Keywords: long duration spaceflight; astronaut performance; astronaut training; human performance, depression; psychological factors
Abstract: The aim of this report is to address a recommendations made by the NASA Human Research Program Standing Review Panel that the “literature on asthenia should be evaluated (possibly as a psychological or psychosomatic/psycho-physiological analogue of chronic fatigue syndrome)”, in addition to General Recommendation 4, which states that “all reviews must include non-English language materials as well as materials appearing in conferences reports, books, and other non-refereed journal outlets”. This report was a collaborative international work effort focused on the evaluation and determination of the importance of continuing research on asthenia as a possible psychological problem that might affect the optimal psychological functioning of crew members during long-duration space flight missions. This report describes the definitions of asthenia that exist by examining the current literature on this topic, then summarizes interviews that were conducted to represent the different multicultural perspectives of this issue. Conclusions and recommendations specific to both the literature review and the interviews are then discussed.
Keywords: long duration space flight; medical personnel; physicians; flight surgeons; manned Mars missions
Abstract: As NASA and its international partners plan for manned interplanetary space exploration missions, the question of how to provide optimum medical care during long-duration space flight becomes increasingly relevant. In the history of human exploration, disease, injury, and the limitations of human physiology have accounted for more losses than other factors, including technological failures. Most published literature on the subject of the medical requirements for a manned expedition to Mars assumes at least one, if not two, physician-astronaut crewmembers. However, a 2008 NASA ad hoc committee of flight surgeons and space medicine experts observed, “Any additional capability in one area (the medical care system) will require decreased capability in another area.” Flying a physician crewmember to Mars implies the exclusion of a crewmember who may possess a greater depth of knowledge or skill in another field. This paper attempts to answer the following question: what benefits does a mission to Mars gain by including a physician in the crew, and are those benefits essential for crew health and mission success? Is there a medical training level below that of a physician that can meet the needs of the crew while accommodating greater knowledge and skill in another area of expertise?
Keywords: space exploration; planetary environments; planetary surfaces; long duration space flight; Arctic regions; Antarctic regions
Abstract: This report describes a 2-day workshop at the NASA Johnson Space Center discussing lessons learned from traverses in the Earth’s polar regions. Results from this and a previous workshop both indicate highly parallel activities and functional needs. It was also recognized that NASA’s current approach for long-duration planetary surface operations has fundamental differences from any of the operational approaches described by the invited speakers. This workshop arranged for a direct interaction between those who created the history of Arctic and Antarctic traverses with those who are tasked with creating the future history of these traverses on other planets. This report documents the presentations and discusses key findings or lessons. The presentations – visual materials and associated transcripts – are contained in appendices. These appendices are considered the principal knowledge captured during the workshop; the sections that precede these appendices provide background and context for the appendices and capture a summary of the discussions by attendees representing six different NASA Centers and several contractors or universities. A general recommendation is that interaction between the two exploration communities sides (i.e., the polar traverse community and the planetary surface traverse community) should continue with both informal and more formalized events.
Keywords: long duration space flight;astronaut performance; astronaut training; human performance; psychological factors
Abstract: This report is the result of a collaborative effort between NASA’s Behavioral Health & Performance (BHP) Research and Operations Group to investigate and determine the availability of data pertaining to behavioral performance (and other pertinent variables) that have been collected by the laboratories at NASA’s Johnson Space Center. BHP’s Operations and Research groups collaborated to systematically identify what types of performance data are needed in relevant BHP performance domains and also to conduct structured interviews with NASA personnel to identify which data do or do not exist currently (and for instances where such data exist, to evaluate the type, quality, accessibility, and confidentiality of those data). The authors defined outcome categories of performance that encapsulate BHP performance domains, mapped BHP Research Risks and Gaps onto those performance outcome categories, and identified and prioritized indicators for each outcome category. The team identified key points of contact (subject matter experts [SMEs]) as potential interviewees, created a template for structured interview questions about sources and accessibility of performance data, and coordinated and conducted structured interviews with the SMEs. The methodology, results, and implications of this effort, as well as forward work needed, are discussed in this report.
Keywords: long duration space flight; radiation dosage; radiation effects; cancer; extraterrestrial radiation
Abstract: Cancer risk is an important concern for International Space Station (ISS) missions and future exploration missions. An important question concerns the likelihood of a causal association between a crew members’ radiation exposure and the occurrence of cancer. The probability of causation (PC), also denoted as attributable risk, is used to make such an estimate. This report summarizes the NASA model of space radiation cancer risks and uncertainties, including improvements to represent uncertainties in tissue-specific cancer incidence models for never-smokers and the U.S. average population. We report on tissue-specific cancer incidence estimates and PC for different post-mission times for ISS and exploration missions. An important conclusion from our analysis is that the NASA policy to limit the risk of exposure-induced death to 3% at the 95% confidence level largely ensures that estimates of the PC for most cancer types would not reach a level of significance. Reducing uncertainties through radiobiological research remains the most efficient method to extend mission length and establish effective mitigators for cancer risks. Efforts to establish biomarkers of space radiation-induced tumors and to estimate PC for rarer tumor types are briefly discussed.
Keywords: micrometeoroids; debris, space debris; craters, impact damage; craters, satellite surfaces; Hubble Space Telescope
Abstract: Over 6 weeks during the summer of 2009, personnel from two NASA Centers performed a post-flight examination of the Hubble Space Telescope Wide Field Planetary Camera 2 (WFPC2) radiator. The objective was to record details about all micrometeoroid and orbital debris impact features with diameters of 300 µm and larger. By using a digital microscope, the team examined and recorded position, diameter, and depth information for each of the 675 craters. The actual measurements were extracted later from recorded images. Measurements include depth and diameter. Depth was measured from the undisturbed paint surface to the deepest point within the crater. Where features penetrate to the metal, both the depth in the metal and the paint thickness were measured. To compare these survey results with ground-based hypervelocity tests and simulations, several diameter measurements were taken: spall area, area of bare metal, area of discolored (“burned”) metal, and the lips of the central crater. In the largest craters, the diameter at the surface of the metal was also measured. Location of each crater was recorded at the time of inspection. This document presents the methods and results of the crater measurement effort including the size and spatial distributions of the impact features.
Keywords: long duration space flight; astronaut performance; health; carbon dioxide concentration; exposure
Abstract: Out of operational necessity, space platforms function with ambient carbon dioxide (CO2) concentrations in excess of normal atmospheric conditions (0.03% or partial pressure of 0.23 mmHg). NASA’s long-duration Spacecraft Maximum Allowable Concentration for CO2 is 0.7% (pp CO2 of 5.3mmHg). Extensive terrestrial studies support this level as safe and unlikely to cause adverse effects; however, International Space Station crews routinely report symptoms of acute CO2 toxicity (e.g., headaches, lethargy) that correlate with relative elevations of cabin CO2 below the permissible level. It is unclear if the unique environment of space results in increased sensitivity to CO2 or if other confounding factors are present. Regardless, acute symptom presentation at levels significantly lower than expected prompts the need to reevaluate the potential for adverse effects from long-term exposure. NASA’s continued commitment to long-duration space flight makes it imperative to evaluate the impact of chronic exposure on the mission and astronaut health. With no definitive research to provide insight into current symptoms, potential avenues of action include incorporating quantifiable methods of measuring crew CO2 burden, developing a robust study to examine various low-to-moderate CO2 concentrations on human subjects in microgravity and/or implementing design requirements for reduced CO2 levels on future space platforms.
Keywords: space exploration; space habitats; habitibility; lunar environment; lunar exploration; Constellation Program
Abstract: The primary purpose of the 2009 Desert Research and Technology Studies (DRATS) test was to conduct a quantitative habitability and usability evaluation of the Space Exploration Vehicle (SEV) 1B prototype during a high-fidelity simulation of a 14-day Constellation Program lunar mission. Although future exploration operations are expected to involve two SEVs, the operations at DRATS 2009 focused primarily on operations by a single SEV with a two-person crew because only one mobile SEV prototype was available for testing. A two-person crew remained within the SEV for the entire 14-day mission, leaving the vehicle only through the suit ports to perform extravehicular activities (EVAs). Standard metrics were used to longitudinally quantify habitability and usability of all aspects of the SEV prototype. Vehicle and crewmember descriptive statistics were collected, including task times for EVA and intravehicular activity, distances traveled, scientific productivity, and egress and ingress durations. Multiple design modifications were identified, but the data indicated that the overall SEV habitability and human factors to be acceptable for a 14-day mission. The SEV prototype was also found to be acceptable for 24 hours of habitation by four crewmembers, as assessed during a simulated crew rescue scenario on the final day of the mission.
Keywords: long duration space flight; shielding; radiation shielding; galactic cosmic rays; radiation effects; cancer;
Abstract: It remains a challenge for NASA to protect astronauts from galactic cosmic rays (GCRs) and solar particle events (SPEs) during long-duration missions. Shielding of SPEs is understood scientifically, which has led to readily available technology solutions, with optimization of specific designs to minimize launch mass. However, high-energies and secondary radiation of GCR limit most shielding approaches to small reductions from a baseline shielding configuration. We make a revised assessment of shielding materials performance based on newly defined NASA track structure dependent radiation quality factors, and most recent uncertainty analysis of space radiation cancer risks. Comparisons of liquid hydrogen, polyethylene, water, and epoxy shielding to aluminum for one-layer configurations with depths of 5 to 40 g/cm2, or two-layer configurations with an outer 10 g/cm2 aluminum layer, are considered. Statistically significant improvements in GCR risk reduction relative to aluminum shielding can be obtained with hydrocarbon materials with significant hydrogen content. Comparisons for several spacecraft designs for certain radiation environments are discussed. Liquid hydrogen remains the optimal shielding material; however, its performance can be overestimated if secondary radiation produced in tissue or the vessel containing the hydrogen are not considered. Nevertheless, developing new multifunctional shielding materials with higher hydrogen content compared to polyethylene is advocated.
Keywords: long duration space flight; near Earth asteroid; medical science; health; analogs
Abstract: As space exploration is directed towards destinations beyond low-Earth orbit, the consequent new set of medical risks will drive requirements for new capabilities and more resources to ensure crew health. The Space Medicine Exploration Medical Conditions List (SMEMCL), developed by the Exploration Medical Capability element of the Human Research Program, addresses the risk of “unacceptable health and mission outcomes due to limitations of in-flight medical capabilities”. It itemizes 85 evidence-based clinical requirements for eight different mission profiles and identifies conditions warranting further research and technology development. Each condition is given a clinical priority for each mission profile. Four conditions—intra-abdominal infections, skin lacerations, anaphylaxis, and behavioral emergencies—were selected as a starting point for analysis. A systematic literature review was performed to understand how these conditions are treated in austere, limited-resource, space-analog environments (i.e., high-altitude and mountain environments, submarines, military deployments, Antarctica, isolated wilderness environments, in-flight environments, and remote, resource-poor, rural environments). These environments serve as analogs to spaceflight because of their shared characteristics (limited medical resources, delay in communication, confined living quarters, difficulty with resupply, variable time to evacuation). Treatment of these four medical conditions in austere environments provides insight into medical equipment and training requirements for exploration-class missions.
Keywords: sensory deprivation, social isolation, stress, countermeasures, long-duration space flight
Abstract: Long-duration space flight presents several challenges to the behavioral health of crew members. The environment that they are likely to experience will be isolated, confined, and extreme (ICE) and, as such, crew members will experience extreme sensory deprivation and social isolation. The current paper briefly notes the behavioral, cognitive, and affective consequences of psychological stress induced by ICE environments and proposes nine countermeasures aimed at mitigating the negative effects of sensory deprivation and social isolation. Implementation of countermeasures aims to maintain successful crew performance and psychological well-being in a long-duration space flight mission.
Keywords: in vitro methods and tests; viruses; 3D in vitro human respiratory epithelia, respiratory syncytial virus, parainfluenza virus type 3, virus attenuation, cytokine profile
Abstract: Respiratory syncytial virus and parainfluenza virus cause severe respiratory disease, especially in infants, children, and the elderly. An in vitro model that accurately mimics infection of the human respiratory epithelium would facilitate vaccine development greatly. Monolayer cultures traditionally used to study these viruses do not accurately and precisely differentiate the replication efficiencies of wild type and attenuated viruses. Therefore, we engineered novel three-dimensional tissue-like assemblies of human bronchio-epithelial cells to produce a more physiologically relevant in vitro model of the human respiratory epithelium. Tissue-like assemblies resemble human respiratory epithelium structurally and by expression of differentiated epithelial cell markers. Most significantly, wild type viruses exhibited a clear growth advantage over attenuated strains in tissue-like assemblies unlike monolayer cultures. In addition, the tissue-like assemblies responded to virus infection by secreting pro-inflammatory mediators similar to the respiratory epithelia of infected children. These characteristics make the tissue-like assembly model a valuable platform technology to develop and evaluate live, attenuated respiratory virus vaccine candidates for human use.
Keywords: telemedicine; aerospace medicine; near Earth asteroid; medical personnel; long duration space flight
Abstract: The Exploration Medical Capability Element of the Human Research Program at NASA Johnson Space Center organized the 2011 Telemedicine Workshop to bring together leaders in remote medicine. The workshop participants were asked to outline the medical operational concept for a crewed mission to a near-Earth asteroid (NEA) and to identify areas for future work and collaboration. The objectives of the workshop were to document the medical operations concept (OpsCon) for a crewed mission to a NEA, to determine the gaps between current capabilities and the capabilities outlined in the OpsCon, to identify the research required to close these gaps, and to discuss potential collaborations with external-to-NASA organizations with similar challenges. The workshop deliverables are this summary report, the finalized medical OpsCon document, an updated telemedicine research plan, and a list of potential collaborations. The sections within this paper summarize the discussions held during the workshop and the conclusions reached by the workshop participants. These findings will be incorporated into the OpsCon document.
Keywords: open source licensing; software development tools; internet resources
Abstract: On March 29 & 30, 2011, NASA hosted its first Open Source Summit (OSS) at Ames Research Center in Mountain View, California. The event brought engineers and policy makers from across NASA together with well-respected members of the open source community to discuss current challenges with NASA’s open source policy framework, and propose modifications that would make it easier for NASA to develop, release, and use open source software. Open source brings numerous benefits to NASA software projects, including increased software quality, reduced development costs, faster development cycles, and reduced barriers to public-private collaboration through new opportunities to commercialize NASA technology. Although open source release has already provided some potential benefits, the full benefits can only be realized if NASA is able to establish processes, policies, and culture needed to encourage and support open source development. This will require expanding open source activities beyond releasing software only after completion and finding new ways to support two-way collaboration with an open development community throughout the software lifecycle. This document provides a snapshot of the activities during the OSS and summarizes the major issues and recommendations received from in-person attendees, as well as through the various online venues used during the event.
Keywords: dentistry; aerospace medicine; health; long duration space flight
Abstract: The Human Research Program assigned the Exploration Medical Capability (ExMC) Element the responsibility of addressing the risk associated with “the inability to adequately recognize or treat an ill or injured crewmember.” The dental working group meeting held on March 23, 2012, addressed this risk as it applies to dental risks. Specifically, the ExMC gap addressed by this document is ExMC 4.11: Limited dental care capabilities. The Space Medicine Exploration Medical Condition List (SMEMCL) was created to define the set of medical conditions most likely to occur during a distinct mission profile, as the first step in addressing the aforementioned risk. According to the SMEMCL, the in-flight dental system shall address caries, crown replacement, filling replacement, pulpitis, abscess, and tooth avulsion and loss. Cracked, split teeth, and fractured cusps and other conditions were not addressed. Models of near-Earth asteroid and Mars missions predict dental emergencies to be one of the top five conditions to impact mission objectives. Anecdotal observations by NASA flight surgeons have noted dental emergencies requiring root canal happening as close as 2 weeks before a launch. If such an emergency was missed on screening and occurred in flight, the likelihood of adversely affecting mission objectives is high.
Keywords: dentistry; aerospace medicine; health; long duration space flight
Abstract: All exploration class missions—extending beyond Earth’s orbit—differ from existing orbital missions by being of longer duration and often not having a means of evacuation. If an exploration mission extends beyond a year, there will be a greater lapse since the crewmembers’ last terrestrial dental exams. This increased time could increase the chance of a dental emergency such as intractable pain, dental decay requiring a temporary filling, crown replacement, exposed pulp, abscess, tooth avulsion, or toothache. Any dental emergency will have to be treated in-flight with available resources and personnel who may not have extensive training in dental care. Thus, dental emergencies are an important risk to assess.In-flight dental emergencies have been a rare event given current data and records. Long-duration missions raise the probability of a significant in-flight dental emergency similar to those incidents observed preflight. Preflight events requiring root canals had the potential for significant mission impact and occurred within proximity to launch. Given the increasing probability of an event and the potential for mission impact, exploration missions will need to focus on preflight and in-flight prevention and preparing crewmembers by training them how to treat dental emergencies such as caries, pulpitis, abscesses, fractures, and crown displacement.
Keywords: long duration space flight; deep space; habitable volume; systems engineering
Abstract: This document describes a concept of operations (ConOps) for a habitat element to be used by human crews on future deep space missions; that is, missions well beyond the low Earth orbit of Space Shuttle and International Space Station missions of the past few decades. As one facet of a number of studies conducted by NASA’s Human Spaceflight Architecture Team to better understand possible implementations of what the U.S. Human Spaceflight Plans Committee (also known as the Augustine Committee) has named the “flexible path,” a workshop was conducted to consider how best to define and quantify “habitable volume” for these future deep space missions. One conclusion reached during this workshop was the need for a description of the scope and scale of these missions and the resulting capabilities needed for a Deep Space Habitat (DSH) element. A group of workshop attendees was established to prepare a ConOps document to address this need. The ConOps, as developed by this group, was structured to identify and capture nominal activities and functions that were likely to occur on the DSH for a range of design reference missions that encompass the currently envisioned flexible path.
Keywords: VI, visual inspection, NDT, nondestructive testing, NDE, nondestructive evaluation, CPV, composite pressure vessel, COPV, composite overwrapped pressure vessel
Abstract: Visual inspection (VI) of composite structures provides an effective, wide field survey to ensure design and material compliance is maintained for the entire service life of the manufactured component. Visual inspection is one of the most commonly used nondestructive inspection methods to assess surface defects on composites. By applying visual inspection elements, mechanical damage that could affect component residual strength can be identified and a disposition reached before a potentially catastrophic event occurs. This technique is non-contact and applied at all stages of the composite structure's processing and use. Additionally, VI is required to be performed in all service environments until decommission. By following Level I and Level II damage accept/reject criteria set forth in this document, the Material Review (MR) process can be initiated. This nondestructive evaluation (NDE) method should be complemented with additional NDE methods to best understand the nature of the observed indications. VI identification followed by interrogation by effective complimentary NDE methods, the final Material Review Board (MRB) disposition of the component can be effectively achieved.
Keywords: medical equipment; surgery; infections; contaminants; long duration spaceflight
Abstract: Equipment sterilization is widely accepted as a critical component of any surgical procedure and is necessary for mitigating infection, morbidity, and mortality. Spacecraft environments are not sterile environments and may harbor pathogens; therefore, there is a need for disinfection if medical equipment is to be used more than once. In planning for surgical procedures in space flight, it is important to consider tools and procedures in relation to their intended purpose, risk of pathogen transmission, and ideal level of disinfection to determine disinfection requirements. Currently, there are no reports of in-flight surgical emergencies requiring invasive surgical equipment for treatment—as defined by a de novo break of physiologic barrier of sterility. However, catheters have been used in-flight to treat urinary retention. Catheter use can potentially cause a urinary tract infection, and a catheter being used more than once would benefit from disinfection. Ultrasound use and dental emergencies have necessitated use of semi-invasive equipment on the International Space Station. This gap report explores various technologies that can facilitate disinfection of invasive medical equipment for use onboard spacecraft.
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