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At least 163 records · Page 9Linked to original sources
PubMed1998

The world's first practical flight pressure suit.

The first practical flight pressure suit was developed in 1934 by Wiley Post of global flight fame. B.F. Goodrich Company assisted in the development. The final pressure suit used a liquid oxygen source and had arm and leg joints that permitted easy operation of the flight controls and also enabled walking to and from the aircraft. In his Lockheed Vega, the "Winnie May," Post set unofficial altitude records (as high as 50,000 ft), discovering the jet stream in the process. In March 1935, Post flew from Burbank, CA, to Cleveland, OH, in the stratosphere using the jet stream. At times, his ground speed exceeded 340 mph in a 179 mph aircraft. Post's pioneering accomplishments were the first major practical advance in pressurized flight.

Aerospace Medicine↗
PubMedDate not supplied

Energy utilization rates during shuttle extravehicular activities.

The work rates or energy utilization rates during EVA are major factors in sizing of life support systems. These rates also provide a measure of ease of EVA and its cost in crew fatigue. From the first Shuttle EVA on the STS-6 mission in 1983, we have conducted 59 man-EVA and 341 man-hours of EVA. Energy utilization rates have been measured on each of these EVA. Metabolic rate was measured during each EVA using oxygen utilization corrected for suit leakage. From 1981-1987, these data were available for average data over the EVA or over large segments of the EVA. Since 1987, EVA oxygen utilization data were available at 2-minute intervals. The average metabolic rate on Shuttle EVA (194 kcal/hr.) has been significantly lower than metabolic rates during Apollo and Skylab missions. Peak rates have been below design levels, infrequent, and of short duration. The data suggest that the energy cost of tasks may be inversely related to the degree of training for the task. The data provide insight on the safety margins provided by life support designs and on the energy cost of Station construction EVA.

Aerospace Medicine↗
PubMed2000

[Human physiological regulation in the closed suit with no ventilation].

Objective. To study the effects of the Experimental Closed Suit (ECS) with no active ventilation on human physiological functions and its anti-asphyxic role. Method. Five young healthy male subjects, aged 18-21 years, were tested in the ECS with no active ventilation and no oxygen supply (NAVANOS) when the gas regulatory valve switch was placed on A or B position respectively. Result. (1) Under 1 atm air pressure, each subject could endure at least 15 min while they were aware and resting in the ECS with NAVANOS; (2) There was a balancing period or plateau of the oxygen and the carbon dioxide pressure in the vicinity of the mouth in 5 to 7 min after the sealed helmet was closed, and this period lasted to the end of each test; (3) During the 8-10 min balancing period, the oxygen partial pressure in the vicinity of the mouth ranged from 15.0 to 16.4 kpa, which was slightly hypoxic, and the range of the carbon dioxide partial pressure was 5.21 to 6.49 kPa, which was within the CO2 concentration-time curve of human physiological endurance; (4) No significant difference in human physiological parameters was found when the regulatory valve was placed on A or B position. Conclusion. The anti-asphyxic time of ECS with NAVANOS could at least last 15 min under 1 atm air pressure while the subjects were aware and resting.

Adolescent↗
PubMed1996

Locomotion while load-carrying in reduced gravities.

Supporting the mass of a protective suit and portable life support system (PLSS) will impose an energy requirement on planetary astronauts. To design extravehicular protective equipment for planetary missions, scientists must learn more about human physical capabilities while load-carrying in reduced gravities. In this study, an underwater treadmill and weighting system were used to simulate reduced-gravity locomotion while load-carrying. The test matrix included 3 gravity levels, 6 subjects, 2 locomotion speeds, and a range of load sizes. Energy expenditure, calculated from measured oxygen consumption, is positively correlated with gravity level, speed, and load size. The data are used to project that individuals in average physical condition will be able to walk for 8 h on the Moon while carrying up to 170% of their body mass without undue fatigue, and on Mars with up to 50% of their body mass. These approximate limits, especially for Martian gravity, may prove quite a challenge for designers of advanced protective systems. Requirements for regenerable and non-venting PLSS components have been driving the total projected masses of advanced PLSSs increasingly higher, perhaps beyond what is reasonable to carry. However, the larger mass can be beneficial in maintaining bone mass. Using Whalen's model (1988), the daily planetary walking times required to maintain bone mass were calculated for a range of carried load sizes. The calculated times were unattainably high, suggesting that some combination of loads carrying and supplemental bone maintenance measures will likely be required to maintain bone mass in reduced gravity environments.

Bone Density↗
PubMed2006

Comparison of efficacy of Adeli suit and neurodevelopmental treatments in children with cerebral palsy.

This study compared the efficacy of Adeli suit treatment (AST) with neurodevelopmental treatment (NDT) in children with cerebral palsy (CP). Twenty-four children with CP, Levels II to IV according to the Gross Motor Function Classification System (GMFCS), were matched by age and functional status and randomly assigned to the AST or NDT treatment groups. In the AST group (n=12; eight males, four females; mean age 8.3 y [SD 2.0]), six children had spastic/ataxic diplegia, one triplegia and five spastic/mixed quadriplegia. In the NDT group (n=12; nine males, three females; mean age 8.1 y [SD 2.2]), five children had spastic diplegia and seven had spastic/mixed quadriplegia. Both groups were treated for 4 weeks (2 hours daily, 5 days per week, 20 sessions). To compare treatments, the Gross Motor Function Measure (GMFM-66) and the mechanical efficiency index (EIHB) during stair-climbing were measured at baseline, immediately after 1 month of treatment, and 10 months after baseline. The small but significant time effects for GMFM-66 and EIHB that were noted after 1 month of both intensive physiotherapy courses were greater than expected from natural maturation of children with CP at this age. Improvements in motor skills and their retention 9 months after treatment were not significantly different between the two treatment modes. Post hoc analysis indicated a greater increase in EIHB after 1 month (p=0.16) and 10 months (p=0.004) in AST than that in NDT, predominantly in the children with higher motor function (GMFCS Levels II and III). The results suggest that AST might improve mechanical efficiency without a corresponding gain in gross motor skills, especially in children with higher levels of motor function.

Brain↗
PubMedDate not supplied

Skylab task and work performance (experiment M-151--time and motion study).

The primary objective of Experiment M151 was to study by means of time and motion analytic techniques the inflight adaptation of Skylab crewmen to a variety of task situations involving different types of activity. A parallel objective was to examine astronaut inflight performance for any behavioral stress effects associated with the working and living conditions of the Skylab environment. Training data provided the basis for comparison of preflight and inflight performance. Efficiency was evaluated through the adaptation function, namely, the relation of performance time over task trials. The results indicate that the initial changeover from preflight to inflight (or, from 1-G to zero-G) was accompanied by a substantial increase in performance time for most work and task activities. Equally important was the finding that crewmen adjusted rapidly to the weightless environment and became proficient in developing techniques with which to optimize task performance. By the end of the second inflight trial, most of the activities were performed almost as efficiently as on the last preflight trial. In addition, the analysis demonstrated the sensitivity of the adaptation function to differences in task and hardware configuration. The function was found to be more regular and less variable inflight than preflight. Translation and control of masses (large or small) were accomplished easily and efficiently through the rapid development of the arms and legs (and the entire body) as subtle guidance and restraint systems. Finally, the adaptation function provided no evidence of behavioral stress effects attributable to the Skylab environment.

Adaptation, Physiological↗
PubMedDate not supplied

Emergency and rescue considerations for manned space missions.

Man in space is totally dependent upon spacecraft systems. particularly those providing Environmental Control and Life Support (ECLS). It is therefore required that the design of manned spacecraft systems include provision for backup emergency and rescue modes of operation to insure adequate crew safety margin. This paper discusses safety, emergency and rescue provisions included in the Space Transportation System (STS), with emphasis on ECLS subsystems. Similar discussion is included for systems projected for use in future, extended duration manned space missions.

Emergencies↗
PubMed1994

EVA design: lessons learned.

Extravehicular Activities (EVAs) are very demanding and specialized space flight activities. There are many aspects to consider in the design of hardware, tools, and procedures to be used on an EVA mission. To help minimize costs and optimize the EVA productivity, experience shows that astronauts should become involved early in the design process.

Astronauts↗
PubMed1994

EVA safety design guidelines.

An Extravehicular Mobility Unit is a closed and isolated environment that protects the astronaut from exposure to space environment. Eighty-four percent of the possible hardware failures occurring during Extravehicular Activity (EVA) would result in an abort of the EVA. Fifty-two percent of these failure modes would result in a loss of a critical life support function and directly compromise crew safety. Crew safety is not, however, limited to controlling hardware failures. Safety can be compromised by improper in-flight servicing or induced by interfacing equipment during EVA related activity. This paper addresses these potential hazard sources and approaches used to enhance equipment reliability and astronaut safety.

Air Conditioning↗
PubMed1994

Rapid assessment of radiobiological doses for terrestrial and interplanetary space missions.

This paper presents the doses levels expected in orbits in chart form, covering the range 300-800 km of altitude and 0-90 degrees of inclination behind shieldings similar to the Hermes spacecraft and the EVA spacesuit matter distributions. These charts allow users to rapidly find the radiobiological dose received in the most critical organs of the human body either in normal situations or during a large solar event. Outside the magnetosphere, during interplanetary or lunar missions, when the dose received during crossing of the radiation belts become negligible, the dose is due to galactic cosmic rays (GCR) and solar flares. The correct radiobiological assessment of the components of this radiation field becomes a major problem. On the Moon a permanent ground-based station can be shielded by lunar materials against meteoroids and radiations. The radiobiological hazard, essentially linked to the solar flare risk during the transfer phase and the extra-station activities, may be solved by mission planning. For interplanetary flights the problem comes from both increased risk of solar events and from the continuous exposure to GCR. These energetic particles cannot be easily stopped by shieldings; cost considerations imply that more effective materials must be used. Impact on the vehicle design and the mission planning is important.

Atlantic Ocean↗
PubMed1995

EVA-related activities in Japan.

Recognizing the importance and fertility of the extra vehicular activity technologies in future space development and utilization, some related research activities have been conducted in Japan, though it has not committed itself to developing its own manned space flight capability. The purpose of this paper is to introduce and evaluate these EVA-related activities and to indicate the next step for Japan to get into the era of manned space activities including EVA in reality.

Carbon Dioxide↗
PubMedDate not supplied

The International Space Station: a pathway to the future.

Nearly six years after the launch of the first International Space Station element, and four years after its initial occupation, the United States and our 6 international partners have made great strides in operating this impressive Earth orbiting research facility. This past year we have done so in the face of the adversity of operating without the benefit of the Space Shuttle. In his January 14, 2004, speech announcing a new vision for America's space program, President Bush affirmed the United States' commitment to completing construction of the International Space Station by 2010. The President also stated that we would focus our future research aboard the Station on the long-term effects of space travel on human biology. This research will help enable human crews to venture through the vast voids of space for months at a time. In addition, ISS affords a unique opportunity to serve as an engineering test bed for hardware and operations critical to the exploration tasks. NASA looks forward to working with our partners on International Space Station research that will help open up new pathways for future exploration and discovery beyond low Earth orbit. This paper provides an overview of the International Space Station Program focusing on a review of the events of the past year, as well as plans for next year and the future.

Extravehicular Activity↗
PubMed2005

Finger heat flux/temperature as an indicator of thermal imbalance with application for extravehicular activity.

The designation of a simple, non-invasive, and highly precise method to monitor the thermal status of astronauts is important to enhance safety during extravehicular activities (EVA) and onboard emergencies. Finger temperature (Tfing), finger heat flux, and indices of core temperature (Tc) [rectal (Tre), ear canal (Tec)] were assessed in 3 studies involving different patterns of heat removal/insertion from/to the body by a multi-compartment liquid cooling/warming garment (LCWG). Under both uniform and nonuniform temperature conditions on the body surface, Tfing and finger heat flux were highly correlated with garment heat flux, and also highly correlated with each other. Tc responses did not adequately reflect changes in thermal balance during the ongoing process of heat insertion/removal from the body. Overall, Tfing/finger heat flux adequately reflected the initial destabilization of thermal balance, and therefore appears to have significant potential as a useful index for monitoring and maintaining thermal balance and comfort in extreme conditions in space as well as on Earth.

Adult↗
PubMed2001

Martian polar expeditions: problems and solutions.

The Martian polar ice caps are regions of substantial scientific interest, being the most dynamic regions of Mars. They are volatile sinks and thus closely linked to Martian climatic conditions. Because of their scale and the precedent set by the past history of polar exploration on Earth, it is likely that an age of polar exploration will emerge on the surface of Mars after the establishment of a capable support structure at lower latitudes. Expeditions might be launched either from a lower latitude base camp or from a human-tended polar base. Based on previously presented expeditionary routes to the Martian poles, in this paper a "spiral in-spiral out" unsupported transpolar assault on the Martian north geographical pole is used as a Reference expedition to propose new types of equipment for the human polar exploration of Mars. Martian polar "ball" tents and "hover" modifications to the Nansen sledge for sledging on CO2-containing water ice substrates under low atmospheric pressures are suggested as elements for the success of these endeavours. Other challenges faced by these expeditions are quantitatively and qualitatively addressed.

Carbon Dioxide↗
PubMed1999

Biomedical study on combined effects of simulated weightlessness and emergent depressurization of spacecraft.

Cabin emergent depressurization (CED) may occur in spacecraft during manned space flight. The purpose of this paper was to study the combined effects of simulated weightlessness (SW) and CED factors on humans and animals. It was found that the amplitude of T wave of human electrocardiograms (ECG) significantly decreased in bed rest and hypoxia compared with the control condition (P<0.05), and that suspension with pure O2 induced severer edema in the lungs of rats than that in only a pure O2 environment. SW and pure O2 caused middle ear congestion and decreased the barofunction during pressure changes. These results indicate that human response to CED factors become more serious under SW because of the blood redistribution.

Aerospace Medicine↗
PubMed2001

Radiation dose from reentrant electrons.

In estimating the crew exposures during an extra vehicular activity (EVA), the contribution of reentrant electrons has always been neglected. Although the flux of these electrons is small compared to the flux of trapped electrons, their energy spectrum extends to several GeV compared to about 7 MeV for trapped electrons. This is also true of splash electrons. Using the measured reentrant electron energy spectra, it is shown that the dose contribution of these electrons to the blood forming organs (BFO) is more that 10 times greater than that from the trapped electrons. The calculations also show that the dose-depth response is a very slowly changing function of depth, and thus adding reasonable amounts of additional shielding would not significantly lower the dose to BFO.

Aerospace Medicine↗
PubMed1999

Shielding from solar particle event exposures in deep space.

The physical composition and intensities of solar particle event exposures of sensitive astronaut tissues are examined under conditions approximating an astronaut in deep space. Response functions for conversion of particle fluence into dose and dose equivalent averaged over organ tissues are used to establish significant fluence levels and the expected dose and dose rates of the most important events from past observations. The BRYNTRN transport code is used to evaluate the local environment experienced by sensitive tissues and used to evaluate bioresponse models developed for use in tactical nuclear warfare. The present results will help to clarify the biophysical aspects of such exposure in the assessment of RBE and dose rate effects and their impact on design of protection systems for the astronauts. The use of polymers as shielding material in place of an equal mass of aluminum would provide a large safety factor without increasing the vehicle mass. This safety factor is sufficient to provide adequate protection if a factor of two larger event than has ever been observed in fact occurs during the mission.

Bone Marrow↗