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At least 649 records · Page 36Linked to original sources
PubMed1996

Bioregenerative life support systems for long-term space habitation: a conceptual approach.

Life support systems represent one of the most critical aspects of human space exploration. Future long-term missions such as the establishment of human-tended Lunar and Martian bases require closed life support systems. A conceptual approach to an Engineered Closed/Controlled EcoSystem incorporating bioregenerative capabilities by integrating humans, plants, and waste management processes is presented. The integration of physical/chemical and biological waste treatment processes is suitable for supporting plant growth through hydroponics and materially closing the human and plant metabolic loops. This conceptual design separates wastes into individual loops for treatment according to the specific metabolic needs of humans and plants. The means through which an integrated Engineered Closed/Controlled EcoSystem meets the life support objectives of long-term space habitation are summarized.

Biomass↗
PubMed1989

Use of Martian resources in a Controlled Ecological Life Support System (CELSS).

The exploration of Mars has long been considered as a major goal in the exploration of the Solar system. The Space Station Freedom will make such missions feasible because it will provide a site for the assembly and launch of the large vehicles required. Interest in manned visits to Mars often focus on the possibility of collecting information about the origin of that planet, & hence of the solar system, including the Earth. Interest also involves the history of the planet, its past record of geological and fluvial activity, atmospheric and thermal history and surface chemical activity. The latter is of particular interest to exobiologists who would like to seek evidence of pre-biological physical and chemical activity involving organic molecules. Finally, there is interest in the possibility of planetary ecosynthesis, i.e. specific intervention in the evolution of Mars that could result in the development of a second habitable planet in the solar system. The scenarios for visits and the establishment of bases on Mars are being developed now. The intent of this paper is to consider various possibilities for crew life support on Mars and particularly to explore the use of Martian resources as life support materials.

Carbon Dioxide↗
PubMed1993

Multicultural factors in the space environment: results of an international shuttle crew debrief.

There is increasing interest and concern about the multicultural and multinational factors which might negatively affect adjustment and performance of Space Station Freedom (SSF) crews, living and working for long periods of time in the space environment. To begin identifying potential problem areas, a crew debrief questionnaire (called an "International Crew Debrief") was mailed to U.S. astronauts who flew on Shuttle missions between 1981-1990 with one or more crewmembers from other countries. There were 20 U.S. astronauts who flew on international space missions; 9 of these responded to the questionnaire, for a return rate of 45%. There were 42 incidents reported: 9 in the preflight period; 26 inflight; and 7 in the postflight period. Most of these incidents were rated as having a low or medium impact, but five of the inflight incidents were rated to have a "high" mission impact. A number of causes for the problems were listed, and are discussed. Debrief respondents provided useful and timely recommendations on preflight training which may help facilitate the integration of multinational crews, and prevent multicultural or multinational factors from interfering with mission operations.

Cultural Characteristics↗
PubMed2001

The biomedical challenges of space flight.

Space medicine has evolved considerably through past U.S. missions. It has been proven that humans can live and work in space for long durations and that humans are integral to mission success. The space medicine program of the National Aeronautics and Space Administration (NASA) looks toward future long-duration missions. Its goal is to overcome the biomedical challenges associated with maintaining the safety, health, and optimum performance of astronauts and cosmonauts. This program investigates the health effects of adaptation to microgravity: the nature of their pathologies, the effects of microgravity on pathophysiology, and the alterations in pharmacodynamics and treatment. A critical capability in performing research is the monitoring of the health of all astronauts and of the spacecraft environment. These data support the evidence-based approach to space medicine, incorporating past studies of microgravity-related conditions and their terrestrial counterparts. This comprehensive approach will enable safe and effective exploration beyond low Earth orbit.

Adaptation, Physiological↗
PubMed1991

Orthostatic function during a stand test before and after head-up or head-down bedrest.

Astronauts may exhibit orthostatic dysfunction upon returning to 1 g after space flight. Understanding cardiovascular changes at 0 G will provide insights into the mechanisms of the loss of orthostatic tolerance, whether due to space flight or bedrest. Bedrest is one model used to produce cardiovascular changes that are associated with space flight. In the current study, young male adults were placed at -5 degrees, +10, +20, or +42 degrees bedrest (0, 1/6, 1/3, and 2/3g, respectively) for 6 hours on 4 different days. This was preceded and followed by a stand test: 5 minutes in the supine position, and then 5 minutes in the standing position, with the feet 9 inches apart and 6 inches from the wall. Cardiovascular values were measured at 1-minute intervals. Systolic and diastolic pressures were measured using an automated blood pressure device; mean arterial pressure (MAP; mm Hg) was calculated. Heart rate (bpm) and cardiac parameters were measured with a thoracic impedance device. Minute 3, 4, and 5 values were used to determine whether there were time or angle effects. Of six subjects, one reported nausea upon 3 minutes of standing after 6 hours of bedrest at -5 degrees. The same subject was lightheaded in the first minute of standing after 6 hours of bedrest at +10 degrees. Mean heart rate pre-bedrest in the supine position was 63 and increased by 24 bpm on standing. Heart rate post-bedrest in the supine position was 65 and increased by 35 bpm on standing; standing heart rate increased 11 bpm after -5 degrees bedrest. The increases after +10 degrees, +20 degrees, and +42 degrees tilts were 4, 3, and 4 bpm, respectively. Changes in the mean arterial blood pressure were minimal. Results from the stand test pre- and post- 6 hours of bedrest at -5 degrees but not at +10 degrees, +20 degrees, or +42 degrees are similar to those after space flight.

Adult↗
PubMed1994

Insect gravitational biology: ground-based and shuttle flight experiments using the beetle Tribolium castaneum.

Many of the traditional experimental advantages of insects recommend their use in studies of gravitational and space biology. The fruit fly, Drosophila melanogaster, is an obvious choice for studies of the developmental significance of gravity vectors because of the unparalleled description of regulatory mechanisms controlling oogenesis and embryogenesis. However, we demonstrate that Drosophila could not survive the conditions mandated for particular flight opportunities on the Space Shuttle. With the exception of Drosophila, the red flour beetle, Tribolium castaneum, is the insect best characterized with respect to molecular embryology and most frequently utilized for past space flights. We show that Tribolium is dramatically more resistant to confinement in small sealed volumes. In preparation for flight experiments we characterize the course and timing of the onset of oogenesis in newly eclosed adult females. Finally, we present results from two shuttle flights which indicate that a number of aspects of the development and function of the female reproductive system are not demonstrably sensitive to microgravity. Available information supports the utility of this insect for future studies of gravitational biology.

Animals↗
PubMed1995

Effect of crop development on biogenic emissions from plant populations grown in closed plant growth chambers.

The Biomass Production Chamber at John F. Kennedy Space Center is a closed plant growth chamber facility that can be used to monitor the level of biogenic emissions from large populations of plants throughout their entire growth cycle. The head space atmosphere of a 26-day-old lettuce (Lactuca sativa cv. Waldmann's Green) stand was repeatedly sampled and emissions identified and quantified using GC-mass spectrometry. Concentrations of dimethyl sulphide, carbon disulphide, alpha-pinene, furan and 2-methylfuran were not significantly different throughout the day; whereas, isoprene showed significant differences in concentration between samples collected in light and dark periods. Volatile organic compounds from the atmosphere of wheat (Triticum aestivum cv. Yecora Rojo) were analysed and quantified from planting to maturity. Volatile plant-derived compounds included 1-butanol, 2-ethyl-1-hexanol, nonanal, benzaldehyde, tetramethylurea, tetramethylthiourea, 2-methylfuran and 3-methylfuran. Concentrations of volatiles were determined during seedling establishment, vegetative growth, anthesis, grain fill and senescence and found to vary depending on the developmental stage. Atmospheric concentrations of benzaldehyde and nonanal were highest during anthesis, 2-methylfuran and 3-methylfuran concentrations were greatest during grain fill, and the concentration of the tetramethylurea peaked during senescence.

Biomass↗
PubMed1987

Space motion sickness preflight adaptation training: preliminary studies with prototype trainers.

Preflight training frequently has been proposed as a potential solution to the problem of space motion sickness. The paper considers successively the otolith reinterpretation, the concept for a preflight adaptation trainer and the research with the Miami University Seesaw, the Wright Patterson Air-Force Base Dynamic Environment Simulator and the Visually Coupled Airborne Systems Simulator prototype adaptation trainers.

Adaptation, Physiological↗
PubMed1989

The biological clock of Neurospora in a microgravity environment.

The circadian rhythm of conidiation in Neurospora crassa is thought to be an endogenously derived circadian oscillation; however, several investigators have suggested that circadian rhythms may, instead, be driven by some geophysical time cue(s). An experiment was conducted on space shuttle flight STS-9 in order to test this hypothesis; during the first 7-8 cycles in space, there were several minor alterations observed in the conidiation rhythm, including an increase in the period of the oscillation, an increase in the variability of the growth rate and a diminished rhythm amplitude, which eventually damped out in 25% of the flight tubes. On day seven of flight, the tubes were exposed to light while their growth fronts were marked. Some aspect of the marking process reinstated a robust rhythm in all the tubes which continued throughout the remainder of the flight. These results from the last 86 hours of flight demonstrated that the rhythm can persist in space. Since the aberrant rhythmicity occurred prior to the marking procedure, but not after, it was hypothesized that the damping on STS-9 may have resulted from the hypergravity pulse of launch. To test this hypothesis, we conducted investigations into the effects of altered gravitational forces on conidiation. Exposure to hypergravity (via centrifugation), simulated microgravity (via the use of a clinostat) and altered orientations (via alterations in the vector of a 1 g force) were used to examine the effects of gravity upon the circadian rhythm of conidiation.

Biological Clocks↗
PubMed1994

Clover development during spaceflight: a model system.

The development of legume root nodules was studied as a model system for the examination of gravitational effects on plant root development. In order to examine whether rhizobial association with clover roots can be achieved in microgravity, experiments were performed aboard the KC-135 parabolic aircraft and aboard the sounding rocket mission Consort 3. Binding of rhizobia to roots and the initial stages of root nodule development successfully occurred in microgravity. Seedling germination experiments were performed in the sliding block device, the Materials Dispersion Apparatus, aboard STS-37. When significant hydration of the seeds was achieved, normal rates of germination and seedling development were observed.

Cell Differentiation↗
PubMed1996

Epidemiology of Staphylococcus aureus during space flight.

Staphylococcus aureus was isolated over 2 years from Space Shuttle mission crewmembers to determine dissemination and retention of bacteria. Samples before and after each mission were from nasal, throat, urine, and feces and from air and surface sampling of the Space Shuttle. DNA fingerprinting of samples by digestion of DNA with SmaI restriction endonuclease followed by pulsed-field gel electrophoresis showed S. aureus from each crewmember had a unique fingerprint and usually only one strain was carried by an individual. There was only one instance of transfer between crewmembers. Strains from interior surfaces after flight matched those of crewmembers, suggesting microbial fingerprinting may have forensic application.

DNA Fingerprinting↗
PubMed1996

Presence of mind: a reaction to Thomas Sheridan's "Further musings on the psychophysics of presence."

An operator's sense of remote presence during teleoperation or use of virtual environment interfaces is analyzed as to what characteristics it should have to qualify it as an explanatory scientific construct. But the implicit goal of designing virtual environment interfaces to maximize presence is itself questioned in a second section in which examples of human-machine interfaces beneficially designed to avoid a strong sense of egocentric presence are cited. In conclusion, it is argued that the design of a teleoperation or virtual environment system should generally focus on the efficient communication of causal interaction. In this view the sense of presence, that is of actually being at the simulated or remote workplace, is an epiphenomena of secondary importance for design.

Computer Graphics↗
PubMed1984

Experiments on plants grown in space. Status and prospects.

Space flight provides a unique capability to gravitational research by providing an environment in which gravity can be manipulated below the Earth norm of 1 to a state comparable to weightlessness. Although space experiments with seeds and plants have been conducted for almost 25 years, we are only now entering an era that promises the capability of routinely conducting controlled plant experiments in space. Results from experiments with higher plants and seeds flown thus far in both manned and unmanned spacecraft from both the USA and USSR are briefly summarized. An overview of the current status of space biology experimentation as it relates to plants is presented and present and future opportunities to conduct plant experiments under space flight conditions are discussed.

Gravitation↗