Multiple-task performance on a computer-simulated life support system during a space mission simulation

This paper presents an experiment which examined the effects of isolation and confinement during a simulation of a short-term space mission. During the 7-day spaceflight simulation, four Canadian astronauts were tested daily on a 30-min performance task. The task, CAMS (Cabin Air Management System), represents a computer-based simulation of a generic life support system. As a multiple-task environment, it allows the measurement of a wide range of task management variables such as primary and secondary task performance, and system control activities. Measures of subjective state variables were also taken. The results did not show any evidence of serious performance decrements for any crew member. The analysis revealed different adjustment patterns with which crew members responded as a function of mission duration and variations in workload. Among the secondary tasks employed, prospective memory was found to be more sensitive than reaction time to increases in workload. The paper concludes with a discussion of the utility of spaceflight simulations and computer-based simulations of space work.     

Fluid volumes changes induced by spaceflight

The blood volume (BV), plasma volume (PV), and extracellular fluid volume changes produced in crewmembers during spaceflights of 11-84 days were compared to changes after 14 or 28 days of bedrest. Spaceflight and bedrest produce approximately equal BV changes but the recorded PV change after spaceflight was less. However, the diurnal change in PV may explain the smaller decreases recorded after spaceflight. The cardiovascular deconditioning caused by spaceflight and bedrest was compared using the mean heart rate response to lower body negative pressure (LBNP) testing at -50 mmHg pressure. These tests show approximately equal LBNP produced heart rate changes after bedrest and spaceflight. A countermeasure which includes 4 hr of LBNP treatment at -30 mmHg and the ingestion of one l. of saline was studied and found capable of returning the heart rate response and the PV of bedrested subjects to control (prebedrest) levels suggesting that it would be useful to the crewmembers after a spaceflight.     

美国载人航天安全要求和管理

安全问题对载人航天的成败至关重要.文章介绍了美国NASA在载人航天安全管理方面的有关标准和管理文件.文章也不排斥人的安全意识对载人航天的安全十分关键.     

Spatial factors and muscle spindle input influence the generation of neuromuscular responses to stimulation of the human foot

Removal of the mechanical pressure gradient on the soles leads to physiological adaptations that ultimately result in neuromotor degradation during spaceflight. We propose that mechanical stimulation of the soles serves to partially restore the afference associated with bipedal loading and assists in attenuating the negative neuromotor consequences of spaceflight. A dynamic foot stimulus device was used to stimulate the soles in a variety of conditions with different stimulation locations, stimulation patterns and muscle spindle input. Surface electromyography revealed the lateral side of the sole elicited the greatest neuromuscular response in ankle musculature, followed by the medial side, then the heel. These responses were modified by preceding stimulation. Neuromuscular responses were also influenced by the level of muscle spindle input. These results provide important information that can be used to guide the development of a “passive” countermeasure that relies on sole stimulation and can supplement existing exercise protocols during spaceflight.     

Plant molecular biology in the space station era: utilization of KSC fixation tubes with RNAlater

Spaceflight experiments involving biological specimens face unique challenges with regard to the on orbit harvest and preservation of material for later ground-based analyses. Preserving plant material for gene expression analyses requires that the tissue be prepared and stored in a manner that maintains the integrity of RNA. The liquid preservative RNAlater (Ambion) provides an effective alternative to conventional freezing strategies, which are limited or unavailable in current spaceflight experiment scenarios. The spaceflight use of RNAlater is enabled by the Kennedy space center fixation tube (KFT), hardware designed to provide the necessary containment of fixatives during the harvest and stowage of biological samples in space. Pairing RNAlater with the KFT system provides a safe and effective strategy for preserving plant material for subsequent molecular analyses, a strategy that has proven effective in several spaceflight experiments. Possible spaceflight scenarios for the use of RNAlater and KFTs are explored and discussed.     

航天记录器的发展和转型

概述中国航天记录器近五十年的发展历程,阐述航天记录器技术转型的十年过程,简要介绍目前航天记录器应用的新进展。     

一种载人航天概率风险评价数据选用与分析方法

概率风险评价(PRA)方法是一项成熟的量化风险评估技术,而可靠性相关数据不足,制约着该方法在国内载人航天领域的应用。针对这一问题,结合NASA的PRA工作经验,提出了一种适合国内载人航天PRA数据选用与分析的方法,综合运用产品的通用数据与特定数据,采用贝叶斯等数据融合方法,对产品进行量化评价。通过航天典型产品案例,与经典评估方法进行对比分析,结果表明,此方法更能反映产品的失效特性。文章提出的方法,可用于载人航天等具有小子样特征的产品PRA数据的选用与分析,为我国载人航天开展PRA工作提供参考。     

Mission success regulations,their effect on ELV launch success and the applicability to regulating commercial human spaceflight

As the human spaceflight industry grows the agencies charged with regulating that industry meet significant challenges. An improvement in launch success would improve the safety for the crew and passengers of a commercial human spaceflight. With respect to ELV launches, NASA's regulations over civil launches are mission success oriented while commercial launches regulated by the FAA-AST, the agency that will also be charged with human spaceflight, takes a more public safety oriented stance. A comparison of the launch success between civil and commercial launches is used to inform the decision on whether or not mission success would be an appropriate regulatory stance for the FAA-AST. The results show that there is no significant difference in launch success between civil and commercial ELV launches. Because of this and because the industry is wary of over regulation, there is indication that a mission success oriented stance might not be appropriate for regulating commercial human spaceflight.     

When will we see a Golden Age of Spaceflight?

The supposed parallels between the development of aviation and of spaceflight are not as great as believed. The most significant differences are the public expectation that spaceflight, unlike aviation, is a matter for governments and the notion that, because it is so technically challenging, it must always be expensive. Early aviation was massively spurred on by the offer of lucrative prizes for the achievement of certain feats and by the activities of private barnstormers. The successfully attained X Prize has been the first attempt to do the same for spaceflight. The creation of further prizes could be the best way of promoting greater public involvement in space and commercially developing the sector.     

Vascular functions in humans following cardiovascular adaptations to spaceflight

Purpose: Diminished vascular function is a primary cardiovascular risk of spaceflight identified in the 2004 NASA Bioastronautics Critical Path Roadmap based on: (1) structural and functional alterations in arterial vessels of animals undergoing hindlimb unloading and; (2) lower peripheral vascular resistance (PVR) in astronauts who became presyncopal after spaceflight.Methods: We conducted a critical review of published data obtained from spaceflight and relevant ground-based microgravity simulations in an effort to interpret the meaning of altered responses in PVR and their relationship to postflight presyncope.Results: Presyncope reported in astronauts on landing day was associated with lower peripheral resistance. However, non-presyncopal astronauts demonstrated significantly elevated vascular resistance in the upright posture after compared with before spaceflight. Results from both space and ground experiments suggest that preflight maximal vasoconstrictor capacity is inherently lower in presyncopal astronauts, but unaltered by spaceflight.Conclusions: Vasoconstrictor reserve is associated with lower blood volume adaptation to microgravity. Rather than reduced vascular function, low inherent maximal vasoconstrictor capacity and reduced vasoconstrictor reserve secondary to decreased circulating vascular volume explain lower peripheral vascular resistance in astronauts who experience presyncopal episodes on landing day.     

航天型号进度控制研究

针对航天型号研制生产的现状,分析了航天型号进度控制的原理,介绍了航天型号进度控制的流程和方法,深入分析了当前进度管理中存在的问题,并结合项目管理理论提出了解决这些问题的总体思路和相应的调整措施。对及时推广和应用先进型号进度控制方法,推动航天型号的持续高速发展具有重要的现实意义。     

Distributed communication and psychosocial performance in simulated space dwelling groups

The present report describes the development and application of a distributed interactive multi-person simulation in a computer-generated planetary environment as an experimental test bed for modeling the human performance effects of variations in the types of communication modes available, and in the types of stress and incentive conditions underlying the completion of mission goals. The results demonstrated a high degree of interchangeability between communication modes (audio, text) when one mode was not available. Additionally, the addition of time pressure stress to complete tasks resulted in a reduction in performance effectiveness, and these performance reductions were ameliorated via the introduction of positive incentives contingent upon improved performances. The results obtained confirmed that cooperative and productive psychosocial interactions can be maintained between individually isolated and dispersed members of simulated spaceflight crews communicating and problem-solving effectively over extended time intervals without the benefit of one another's physical presence.     

The essential role of human spaceflight

The question is: should the United States and nations at large pursue a human spaceflight program (and if so, why)? I offer an unwavering positive answer to this question, and state the reasons for it while considering the broad challenges and benefits of (human) spaceflight. Space exploration is a human activity that is intrinsically forward-looking, and as such, has positive potential. Both national and international space programs can galvanize the population, inspire the youth, foster job-creation, and motivate the existing workforce. The nature of the enterprises involved—their scale, novelty, and complexity—requires a steady and continuous upward progression toward greater societal, scientific and technological development. That is, in order to overcome the challenges of human spaceflight, progress is required. More to the point, the survival of humanity depends on expanding beyond the confines of our planet. Human spaceflight, in short, presents us with an opportunity to significantly advance the nation and the global community.     

Caenorhabditis elegans survives atmospheric breakup of STS-107, space shuttle Columbia

The nematode Caenorhabditis elegans, a popular organism for biological studies, is being developed as a model system for space biology. The chemically defined liquid medium, C. elegans Maintenance Medium (CeMM), allows axenic cultivation and automation of experiments that are critical for spaceflight research. To validate CeMM for use during spaceflight, we grew animals using CeMM and standard laboratory conditions onboard STS-107, space shuttle Columbia. Tragically, the Columbia was destroyed while reentering the Earth's atmosphere. During the massive recovery effort, hardware that contained our experiment was found. Live animals were observed in four of the five recovered canisters, which had survived on both types of media. These data demonstrate that CeMM is capable of supporting C. elegans during spaceflight. They also demonstrate that animals can survive a relatively unprotected reentry into the Earth's atmosphere, which has implications with regard to the packaging of living material during space flight, planetary protection, and the interplanetary transfer of life.     

Respective effects of hindlimb suspension, confinement and spaceflight on myotendinous junction ultrastructure

This study compares the effects of 14-day confinement and spaceflight with the respective effects of 8, 18 and 29-day hindlimb suspension on rat soleus and plantaris MTJ ultrastructure. Independently of the experimental situation, greater morphological changes were observed in the soleus as compared to the plantaris MTJ. 18 days of suspension and 14 days of confinement resulted in ultrastructural modifications of the digit-like processes in the soleus MTJ. Additional changes were observed in the myofibrils, microtendon and tendon after 29 days of suspension and 4 days of spaceflight. These results emphasize the influence of the intensity and duration of the muscle loading on the MTJ ultrastructure.     

The use of micro-worlds for human factors research in extended spaceflight.

This article provides an analysis of the utility of micro-worlds for human factors research in extended spaceflight. It outlines potential areas of application of the micro-world research paradigm in the context of spaceflight. While the research literature provides several examples of micro-worlds that simulate different work environments of high complexity, little work has been done with this tool in the operational environment of spaceflight. The author presents a micro-world, called CAMS, that has been especially developed for use in space-related research. The results from a research programme (comprising seven studies using CAMS) are presented. Based on a comparative analysis of the benefits and limitations of micro-worlds compared to other simulation types, the author argues that micro-worlds can be a very effective tool, provided their inherent limitations are taken into consideration.     

The ankle ergometer: a new tool for quantifying changes in mechanical properties of human muscle as a result of spaceflight

A mechanical device for studying changes in mechanical properties of human muscle as a result of spaceflight is presented. Its main capacities are to allow during a given experiment investigation of both contractile and visco-elastic properties of a musculo-articular complex using respectively isometric contractions, isokinetic movements, quick-release tests and sinusoidal perturbations. This device is a motor driven ergometer associated to an experimental protocol designed for pre- and post-flight experiments. As microgravity preferentially affects postural muscles, the apparatus was designed to test muscle groups crossing the ankle joint. Three subjects were tested during the Euromir '94 mission. Preliminary results obtained on the european astronaut are briefly reported. During the next two years the experiments will be performed during six missions.     

Management dynamics of NASA''s human spaceflight programs

The public management dynamics of human spaceflight at NASA in the post-Apollo era—Space Shuttle, International Space Station, and the United States national vision for space exploration—are examined. A number of variables are applied to assess this. Public management processes are identified as a function of political accountability, organizational decision-making and cultures, and technical aspects directed at high reliability and safety of the large-scale, complex, and high-risk technologies that characterize NASA's human spaceflight programs. The findings indicate that these variables are causally linked to management outcomes through dynamics of centralized and decentralized organizational approaches. The success or failure of NASA's human spaceflight programs are linked to organizational management based on dynamics between centralized aspects of management, like controls over cost and schedule, and decentralized aspects, such as engineering authority over technical development.     

Reconstituting the US space programme

This response to Alex Roland's article, ‘Priorities in space for the USA’, argues that his analysis and conclusions are based on shaky historical evidence. Professor Roland's interpretation of NASA's priorities since 1959 is challenged, and it is pointed out that the manned spaceflight programme has widespread support in the USA. The most important issue, raised by the article but not treated extensively enough, is whether the pursuit of the widely accepted emphasis on manned spaceflight is a large-scale societal mistake.