Keywords:

Abstract:

Keywords: Muscular strength, weightlessness, astronaut performance, torque

Abstract: Strength, the capability to produce an external force, is one of the most important determining characteristics of human performance. Knowledge of strength capabilities of a group of individuals can be applied to designing equipment and workplaces, planning procedures and tasks, and training individuals. In the space program, with the high risk and cost associated with spaceflight, information pertaining to human performance is important to ensure mission success and safety. Knowledge of individuals' strength capabilities in weightlessness is of interest to NASA, including workplace design, tool development, and mission planning. The weightless environment of space places the human body in a completely different context. Astronauts perform a variety of manual tasks while in orbit. Their ability to perform these tasks is partly determined by their strength capability as demanded by that particular task. An important step in task planning, development, and evaluation is to determine the ability of the humans performing it. This can be accomplished by using quantitative techniques to develop a database of human strength capabilities in weightlessness. If strength characteristics are known, equipment and tools can be built to optimize the operators' performance. There is a spectrum of ways of looking at strength, from basic research to applied engineering. This study examined strength in performing a simple task, specifically, using a tool to apply a torque to a fixture.

Keywords: students, Texas Fly High Program; KC-135 aircraft; weightlessness; vehicle, recovery; Space Station; interactive control; control equipment

Abstract: This report was created by students from Longview High School, Longview, Texas. Longview High School was selected from a group of Texas high schools to participate in the 1999 Texas Fly High Program. This program gives Texas high school students a chance to work with NASA engineers to design and fly a real-world experiment aboard the KC-135 during zero-g parabolas. Jeffrey Fox’s role was to provide a concept for the experiment and to mentor the students in its design and testing. The students were responsible for executing all phases of the project. The X-38 Project Office at the Lyndon B. Johnson Space Center Johnson Space is designing a crew return vehicle (CRV) to be docked at the International Space Station for crew rescue in an emergency. Vehicle controls will be almost completely automated, but a few functions will be manually controlled. Four crew input control devices were selected for evaluation by Longview High School students as part of the 1999 Texas Fly High program. These were (1) Logitech Trackman Marble (optical trackball), (2) Smart Cat Touchpad, (3) Microsoft SideWinder 3D-Pro Joystick, and (4) Microsoft SideWinder Gamepad. In two flight tests in the KC-135 aircraft and a series of ground tests, the devices were evaluated for ability to maneuver an on-screen cursor, level of accuracy, ease of handling blind operations, and level of user comfort in microgravity. The tests results led to recommendation of further tests with the Joystick and the Trackman by astronauts and actual space station residents.

Keywords: orbital debris; space debris; aerogel; orbital debris collector; microscopes; spectroscopy

Abstract: The Mir Environmental Effects Package (MEEP) was deployed on the Mir station and retrieved after 18 months in space. The payload included the orbital debris collector (ODC), designed and built at the Johnson Space Center to capture and return analyzable residues of the manmade and natural particulate environment in low-Earth orbit for a detailed assessment of its compositional makeup and potential origins. The ODC exposed 2 identical trays, with highly porous, low-density Si02 aerogel as the basic collector medium, pointed in opposite directions. The aerogel was expected to gently decelerate and capture hypervelocity particles, as opposed to other media that resulted in melting or vaporization of many impactors. Even cursory examination of the returned ODC collectors revealed a surprising variety of impact features. The compositional analyses using scanning electron microscope-energy-dispersive X-ray spectroscopy concentrated on a survey-type inventory of diverse particle types and associated impact features. Detections, in the form of carrot-shaped tracks and shallow pits, included metallic Al, stainless steel, soldering compounds, human waste, and paint flakes. Many pits contained no detectable impactor residue (it was assumed to have vaporized), but most of the tracks contained analyzable residue. The study showed that aerogel would be useful for future low-velocity impact analysis.

Keywords: decompression sickness, decompression models, survival models, meta-analysis, rapid decompression, aircraft operations

Abstract: Estimating the risk of decompression sickness (DCS) in aircraft operations remains a challenge, making the reduction of this risk through the development of operationally acceptable denitrogenation schedules difficult. In addition, the medical recommendations which are promulgated are often not supported by rigorous evaluation of the available data, but are instead arrived at by negotiation with the aircraft operations community, are adapted from other similar aircraft operations, or are based upon the opinion of the local medical community. We present a systematic approach for defining DCS risk in aircraft operations by analyzing the data available for a specific aircraft, flight profile, and aviator population. Once the risk of DCS in a particular aircraft operation is known, appropriate steps can be taken to reduce this risk to a level acceptable to the applicable aviation community. Using this technique will allow any aviation medical community to arrive at the best estimate of DCS risk for its specific mission and aviator population and will allow systematic reevaluation of the decision regarding DCS risk reduction when additional data are available.

Keywords: solar arrays, plumes, momentum transfer, rarefied gas dynamics

Abstract: Measurements of momentum transfer coefficients were made for gas-surface interactions between the Space Shuttle reaction control jet plume gases and the solar panel array materials to be used on the International Space Station. Actual conditions were simulated using a supersonic nozzle source to produce beams of the gases with approximately the same average velocities as the gases have in the Shuttle plumes. Samples of the actual solar panel materials were mounted on a torsion balance that was used to measure the force exerted on the surfaces by the molecular beams. Measurements were made with H2, N2, CO, and CO2 incident upon the solar array material, Kapton, SiO2-coated Kapton, and Z93-coated Al. The measurements showed that molecules scatter from the surfaces more specularly as the angle of incidence increases and that the scattering behavior has a strong behavior has a strong dependence upon both the incident gas and velocity. These results show that for some technical surfaces the simple assumption of diffuse scattering with complete thermal accommodation is entirely is entirely inadequate. It is clear that additional measurements are required to produce models that more accurately describe the gas-surface interactions encountered in rarefied flow regimes.

Keywords: man environment interactions; environment pollution; space pollution; earth orbital environments; orbital debris; pollution; space debris

Abstract: Before 1990, knowledge of the orbital debris environment could be broken down into 2 size regimes. For low Earth orbiting objects larger than 10-20 cm in diameter, the U.S. Space Command maintains a catalog which includes debris as well as satellites and rocket bodies. The diameter limit is the result of the wavelengths and sensitivities of the radars used. To better characterized the orbital debris environment, NASA began using the DOD-funded Haystack radar; in return, NASA paid for the construction of the Haystack auxiliary radar. The Haystack Orbital Debris Data Review Panel was established in 1996 to consider the adequacy of the data on orbital debris gathered over the past several years with the Haystack radar, and the accuracy of the methods used to estimate the flux vs. size relationship for this debris. This paper discusses specific issues addressed by the Panel, interpretation of these issues, the current status of the measurement and analysis program NASA is conducting, the statistical aspects in use of the Haystack radar data, the Panel's conclusions on these issues, and recommendations.

Keywords: motion, motion perception, perception, control, adaptive control

Abstract: The purpose of this report is to identify the essential characteristics of goal-directed whole-body motion. The report is organized into three major sections. Section 2 reviews general themes from ecological psychology and control-systems engineering that are relevant to the perception and control of whole-body motion. These themes provide an organizational framework for analyzing the complex and interrelated phenomena that are the defining characteristics of whole-body motion. Section 3 applies the organizational framework from the first section to the problem of perception and control of aircraft motion. This is a familiar problem in control-systems engineering and ecological psychology. Section 4 examines an essential but generally neglected aspect of vehicular control: coordination of postural control and vehicular control. To facilitate presentation of this new idea, postural control and its coordination with vehicular control are analyzed in terms of conceptual categories that are familiar in the analysis of vehicular control.

Keywords: seats; levers; spacecraft equipment; spacecraft cabins; spacecraft structures; backrests; resistance; pulling

Abstract: In 1999, a Shuttle crewmember was unable to operate the backrest lever for the lightweight seat in microgravity. It's essential that crewmembers can adjust this backrest lever, which is tilted forward during launch and then moved backward upon reaching orbit. This adjustment's needed to cushion the crew during an inadvertent crash landing situation. JSC's Anthropometric and Biomechanics Facility evaluated the seat controls and provided recommendations on whether the seat lever positions and operations should be modified.The original Shuttle seats were replaced with new lightweight seats whose controls were moved. They designed a 12-person experiment to investigate the amount of pull force exerted by suited subjects, when controls were placed in the front and back of the lightweight seat. Subjects performed the pull test. The results showed that, in general, the subjects were able to pull on the lever at the back position with only about half the amount of force they exerted on the front lever. Also, the subjects wearing pressurized suits were unable to reach the lever when located at the back, and the pull forces diminished about 50% when they wore the pressurized suits. We recommended that levers not be located in the back and that we need further investigation to see whether the front lever could be ajusted to increase the leverage for crewmembers wearing the pressurized suit.

Keywords: data processing; design analysis; factor analysis; postflight analysis; databases; data correlation; data recording; human factors engineering; anomalies; flight optimization; flight safety; adaptive control; systems analysis; data base management system;

Abstract: The space operations incident reporting tool (SOIRT) is an instrument used to record information about an anomaly occurring during flight which may have been due to insufficient and/or inappropriate application of human factors knowledge. Space Shuttle crewmembers participated in a usability test of the tool after missions STS-70 and STS-73. Since NASA currently has no system for continuous collection of this type of information, we developed the SOIRT to report issues such as reach envelope constraints, control operation difficulties, and vision impairments. However, if the SOIRT were to become a formal NASA process, information from crewmembers could be collected in a database and made available to individuals responsible for improving in-flight safety and productivity. Potential benefits include documentation to justify the redesign or development or new equipment or systems, provide the mission planners with a method for identifying past incidents, justify the development of timelines and mission scenarios, and require the creation of more appropriate work and rest cycles.

Keywords: space station; health; space crews; rescue operations; medical equipment; medical sciences; medicine; medical personnel; medical services

Abstract: In developing a permanently crewed space station, the importance of medical care has been continually reaffirmed; and the health maintenance facility (HMF) is an integral component. It has diagnostic, therapeutic, monitoring, and information management capability. It is designed to allow supportive care for non-life-threatening illnesses, moderate to severe, possibly life-threatening illnesses; and severe, incapacitating, life-threatening illnesses. Since the HMF will not have a general surgical capability, the need for emergency escape and recovery methods has been studied. Medical risk assessments have determined that it is impossible to accurately predict the incidence of cremember illness or injury. A best estimate is 1:3 per work-year, with 1 percent of those needing an ACRV. For an eight-person crew, this means that one ACRV will be used every 4 to 12 years. The ACRV would serve atleast three basic objectives as a crew return if the Shuttle is unavailable; an escape vehicle from a major time-critical space station emergency; and a full or partial crew return vehicle for a medical emergency. The focus of this paper is the third objective for the ACRV.

Keywords: fuel, solid fuel, diffusion flame, extinction, gas-phase radiation, kinetics, surface radiation

Abstract: This is the first attempt to analyze both radiation and detailed kinetics on the burning and extinction of a solid fuel in a stagnation-point diffusion flame. We present a detailed and comparatively accurate computation model of a solid fuel flame along with a quantitative study of the kinetics mechanism, radiation interactions, and the extinction limits of the flame. A detailed kinetics model for the burning of solid trioxane (a trimer of formaldehyde) is coupled with a narrowband radiation model with carbon dioxide, carbon monoxide, and water vapor as the gas-phase participating media. The solution of the solid trioxane diffusion flame over the flammable regime is presented in some detail, as this is the first solution of a heterogeneous trioxane flame. We then compare the adiabatic solution to solutions that include the surface radiation only and gas-phase and surface radiation using a black surface model. The analysis includes discussion of detailed flame chemistry over the flammable regime and, in particular, at the low stretch extinction limit. We emphasize the low stretch regime of the radiatively participating flame, since this is the region representative of microgravity flames. When only surface radiation is included, two extinction limits exist, and the burning rate and maximum flame temperatures are lower, as expected. With the inclusion of surface and gas-phase radiation, results show that, while flame temperatures are lower, the burning rate of the trioxane diffusion flame may actually increase at low stretch rate due to radiative feedback from the flame to the surface.

Keywords: Expert Systems, Programming Languages, Computer Techniques

Abstract: Expert systems are computer programs which emulate human expertise in well defined problem domains. The potential payoff from expert systems is high: valuable expertise can be captured and preserved, repetitive and/or mundane tasks requiring human expertise can be automated, and uniformity can be applied in decision making processes. The C Language Integrated Production System (CLIPS) is an expert system building tool, developed at the Johnson Space Center, which provides a complete environment for the development and delivery of rule and/or object based expert systems. CLIPS was specifically designed to provide a low cost option for developing and deploying expert system applications across a wide range of hardware platforms. The development of CLIPS has helped to improve the ability to deliver expert system technology throughout the public and private sectors for a wide range of applications and diverse computing environments. The Third Conference on CLIPS provided a forum for CLIPS users to present and discuss papers relating to CLIPS applications, uses, and extensions.

Keywords: Apollo, Apollo Lunar Experiment Module, reduced gravity, manned lunar surface vehicles, lunar dust, lunar roving vehicles, astronauts, tools

Abstract: This catalog reviews Apollo mission reports, preliminary science reports, technical crew debriefings, lunar surface operations plans, and various relevant lunar experiment documents, collecting engineering- and operation-specific information by experiment. It is organized by discrete experimental and equipment items emplaced or operated on the lunar surface or at zero gravity during the Apollo missions. It also attempts to summarize some of the general problems encountered on the surface and provides guidelines for the design of future lunar surface experiments with an eye toward operations. Many of the problems dealt with on the lunar surface originated from just a few novel conditions that manifested themselves in various nasty ways. Low gravity caused cables to stick up and get caught on feet, and also made it easy for instruments to tip over. Dust was a problem and caused abrasion, visibility, and thermal control difficulties. Operating in a pressure suit limited a person's activity, especially in the hands. I hope to capture with this document some of the lessons learned from the Apollo era to make the jobs of future astronauts, principle investigators, engineers, and operators of lunar experiments more productive.

Keywords: eye movements; image processing; algorithms; eyes; pupils; pupil size; least squares method; centroids;

Abstract: This paper describes a video eye-tracking algorithm which searches for the best fit of the pupil modeled as a circular disk. The algorithm is robust to common image artifacts such as the droopy eyelids and light reflections while maintaining the measurement resolution available by the centroid algorithm. The presented algorithm is used to derive the pupil size and center coordinates, and can be combined with iris-tracking techniques to measure ocular torsion. A comparison search method of pupil candidates using pixel coordinate reference lookup tables optimizes the processing requirements for a least square fit of the circular disk model. This paper includes quantitative analyses and simulation results for the resolution and the robustness of the algorithm. The algorithm presented in this paper provides a platform for a noninvasive, multidimensional eye measurement system which can be used for clinical and research applications requiring the precise recording of eye movements in three-dimensional space.

Keywords: mass; extravehicular activity; postural control; human-environment interactions; nested control systems

Abstract: This report describes the theoretical and operational foundations for our analysis of skill in extravehicular mass handling. A review of our research on postural control, human-environment interactions, and exploratory behavior in skill acquisition is used to motivate our analysis. This scientific material is presented within the context of operationally valid issues concerning extravehicular mass handling. We describe the development of meaningful empirical measures that are relevant to a special class of nested control systems: manual interactions between an individual and the substantial environment. These measures are incorporated into a unique empirical protocol implemented on NASA's principal mass handling simulator, the precision air-bearing floor, in order to evaluate skill in extravehicular mass handling. We discuss the components of such skill with reference to the relationship between postural configuration and controllability of an orbital replacement unit, the relationship between orbital replacement unit control and postural stability, the relationship between antecedent and consequent postural movements. Finally, we describe our expectations regarding the operational relevance of the empirical results as it pertains to extravehicular activity tools, training, monitoring, and planning.

Keywords: mass; extravehicular activity; postural control; human-environment interactions; nested control systems

Abstract: In this report we describe the details of our empirical protocol for investigating skill in extravehicular mass handling using NASA's principal mass handling simulator, the precision air-bearing floor. Contents of this report include a description of the necessary modifications to the mass handling simulator; choice of task; and the description of an operationally relevant protocol. Our independent variables are presented in the context of the specific operational issues they were designed to simulate. The explanation of our dependent variables focuses on the specific data processing procedures used to transform data from common laboratory instruments into measures that are relevant to a special class of nested control systems (discussed in Volume I): manual interactions between an individual and the substantial environment. The data reduction is explained in the context of the theoretical foundation described in Volume I. Finally, as a preface to the presentation of the empirical data in Volume III of this report series, a set of detailed hypotheses is presented.

Keywords: pressure reduction; decompression sickness; hypobaric atmospheres; altitude chamber; tissue ratio; extravehicular activity

Abstract: It is important to understand the risk of serious hypobaric decompression sickness (DCS) to develop procedures and treatment responses to mitigate the risk. Since it is not ethical to conduct prospective tests about serious DCS with humans, the necessary information was gathered from 73 published reports. We hypothesize that a 4-hr 100% oxygen (O2) prebreathe results in a very low risk of serious DCS, and test this through analysis. We evaluated 258 tests containing information from 79,366 exposures in altitude chambers. Serious DCS was documented in 918 men during the tests. A risk function analysis with maximum likelihood optimization was performed to identify significant explanatory variables, and to create a predictive model for the probability of serious DCS. Useful variables were Tissue Ratio, the planned time spent at altitude, and whether or not repetitive exercise was performed at altitude. A prebreathe and decompression profile Shuttle astronauts use for extravehicular activity (EVA) includes a 4-hr prebreathe with 100% O2, an ascent to P2 = 4.3 lb per sq. in. absolute, and a Talt = 6 hr. Given 100 Shuttle EVAs to date and no report of serious DCS, the true risk is less than 0.03 with 95% confidence. It is problematic to estimate the risk of serious DCS since it appears infrequently, even if the estimate is based on thousands of altitude chamber exposures. The true risk to astronauts may lie between the extremes of the confidence intervals since the contribution of other factors, particularly exercise, to the risk of serious DCS during EVA is unknown. A simple model that only accounts for four important variables in retrospective data is still helpful to increase our understanding about the risk of serious DCS.

Keywords: Vlasov-Maxwell Equation; equations; Vlasov Equations; Maxwell Equations; electron distribution; Jacobi Equation; hypergeometric functions

Abstract: A spectral method algorithm is developed for the numerical solution of the full six-dimensional Vlasov-Maxwell system of equations. Here, the focus is on the electron distribution function, with positive ions providing a constant background. The algorithm consists of a Jacobi polynomial-spherical harmonic formulation in velocity space and a trigonometric formulation in position space. A transform procedure is used to evaluate nonlinear terms. The algorithm is suitable for performing moderate resolution simulations on currently available supercomputers for both scientific and engineering applications.

Keywords: histories; documentation; records; simulator; simulation; thermal-vacuum; vacuum; rotation; temperature; mobility; lunar; environment; laboratory

Abstract: Few undertakings in the history of humanity can compare to the great technological achievement known as Project Apollo. Among those who witnessed Armstrong’s flickering television image were thousands of people who had directly contributed to this historic moment. Amongst those in this vast anonymous cadre were the personnel of the Space Environment Simulation Laboratory (SESL) at the Manned Spacecraft Center (MSC) in Houston, Texas. SESL houses two large thermal-vacuum chambers with solar simulation capabilities. At a time when NASA engineers had a limited understanding of the effects of extremes of space on hardware and crews, SESL was designed to literally create the conditions of space on Earth. With interior dimensions of 90 feet in height and a 55-foot diameter, Chamber A dwarfed the Apollo command/service module (CSM) it was constructed to test. The chamber’s vacuum pumping capacity of 1 x 10-6 torr can simulate an altitude greater than 130 miles above the Earth. A lunar plane capable of rotating a 150,000-pound test vehicle 180 deg replicates the revolution of a craft in space. To reproduce the temperature extremes of space, interior chamber walls cool to -280°F as two banks of carbon arc modules simulate the unfiltered solar light/heat of the Sun.With capabilities similar to that of Chamber A, early Chamber B tests included the Gemini modular maneuvering unit, Apollo EVA mobility unit and the lunar module. Since Gemini astronaut Charles Bassett first ventured into the chamber in 1966, Chamber B has assisted astronauts in testing hardware and preparing them for work in the harsh extremes of space.

Keywords: radiation, galactic cosmic rays, fluence, radiation absorption, radiation shielding, radiation transport

Abstract: space radiation transport models for shielding applications. The NASA space radiation transport model now predicts dose and dose equivalent in Earth and Mars orbit to an accuracy of +20%. However, larger error may occur in particle fluence predictions and there is interest in further assessments and improvements in NASA’s space radiation transport model. In this paper we consider the effects of the isotopic composition of the primary galactic cosmic rays (GCR) and the isotopic dependence of nuclear fragmentation cross-sections on the solution to transport models used for shielding studies. Satellite measurements are used to describe the isotopic composition of the GCR. Using NASA’s quantum multiple-scattering theory of nuclear fragmentation (QMSFRG) and high-charge and energy (HZETRN) transport code, we study the effect of the isotopic dependence of the primary GCR composition and secondary nuclei on shielding calculations. The QMSFRG is shown to accurately describe the iso-spin dependence of nuclear fragmentation. The principle finding of this study is that large errors (+100%) will occur in the mass-fluence spectra when comparing transport models that use a complete isotopic-grid (~170 ions) to ones that use a reduced isotopic-grid, for example the 59 ion-grid used in the HZETRN code in the past, however less significant errors (<20%) occur in the elemental-fluence spectra. Because a complete isotopic-grid is readily handled on small computer workstations and is needed for several applications studying GCR propagation and scattering, it is recommended that they be used for future GCR studies.

Keywords: decompression sickness, extravehicular activity, Hypobaric Decompression Sickness Databank, Cox proportional hazards model, censoring, frailty model, model validation

Abstract: In this paper we fit Cox proportional hazards models to a subset of data from the Hypobaric Decompression Sickness Databank. The data bank contains records on the time to decompression sickness (DCS) and venous gas emboli (VGE) for over 130,000 person-exposures to high altitude in chamber tests. The subset we use contains 1,321 records, with 87% censoring, and has the most recent experimental tests on DCS made available from Johnson Space Center. We build on previous analyses of this data set by considering more expanded models and more detailed model assessments specific to the Cox model. Our model, which is stratified on the quartiles of the final ambient pressure at altitude, includes the final ambient pressure at altitude as a nonlinear continuous predictor, the computed tissue partial pressure of nitrogen at altitude, and whether exercise was done at altitude. We conduct various assessments of our model, many of which are recently developed in the statistical literature, and conclude where the model needs improvement. We consider the addition of frailties to the stratified Cox model, but found that no significant gain was attained above a model that does not include frailties. Finally, we validate some of the models that we fit.

Keywords: glovebox, foot restraint, microgravity, posture, restraint, interfaces

Abstract: Various gloveboxes (GBXs) have been used aboard the Shuttle and ISS. Though the overall technical specifications are similar, each GBX's crew interface is unique. JSC conducted a series of ergonomic evaluations of the various glovebox designs to identify human factors requirements for new designs to provide operator commonality across different designs. We conducted 2 0g evaluations aboard the Shuttle to evaluate the material sciences GBX and the General Purpose Workstation (GPWS), and a KC-135 evaluation to compare combinations of arm hole interfaces and foot restraints (flexible arm holes were better than rigid ports for repetitive fine manipulation tasks). Posture analysis revealed that the smallest and tallest subjects assumed similar postures at all four configurations, suggesting that problematic postures are not necessarily a function of the operator’s height but a function of the task characteristics. There was concern that the subjects were using the restrictive nature of the GBX’s cuffs as an upper-body restraint to achieve such high forces, which might lead to neck/shoulder discomfort. EMG data revealed more consistent muscle performance at the GBX; the variability in the EMG profiles observed at the GPWS was attributed to the subjects’ attempts to provide more stabilization for themselves in the loose, flexible gauntlets. Tests revealed that the GBX should be designed for a 95 percentile American male to accommodate a neutral working posture. In addition, the foot restraint with knee support appeared beneficial for GBX operations. Crew comments were to provide 2 foot restraint mechanical modes, loose and lock-down, to accommodate a wide range of tasks without egressing the restraint system. Thus far, we have developed preliminary design guidelines for GBXs and foot restraints.

Keywords: symmetry, transformations, regions, models, robotics, translational motion

Abstract: This paper discusses the problem of automatically generating stable grasp regions for a robotic end effector on a target object, given a model of the end effector and the object. In order to generate grasping regions, an initial valid grasp transformation from the end effector to the object is obtained based on form closure requirements, and appropriate rotational and translational symmetries are associated with that transformation in order to construct a valid, continuous grasping region. The main result of this algorithm is a list of specific, valid grasp transformations of the end effector to the target object, and the appropriate combinations of translational and rotational symmetries associated with each specific transformation in order to produce a continuous grasp region.

Keywords: Hubble Space Telescope, orbital replacement units, extravehicular activity, spacewalks, International Space Station, zero-g environment, PABF, COSTAR, motion analysis

Abstract: The STS-61 mission was for servicing the Hubble Space Telescope (HST), which had been providing valuable information; but modifications were necessary to correct the degraded performance of several components. In addition to servicing orbital replacement units (ORUs), STS-61 crew members replaced the HST solar arrays and performed other maintenance. Without a correction to the optical flaw, usefulness of the HST in the visible light spectrum would have been less than optimal. Also, although NASA had considerable experience in on-orbit extravehicular activities (EVAs), it had never performed such a quantity of complex EVAs as was scheduled for this mission (5 days of EVA and high demands on the crew members and the ground team); it was to be an indication of NASA preparedness to build and maintain a space station. Quality training, therefore, had to be provided so that there were no significant surprises during the tasks of this mission. The purpose of this study was to validate the training techniques for STS-61 crew members in a simulated zero-g environment and to simulate and monitor the reaction of test subjects who were maneuvering the ORU. It was hoped that this study would provide information concerning whether the crew, while moving ORUs, could react to, and counteract comfortably, those forces imparted by the simple motions of mass and inertia. Four subjects participated in our study; tests were conducted on the PABF; mockups were built to simulate the mass characteristics of the COSTAR . Video cameras obtained video data for motion analysis. The main objective of this study was to determine the forces and moments applied and encountered by test subjects during the RMS run start/stop condition.

Keywords: space debris, space pollution

Abstract:

Keywords: carbon nanotubes, scanning electron microscopy, energy-dispersive X-ray spectroscopy, transmission electron microscopy, X-ray diffractometry, thermogravimetric analysis

Abstract: This report summarizes the comparison of a variety of procedures used to purify carbon nanotubes. Carbon nanotube material is produced by the arc process and laser over process. Most of the procedures are tested using laser-grown, single-wall nanotube material. The material is characterized at each step of the purification procedures by using different techniques including a scanning electron microscope, energy-dispersive X-ray spectroscopy, a transmission electron microscopy, Raman, X-ray diffractometry, a thermogravimetric analysis, nuclear magnetic resonance, and high-performance liquid chromatography. The identified impurities are amorphous and grphitic carbon, catalyst particle aggregates, fullerenes, and hydrocarbons. Solvent extraction and low-temperature annealing are used to reduce the amount of volatile hydrocarbons and dissolve fullerenes. Metal catalysts and amorphous as well as graphitic carbon are oxidized by reflux in acids including HCl, HNO3 and HF and other oxidizers such as H2O2. High-temperature annealing in vacuum and in inert atmosphere helps to improve the quality of single-wall nanotubes by increasing crystallinity and reducing intercalation.

Keywords:

Abstract: The White Sands Test Facility (WSTF) government-contractor team began the International Organization for Standardization (ISO) 9001 implementation on October 3, 1994. The team of approximately 550 personnel then received a well-earned certification from the Det Norske Veritas (DNV) organization on October 20, 1995, approximately a year later. This was the first certification of both a National Aeronautics and Space Administration (NASA) installation and joint government-contractor partnership. The NASA Associate Administrator for Safety and Mission Assurance, Frederick Gregory, congratulated the NASA and site support contractor team for earning certification and indicated that WSTF was a benchmark for NASA. In recognition of this unique achievement, Vice President Al Gore’s National Performance Review recognized WSTF for exceptional progress in reinventing government. National Performance Review Project Director Bob Stone presented the prestigious Hammer Award on March 4, 1996. The ISO audit team had only five minor findings in contrast to the 20 to 30 that are usually associated with certification audits. Additionally, the quality system was put in place in a surprisingly short time, considering the magnitude of changes made to the documentation system. Overall, certification of ISO 9001 emphasized WSTF’s commitment to preeminence and demonstrated that the facility is well positioned to perform quality testing for domestic and international government and commercial entities. This document is designed to encourage others to apply the ISO family of standards to their organizations and assist them in their efforts by providing the WSTF certification approach and lessons learned. ISO 9000 background information and WSTF post-certification survey data are included in the attachments. Other helpful references are included in the appendixes.

Keywords: space shuttle missions; Mir Space Station; astronaut performance; astronauts;

Abstract: This report consists of inputs from each of the Phase 1 Program Joint Working Groups. The Working Groups were tasked to describe the organizational structure and work processes that they used during the program, joint accomplishments, lessons learned, and applications to the International Space Station Program. This report is a top-level joint reference document that contains information of interest to both countries.

Keywords: motion, motion perception, perception, control, adaptive control

Abstract: This report reviews the operational demands made of a Shuttle pilot or commander within the context of a proven empirical methodology for describing human sensorimotor performance and whole-body coordination in mechanically and perceptually complex environments. The conclusions of this review pertain to a) methods for improving our understanding of the psychophysics and biomechanics of visual/manual control and whole-body coordination in space vehicle cockpits. b) the application of scientific knowledge about human perception and performance in dynamic inertial conditions to the development of technology, procedures, and training for personnel in space vehicle cockpits. c) recommendations for mitigation of safety and reliability concerns about human performance in space vehicle cockpits. d) in-flight evaluation of flight crew performance during nominal and off-nominal launch and reentry scenarios.

Keywords: Moon, Human Exploration, Lunar Science, Technology Demonstrations, Human Health and Performance, Candidate Sites, Timelines

Abstract: The goals and objectives of future lunar exploration are defined in terms of science, preparation for long-duration stays on the Moon, preparation for human exploration of Mars, exploring the possibility of economic uses of the Moon, and maintaining the health and performance of humans and machines on the Moon. These objectives can be met by carrying out a set of functional activities on the Moon such as scientific field investigations; sample collection and analysis; deployment of surface scientific instruments such as seismometers and telescopes; teleoperation of exploration and technology demonstration systems; intravehicular activity, maintenance and repair; and other activities. These are combined into a set of surface exploration mission options. Short-stay missions (e.g., 4 people for 4 days) that principally address scientific and technology verification are defined for three different types of sites, and long-stay missions (e.g., 4 people for 30 days), which can build up infrastructure for longer duration stays, are defined for two sites, including a south polar site. Representative timelines for crew surface activities are presented.This document is considered to be a snapshot that will be revised as the nature of human lunar missions become better understood.

Keywords: charged coupled devices; debris; space debris; telescopes; Earth orbital environments; geosynchronous orbits; Schmidt cameras; Schmidt telescope

Abstract: NASA has been using the charged coupled device (CCD) debris telescope (CDT)—a transportable 32-cm Schmidt telescope located near Cloudcroft, New Mexico—to help characterize the debris environment in geosynchronous Earth orbit (GEO). The CDT is equipped with a SITe 512 x 512 CCD camera whose 24 m2 (12.5 arc sec) pixels produce a 1.7 x 1.7-deg field of view. The CDT system can therefore detect 17th-magnitude objects in a 20-sec integration corresponding to an ~0.6-m diameter, 0.20 albedo object at 36,000 km. The telescope pointing and CCD operation are computer controlled to collect data automatically for an entire night. The CDT has collected more than 1500 hrs of data since November 1997. This report describes the collection and analysis of 58 nights (~420 hrs) of data acquired in 1998.

Keywords: plasma control; magnetohydrodynamics; plasma turbulence; plasmas (physics); Fourier transformation; Liouville theorem; pseudoscalars; ergodic process

Abstract: Plasmas, such as those found in the space environment or in plasma confinement devices, are often modeled as electrically conducting fluids. When fluids and plasmas are energetically stirred, regions of highly nonlinear, chaotic behavior known as turbulence arise. Understanding the fundamental nature of turbulence is a long-standing theoretical challenge. The present work describes a statistical theory concerning a certain class of nonlinear, finite dimensional, dynamical models of turbulence. These models arise when the partial differential equations describing incompressible, ideal (i.e., non-dissipative) homogeneous fluid and magnetofluid (i.e., plasma) turbulence are Fourier transformed into a very large set of ordinary differential equations. These equations define a divergenceless flow in a high-dimensional phase space, which allows for the existence of a Liouville theorem, guaranteeing a distribution function based on constants of the motion (integral invariants). The novelty of these particular dynamical systems is that there are integral invariants other than the energy, and that some of these invariants behave like pseudoscalars under two of the discrete symmetry transformations of physics, parity and charge conjugation. In this work the "rugged invariants" of ideal homogeneous turbulence are shown to be the only significant scalar and pseudoscalar invariants. The discovery that pseudoscalar invariants cause symmetries of the original equations to be dynamically broken and induce a nonergodic structure on the associated phase space is the primary result presented here. Applicability of this result to dissipative turbulence is also discussed.

Keywords: metamorphism (geology); beds (geology); geology; geomorphology; geophysics;

Abstract: We collected ~ 400 rock chips in continuous vertical profile at Meteor Crater, Arizona, representing - from bottom to top - the Coconino, Toroweap, Kaibab, and Moenkopi Formations to support ongoing compositional analyses of the impact melts and their stratigraphic source depth(s) and other studies at Meteor Crater that depend on the composition of the target rocks. These rock chips were subsequently pooled into 23 samples for compositional analysis by XRF methods, each sample reflecting a specific stratigraphic “subsection” ~ 5-10 m thick. We determined the modal abundance of quartz, dolomite, and calcite for the entire Kaibab Formation at vertical resolutions of 1-2 meters. The Coconino Formation composes the lower half of the crater cavity. It is an exceptionally pure sandstone. The Toroweap is only 2 m thick and compositionally similar to Coconino; therefore, it is not a good compositional marker horizon. The Kaibab Formation is ~ 80 m thick. XRD studies show that the Kaibab Formation is dominated by dolomite and quartz, albeit in highly variable proportions; calcite is a minor phase at best. The Kaibab at Meteor Crater is therefore a sandy dolomite rather than a limestone, consistent with pronounced facies changes in the Permian of SE Arizona over short vertical and horizontal distances. The Moenkopi forms the 12 m thick cap rock and has the highest Al2O3 and FeO concentrations of all target rocks. With several examples, we illustrate how this systematic compositional and modal characterization of the target ideologies may contribute to an understanding of Meteor Crater, such as the depth of its melt zone, and to impact cratering in general, such as the liberation of CO2 from shocked carbonates.

Keywords: Research Projects, Research and Development, NASA Programs, Technology Utilization, Space Technology Experiments

Abstract: Issued as a companion to Johnson Space Center's Research and Technology Annual Report, which reports JSC accomplishments under NASA Research and Technology Operating Plan (RTOP) funding, this report describes 47 additional projects that are funded through sources other than the RTOP. Emerging technologies in four major disciplines are summarized: space systems technology, medical and life sciences, mission operations, and computer systems. Although these projects focus on support of human spacecraft design, development, and safety, most have wide civil and commercial applications in areas such as advanced materials, superconductors, advanced semiconductors, digital imaging, high density data storage, high performance computers, optoelectronics, artificial intelligence, robotics and automation, sensors, biotechnology, medical devices and diagnosis, and human factors engineering.

Keywords: biostimulation; photbiology; laser therapy; nanotechnology; nanobacteria; biomineralization; biofilm; biological systems; molecular; biology

Abstract: The International NASA/DARPA Photobiology Conference held at the Johnson Space Center in Houston/TX demonstrated where low level laser therapy (LLLT), respectively low intensity light activated biostimulation (LILAB) and nanotechnological applications employing photobiomodulation techniques will presumably go in the next ten years. The conference was a continuation of the 1st International Conference on Nearfield Optical Analysis organized by Andrei Sommer (ENSOMA Lab, University of Ulm, Germany) in November 2000 at Castle Reisensburg, Germany, which started with a group of ten scientists from eight different countries. The 2nd conference was co-sponsored by DARPA, NASA-JSC and the Medical College of Wisconsin. The 2nd conference hosted 40 international experts from universities, research institutes, agencies and industry. Materials published here are expected to become milestones forming a novel platform in biomedical photobiology. The multidisciplinary group of researchers focused on LLLT/LILAB-applications under extreme conditions expected to have beneficial effects particularly in space, on submarines, and under severe battlefield conditions. The group also focused on novel technologies with possibilities allowing investigating the interaction of light with biological systems, molecular mechanisms of wound healing, bone regeneration, nerve regeneration, pain modulation, as well as biomineralization and biofilm formation processes induced by nanobacteria. The proceedings of the 2nd NOA, together with the proceedings of the previous meeting held in Germany (Journal of Clinical Laser Medicine & Surgery, 2001, 19, 109-112) demonstrated the synergistic interplay and complementary output of a coherent approach to interrelated scientific questions of excessive clinical relevance, offering results beyond any previous expectation. The 3rd NOA is scheduled for 2002, in Brazil.

Keywords: human factors engineering; spacecraft design; human performance; human tolerances; human behavior; aerospace engineering; long-duration spaceflight; human safety

Abstract: These guidelines and capabilities identify points of intersection between human spaceflight crews and mission considerations such as architecture, vehicle design, technologies, operations, and science requirements. In these pages we provide clear, top-level guidelines for human-related exploration studies and technology research that will address common questions and requirements. The human element is likely the most complex and difficult element of mission design because it significantly influences every aspect of mission planning - from basic parameters, such as duration, to more complex trade-offs including mass, volume, power, risk, and cost. Beyond a cause-and-effect statement, human-driven requirements are highly variable because of destination, operational environment, mission objectives, and more. Often a precise quantification of parameters for a human mission is difficult without further study or arriving at a precise definition of a specific mission architecture. Each mission design requires several iterations as the effects of the crew on the system architecture (and vice versa) coalesce. We thus see this document as a tool that mission designers can use to understand the many trade-offs inherent in planning a human spaceflight mission, with an emphasis on human safety, health, and performance.

Keywords: posture, human body, microgravity, physiological effects, gravitational physiology, human factors engineering

Abstract: Research has shown that the space environment induces physiological changes in the human body, such as fluid shifts in the upper body and chest cavity, spinal lengthening, muscular atrophy, space motion sickness, cardiopulmonary deconditioning, and bone mass loss, as well as some changes in visual perception. These require a period of adaptation and can substantially affect both crew member performance and posture. These physiological effects, when work activities are conducted, have been known to impact the body’s center of gravity, reach, flexibility, and dexterity. All these aspects of posture must be considered to safely and efficiently design space systems and hardware. NASA has documented its microgravity body posture in the Man-Systems Integration Standards (MSIS); the space community uses the MSIS posture to design workstations and tools for space application. However, the microgravity body posture should be further investigated for several reasons, including small sample size in previous studies, possible imprecision, and lack of detail. JSC undertook this study to investigate human body posture exhibited under microgravity conditions. STS-57 crew members were instructed to assume a relaxed posture that was not oriented to any work area or task. Crew members were asked to don shorts and tank tops and to be blindfolded while data were recorded. Video data were acquired once during the mission from each of the six crew members. No one crew member exhibited the typical NBP called out in the MSIS; one composite posture is not adequate. A range of postures may be more constructive for design purposes. Future evaluations should define precise posture requirements for workstation, glove box, maintenance, foot-restraint, and handhold activities.

Keywords: exercise physiology; human body; locomotion; physiological effects; treadmills; physical exercise; contingency

Abstract: The treadmill with vibration isolation system (TVIS) was developed to counteract cardiovascular, musculoskeletal, and neurovestibular deconditioning during long-duration missions to the ISS. However, recent hardware failures have necessitated the development of a short-term, temporary contingency exercise countermeasure for TVIS until nominal operations could be restored. The purpose of our evaluation was twofold: 1) to examine whether a slick-plate/contingency exercise surface (CES) could be used as a walking/running surface and could elicit a heart rate (HR) ³ 70% HR maximum and 2) to determine the optimal hardware configuration, in microgravity, to simulate running/walking in a 1-g environment. One subject participated in the slick surface evaluation and two subjects participated in the microgravity evaluation of the slick surface configuration. During the slick surface evaluation, the subject was suspended in a parachute harness and bungee cord configuration to offset the subject’s body weight. Using another bungee cord configuration, we added a vertical load back to the subject, who was then asked to run for 20 minutes on the slick surface. The microgravity evaluation simulated the ISS TVIS, and we evaluated two different slick surfaces for use as a CES. We evaluated each surface with the subject walking and running, with and without a handrail, and while wearing either socks or nylon booties over shoes. In the slick surface evaluation, the subject ran for 20 minutes and reached a maximum HR of 170 bpm. In the microgravity evaluation, the subjects chose the aluminum plate coated with Tufram as the CES, while wearing a pair of nylon booties over running shoes and using a handrail, as the optimal hardware configuration.

Keywords: orbital debris, meteoroids, hypervelocity impact, shielding, ISS, Shuttle, Orbiter, CONTOUR, impact protection, Hypervelocity Impact Technology Facility

Abstract: This report provides innovative, low-weight shielding solutions for spacecraft and the ballistic limit equations that define the shield's performance in the meteoroid/debris environment. Analyses and hypervelocity impact testing results are described that have been used in developing the shields and equations. Spacecraft shielding design and operational practices described in this report are used to provide effective spacecraft protection from meteoroid and debris impacts. Specific shield applications for the International Space Station (ISS), Space Shuttle Orbiter and the CONTOUR (Comet Nucleus Tour) space probe are provided. Whipple, Multi-Shock and Stuffed Whipple shield applications are described.

Keywords: decompression sickness, extravehicular activity, NASA Decompression Sickness Database, Prebreathe Reduction Protocol Database, spacesuit, venous gas emboli

Abstract: One hundred and three cases of hypobaric decompression sickness (DCS) are documented, with 6 classified as Type II DCS. The presence and grade of venous gas emboli (VGE) are part of the case descriptions. Cases were diagnosed from 731 exposures in 5 different altitude chambers from 4 different laboratories between the years 1982 and 1999. Research was funded by NASA to develop operational prebreathe (PB) procedures that would permit safe extravehicular activity from the Space Shuttle and International Space Station using an extravehicular mobility unit (spacesuit) operated at 4.3 psia. Both vehicles operate at 14.7 psia with an "air" atmosphere, so a PB procedure is required to reduce nitrogen partial pressure in the tissues to an acceptable level prior to depressurization to 4.3 psia. Thirty-two additional descriptions of symptoms that were not diagnosed as DCS together with VGE information are also included. The information for each case resides in logbooks from 32 different tests. Additional information is stored in the NASA Decompression Sickness Database and the Prebreathe Reduction Protocol Database, both maintained by the Environmental Physiology Laboratory at the Johnson Space Center. Both sources were reviewed to provide the narratives that follow.

Keywords: trauma; acute trauma; pulmonary; critical care; ISS; International Space Station

Abstract: The NASA critical path road map identifies “trauma and acute medical problems” as a clinical capability risk category. Specific risks include major trauma, organ laceration or contusion, hemoperitoneum, pulmonary failure, pneumo- and hemothorax, burn, open bone fracture, blunt head trauma, and penetrating injury. Risk mitigation includes capability for critical care monitoring. Currently, the ISS Crew Health Care System does not provide such capability. The Clinical Space Medicine Strategic Planning Forum (1997) identified developing trauma care capabilities as a top priority for space medicine. The Clinical Care Capability Development Project (CCCDP) subsequently undertook the task to address this need. In January 2000, JSC Medical Operations Branch was invited to participate in the RIMPAC 2000/Strong Angel exercise, which involved seven nations and several public health and disaster-response organizations, establishing a 300-person mock refugee camp to simulate mass dislocation due to conflict or natural disaster. A wireless network and satellite system connected the camp to the East Carolina University School of Medicine. One of Strong Angel’s objectives was to build a nomadic computing network matrix to link the 7 countries participating in this exercise through the ECU bridge. Medical Operations personnel used this exercise to evaluate critical care monitors in a real-world telemedicine setting analogous to ISS conditions and to simulate potential ISS medical scenarios. This exercise afforded a unique opportunity to work with commercial vendors and evaluate their leading-edge technology and evaluate the feasibility of treating an astronaut aboard ISS using limited medical resources. These opportunities were consistent with the CCCDP critical path toward enhancing long-term Advanced Life Support System capabilities.

Keywords: microgravity, orthostasis, exercise countermeasures, aerobic exercise, blood pressure, extravehicular activity, EVA

Abstract: The purpose of this study was to determine whether exercise performed by Space Shuttle crewmembers during short-duration spaceflights (9-16 d) affects the heart rate (HR) and blood pressure (BP) responses to standing within 2-4 hr of landing. Thirty crewmembers performed self-selected in-flight exercise and maintained exercise logs to monitor their exercise intensity and duration. A 10-min stand test, preceded by at least 6 min of quiet supine rest, was completed 10-15 d before launch (PRE) and within four hours of landing (POST). Based upon their in-flight exercise records, subjects were grouped as either high (HIex: = 3x/week, HR = 70% HRmax, = 20 min/session, n = 11), medium (MEDex: = 3x/week, HR = 70% HRmax, = 20 min/session, n = 10), or low (LOex: = 3x/week, HR and duration variable, n = 11) exercisers. HR and BP responses to standing were compared between groups (ANOVA, or analysis of variance, P < 0.05). There were no PRE differences between the groups in supine or standing HR and BP. Although POST supine HR was similar to PRE, all groups had an increased standing HR compared to PRE. The increase in HR upon standing was significantly greater after flight in the LOex group (36 ± 5 bpm) compared to HIex or MEDex groups (25 ± 1 bpm; 22 ± 2 bpm). Similarly, the decrease in pulse pressure (PP) from supine to standing was unchanged after spaceflight in the MEDex and HIex groups, but was significantly less in the LOex group (PRE: -9 ± 3; POST: -19 ± 4 mmHg). Thus, moderate to high levels of in-flight exercise attenuated HR and PP responses to standing after spaceflight compared.

Keywords: television cameras; cameras; photographic film; Hasselblad; electronic still camera; camcorder; video recorder; high-definition television; television equipment

Abstract: As part of Detailed Test Objective 700-17A, astronauts acquired Earth observation images from orbit using a high-definition television (HDTV) camcorder. Here we provide a summary of qualitative findings following completion of tests during missions STS (Space Transport System)-93 and STS-99. We compared HDTV imagery stills to images taken using payload bay video cameras, Hasselblad film camera, and electronic still camera. We also evaluated the potential for motion video observations of changes in sunglint and the use of multi-aspect viewing to image aerosols. Spatial resolution and color quality are far superior in HDTV images compared to National Television Systems Committee (NTSC) video images. Thus, HDTV provides the first viable option for video-based remote sensing observations of Earth from orbit. Although under ideal conditions, HDTV images have less spatial resolution than medium-format film cameras, such as the Hasselblad, under some conditions on orbit, the HDTV image acquired compared favorably with the Hasselblad. Of particular note was the quality of color reproduction in the HDTV images. HDTV and electronic still camera (ESC) were not compared with matched fields of view, and so spatial resolution could not be compared for the two image types. However, the color reproduction of the HDTV stills was truer than colors in the ESC images. As HDTV becomes the operational video standard for Space Shuttle and Space Station, HDTV has great potential as a source of Earth-observation data. Planning for the conversion from NTSC to HDTV video standards should include planning for Earth data archiving and distribution.

Keywords: International Space Station; Space Shuttle; Mir; cleaning; cleanliness; zero gravity; showers; human body

Abstract: Note: This document was originally published in 1997 as an International Space University Master of Space Studies student's project. While the specifics may be a little dated, the results gleaned are still relevant and valid. Johnson Space Center is now abuzz with preparations for the International Space Station. The work on various systems for the U.S. Habitation module will begin in 1998. As a prelude, the Flight Crew Support Division perceived the need to take a closer, more critical look at planning the Whole Body Cleansing function for ISS. This report is an attempt to retrieve all data available on whole body cleansing mechanisms used, past and present, by the Russians and the Americans, analyze it and create design concepts for products for zero-g cleansing on ISS. This report takes a close look at the Skylab collapsible shower, the Mir shower/sauna, the full body cleansing methods currently in use on board the Shuttle and Mir, and at the whole body shower designed and tested for Space Station Freedom. It attempts to "listen" carefully to what Mir astronauts have to say about their personal hygiene experiences during their recent stays on Mir. The findings in the report call for a change in paradigm. What is good for Earth conditions is not necessarily good for zero-g! It concludes that a shower is not a good idea for ISS. The final concept that is proposed reflects very strongly what the Mir astronauts would like to have and to use on a station like ISS. The report concludes with directions of how to take the "idea" further and realize it in the form of a product system for whole body cleansing on board ISS.

Keywords: Research Projects, Research and Development, NASA Programs, Technology Utilization, Space Technology Experiments

Abstract: Johnson Space Center research and technology accomplishments during fiscal year 1993 are described and principal researchers and technologists are identified as contacts for further information. Each of the four sections gives a summary of overall progress in a major discipline, followed by detailed, illustrated descriptions of significant tasks. The four disciplines are Life Sciences, Human Support Technology, Solar System Sciences, and Space Systems Technology. The report is intended for technical and management audiences throughout NASA and the worldwide aerospace community. An index lists project titles, funding codes, and principal investigators.

Keywords: manned spaceflight; histories; manned Mars missions; Mars probes; Mars environment; strategy; mission planning; Viking Mars Program

Abstract: The history of human Mars mission planning from the early 1950s through the 1960s is examined. For centuries, Mars has been an object of fascination and, since the 1800s, science fiction authors have imagined what it would be like for humans to travel to that planet. Space enthusiasts have shared this dream and as early as the 1950s were presenting feasible proposals for human missions to Mars. Since the creation of NASA, the Agency has maintained the idea of human Mars missions as an important long-term goal. Throughout its history, NASA has conducted studies aimed at landing an astronaut on Mars. NASA's current strategic plan still includes this goal. Therefore, it is important to look at previous planning efforts to see what work has been accomplished and to discover lessons that future planners can apply to their programs.

Keywords: composite materials; pressure vessel design; pressure vessels; impact damage; materials

Abstract: This document represents efforts accomplished at the NASA Johnson Space Center White Sands Test Facility in support of the Enhanced Technology for Composite Overwrapped Pressure Vessels Program, a joint research and technology effort among the U.S. Air Force, NASA, and the Aerospace Corporation.WSTF performed testing for several facects of the program. Testing that contributed to the Task 3.0 COPV database extension objective included baseline structural strength, failure mode and safe-life, impact damage tolerance, sustained load/impact effect, and materials compatibility. WSTF was also responsible for establishing impact protection and control requirements under Task 8.0 of the program. This included developing a methodology for establishing an impact control plan.Seven test reports detail the work done at WSTF. As such, this document contributes to the database of information regarding COPV behavior that will ensure performance benefits and safety are maintained throughout vessel service life.

Keywords: decompression sickness; doses, biological effects; altitude sickness; decompression; altitude simulation; exercise physiology; extravehicular activity

Abstract: Decompression sickness (DCS) is a complex, multivariable problem. A mathematical description or model of the likelihood of DCS requires a large amount of quality research data, ideas on how to define a decompression dose using physical and physiological variables, and an appropriate analytical approach. It also requires a high-performance computer with specialized software. I have used published DCS data to develop my decompression doses, which are variants of equilibrium expressions for evolved gas plus other explanatory variables. My analytical approach is survival analysis, where the time of DCS occurrence is modeled. My conclusions can be applied to simple hypobaric decompressions - ascents lasting from 5 to 30 minutes - and, after minutes to hours, to denitrogenation (prebreathing). They are also applicable to long or short exposures, and can be used whether the sufferer of DCS is at rest or exercising at altitude. Ultimately I would like my models to be applied to astronauts to reduce the risk of DCS during spacewalks, as well as to future spaceflight crews on the Moon and Mars.

Keywords: plants (botany); plant roots; plant stress; microgravity; porous materials; porosity; microporosity

Abstract: This NASA Technical Memorandum is a compilation of presentations and discussions in the form of minutes from a workshop entitled Plant Production Systems for Microgravity: Critical Issues in Water, Air, and Solute Transport Through Unsaturated Porous Media held at NASA’s Johnson Space Center, July 24-25, 2000. This workshop arose from the growing belief within NASA’s Advanced Life Support Program that further advances and improvements in plant production systems for microgravity would benefit from additional knowledge of fundamental processes occurring in the root zone. The objective of the workshop was to bring together individuals who had expertise in various areas of fluid physics, soil physics, plant physiology, hardware development, and flight tests to identify, discuss, and prioritize critical issues of water and air flow through porous media in microgravity. Participants of the workshop included representatives from private companies involved in flight hardware development and scientists from universities and NASA Centers with expertise in plant flight tests, plant physiology, fluid physics, and soil physics.

Keywords: space missions, anomalies, memory (computers), computer storage devices, integrated

Abstract: This paper describes a Web-based system to support the temporary Anomaly Response Team formed from distributed subteams in Space Shuttle and International Space Station missions. The system was designed for easy and flexible creation of small collections of files and links associated with work on a particular anomaly. The system supports privacy and levels of formality for the subteams. First we describe the supported groups and an anomaly response scenario. Then we describe the support system prototype, the Anomaly Response Tracking and Integration System (ARTIS). Finally, we describe our evaluation approach and the results of the evaluation.

Keywords: aviator decompression sickness, skin mottling, skin bends, bubbles, skin lesion, cutaneous circulation

Abstract: There is disagreement about the pathophysiology, classification, and treatment of cutis marmorata (CM), so there is disagreement about the disposition and medical status of a person that had CM. CM is rare, associated with stressful decompressions, and may be associated with serious signs and symptoms of decompression sickness (DCS). CM presents as purple or bluish-red skin mottling, often in the pectoral region, shoulders, chest, or upper abdomen. It is unethical to induce CM in humans so all information comes from retrospective analysis of case reports, or from animal models. A literature search, seven recent case reports from the Johnson Space Center and Brooks Air Force Base Hypobaric DCS Databases, interviews with DCS treatment experts, and responses to surveys provided the factual information used to arrive at our conclusions and recommendations. The weight of evidence indicates that CM is a local, not centrally mediated or systemic response to bubbles. It is unclear whether obstruction of arterial or venous blood flow is the primary insult since the lesion is reported under either condition. Any neurological or cardiovascular involvements are coincidental, developing along the same time course. The skin could be the source of the bubbles due to its mass, the associated layer of fat, and the variable nature of skin blood flow. CM should not be categorized as Type II DCS, should be included with other skin manifestations in a category called cutaneous DCS, and hyperbaric treatment is only needed if ground level oxygen is ineffective in the case of altitude-induced CM.

Keywords: Antarctic regions, space exploration, Mars surface, planetary environments

Abstract: Four Antarctic explorers were invited to a workshop at Johnson Space Center (JSC) to provide expert assessments of NASA's current understanding of future human exploration missions beyond low Earth orbit. These explorers had been on relatively sophisticated, extensive Antarctic expeditions with sparse or nonexistent support infrastructure in the period following World War II through the end of the International Geophysical Year. Their experience was similar to that predicted for early Mars or other planetary exploration missions. For example: one Antarctic expedition lasted 2 years with only one planned resupply mission and contingency plans for no resupply missions should sea ice prevent a ship from reaching them; several traverses across Antarctica measured more than 1000 total miles, required several months to complete, and were made without maps (because they did not exist) and with only a few aerial photos of the route; and the crews of 6 to 15 were often international in composition. At JSC, the explorers were given tours of development, training, and scientific facilities, as well as documentation of operational scenarios for future planetary exploration. This report records their observations about these facilities and plans in answers to a series of questions provided to them before the workshop.

Keywords: flight control; spacecraft control; reentry vehicles; dynamics; equations of motion; nonlinear equations; control systems design

Abstract: This report addresses issues in developing a flight control design for vehicles operating across a broad flight regime and with highly nonlinear physical descriptions of motion. Specifically it addresses the need for reentry vehicles that could operate through reentry from space to controlled touchdown on Earth. The latter part of controlled descent is achieved by parachute or paraglider or by an automatic or a human-controlled landing similar to that of the Orbiter. Since this report addresses the specific needs of human-carrying (not necessarily piloted) reentry vehicles, it deals with highly nonlinear equations of motion, and their generated control systems must be robust across a very wide range of physics. Thus, this report deals almost exclusively with some form of dynamic inversion (DI). Two vital aspects of control theory noninteracting control laws and the transformation of nonlinear systems into equivalent linear systems are embodied in DI. Though there is no doubt that the mathematical tools and underlying theory are widely available, there are open issues as to the practicality of using DI as the only or primary design approach for reentry vehicles. This report provides a set of guidelines that can be used to determine the practical usefulness of the technique.

Keywords: Time-varying electromagnetic field, rotating wall vessel, three-dimensional culture, neural tissue regeneration

Abstract: The present investigation details the development of model systems for growing two and three-dimensional human neural progenitor cells within a culture medium facilitated by a time-varying electromagnetic field (TVEMF). The cells and culture medium are contained within a two or three-dimensional culture vessel, and the electromagnetic field is emitted from an electrode or coil. These studies further provide methods to promote neural tissue regeneration by means of culturing the neural cells in either configuration. Grown in two-dimensions, neuronal cells extended longitudinally forming tissue strands extending axially along and within electrodes comprising electrically conductive channels or guides through which a time-varying electrical current was conducted. In the three-dimensional aspect exposure to TVEMF resulted in the development of three-dimensional aggregates, which emulated organized neural tissues. In both experimental configurations, the proliferation rate of the TVEMF cells was 2.5 to 4.0 times the rate of the non-waveform cells. Each of the experimental embodiments resulted in similar molecular genetic changes regarding the growth potential of the tissues as measured by gene chip analyses, which measured more than 10,000 human genes simultaneously

Keywords: venous gas emobli; bubbles; decompression sickness; bends; extravehicular activity; goodness of fit; accuracy, predictive; random effects; distribution, lognormal

Abstract: Venous gas emboli (VGE) (gas bubbles in venous blood) are associated with an increased risk of decompression sickness (DCS) in hypobaric environments. A high grade of VGE can be a precursor to serious DCS. In this paper, we model time to Grade IV VGE considering a subset of individuals assumed to be immune from experiencing VGE. Our data contain monitoring test results from subjects undergoing up to 13 denitrogenation test procedures prior to exposure to a hypobaric environment. The onset time of Grade IV VGE is recorded as contained within certain time intervals. We fit a parametric (lognormal) mixture survival model to the interval- and right-censored data to account for the possibility of a subset of cured individuals who are immune to the event. Our model contains random subject effects to account for correlations between repeated measurements on a single individual. Model assessments and cross-validation indicate that this limited failure population mixture model is an improvement over a model that does not account for the potential of a fraction of cured individuals. We also evaluated some alternative mixture models. Predictions from the best fitted mixture model indicate that the actual process is reasonably approximated by a limited failure population model.

Keywords: Research and Development, Technology Transfer, Discretionary Fund, NASA Programs, Space Technology Experiments

Abstract: As an independent research medium, the Johnson Space Center Director's Discretionary Fund often initiates investigations of significant value to NASA with eventual application to commercial uses. The projects provide technical support to the NASA mission and development opportunities for the science and engineering staff. Thirty-six projects were supported from the $1,779,000 in FY93 funds. Some notable projects that made outstanding progress and produced significant results: multilayer microspheres of medication were processed in microgravity; virtual environment techniques were used for visualization of repair tasks and training in the successful repair of the Hubble Space Telescope; a prototype axial flow pump for heart ventricle assist was demonstrated in a calf implant; the electronic still camera rapidly transmitted high resolution images from the Space Shuttle; water was obtained from a lunar soil sample and from lunar soil simulant, confirming a patented oxygen extraction process; a regenerative water recovery system was demonstrated; patent disclosures were made on a dried blood sampling method.

Keywords: Radiation Hazards, Planetary Environments, Cancer, Space Exploration, Risk

Abstract: In this paper we discuss expected lifetime excess cancer risks for astronauts returning from exploration class missions. For the first time we make a quantitative assessment of uncertainties in cancer risk projections for space radiation exposures. Late effects from the high charge and energy (HZE) ions present in the galactic cosmic rays including cancer and the poorly undersood risks to the central nervous system constitute the major risks. Methods used to project risk in low Earth orbit are seen as hightly uncertain for projecting risks on exploration missions because of the limted radiobiology data available for estimating HZE ion risks. Cancer risk projections are described as a product of many biological and physical factors, each of which has a differential range of uncertainty due to lack of data and knowledge. Monte-Carlo sampling from subjective error distributions represents the lack of knowledge in each factor to quantify risk projection overall uncertainty. Cancer risk analysis is applied to several exploration mission scenarios. At solar minimum, the number of days in space where career risk of less than the limiting 3% excess cancer mortality can be asssured at a 95% confidence level is found to be only of the order of 100 days.

Keywords: computer programming; computer modeling; orbital debris; space debris; population modeling; low Earth orbit; collision risk; risk assessment

Abstract: The NASA Orbital Debris Program Office at Johnson Space Center has developed a new computer-based orbital debris engineering model, ORDEM2000, which describes the orbital debris environment in the low Earth orbit region between 200 and 2000 km altitude. The model is appropriate for those engineering solutions requiring knowledge and estimates of the orbital debris environment (debris spatial density, flux, etc.). ORDEM2000 can also be used as a benchmark for ground-based debris measurements and observations. We incorporated a large set of observational data, covering the object size range from 10 mm to 10 m, into the ORDEM2000 debris database, utilizing a maximum likelihood estimator to convert observations into debris population probability distribution functions. These functions then form the basis of debris populations. We developed a finite element model to process the debris populations to form the debris environment. A more capable input and output structure and a user-friendly graphical user interface are also implemented in the model. ORDEM2000 has been subjected to a significant verification and validation effort.This document describes ORDEM2000, which supersedes the previous model, ORDEM96. The availability of new sensor and in situ data, as well as new analytical techniques, has enabled the construction of this new model. Section 1 describes the general requirements and scope of an engineering model. Data analyses and the theoretical formulation of the model are described in Sections 2 and 3. Section 4 describes the verification and validation effort and the sensitivity and uncertainty analyses. Finally, Section 5 describes the graphical user interface, software installation, and test cases for the user.

Keywords: ultrasound; video data; video equipment; video tape recorders; echocardiography; sonography; Doppler; field rate; MPEG; resolution; radiology; analog; digital

Abstract: Most medical equipment on the International Space Station (ISS) is manifested as part of the U.S. or the Russian medical hardware systems. However, certain medical hardware is also available as part of the Human Research Facility. The HRF and the JSC Medical Operations Branch established a Memorandum of Agreement for joint use of certain medical hardware, including the HRF ultrasound system, the only diagnostic imaging device currently manifested to fly on ISS. The outcome of a medical contingency may be changed drastically, or an unnecessary evacuation may be prevented, if clinical decisions are supported by timely and objective diagnostic information. In many higher-probability medical scenarios, diagnostic ultrasound is a first-choice modality or provides significant diagnostic information. Accordingly, the Clinical Care Capability Development Project is evaluating the HRF ultrasound system for its utility in relevant clinical situations on board ISS. For effective management of these ultrasound-supported ISS medical scenarios, the resulting data should be available for viewing and interpretation on the ground, and bidirectional voice communication should be readily available to allow ground experts (sonographers, physicians) to provide guidance to the Crew Medical Officer. It may also be vitally important to have the capability of real-time guidance via video uplink to the CMO-operator during an exam to facilitate the diagnosis in a timely fashion. In this document, we strove to verify that the HRF ultrasound video output is compatible with the ISS video system, identify ISS video system field rates and resolutions that are acceptable for varying clinical scenarios, and evaluate the HRF ultrasound video with a commercial, off-the-shelf video converter, and compare it with the ISS video system.

Keywords: hydrogen, combustion, flammability, detonation, fire, slush, hazards, hydrogen embrittlement, hazards analysis

Abstract: The physical and combustion properties of hydrogen give rise to hazards that one must consider when designing and operating a hydrogen system. One of the major concerns is fire or detonation because of hydrogen’s wide flammability range, low ignition energy, and flame speed. Other concerns include contact and interaction with materials, such as the hydrogen embrittlement of materials and the formation of hydrogen hydrides. The low temperature of liquid and slush hydrogen bring other concerns related to material compatibility and pressure control; this is especially important when dissimilar, adjoining materials are involved. The potential hazards arising from these properties and design features necessitate a proper hydrogen hazards analysis before introducing a material, component, or system into hydrogen service. The objective of this guide is to describe the NASA Johnson Space Center White Sands Test Facility hydrogen hazards analysis method one should perform before hydrogen is used in components and/or systems. The method is consistent with standard practices for analyzing hazards. It is recommended that this analysis be made before implementing a hydrogen component qualification procedure. A hydrogen hazards analysis is a useful tool for hydrogen-system designers, system and safety engineers, and facility managers. A hydrogen hazards analysis can identify problem areas before hydrogen is introduced into a system, preventing damage to hardware, delay or loss of mission or objective, and possible injury or loss of life. This guide is based on information from the NASA Safety Standard for Hydrogen and Hydrogen Systems (NSS 1740.16) and experience derived from the development of a similar protocol for oxygen system hazards analysis. It was previously published as TP-WSTF-937

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: radiation, shielding, space suit, electrons, space radiation, anisotropy, radiation damage, radiation protection, albedo, EMU, low Earth orbit

Abstract: This publication describes recent investigations that evaluate radiation shielding characteristics of NASA’s and the Russian Space Agency’s space suits. The Introduction describes the suits and presents goals of several experiments performed with them. The first chapter provides background information about the dynamic radiation environment experienced at ISS and summarizes radiation health and protection requirements for activities in low Earth orbit. Supporting studies report the development and application of a computer model of the EMU space suit and the difficulty of shielding EVA crewmembers from high-energy reentrant electrons, a previously unevaluated component of the space radiation environment. Chapters 2 through 6 describe experiments that evaluate the space suits' radiation shielding characteristics. Chapter 7 describes a study of the potential radiological health impact on EVA crewmembers of two virtually unexamined environmental sources of high-energy electrons - reentrant trapped electrons and atmospheric albedo or “splash” electrons. The radiological consequences of those sources have not been evaluated previously and, under closer scrutiny. A detailed computational model of the shielding distribution provided by components of the NASA astronauts’ EMU is being developed for exposure evaluation studies. The model is introduced in Chapters 8 and 9 and used in Chapter 10 to investigate how trapped particle anisotropy impacts female organ doses during EVA. Chapter 11 presents a review of issues related to estimating skin cancer risk from space radiation. The final chapter contains conclusions about the protective qualities of the suit brought to light from these studies, as well as recommendations for future operational radiation protection investigations and practices. The recent programmatic focus on radiation protection for EVA exposures is only one component of the NASA Space Radiation Health Project Office’s proactive management of radiation protection for human activities in space. Ionizing radiation exposures to long-term ISS crewmembers are increased by a factor of ~10 or more above typical Space Shuttle experiences, and it is quite possible that some individuals will receive doses that will restrict their time allowed on EVA or on orbit. Anticipation of these events prompted programmatic reviews and development of improved technologies and new procedures for the radiation mission support team, including near-real-time space weather monitoring, information analysis, integration, and reporting to flight surgeons and mission controllers. New research and dosimetry technologies and skills acquired by the NASA Space Radiation Health Project Office and its supporting research programs include improved spacecraft environmental and personnel dosimetry, improved ground-based physics and radiation transport models, leading-edge radiobiology studies of the deleterious effects of space-like ionizing radiation fields, and broadening and deepening investigations of risk analysis.