Keywords: long duration spaceflight; behavioral health; performance; communication delay
Abstract: The Behavioral Health and Performance Element (BHP) of the NASA Human Research Program (HRP) conducted a research study to examine the impact of implementing experimental communication delays to-and-from the International Space Station (ISS) on individual and team factors and outcomes, including performance, well-being and related perceptions of autonomy and communication quality. To date, very few studies have observed teams in remote environments that perform without communication with management teams (e.g., mission control), and no such studies have been conducted during long-duration expeditions or missions. This study addressed the operationally-constrained criterion of a HRP Directed Research Project (DRP) and was a time-constrained requirement as we: 1) utilized an available ISS Increment to implement this study, 2) incorporated the results of this study to identify future near-term research tasks that relate to autonomy and what countermeasures will be needed to adequately prepare for autonomous long duration missions, and 3) guided future NASA Research Announcement (NRA) calls based on the conclusions that are drawn from this study that will address and close research gaps (including Team Gaps 1, 6, and 7 as well as inform BMed Gaps 1 and 2).
Keywords: long-duration space flight; extreme environments; psychological stress; behavioral health; reintegration; radiation
Abstract: Space flight occurs in extreme environments. As a result, crew member selection processes are stringent and rigorous. Despite the existence of these processes, behavioral problems and psychological stress can emerge among astronauts. As NASA shifts its focus towards long-duration human exploration missions to asteroids and Mars, increased attention has been directed towards understanding the behavioral health needs of those astronauts selected to participate in these missions. Furthermore, astronauts will spend greater periods of time in confined and dangerous environments and, upon their return to Earth, will have to reintegrate into families and social contexts that will have changed considerably during their absence. As the length of space flight increases, rates of behavioral health problems such as depression, anxiety, and neurocognitive deficits are also expected to increase. The purpose of the current report is to provide an overview of the likely contributors to astronauts’ post-mission behavioral health, a description of existing and potential future methods for assessing and monitoring astronauts’ behavioral health following their return from long-duration space flight, possible countermeasures to mitigate and offset threats to astronauts’ post-mission behavioral health, and recommended directions for future NASA research to address existing knowledge gaps in behavioral health assessment among astronauts.
Keywords: life support system; environments; environmental control; systems integration; advanced life support; long duration spaceflight
Abstract: This User’s Guide describes the basic operation of the Advanced Life Support Sizing Analysis Tool (ALSSAT) version 12.3, which is the Fiscal Year 2016 release. This guide describes how to run ALSSAT and the purpose of each entry requested by the graphical user interface (GUI). An example of ALSSAT using the GUI is presented as are the corresponding results. As additional references, the ALSSAT variables list and an acronym and abbreviation list are also provided. The User’s Guide is designed to allow users to run ALSSAT without further direction.
Keywords: long duration spaceflight; extreme environments; analog environments; adaptability; behavioral health
Abstract: As NASA prepares for long-duration, crewed missions into deep outer space, it needs to have a better understanding as to why some individuals adapt and adjust better than others to the extreme demands of space living. Drawing upon evidence from multiple sources, the present report identifies the factors associated with individual differences in adaptability to isolated, confined and extreme (ICE) environments, and discusses implications for selection and sustainment of astronauts on long-duration missions. While the present results do not permit a rank-ordering of the relative importance of these variables, we are fairly confident that the most relevant variables are contained within this set. Based on this preliminary evidence, we discuss some implications for astronaut selection and training, and provide suggested countermeasures for preserving adaptability during long-duration missions. Additional research is needed to improve measurement strategies, verify causal directions, and understand the complex interactions and underlying processes involved in positive human adaptation to the physical and psychosocial challenges of life in deep space.
Keywords: acceleration; acceleration tolerance; acceleration protection; impact; landings; escape systems
Abstract: Currently, NASA occupant protection standards are primarily based on the Multi-Axial Dynamic Response Criteria, which NASA refers to as the Brinkley Dynamic Response Criterion (BDRC). The BDRC was developed by the United States Air Force and adopted by NASA in the mid-1990s during the development of the Assured Crew Return Vehicle and evaluation of the Soyuz three-person crew vehicle landing impact tests. BDRC criterion includes a dynamic model, used to evaluate the risk of injury using a series of lumped parameter models with mass, spring, and damping properties. During BDRC development, model responses were related to human injury data to develop low, medium, and high injury risk limits. Because its simplicity, the BDRC is very attractive to designers. However, because of these simplifications and the specific characteristics of the seating systems used, application criteria or rules are necessary to correctly apply the model and interpret the results. In addition, several limitations have been identified that limit the injury prediction capabilities of the model. The purpose of this document is to review the BDRC development, document the rules necessary to apply the BDRC, identify limitations for NASA’s application, and describe additional testing and analysis methods necessary to supplement the BDRC.
Keywords: extravehicular activity, astronaut health, training, EVA training, neutral buoyancy, weightlessness
Abstract: During a spacewalk, designated as extravehicular activity (EVA), an astronaut ventures from the protective environment of the spacecraft into the vacuum of space. EVAs are among the most challenging tasks during a mission, as they are complex and place the astronaut in a highly stressful environment dependent on the spacesuit for survival. Due to the complexity of EVA, NASA has conducted various training programs on Earth to mimic the environment of space and to practice maneuvers in a more controlled and forgiving environment. The EVA Suit Exposure Tracker (EVA SET) dataset is a compilation of ground-based training activities using the extravehicular mobility unit (EMU) in neutrally buoyant pools to enhance EVA performance on orbit. These data can be used by the current ISS program and future exploration missions by informing physicians, researchers, and operational personnel on the risks of EVA training in order that future suit and mission designs incorporate greater safety. The purpose of this technical report is to document briefly the various facilities where NASA astronauts have performed EVA training while describing in detail the EVA training records used to generate the EVA SET dataset.
Keywords: transmitter; receiver; attenuator; probabilty of acquisition; signal
Abstract: A receiver is said to have “acquired” a signal when it concludes a search of its range of acquisition frequencies by correctly locking onto the signal from an intended transmitter. One test that the Electronic Systems Test Laboratory [ESTL] commonly performs on radio receivers is a Probability of Acquisition test [POA]. This test is used to determine the threshold amount of Total Received Power [TRP] which is needed for the receiver to acquire in an operationally usable amount of time. The TRP at the receiver’s antenna port is reduced to the point that the receiver is not always able to recognize the presence of the transmitted signal. The receiver is then given 25 opportunities to acquire the signal. Any time the receiver acquires, the transmitted signal is removed momentarily to force the receiver to search again. The number of successful opportunities normalized by the number of trials is the measured probability of acquisition represented by the 25-sample trial. Typically, the Total Received Power needed to achieve 90% probability of acquisition is selected to represent the entire curve, and the system either passes or fails based on that number. The resolution of the test is obvious: possible outcomes are at 4% spacings, so the measurement cannot be resolved more finely than 4%. The tolerance is not so obvious. This paper examines the measurement accuracy of the Probability of Acquisition test itself. It is intended that this information will be useful in analyzing data taken in the ESTL.
Keywords: theoretical model; percent data loss; frame synchronization; probability; bit error; percent data loss
Abstract: This document presents a theoretical model for calculating percent data loss (PDL) for a given frame synchronization strategy based on the input bit error probability and the length of a frame sync word. Probability of a bad frame sync pattern for the in-lock case and for the out-of lock case is calculated using the bit error probability and the number of acceptable errors in a frame sync pattern. Then, probabilities for the in-lock case and for the out-of-lock case are used to generate a state transition matrix (solved for the probability of being out-of-lock) which is the percent data loss. The theoretical model is used to predict performance for a variety of frame sync strategies, and the results are compared to measurements taken during the STS-48 Anomaly Investigation at ESTL. Finally, the number of frames required for a given measurement accuracy and result confidence is calculated using Tchebysheff's inequality. It is shown that the ESTL standard of 10000 frames is adequate for percent data loss measurements of greater than 2 percent for a 10-percent accuracy and 95-percent measurement confidence.
Keywords: long duration spaceflight; training; teamwork; exloration missions; behavioral health
Abstract: As part of NASA’s ongoing effort to enhance the teamwork training curriculum for long-duration exploration mission (LDEM) teams, we conducted a comprehensive training needs analysis dedicated to identifying critical needs and gaps in the agency’s existing curriculum and to providing general nonprescriptive recommendations for effectively and efficiently addressing these needs/gaps. Several complementary investigative methods were employed, including interviews with 13 subject matter experts, archival analysis of interview data previously collected from 12 astronauts with long-duration space flight experience, a review of recent LDEM astronaut job analysis findings, analysis of existing NASA teamwork training materials, a review of the relevant scientific literatures, and rigorous content mapping of the data resulting from each of these activities. As a result, 17 critical teamwork training needs/gaps were identified and 23 recommendations for addressing them were formulated. These needs/gaps and recommendations clustered into 7 broad categories, including needs/gaps and recommendations related to the: 1) content of the teamwork training, 2) consistency of the teamwork training content, 3) methods used to develop teamwork competencies, 4) amount of teamwork training provided, 5) timing of teamwork training, 6) types of participants who receive teamwork training, and the 7) methodologies used to evaluate NASA’s current teamwork training programs.
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