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NASA NTRS1977

Nevada Test Site craters used for astronaut training

Craters produced by chemical and nuclear explosives at the Nevada Test Site were used to train astronauts before their lunar missions. The craters have characteristics suitable for reconnaissance-type field investigations. The Schooner test produced a crater about 300 m across and excavated more than 72 m of stratigraphic section deposited in a fairly regular fashion so that systematic observations yield systematic results. Other features common on the moon, such as secondary craters and glass-coated rocks, are present at Schooner crater. Smaller explosive tests on Buckboard Mesa excavated rocks from three horizontal alteration zones within basalt flows so that the original sequence of the zones could be determined. One crater illustrated the characteristics of craters formed across vertical boundaries between rock units. Although the exercises at the Nevada Test Site were only a small part of the training of the astronauts, voice transcripts of Apollo missions 14, 16, and 17 show that the exercises contributed to astronaut performance on the moon.

Moore, H. J.↗

NASA NTRS1991

Psychiatric diagnoses in a group of astronaut applicants

Between 1959 and 1987, the psychiatric evaluation of astronaut candidates evolved from a 30-h intensive examination evaluating applicants for psychopathology, and studying their performance under stress, to a 2-h clinical interview whose structure and contents were determined by the individual examiner. Evaluations done during these years applied both psychiatric (or, 'select-out') criteria and psychological (or, 'select-in') criteria. In an attempt to more rigorously define the psychiatric, 'select-out' component, a standardized, semistructured clinical interview was developed to identify the presence or history of psychiatric disorders listed in the Diagnostic and Statistical Manual of Mental Disorders, 3rd Ed. ('DSM-III'). A total of 117 astronaut applicants underwent this clinical interview as part of a comprehensive medical evaluation during a recent astronaut selection. Of the 117 applicants, 9 (7.7 percent) met DSM-III criteria for a variety of Axis I and Axis II diagnoses, including V-code diagnoses.

Santy, Patricia A.↗

NASA NTRS1991

End effector with astronaut foot restraint

The combination of a foot restraint platform designed primarily for use by an astronaut being rigidly and permanently attached to an end effector which is suitable for attachment to the manipulator arm of a remote manipulating system is described. The foot restraint platform is attached by a brace to the end effector at a location away from the grappling interface of the end effector. The platform comprises a support plate provided with a pair of stirrups for receiving the toe portion of an astronaut's boots when standing on the platform and a pair of heel retainers in the form of raised members which are fixed to the surface of the platform and located to provide abutment surfaces for abutting engagement with the heels of the astronaut's boots when his toes are in the stirrups. The heel retainers preclude a backward sliding movement of the feet on the platform and instead require a lifting of the heels in order to extract the feet. The brace for attaching the foot restraint platform to the end effector may include a pivot or swivel joint to permit various orientations of the platform with respect to the end effector.

Monford, Leo G., Jr.↗

NASA NTRS1991

Facing page test for the astronaut science advisor presentation

The goal of the Astronaut Science Advisor (ASA) project is to improve the scientific return of experiments performed in space by providing astronaut experimenters with an 'intelligent assistant' that encapsulates much of the domain- and experiment-related knowledge commanded by the Principal Investigator (PI) on the ground. By using expert systems technology and the availability of flight-qualified personal computers, it is possible to encode the requisite knowledge and make it available to astronauts as they perform experiments in space. The system performs four major functions: diagnosis and troubleshooting of experiment apparatus, data collection, protocol management, and detection of interesting data. The experiment used for development of the system measures human adaptation to weightlessness in the context of the neurovestibular system. This so-called 'Rotating Dome' experiment was flown on the recent Spacelab Life Sciences One (SLS-1) Mission. This mission was used as an opportunity to test some of the system's functionality. Experiment data was downlinked from the orbiter, and the system then captured the data and analyzed it in real time. The system kept track of the time being used by the experiment, recognized occurrences of interesting data, summarized data statistically and generated potential new protocols that could be used to optimize the course of the experiment.

Compton, Michael M.↗

NASA NTRS1991

An expert system for astronaut scientists

A novel application of expert system technology is developed for real-time advice to an astronaut during the performance of a crew intensive experiment. The provision of an on-board computer expert, containing much of the reasoning base of the real Principal Investigator, will permit the astronaut to act more as a scientist co-worker in future Spacelab and Space Station missions. The long duration of flight increments and the large number of experiments envisioned for Space Station Freedom make the increase in astronaut productivity particularly valuable. A first version of the system was evaluated on the ground during the recent Spacelab SLS-1 flight.

Young, L. R.↗

NASA NTRS1992

Astronaut candidate strength measurement using the Cybex 2 and the LIDO Multi-Joint 2 dynamometers

The Anthropometry and Biomechanics Laboratory in the man-Systems division at NASA's Johnson Space Center has as one of its responsibilities the anthropometry and strength measurement data collection of astronaut candidates. The anthropometry data is used to ensure that the astronaut candidates are within the height restrictions for space vehicle and space suit design requirements, for example. The strength data is used to help detect abnormalities or isolate injuries to muscle groups that could jeopardize the astronauts safety. The Cybex II Dynamometer has been used for strength measurements from 1985 through 1991. The Cybex II was one of the first instruments of its kind to measure strength and similarity of muscle groups by isolating the specific joint of interest. In November 1991, a LIDO Multi-Joint II Dynamometer was purchased to upgrade the strength measurement data collection capability of the Anthropometry and Biomechanics Laboratory. The LIDO Multi-Joint II Dynamometer design offers several advantages over the Cybex II Dynamometer including a more sophisticated method of joint isolation and a more accurate and efficient computer based data collection system.

Carroll, Amy E.↗

NASA NTRS1990

PI-in-a-box: An expert system to advise astronauts during experiments

Perhaps the scarcest resource for manned flight experiments - on Spacelab or on Space Station Freedom - will continue to be crew time. To maximize the efficiency of the crew, and to make use of their abilities to work as scientist collaborators as well as equipment operators, normally requires more training in a wide variety of disciplines than is practical. The successful application of on-board expert systems, as envisioned by the 'Principal Investigator (PI)-in-a-Box' program, should alleviate the training bottleneck and provide the astronaut with the guidance and coaching needed to permit him or her to operate an experiment according to the desires and knowledge of the PI, despite changes in conditions. In addition to the functions of providing expert devise concerning scheduling and repair, the program should bring the astronaut into the scientific evaluation phase of an experiment by sharing with him the guidance and observations regarding the relevance and importance of data as it is being generated. Initial reaction from the astronaut community has been positive.

Young, Laurence R.↗

NASA NTRS1993

Exposure fluctuations of astronauts due to orientation

The dose incurred in an anisotropic environment depends on the orientation of the astronaut's body relative to the direction of the radiation field. The fluctuations in exposure of specific organs due to astronaut orientation are found to be a factor of 2 or more in a typical space habitation module and typical space radiations. An approximation function is found that overestimates astronaut exposure in most cases studied and is recommended as a shield design guide for future space missions.

Wilson, John W.↗

NASA NTRS1992

Magnetic Resonance Imaging (MRI) of skeletal muscles in astronauts after 9 days of space flight

Skylab data indicated that prolonged exposure of human subjects to microgravity environment causes significant muscle atrophy accompanied by reduced muscle strength and fatigue resistance. The objective of this study was to determine decrements in muscle size, if any, in the soleus and gastrocnemius muscles of male and female astronauts after 9 days of space flight. Methods: Eight astronauts, one female and seven male, between the ages of 31 and 59 years 59-84 kg in body weight were examined by MRI 2-3 times preflight within 16 days before launch, and 2 days, (n=6) and seven days (n=3) after landing. The right leg muscles (gastroc-soleus) were imaged with a lower extremity coil in magnets operating at 1.0 or 1.5 Tsela. The imaging protocol consisted of spin echo with a Tr of 0.70 - 1.5 sec. Thirty to forty 3-5 mm thick slices were acquired in 256 x 128 or 256 x 256 matrices. Acquisition time lasted 20-40 minutes. Multiple slices were measured by computerized planimetry. Results: Compared to the preflight, the cross-sectoral areas (CSA) of the soleus, gastrocnemius, and the leg, at 2 days after landing were reduced (at least p less than 0.05) 8.9 percent, 13.2 percent, and 9.5 percent respectively. The soleus and the leg of three astronauts evaluated at 7 days postflight did not show full recovery compared to the preflight values. Conclusions: It is concluded that l9-days of space flight may cause significant decreases in CSA of the leg muscles. The factors responsible for this loss need further determination.

Jaweed, M.↗

NASA NTRS1999

Psychological Selection of NASA Astronauts for International Space Station Missions

During the upcoming manned International Space Station (ISS) missions, astronauts will encounter the unique conditions of living and working with a multicultural crew in a confined and isolated space environment. The environmental, social, and mission-related challenges of these missions will require crewmembers to emphasize effective teamwork, leadership, group living and self-management to maintain the morale and productivity of the crew. The need for crew members to possess and display skills and behaviors needed for successful adaptability to ISS missions led us to upgrade the tools and procedures we use for astronaut selection. The upgraded tools include personality and biographical data measures. Content and construct-related validation techniques were used to link upgraded selection tools to critical skills needed for ISS missions. The results of these validation efforts showed that various personality and biographical data variables are related to expert and interview ratings of critical ISS skills. Upgraded and planned selection tools better address the critical skills, demands, and working conditions of ISS missions and facilitate the selection of astronauts who will more easily cope and adapt to ISS flights.

Galarza, Laura↗

NASA NTRS1998

Incidence of Epstein-Barr Virus in Astronaut Saliva During Spaceflight

Astronauts experience psychological and physical stresses that may result in re-activation of latent viruses during spaceflight, potentially increasing the risk of disease among crew members. The shedding of Epstein-Barr virus (EBV) in the saliva of astronauts will increase during spaceflight. A total of 534 saliva specimens were collected from 11 EBV-seropositive astronauts before, during, and after four space shuttle missions. The presence of EBV DNA in saliva, assessed by polymerase chain reaction (PCR), was used to determine shedding patterns before, during, and after spaceflight. EBV DNA was detected more frequently before flight than during (p less than 0.001) or after (p less than 0.01) flight. No significant difference between the in-flight and postflight periods was detected in the frequency of occurrence of EBV DNA. The increased frequency of shedding of EBV before flight suggests that stress levels may be greater before launch than during or after spaceflight.

Payne, Deborah A.↗

NASA NTRS1999

Marked Exacerbation of Orthostatic Intolerance After Long vs. Short-Duration Spaceflight in Veteran Astronauts

The incidence of postflight orthostatic intolerance following short-duration spaceflight is about 20%. However, the incidence following long-duration spaceflight is unknown. We performed tilt tests on six astronauts before and after their long-duration (129 - 190 days) spaceflights and compared these data to those obtained during stand tests before and after their previous short-duration missions and also to tilt test data from 20 different short-duration (8 - 16 days) flight astronauts. Five of these six became presyncopal during tilt testing after long-duration flights: only one had become presyncopal during stand testing after short-duration flights. Five of the twenty astronauts who flew on other short-duration flights, became presyncopal during upright tilt on landing day. Long-duration presyncopal subjects had lower stroke volumes, lower cardiac outputs and higher peripheral vascular resistance than short-duration presyncopal subjects, but their heart rate responses were not different. One subject had subnormal norepinephrine release with upright posture after a long but not short flight. Plasma volume losses were not greater after long flights. Long-duration spaceflight markedly increases orthostatic intolerance, probably related to altered autonomic function.

Fritsch-Yelle, Janice M.↗

NASA NTRS1998

Effectiveness of an Expert System for Astronaut Assistance on a Sleep Experiment

Principal Investigator-in-a-Box ([PI]) is an expert system designed to train and assist astronauts with the performance of an experiment outside their field of expertise, particularly when contact with the Principal Investigators on the ground is limited or impossible. In the current case, [PI] was designed to assist with the calibration and troubleshooting procedures of the Neurolab Sleep and Respiration Experiment during the pre-sleep period of no ground contact. It displays physiological signals in real time during the pre-sleep instrumentation period, and alerts the astronauts when a poor signal quality is detected. Results of the first study indicated a beneficial effect of [PI] and training in reducing anomaly detection time and the number of undetected anomalies. For the in-flight performance, excluding the saturated signals, the expert system had an 84.2% detection accuracy, and the questionnaires filled out by the astronauts showed positive crew reactions to the expert system.

Heher, Dennis↗

NASA NTRS2003

Quantifying Astronaut Tasks: Robotic Technology and Future Space Suit Design

The primary aim of this research effort was to advance the current understanding of astronauts' capabilities and limitations in space-suited EVA by developing models of the constitutive and compatibility relations of a space suit, based on experimental data gained from human test subjects as well as a 12 degree-of-freedom human-sized robot, and utilizing these fundamental relations to estimate a human factors performance metric for space suited EVA work. The three specific objectives are to: 1) Compile a detailed database of torques required to bend the joints of a space suit, using realistic, multi- joint human motions. 2) Develop a mathematical model of the constitutive relations between space suit joint torques and joint angular positions, based on experimental data and compare other investigators' physics-based models to experimental data. 3) Estimate the work envelope of a space suited astronaut, using the constitutive and compatibility relations of the space suit. The body of work that makes up this report includes experimentation, empirical and physics-based modeling, and model applications. A detailed space suit joint torque-angle database was compiled with a novel experimental approach that used space-suited human test subjects to generate realistic, multi-joint motions and an instrumented robot to measure the torques required to accomplish these motions in a space suit. Based on the experimental data, a mathematical model is developed to predict joint torque from the joint angle history. Two physics-based models of pressurized fabric cylinder bending are compared to experimental data, yielding design insights. The mathematical model is applied to EVA operations in an inverse kinematic analysis coupled to the space suit model to calculate the volume in which space-suited astronauts can work with their hands, demonstrating that operational human factors metrics can be predicted from fundamental space suit information.

Newman, Dava↗

NASA NTRS1999

Astronaut Exposures to Ionizing Radiation in a Lightly-Shielded Spacesuit

The normal working and living areas of the astronauts are designed to provide an acceptable level of protection against the hazards of ionizing radiation of the space environment. Still there are occasions when they must don a spacesuit designed mainly for environmental control and mobility and leave the confines of their better-protected domain. This is especially true for deep space exploration. The impact of spacesuit construction on the exposure of critical astronaut organs will be examined in the ionizing radiation environments of free space, the lunar surface and the Martian surface. The computerized anatomical male model is used to evaluate astronaut self-shielding factors and to determine space radiation exposures to critical radiosensitive human organs.

Wilson, J. W.↗

NASA NTRS2001

Peripheral leukocyte subpopulations and catecholamine levels in astronauts as a function of mission duration

OBJECTIVE: The objective of this study was to determine the effects of spaceflight duration on immune cells and their relationship to catecholamine levels. METHODS: Eleven astronauts who flew aboard five different US Space Shuttle flights ranging in duration from 4 to 16 days were studied before launch and after landing. RESULTS: Consistent with prior studies, spaceflight was associated with a significant increase in the number of circulating white blood cells (p <.01), including neutrophils (p <.01), monocytes (p <.05), CD3+CD4+ T-helper cells (p <.05), and CD19+ B cells (p <.01). In contrast, the number of CD3-CD16+56+ natural killer cells was decreased (p <.01). Plasma norepinephrine levels were increased at landing (p <.01) and were significantly correlated with the number of white blood cells (p <.01), neutrophils (p <.01), monocytes (p <.01), and B cells (p <.01). Astronauts who were in space for approximately 1 week showed a significantly larger increase on landing in plasma norepinephrine (p =.02) and epinephrine (p =.03) levels, as well as number of circulating CD3+CD4+ T-helper cells (p <.05) and CD3+CD8+ T-cytotoxic cells (p <.05) as compared with astronauts in space for approximately 2 weeks. CONCLUSIONS: The data suggest that the stress of spaceflight and landing may lead to a sympathetic nervous system-mediated redistribution of circulating leukocytes, an effect potentially attenuated after longer missions.

Flight Experiment↗

NASA NTRS2005

Resolving Risks in Individual Astronauts: A New Paradigm for Critical Path Exposures

The limited number of astronauts available for risk-assessment prevents classic epidemiologic study, and thereby requires alternative approach to assessing risks within individual astronauts exposed to toxic agents identified within the Bioastronautics Critical Path Roadmap (BCPR). Developing a system of noninvasive real-time biodosimetry that provides large datasets for analyses before, during, and after missions for simultaneously determining 1) the kinds of toxic insult, 2) the degree of that insult, both within tissues absorbing that insult, would be usehl for resolving statistically significant risk-assessment in individual astronauts. Therefore, a currently achievable multiparametric paradigm is presented for use in analyzing gene-expression and protein-expression so as to establish predictive outcomes.

Richmond, Robert C.↗

NASA NTRS2007

Hypovolemia Induced Orthostatic Hypotension in Presyncopal Astronauts and Normal Subjects Relates to Hypo-Sympathetic Responsiveness

Circulating blood volume is reduced during spaceflight, leaving astronauts hemodynamically compromised after landing. Because of this hypovolemia, crew members are able to withstand a postflight 10 minute upright tilt test only if they are able to mount a hyper-sympathetic response. Previous work from this laboratory has shown that about 30% of astronauts, primarily female, have postflight sympathetic responses to tilt that are equal to or less than their preflight responses and thus, they become presyncopal. Part of the mission of the cardiovascular lab at the Johnson Space Center is to identify susceptible crewmembers before flight so that individualized countermeasures can be prescribed. The goal of this study was to develop a ground based model of hypovolemia that could be used for this purpose We tested the hypothesis that hypovolemia alone, in the absence of spaceflight, would reproduce the landing day rate of presyncope during upright tilt in normal volunteers. Further, we hypothesized that, during hypovolemia, subjects who had sympathetic responses that were equal to or less than their normovolemic responses would become presyncopal during upright tilt tests. We studied 20 subjects, 13 male and 7 female, on two separate occasions: during normovolemia and hypovolemia. We induced hypovolemia with intravenous furosemide 40 hours prior to the experiment day, followed by a 10MEq Na diet. On the normovolemia and hypovolemia test days, plasma volume, tilt tolerance and supine and standing arterial pressure, heart rate and plasma norepinephrine levels were measured. A two factor, repeated measures analysis of variance was performed to examine the differences between group (presyncopal vs. non-presyncopal) and day (normovolemia vs. hypovolemia) effects. There were no differences in baseline arterial pressure between normovolemia and hypovolemia or between presyncopal and non-presyncopal groups, but heart rates were higher with hypovolemia in both groups (presyncopal: 70 5 bpm vs. 63 3 bpm, P = 0.003, non-presyncopal: 59 2 bpm vs. 52 2 bpm, P = 0.003). Similar to patterns reported after flight, non-presyncopal subjects had greater norepinephrine responses to tilt during hypovolemia compared to normovolemia (580 79 vs. 298 37 pg/ml, P < 0.05), but presyncopal subjects did not (180 44 vs. 145 32 pg/ml, P = NS). This new model has the potential to accelerate the development of countermeasures and save flight resources. It can be used to identify astronauts who will become presyncopal on landing day, so that prospective, individualized countermeasures can be developed. In addition, it can also be used to screen candidate countermeasures prior to requests for bed rest or inflight resources.

Meck, Janice V.↗