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PubMed1998

Evaluating the feasibility of biological waste processing for long term space missions.

Recycling waste products during orbital (e.g., International Space Station) and planetary missions (e.g., lunar base, Mars transit mission, Martian base) will reduce storage and resupply costs. Wastes streams on the space station will include human hygiene water, urine, faeces, and trash. Longer term missions will contain human waste and inedible plant material from plant growth systems used for atmospheric regeneration, food production, and water recycling. The feasibility of biological and physical-chemical waste recycling is being investigated as part of National Aeronautics and Space Administration's (NASA) Advanced Life Support (ALS) Program. In-vessel composting has lower manpower requirements, lower water and volume requirements, and greater potential for sanitization of human waste compared to alternative bioreactor designs such as continuously stirred tank reactors (CSTR). Residual solids from the process (i.e. compost) could be used a biological air filter, a plant nutrient source, and a carbon sink. Potential in-vessel composting designs for both near- and long-term space missions are presented and discussed with respect to the unique aspects of space-based systems.

Biodegradation, Environmental↗
PubMed2003

Psychological issues relevant to astronaut selection for long-duration space flight: a review of the literature.

This technical paper reviews the current literature on psychological issues relevant to astronaut selection for long-duration space flights. Interpersonal problems have been and remain a recurring problem for both short and long-duration space flights. Even after completion of the space mission, intense psychological aftereffects are reported. The specific behavioral problems experienced during United States and Soviet Union space flights are reviewed, specifically addressing contentious episodes and impaired judgments that occurred during the Mercury, Apollo, and Skylab missions. Psychological tests used in the selection process for the space program have focused primarily on the detection of gross psychopathologies in potential candidates. Although these psychological instruments excluded some people from becoming astronauts, the battery of tests failed to predict which individuals would manifest behavioral aberrations in judgment, cooperative functioning, overt irritability, or destructive interpersonal actions.

Aerospace Medicine↗
PubMed2000

Thyroid function changes related to use of iodinated water in the U.S. Space Program.

BACKGROUND: The National Aeronautics and Space Administration (NASA) has used iodination as a method of microbial disinfection of potable water systems in U.S. spacecraft and long-duration habitability modules. A review of thyroid function tests of NASA astronauts who had consumed iodinated water during spaceflight was conducted. METHODS: Thyroid function tests of all past and present astronauts were reviewed. Medical records of astronauts with a diagnosis of thyroid disease were reviewed. Iodine consumption by space crews from water and food was determined. Serum thyroid-stimulating hormone (TSH) and urinary iodine excretion from space crews were measured following modification of the Space Shuttle potable water system to remove most of the iodine. RESULTS: Mean TSH significantly increased in 134 astronauts who had consumed iodinated water during spaceflight. Serum TSH, and urine iodine levels of Space Shuttle crewmembers who flew following modification of the potable water supply system to remove iodine did not show a statistically significant change. There was no evidence supporting association between clinical thyroid disease and the number of spaceflights, amount of iodine consumed, or duration of iodine exposure. CONCLUSIONS: It is suggested that pharmacological doses of iodine consumed by astronauts transiently decrease thyroid function, as reflected by elevated serum TSH values. Although adverse effects of excess iodine consumption in susceptible individuals are well documented, exposure to high doses of iodine during spaceflight did not result in a statistically significant increase in long-term thyroid disease in the astronaut population.

Astronauts↗
PubMed1994

The use of medicaments in space--therapeutic measures and potential impact of pharmacokinetics due to weightlessness.

In support of the preparatory programme for the European manned space infrastructure, the Long-Term Programme Office (LTPO) within ESA's Space Station and Microgravity Directorate initiated a series of studies aimed at a better understanding of the physiological and psychological aspects of living in space. In this context, in 1991 MEDES (Institut de medecine et physiologie spatiale) was contracted by the Agency to investigate the type and efficacy of drugs available for use by astronauts during space missions to counteract the effects of weightlessness or for medical treatments. This paper summarises the main outcome of this research, in the context of the so-called 'Pharmemsi Study'. The first part is dedicated to the content of the medical kits used by astronauts in flight, while the second describes how weightlessness can modify the action of drugs (i.e. pharmacodynamics and pharmacokinetics parameters) on the human body. Recommendations are given on 'Space Pharmacopoeia' as well as the areas of research needed to adapt medication to the weightless environment.

Aerospace Medicine↗
PubMedDate not supplied

1985 NASA-Rockwell Space Station Crew Safety Study: results from Mir.

In 1985, Rockwell International (now Boeing--North American) completed the Space Station Crew Safety Alternatives Study for NASA. This five-volume study identified a wide range of potential safety threats and hazards that the crew might encounter on the future International Space Station. These threats included fire, explosion, collision, decompression, contamination, and radiation, among many others. One volume focused on the human factors aspects of safety, featuring the Crew Safety-Human Factors Interaction Model. In this model, a stressor (such as one of the threats) can lead to degraded performance, which can contribute to human error, unless appropriate and effective countermeasures are available to the crew. In 1986, the Soviet Union launched the Mir Space Station, the "second generation" that followed the Salyut series of space stations. The Mir was designed for a five-year life on orbit. It remained in use for fourteen years. During the first ten years, it performed well, with few safety issues. However, during the last four years, the aging station--operating at more than two times beyond its design lifetime--encountered a variety of safety hazards and human factors issues. Despite these often serious problems, the Mir crews always found a way to save the station, and no crew member was seriously injured or killed. This paper evaluates the safety record on Mir, and compares it to the NASA-Rockwell study, that was contemporaneous with the construction and launch of Mir. This comparison and analysis can provide a foundation for future space crew safety and related human factors support.

Communication↗
PubMed2004

Group interactions during space missions.

INTRODUCTION: Previous anecdotal reports from space and results from space simulation studies on Earth have suggested that the group interactions of crewmembers during space missions can be problematic in ways that can negatively affect crew safety and the accomplishment of mission goals. METHODS: To assess the interpersonal environment of space crewmembers, we used a set of standard questionnaires that were completed by 5 astronauts, 8 cosmonauts, and 58 American and Russian mission control personnel who participated in the Shuttle/Mir Program. RESULTS: Although we did not find strong evidence supporting predicted decrements in tension and cohesion during the second half of the missions, we did find that both crewmembers and mission control personnel displaced unpleasant emotions to monitoring personnel outside of their group. We also found significant differences between Americans and Russians in terms of measures of satisfaction with their interpersonal and work environments. CONCLUSIONS: These findings suggest a number of countermeasures to help future space crews deal with potential maladaptive group interactions. These countermeasures address issues at the time of selection, during prelaunch training, during the mission itself, and after the crew returns to Earth.

Astronauts↗
PubMed2004

Research on intercultural effectiveness and its relevance to multicultural crews in space.

The planning for and managing of missions in space is changing dramatically due to, among other things, the involvement of more and more national cultures. In light of the need to better understand the influence and management of cultural differences among the crewmembers who will live and work in space in the future, the aim of this paper is threefold. First, some of the key research findings on intercultural effectiveness on Earth are presented and their relevance to the functioning of multicultural crews in space is discussed. Second, issues that will need to be addressed in order to maximize the effective functioning of multicultural teams in space are identified. These include improving the procedures for the screening and selection, intercultural training, monitoring and support, and debriefing and re-entry of astronauts and their families. Finally, the paper concludes with the presentation and discussion of some of the key activities that will need to be undertaken to address these issues and, thereby, enhance the overall functioning of multicultural teams living and working in space.

Astronauts↗
PubMed2005

Human behavioral research in space: quandaries for research subjects and researchers.

With the advent of long-duration spaceflight on board the International Space Station (ISS) and possible future missions beyond low Earth orbit (LEO) such as Mars, it is critical that those at NASA have a realistic assessment of the challenges that will face individuals on long-duration missions so that they can develop preventive and real-time countermeasures to behavioral health issues. While space travellers are very interested in having countermeasures to the deleterious effects of space missions, they have a powerful disincentive to participate in this research if they feel it could in any way negatively affect their flight status. The behavioral issues of isolation and confinement for extended-duration space missions are reviewed. Areas of basic and clinical behavioral research are listed. And the classical clinical model for research is not considered appropriate for the current configuration of the space program. The use of analogue environments and advanced statistical analysis are suggested as ways to address the limited spaceflight research opportunities. The challenge of research subject or patient confidentiality vs. mission safety and issues of personal flight status are addressed.

Adaptation, Physiological↗
PubMed1991

Prediction of space motion sickness susceptibility by disconjugate eye torsion in parabolic flight.

The hypothesis of asymmetric otolith function asserts that physiological or anatomical differences in the two sides of the bilateral gravity-sensing otolith apparatus of the inner ear may be well compensated on Earth, but when exposed to novel gravitational states, the prior compensatory stratagems may be ineffective, leading to unstable vestibular responses and causing the phenomenon of space motion sickness. To investigate this hypothesis, spontaneous eye torsion, a reflex governed by the otolith organs, was examined in the upright position during the hypo- and hypergravity of parabolic flight aboard NASA's KC-135 aircraft in nine former astronauts whose history of space motion sickness was revealed after data analysis had been completed. Results showed that astronauts who had been sick in space had significantly higher scores of disconjugate eye torsion in parabolic flight, and that their responses were consistently different in 1.8 G relative to 0 G compared to astronauts who had not been sick in space. In 1 G, there were no differences in disconjugate eye torsion between the subjects. The results support the asymmetry hypothesis and offer a possible predictive test of space motion sickness.

Disease Susceptibility↗
PubMed1999

The spinal epidural space.

The validity of the concept of an epidural 'space' within the vertebral canal is questioned. An attempt is made to locate the 'space' morphologically, developmentally, and topographically. Following Parkin and Harrison (1985), it is agreed that no actual 'space' exists in the intact living subject. It is suggested that the spinal epidural space satisfies the criteria of Haines (1991) to be considered a "true potential space." As such, and by analogy with other body cavities, it would be better termed the 'epidural cavity', as it was in the 1983 edition of the Nomina Anatomica.

Dura Mater↗
PubMed2000

Is the renal space closed?

The aim of this study is to verify the aperture or the closure of the renal space. The study is undertaken on histological sections of fetuses in the horizontal and sagittal planes. On each side, the kidney and the suprarenal gland are disposed in a space that is closed on all sides. The anterior and posterior layers of the renal fascia fuse at the upper pole of the space to become continuous with the inferior fascia of the diaphragm. Likewise, they merge at the lower pole and at the lateral border of the space to become continuous with the fasciae of the parietal muscles. At the medial border of the space, the two layers merge to continue medially with the peri-aortocaval connective tissue; they penetrate the hilum and beneath it enclose the ureter.

Cadaver↗
PubMed1984

Personal space of incarcerated offenders.

Administered the proxemic test (Kinzel, 1970) and a psychometric test battery to 49 incarcerated offenders on two occasions. Offenders also were rated by staff on their interpersonal behavior, and a 3-year follow-up was undertaken to assess recidivism. Immediate test-retest reliabilities were extremely high in all four directions (.93 to .97), but lower over a 10-week period (.65 to .89). The Behind distance was largest on both occasions. There were no changes in the four distance measures over time. An algebraic formula was devised to calculate Personal Space Area. Age was related inversely to offender's Personal Space (r = -.32, p less than .03). Personality measures, observation ratings, and follow-up outcome data were related inconsistently to Personal Space Area, although there was some indication that offenders with a large personal space were less empathic, less socialized, less accepting of others, received poor evaluations, and were more likely to recidivate. The utility of personal space in the assessment of offenders is discussed.

Adolescent↗
PubMed1975

Developmental morphology of the subarachnoid space and contiguous structures in the mouse.

Development of pia-arachnoidal membranes in the mouse occurs in four stages: the first (prenatal days 10-13) follows closure of the neural tube and is a period of initial vascularization of the developing telencephalon; the second (prenatal days 14-16) is a period of delineation during which the limits of the subarachnoid space are defined; the third (prenatal day 17 to birth) is a period of ensheathment of pia-arachnoidal blood vessels; and the fourth (birth to postnatal day 21) includes addition of smooth muscle to larger vessels, the appearance of macrophages in the subarachnoid space, and a general increase in extracellular collagenous and elastic fibers. The mesenchyme over the telencephalic surface in the 10-day fetus has a typically large extracellular space. By the 13th fetal day cerebrospinal fluid begins to seep into and replace it. The mesenchymal extracellular compartment is reduced peripherally, resulting in a compacted pia-arachnoidal tissue which limits the peripheral extent of the subarachnoid space. By the 21st postnatal day a subarachnoid space typical of the adult animal has been established.

Animals↗
PubMed2002

Influence of bioresorbable, unsintered hydroxyapatite/poly-L-lactide composite films on spinal cord, nerve roots, and epidural space.

The effect of forged unsintered hydroxyapatite/poly-L-lactide (u-HA/PLLA) composite films on spinal cord and nerve roots and its degradation behavior and osteoconductivity in epidural space were compared with those of calcined HA (c-HA)/PLLA and unfilled PLLA films. Partial laminectomy was performed on 20 rabbits, and u-HA/PLLA and PLLA films were implanted in the intervertebral space. Total laminectomy was performed on 30 rabbits to implant u-HA/PLLA, c-HA/PLLA, and PLLA films in both epidural and subcutaneous spaces. For up to 50 weeks, there were no histological changes in the spinal cord or nerve root, and no inflammatory cell infiltration into the epidural space around the films. The rate of decrease in viscosity average molecular weight of both composite films was initially higher than that of PLLA but eventually became lower, although there was no difference in the degradation behavior of the three films in either the epidural or subcutaneous spaces after 50 weeks. Scanning electron microscopic and energy-dispersive X-ray analysis indicated calcium phosphate deposits on the surface of composite films with new bone formation from 4 weeks. The u-HA/PLLA composite film therefore has good biocompatibility, osteoconductivity, and fast primary degradation rate, which may prove compatible with application to spinal surgery.

Animals↗
PubMed1992

Cytokine secretion by immune cells in space.

Cultured, bone marrow-derived macrophages, murine spleen and lymph node cells, and human lymphocytes were tested for their ability to secrete cytokines in space. Lipopolysaccharide-activated bone marrow macrophages were found to secrete significantly more interleukin-1 and tumor necrosis factor when stimulated in space than when stimulated on earth. Murine spleen cells stimulated with poly I:C in space released significantly more interferon-alpha at 1 and 14 hours after stimulation than cells stimulated on earth. Similarly, murine lymph node T cells and human peripheral blood lymphocytes, stimulated with concanavalin A in space, secreted significantly more interferon-gamma than ground controls. These data suggest that space flight has a significant enhancing effect on immune cell release of cytokines in vitro.

Animals↗
PubMed1994

Intracellular and extracellular spaces and the direct quantification of molar intracellular concentrations of phosphorus metabolites in the isolated rat heart using 31P NMR spectroscopy and phosphonate markers.

To quantify metabolite and cation concentrations using NMR spectroscopy, the volumes of intracellular and extracellular spaces must be known. We describe a simple 31P NMR spectroscopic method that employs dimethyl methylphosphonate (DMMP) as a marker of total water space and phenylphosphonate (PPA) as a marker of extracellular space to determine intracellular and extracellular space volumes in the isolated, perfused rat heart. In vivo and in vitro radiolabel studies were used to verify this method. The difference between the total and extracellular water spaces, determined as milliliters/heart, gave the intracellular volume and allowed direct calculation of myocardial creatine phosphate, ATP, and inorganic phosphate concentrations, which were 13.4 mM, 10.1 mM, and 3.4 mM, respectively, for the glucose-perfused rat heart. The extracellular volume decreased by 84% in hearts subjected to 28 min total, global ischemia and increased by 15% during reperfusion. The method described allows the determination of intracellular energy metabolite concentrations in perfused rat heart directly from a single, fully relaxed 31P NMR spectrum.

Animals↗
PubMed1993

Response to added dead space in ventilated preterm neonates and outcome of trial of extubation.

The ventilatory response to an added external dead space was assessed in preterm babies, recovering from respiratory distress syndrome, immediately prior to extubation. All babies were ready for extubation as defined by routine clinical criteria. Baseline measurements of respiratory rate, tidal volume, and minute ventilation were made over a 2 min period using a computerized system consisting of a pneumotachometer connected directly to the proximal end of the endotracheal tube. The measurements were repeated after addition of an external dead space equivalent to 2 anatomical dead spaces (4.4 mL/kg body weight). Thirty-four babies were studied on 40 occasions. Twenty-four infants (60%) were successfully extubated and 16 (40%) required reintubation. Infants in the success and failure groups were matched for gestation at birth, postconceptional age and weight at the time of study, maximum ventilatory requirements, and treatment with methylxanthines. The added external dead space resulted in an increase in minute ventilation in 38 out of the 40 studies. Extubation success and failure groups were compared by expressing the minute ventilation after addition of the external dead space as a percentage of the baseline minute ventilation (%MV1). Successful extubation was associated with a higher median %MV1 compared with babies who failed extubation (156; range, 89.3 to 230; compared to 131; range, 75.2 to 165; P = 0.006). This test may be useful in deciding which babies could be successfully extubated.

Humans↗
PubMed1993

The effect of instrumental dead space on measurement of breathing pattern and pulmonary mechanics in the newborn.

The effect of the instrumental dead space on breathing pattern and the values of pulmonary mechanics was evaluated because of concern about the relatively large dead space of 26 mL in a commercially available system. Sixty-three healthy newborn infants were studied with a system as commercially supplied, and with the dead space eliminated using a 2 L/min biased flow. This led to a significant reduction in mean (+/- SD) values of respiratory rate from 56.8 (+/- 11.7) to 48.2 (+/- 11.7) breath/min (P < 0.0001), tidal volume from 5.2 (+/- 1.3) to 4.9 (+/- 0.9) mL/kg (P < 0.05), minute volume from 284 (+/- 68) to 220 (+/- 63) mL/min/kg (P < 0.0001), and work of breathing from 13.7 (+/- 6.6) to 11.8 (+/- 7.6) g.cm/kg (P < 0.02). There was a significant increase in dynamic lung compliance from 5.2 (+/- 1.5) to 5.6 (+/- 1.2) mL/cm H2O (P < 0.01) but no difference for total pulmonary resistance 39.6 (+/- 22.8) and 38.8 (+/- 22.2) cm H2O/L/sec. This shows that the instrumental dead space prevents measurement of the basal breathing patterns and alters the values of pulmonary mechanics. It is, therefore, important to use equipment with low dead space or make efforts to remove it by using a biased flow system such as we describe when measuring breathing patterns and pulmonary mechanics in the newborn.

Female↗