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PubMed1999

[On ergonomics of spacesuit].

The concept and the connotation of spacesuit ergonomics are specified. The method of ergonomics was applied to spacesuit design and the design demands for comfort, fitting and space compatibility of spacesuit are indicated systematically by applying anthropometry and building spacesuit size system (including weightlessness). Flexibility and posture of spacesuit are indicated with human mechanics (including weightlessness). The present situation of ergonomic research of spacesuit is discussed simply.

Anthropometry↗
PubMed2002

The effect of repeated altitude exposures on the incidence of decompression sickness.

INTRODUCTION: Repeated altitude exposures in a single day occur during special operations parachute training, hypobaric chamber training, unpressurized flight, and extravehicular space activity. Inconsistent and contradictory information exists regarding the risk of decompression sickness (DCS) during such hypobaric exposures. HYPOTHESIS: We hypothesized that four short exposures to altitude with and without ground intervals would result in a lower incidence of DCS than a single exposure of equal duration. METHODS: The 32 subjects were exposed to 3 different hypobaric exposures--condition A: 2 h continuous exposure (control); condition B: four 30-min exposures with descent/ascent but no ground interval between the exposures; condition C: four 30-min exposures with descent/ascent and 60 min of ground interval breathing air between exposures. All exposures were to 25,000 ft with 100% oxygen breathing. Subjects were observed for symptoms of DCS, and precordial monitoring of venous gas emboli (VGE) was accomplished with a SONOS 1000 echo-imaging system. RESULTS: DCS occurred in 19 subjects during A (mean onset 70+/-29 min), 7 subjects in B (60+/-34 min), and 2 subjects in C (40+/-18 min). There was a significant difference in DCS incidence between B and A (p = 0.0015) and C and A (p = 0.0002), but no significant difference between B and C. There were 28 cases of VGE in A (mean onset 30+/-23 min), 21 in B (41+/-35 min), and 21 in C (41+/-32 min) with a significant onset curve difference between B and A and between C and A, but not between B and C. Exposure A resulted in four cases of serious respiratory/neurological symptoms, while B had one and C had none. All symptoms resolved during recompression to ground level. CONCLUSION: Data indicate that repeated simulated altitude exposures to 25,000 ft significantly reduce DCS and VGE incidence compared with a single continuous altitude exposure.

Adolescent↗
PubMed2002

[Effects of head-down bedrest on surface temperature distribution and non-evaporative heat dissipation].

OBJECTIVE: To study effect of simulated weightlessness on non-evaporative heat dissipation from different parts of the human body. METHOD: Body surface temperature distribution of five subjects was measured under -6 degrees head down bedrest for 7 d with HR-II infrared thermography. Non-evaporative heat dissipation was calculated with the heat exchange equations based on surface temperature. RESULT: The temperature difference between torso and extremities increased during bed rest, and the largest was 6.7 degrees C higher than the control on the 3rd day of bed rest. The part of non-evaporative heat dissipation from the torso increased about 6% and that from head-neck increased 2%. At the same time, the parts of heat dissipation from the upper and lower extremities decreased about 3% and 5% respectively. CONCLUSION: The parts of non-evaporative heat dissipation from different areas of the human body changed during simulated weightlessness. This result provided a basis for the flow distribution design of liquid cooling garment of EVA suit.

Arm↗
PubMed2002

Skin microvascular flow during hypobaric exposure with and without a mechanical counter-pressure space suit glove.

INTRODUCTION: Current space suits are rigid, gas-pressurized shells that protect astronauts from the vacuum of space. A tight elastic garment or mechanical-counter-pressure (MCP) suit generates pressure by compression and may have several advantages over current space suit technology. In this study, we investigated local microcirculatory effects produced with and without a prototype MCP glove. METHODS: The right hand of eight normal volunteers was studied at normal ambient pressure and during exposure to -50, -100 and -150 mm Hg with and without the MCP glove. Measurements included the pressure against the hand, skin microvascular flow, temperature on the dorsum of the hand, and middle finger girth. RESULTS: Without the glove, skin microvascular flow and finger girth significantly increased with negative pressure, and the skin temperature decreased compared with the control condition. The MCP glove generated approximately 200 mm Hg at the skin surface; all measured values remained at control levels during exposure to negative pressure. DISCUSSION: Without the glove, skin microvascular flow and finger girth increased with negative pressure, probably due to a blood shift toward the hand. The elastic compression of the material of the MCP glove generated pressure on the hand similar to that in current gas-pressurized space suit gloves. The MCP glove prevented the apparent blood shift and thus maintained baseline values of the measured variables despite exposure of the hand to negative pressure.

Adult↗
PubMed1999

[Physiological basis of human mechanics and its application in the design of pressure suit].

Objective. To discuss the necessity that human mechanics and its physiological basis as applied to the research of human motion in many areas. Method. The motion performance of two aerospace [correction of areospace] pressure suit were studied. Human mechanics and its physiological basis was applied in the design of one suit only. Result. The result showed that good performance was obtained with the suit designed according to this principle which the stipulated actions couldn't be well performanced when wearing the suit not so designed. Conclusion. The research of the application of human mechanics and its physiological basis is necessary and it has better reality and is more scientific than applying biomechanics and robotics.

Aerospace Medicine↗
PubMed2003

Patent foramen ovale and paradoxical systemic embolism: a bibliographic review.

A patent foramen ovale (PFO) has been reported to be an important risk factor for cardioembolic cerebrovascular accidents through paradoxical systemic embolization, and it provides one potential mechanism for the paradoxical systemic embolization of venous gas bubbles produced after altitude or hyperbaric decompressions. Here, we present in a single document a summary of the original findings and views from authors in this field. It is a comprehensive review of 145 peer-reviewed journal articles related to PFO that is intended to encourage reflection on PFO detection methods and on the possible association between PFO and stroke. There is a heightened debate on whether aviators, astronauts, and scuba divers should go through screening for PFO. Because it is a source of an important controversy, we prefer to present the findings in the format of a neutral bibliographic review independent of our own opinions. Each cited peer-reviewed article includes a short summary in which we attempt to present potential parallels with the pathophysiology of decompression bubbles. Two types of articles are summarized, as follows. First, we report the original clinical and physiological findings which focus on PFO. The consistent reporting sequence begins by describing the method of detection of PFO and goal of the study, followed by bulleted results, and finally the discussion and conclusion. Second, we summarize from review papers the issues related only to PFO. At the end of each section, an abstract with concluding remarks based on the cited articles provides guidelines.

Astronauts↗
PubMed2003

Mechanical counter pressure on the arm counteracts adverse effects of hypobaric exposures.

INTRODUCTION: Current space suits have limited movement due to gas pressurization during exposure to the vacuum of space. Alternatively, if pressure is applied by an elastic garment vs. pneumatic garment to produce mechanical counter pressure (MCP), several advantages are possible. In this study, we investigate local microcirculatory and other effects produced with and without a prototype MCP glove and sleeve during exposure to varying levels of vacuum. METHODS: The entire arms of eight male volunteers were studied at normal ambient pressure and during 5 min exposures to -50, -100, and -150 mm Hg with and without the MCP glove and sleeve. Pressure distribution, skin microvascular flow, and temperature were measured. RESULTS: The MCP glove and sleeve generated over 200 mm Hg on the middle finger, dorsum of the hand, and the wrist. However, pressure was significantly lower on the forearm and the upper arm. Without the glove and sleeve, only two of eight subjects tolerated -100 mm Hg. Also, no subject tolerated -150 mm Hg. However, subjects tolerated all vacuum pressures wearing the glove and sleeve. Skin microvascular flow and temperature remained within control values with the glove and sleeve at a chamber pressure of -150 mm Hg. DISCUSSION: The MCP glove and sleeve counteracts adverse effects of vacuum exposures due to lower pressure differentials. Pressure levels over the hand and wrist are similar to those of the current U.S. space suit glove and sleeve, but additional development is required to increase MCP over the forearm and upper arm.

Adult↗
PubMed2003

[A robot measurement system for spacesuit joint torque].

OBJECTIVE: To measure the joint torque of spacesuit so as to evaluate its dynamic force/torque performance. METHOD: A method for measuring the spacesuit joint torque by use of robot technology was proposed in this paper. The design of the measuring strategy and measuring robot was put forward and a mathematical model of the system was given. Then the working space of the robot was analyzed. RESULT: The robot designed is light, compact, easy to operate, and has a large working space. Experimental results demonstrated the effectiveness of the measuring principle and the reliability of the measuring system. CONCLUSION: The system can satisfy the requirements of the spacesuit joint torque measurement.

Biomechanical Phenomena↗
PubMed2003

The Chameleon Suit--a liberated future for space explorers.

Mankind's spacefaring future demands the ability to work freely and frequently in space. Traditional spacesuit systems burden both the spacefarer and the mission, limiting the extent to which this is possible. The spacefarer is burdened by a pressure suit designed for isolation from the environment and a life support system designed to replace everything our environment normally provides. The space mission is burdened by this equipment and the expendable materials to operate and maintain it. We aren't free to work in space as frequently, as long, or in all of the locations envisioned. The NASA Institute for Advanced Concepts (NIAC) has sponsored research on an alternative concept, the "Chameleon Suit", that seeks to liberate future explorers and missions from these limitations. The Chameleon Suit system works with the environment in an adaptive fashion to minimize hardware and expendable materials. To achieve this, functions of the life support system are integrated with the pressure suit using emerging materials and design technology. Technologies under study include shape change polymers and electroemissive materials to modify heat transfer characteristics of the spacesuit "skin" achieving thermoregulation analogous to that in natural biological systems. This approach was shown to be feasible for many space missions during the Phase 1 study program. The current Phase 2 program is investigating more aggressive concepts aimed at eliminating most of the hardware currently included in the spacesuit's life support backpack. This paper describes the concept, study results to date, and possible impacts on future human space exploration.

Biomimetic Materials↗
PubMed2002

EAC trains its first international astronaut class.

After several years of planning and preparation, ESA's ISS training programme has become operational. Between 26 August and 6 September, the European Astronaut Centre (EAC) near Cologne gave the first ESA advanced training course for an international ISS astronaut class. The ten astronauts who took part--two from NASA, four from Japan and four from ESA--had begun their advanced training programme back in 2001 with sessions at the Johnson Space Center (JSC) in Houston and at the Japanese Training Centre in Tsukuba. During their stay in Cologne, the ten astronauts participated in a total of 33 classroom lessons and hands-on training sessions, which gave them a detailed overview of the systems and subsystems of the Columbus module, the Automated Transfer Vehicle (ATV), and the related crew operations tasks. They were also introduced to the four ESA experiment facilities to be operated inside the Columbus module. After their first week of training at EAC, the astronauts were given the opportunity to see the flight model of the Columbus module being integrated at the site of ESA's ISS prime contractor, Astrium in Bremen. The second week of training at EAC included hands-on instruction on the Columbus Data Management System (DMS) using the recently installed Columbus Crew Training Facility. In preparation for the first advanced crew training session at EAC, two Training Readiness Reviews (TRR) were conducted there in June and August. These reviews were supported by training experts and astronauts from NASA, NASDA and CSA (Canada), who were introduced to ESA's advanced training concept and the development process, and then analysed and evaluated the training flow, content and instructional soundness of lessons and courses, as well as the fidelity of the training facilities and the skills of the ESA training instructors. The International Training Control Board (ITCB), made up of representatives from all of the ISS International Partners and mandated to control and coordinate all multilateral training for ISS crew and ground-support personnel, testified to ESA's readiness to provide Advanced Training by declaring the EAC TRR successful. The completion of this first training course was therefore a good opportunity for the Astronaut Training Division to assess the status of its training programme. The comments and recommendations of the training experts and the astronauts who took part have been carefully evaluated and the results are being fed back into the ongoing training development process.

Astronauts↗
PubMed2003

[Experimental research on the effects of hydrophobic coating porous plates on heat dissipation of water sublimator].

OBJECTIVE: To investigate the development method of hydrophobic coating porous plates for water sublimator and carry out an experimental study on hydrophobic coating porous plates. METHOD: Porous plates were coated with Teflon coating solution and a kind of special hydrophobic coating solution. Physical characteristic tests for hydrophobic coating porous plates were conducted. An upgrading breadboard of sublimator was redesigned. Effects of hydrophobic coating porous plates on heat rejection of water sublimator were studied. RESULT: Hydrophobic coating porous plate could evidently increase the water retention pressure, but also increase pressure drop of gas permeability in varying degrees. Heat rejection performance of two kinds of coating plates was different. Performance of coating plate with the special hydrophobic coating solution was better. CONCLUSION: Hydrophobic coating porous plate could improve performance of water sublimator by optimizing coating parameters and technics of Teflon coating solution and the special hydrophobic coating solution.

Equipment Design↗
PubMed2003

[Application prospect of human-artificial intelligence system in future manned space flight].

OBJECTIVE: To make the manned space flight more efficient and safer, a concept of human-artificial (AI) system is proposed in the present paper. METHOD: The task of future manned space flight and the technique requirement with respect to the human-AI system development were analyzed. RESULT: The main points are as follows: 1)Astronaut and AI are complementary to each other functionally; 2) Both symbol AI and connectionist AI should be included in the human-AI system, but expert system and Soar-like system are used mainly inside the cabin, the COG-like robots are mainly assigned for EVA either in LEO flight or on the surface of Moon or Mars; 3) The human-AI system is hierarchical in nature with astronaut at the top level; 4) The complex interfaces between astronaut and AI are the key points for running the system reliably and efficiently. CONCLUSION: As the importance of human-AI system in future manned space flight and the complexity of related technology, it is suggested that the R/D should be planned as early as possible.

Artificial Intelligence↗