and work during each exercise. Heat loss was calculated as the difference between the gross energy expenditure (minus resting metabolism) and the work performed. To determine heat production during aerobic exercise, 14 subjects performed an interval, cycle exercise protocol and 7 subjects performed a continuous, treadmill protocol. Each 30-min. exercise is similar to exercises planned for ISS. Oxygen consumption monitored continuously during the exercises was used to calculate the gross energy expenditure. For cycle exercise, work performed was calculated based on the ergometer’s resistance setting and pedaling frequency. For treadmill, total work was estimated by assuming 25%work efficiency and subtracting the calculated heat production and resting metabolic rate from the gross energy expenditure. This heat production needs to be considered when determining the location of exercise hardware on ISS and designing environmental control systems. These values reflect only the human subject’s produced heat; heat produced by the exercise hardware also will contribute to the heat load.
Keywords: man in the loop test; interim resistance exercise device; International Space Station; exercise; resistance exercise
Abstract: The Interim Resistance Exercise Device (iRED), developed for the International Space Station (ISS), was evaluated using human subjects for a “Man-In-The-Loop Test” (MILT). Thirty-two human subjects exercised using the iRED in a test that was conducted over a 63-working-day period. The subjects performed the same exercises that will be used on board ISS, and the iRED operating constraints that are to be used on ISS were followed. In addition, eight of the subjects were astronauts who volunteered to be in the evaluation in order to become familiar with the iRED and provide a critique of the device. The MILT was scheduled to last for 57,000 exercise repetitions on the iRED. This number of repetitions was agreed to as a number typical of that expected during a 3-person, 17-week ISS Increment. One of the canisters of the iRED failed at the 49,683-repetition mark (87.1% of targeted goal). The remaining canister was operated using the plan for operations if one canister fails during flight (contingency operations). This canister remained functional past the 57,000-repetition mark. This report details the results of the iRED MILT, and lists specific recommendations regarding both operation of the iRED and future resistance exercise device development.
Keywords: interim resistance exercise device; International Space Station; exercise; resistance exercise, ground reaction force, unloading
Abstract: Musculoskeletal unloading in microgravity has been shown to induce losses in bone mineral density, muscle cross-sectional area, and muscle strength. Currently, an Interim Resistive Exercise Device (iRED) is being flown on board the ISS to help counteract these losses. Free weight training has shown successful positive musculoskeletal adaptations. In biomechanical research, ground reaction forces (GRF) trajectories are used to define differences between exercise devices. The purpose of this evaluation is to quantify the differences in GRF between the iRED and free weight exercise performed on a Smith machine during a squat. Due to the differences in resistance properties, inertial loading and load application to the body between the two devices, we hypothesize that subjects using iRED will produce GRF that are significantly different from the Smith machine. There will be differences in bar/harness range of motion and the time when peak GRF occurred in the ROMbar. Three male subjects performed three sets of ten squats on the iRED and on the Smith Machine on two separate days at a 2-second cadence. Statistically significant differences were found between the two devices in all measured GRF variables. Average Fz and Fx during the Smith machine squat were significantly higher than iRED. Average Fy (16.82 ± 6.23; p < .043) was significantly lower during the Smith machine squat. The mean descent/ascent ratio of the magnitude of the resultant force vector of all three axes for the Smith machine and iRED was 0.95 and 0.72, respectively. Also, the point at which maximum Fz occurred in the range of motion (Dzpeak) was at different locations with the two devices.
Keywords: sun; solar cycles; sunspots; solar radiation; solar maximum; radiation absorption; radiation dosage; radiation effects; radiation
Abstract: Since the current solar cycle 23 has progressed near the end of the cycle and accurate solar minimum and maximum occurrences have been defined, a statistical model based on the odd-even behavior of historical sunspot cycles was reexamined. Separate calculations of activity levels were made for the rising and declining phases in solar cycle 23, which resulted in improved projection of sunspots in the remainder of cycle 23. Because a fundamental understanding of the transition from cycle to cycle has not been developed, at this time it is assumed for project purposes that solar cycle 24 will continue at the same activity level in the declining phase of cycle 23. Projection errors in solar cycle 24 can be corrected as the cycle progresses and observations become available because this model is shown to be self-correcting.
Keywords: life support system; life support system, environments; environmental control; systems integration
Abstract: The Metric is one of several measures employed by the NASA to assess the Agency’s progress as mandated by the United States Congress and the Office of Management and Budget. Because any measure must have a reference point, whether explicitly defined or implied, the Metric is a comparison between a selected ALS Project life support system and an equivalently detailed life support system using technology from the Environmental Control and Life Support System (ECLSS) for the International Space Station (ISS). This document provides the official calculation of the Advanced Life Support (ALS) Research and Technology Development Metric (the Metric) for Fiscal Year 2004. The values are primarily based on Systems Integration, Modeling, and Analysis (SIMA) Element approved software tools or reviewed and approved reference documents. For Fiscal Year 2004, the Advanced Life Support Research and Technology Development Metric value is 2.03 for an Orbiting Research Facility and 1.62 for an Independent Exploration Mission.
Keywords: systems analysis; analogs; life support systems; human factors engineering;
Abstract: The Advanced Life Support (ALS) Baseline Values and Assumptions Document (BVAD) provides analysts and modelers as well as other ALS researchers with a common set of initial values and assumptions called a baseline. This baseline provides a common point of origin from which all systems integration, modeling, and analysis element studies will depart. The BVAD identifies quantities that define life support systems from an analysis and modeling perspective; provides a nominal or baseline value plus a range of possible or observed values for each physical quantity identified; and documents each entry with a description of the use, value selection rationale, and appropriate references of that quantity. Specifically, the BVAD allows the life support analysis community to carefully review and evaluate input study assumptions. Each study can benefit from the "best" available input values and assumptions by drawing on information collected by a group of researchers rather than an individual researcher. The BVAD process identifies quantities that are not well-defined by current information, allows researchers from multiple disciplines to effectively and quickly compare results from multiple studies, and allows these researchers to conduct a follow-on study to any previous work because assumptions from each study are clearly available and carefully recorded.
Keywords: decompression sickness, ergometer, exercise physiology,
Abstract: Exercise PB can reduce the risk of decompression sickness on ascent to 4.3 psia when performed at the proper intensity and duration. Data are from seven tests. PB times ranged from 90 to 150 min. High intensity, short duration dual-cycle ergometry was done during the PB. This was done alone, or combined with intermittent low intensity exercise or periods of rest for the remaining PB. Non-ambulating men and women performed light exercise from a semi-recumbent position at 4.3 psia for four hrs. The Research Model with age tested the probability that DCS increases with advancing age. The NASA Model with gender hypothesized that the probability of DCS increases if gender is female. Accounting for exercise and rest during PB with a variable half-time compartment for computed tissue N2 pressure advances our probability modeling of hypobaric DCS. Both models show that a small increase in exercise intensity during PB reduces the risk of DCS, and a larger increase in exercise intensity dramatically reduces risk. These models support the hypothesis that aerobic fitness is an important consideration for the risk of hypobaric DCS when exercise is performed during the PB.
Keywords: near infrared sprectroscopy, elevated skin blood flow, supine rest, NIRS, SBF, sketal muscle, LDV, NIRD
Abstract: Near infrared spectroscopy is a non-invasive technique that allows determination of tissue oxygenation/blood flow based on spectro-photometric quantitation of oxy- and deoxyhemoglobin present within a tissue. This technique has gained acceptance as a means of detecting and quantifying changes in tissue blood flow due to physiological perturbation, such as that which is elicited in skeletal muscle during exercise. Since the NIRS technique requires light to penetrate the skin and subcutaneous fat in order to reach the muscle of interest, changes in skin blood flow may alter the NIRS signal in a fashion unrelated to blood flow in the muscle of interest. The aim of this study was to determine the contribution of skin blood flow to the NIRS signal obtained from resting vastus lateralis muscle of the thigh.
Keywords: heat transfer; temperature distribution; body temperature; heat stress; liquid-cooling garment; reentry; cabin temperature; skin temperature
Abstract: Current flight rules restrict maximum cabin temperature during reentry and landing to protect crewmembers from heat stress. Cabin temperature is affected by the amount of hardware in operation during these activities. To allow for additional operations, the maximum cabin temperature limit must be raised. Crewmembers wear a liquid-cooling garment (LCG) under their Suit during reentry and landing to protect against heat stress. The purpose of our project was to determine whether the LCG could adequately cool when cabin temperature was allowed to reach 80°F. Eight subjects underwent a simulated cabin temperature profile in an environmental chamber. Subjects completed a 10-minute stand test as an assessment of orthostatic tolerance before and after the chamber stay. The secondary objective was to determine whether there was a graded effect of cabin temperatures when the maximums were 75, 80, and 85F. Four suited subjects underwent the simulated temperature profile at these temperatures. Ratings were measured in 15-minute intervals on a 10-minute stand test. No discernible pattern was observed in core or skin temperatures. There appeared to be higher subjective ratings of comfort and heat across the temperature profiles. However, the subjects were able to control sufficiently their body temperatures with self-selected flow rates during these tests.
Keywords: Cosmic Dust, particles, interplanetary dust, luster, size, shape, transparence, color.
Abstract: Since May 1981, NASA has used aircraft to collect cosmic dust particles from Earth’s stratosphere. Specially designed dust collectors are prepared for flight and processed after flight in an ultraclean (class-100) laboratory constructed for this purpose at the Lyndon B. Johnson Space Center in Houston, Texas. Particles are individually retrieved from the collectors, examined and cataloged, and then made available to the scientific community for research. Cosmic dust thereby joins lunar samples and meteorites as an additional source of extraterrestrial materials for scientific study. This catalog summarizes preliminary observations on particles retrieved from many collection surfaces. These surfaces were flat plate collectors, which were coated with silicone oil (dimethyl siloxane) and then flown aboard NASA U-2, ER-2 and WB-57F aircraft. All of the collectors were installed in specially constructed wing pylons which ensured that the necessary level of cleanliness was maintained between periods of active sampling. During successive periods of high altitude (20 km) cruise, the collectors were exposed in the stratosphere by barometric controls and then retracted into sealed storage containers prior to descent. This catalog does not describe new particles; rather, we have revisited all previous catalogued cluster particles, and ascertained how much of each remains for allocation. http://www-curator.jsc.nasa.gov/curator/dust/cdcat16/index.htm
Keywords: extravehicular mobility unit; extravehicular activity; spacesuits; training analysis; symptomology; injuries, impairment; injuries, systems engineering
Abstract: The purpose of this study was to characterize the symptoms and injuries experienced by NASA astronauts during extravehicular activity (space walk) spacesuit training at the Neutral Buoyancy Laboratory at Ellington Field, Houston, Texas. We identified the frequency and incident rates of symptoms by each general body location and characterized mechanisms of injury and effective countermeasures. Based on these findings a comprehensive list of recommendations was made to improve training, test preparation, and current spacesuit components, and to design the next-generation spacesuit. At completion of each test event a comprehensive questionnaire was produced that documented suit symptom comments, identified mechanisms of injury, and recommended countermeasures. As we completed our study we found that most extravehicular mobility unit suit symptoms were mild, self-limited, and controlled by available countermeasures. Some symptoms represented the potential for significant injury with short- and long-term consequences regarding astronaut health and inteference with mission objectives. The location of symptoms and injuries that were most clinically significant was in the hands, shoulders, and feet. Correction of suit symptoms issues will require a multidisciplinary approach to improve prevention, early medical intervention, astronaut training, test planning, and suit engineering.
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