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The seven U.S. Mercury astronauts, all of whom were male, were selected by NASA in 1959 to make the first human space flights. Nevertheless, the era of human space flight started not in the United States but in the Soviet Union with the single-orbit flight of a male cosmonaut, Yuri Gagarin, on Vostok 1 in April 1961. The Soviets also inaugurated female participation in space flight. The first woman to fly in space was Valentina Tereshkova, who spent 3 days on Vostok 6 in 1963. Nineteen years later another Soviet woman, Svetlana Savitskaya, ventured into space on the flight of Soyuz-T7 in August 1982. In June 1983, the first female U.S. astronaut, Sally Ride, joined this elite group of female spacefarers. The process by which the first astronauts were chosen for the U.S. space program was initiated in the late 1950s. The U.S. Government determined that the first groups from which astronauts were to be selected would be limited to military test pilots. Although several women were able to complete the medical selection examinations (the same ones given to the men), none of them qualified for the simple reason that all military test pilots at that time were men. This policy thus effectively delayed space flights by U.S. women for 2 decades [1]. The first U.S. astronaut class to include women was formed in 1978; of that class of 35, 6 were women. To date, more than 45 female career astronauts (pilots or mission specialists) have been selected for the U.S. space program. One female Canadian astronaut and three female payload specialists have flown on the shuttle. Regardless of the relative assets and liabilities of using men or women in future space crews, these crews will include people of both sexes. It is therefore prudent that the reproductive and gynecologic issues associated with selecting, training, and assigning female crewmembers to space missions be examined. This chapter addresses gynecologic medical standards and female astronaut selection, reproductive and operational gynecologic considerations during training and space flight, pregnancy after space flight, and gynecologic considerations for long-duration space flights. [ABSTRACT FROM AUTHOR]

Candidates for space flight are medically screened to ensure the success of each mission by providing healthy crews who are able to perform operational objectives. Screening is carried out according to a framework of medical standards based on operational requirements. Consistent application of medical standards helps to establish an information database against which the assumptions underlying the standards can be objectively reviewed. These standards are revised over time as additional findings are collected. The ultimate goal is to produce rational, evidence-based, refined standards that reflect the operational requirements and the medical risks involved in space flight. By doing so, potentially larger subsets of the population that are today excluded from space flight may be able to participate in future space exploration. [ABSTRACT FROM AUTHOR]

The ISS and future planetary exploration-class missions (e.g., to Mars) will require the incorporation of contemporary telemedicine concepts and technology, tempered by the resource restraints and operational realities of space medicine. This chapter provides an understanding of current telemedicine theory and applications, a historical perspective of space telemedicine, and a prospective view of telemedicine for the ISS and beyond. [ABSTRACT FROM AUTHOR]

Adequate nutritional status is critical to maintaining crew health during extended-duration space flight and postflight rehabilitation. Nutrition issues relate to intake of required nutrients, physiological adaptation to microgravity, psychological adaptation to extreme environments, and countermeasures to ameliorate the negative effects of space flight. Our ability to define the nutrient requirements for space flight and to ensure the provision and intake of those nutrients by spaceflight crews is thus critical for crew health and mission success. Specialized nutritional requirements have only been considered for extended-duration flights—those lasting longer than 30 days. Although adequate nutrition is important on the 1- to 3-week Space Shuttle flights, intake of specific nutrients above or below space-specific requirements for such periods is not thought to be cause for concern. Thus, planning menus for Space Shuttle flights has always used recognized nutritional requirements for adult males and females [1,2]. In this chapter, we will further classify nutritional requirements for long-duration space flight into those for orbital missions, such as on the International Space Station, and those for exploration- class missions. [ABSTRACT FROM AUTHOR]

This chapter was prepared to provide a brief for flight surgeons and chief medical officers who will be diagnosing and treating the dental emergencies of long-duration spaceflight crews. Basic information has been included to help manage a potential emergency situation. A summary of the basic approach to differential diagnosis of dental problems is given in Table 26.1. Although some of the procedures may seem to be below the standard of care advocated by dental healthcare professionals, these procedures will bring the afflicted crewmembers to a stable condition with the least risk of iatrogenic injury, so that they can perform their duties comfortably. Visiting a dentist during an extended-duration space flight is not an option. X rays, root canals, and definitive dental care are luxuries that are not available in space. Moreover, since in-flight equipment and supplies carried into space are limited by constraints on weight and storage space in addition to the requirement that they operate well in microgravity, the dental care-related equipment that can be provided is currently restricted. This restriction, however, should be all but eliminated by the advent of new technologies and the expansion of current technologies. Thus with the construction of long-term space habitats such as the International Space Station already being realized and plans for exploration-class missions maturing, the provision of comprehensive dental treatment to crews during space flights will become not only possible but practicable in the near future. [ABSTRACT FROM AUTHOR]

Omnipresent with human habitation in artificial environments is background and operational noise. Inherent in almost any platform or craft that maintains a human crew in an enclosed cabin is the need for circulation of air to remove metabolic and other adverse waste products and to replenish consumed oxygen. Water and fluid coolants of thermal control systems may also require circulation, typically provided by motorized fans and pumps. Noise generated by such systems is an expected consequence for surface ships, submarines, aircraft, and spacecraft and adds to noise that may be produced by propulsion systems and other operational equipment. Noise in low Earth orbit spacecraft operations has been identified as a significant environmental hazard for human crews. This chapter examines the sources and character of background noise on board orbiting spacecraft, the morbidity and pathophysiology associated with such noise, and aspects of remediation and crew protection. [ABSTRACT FROM AUTHOR]

This chapter reviews ophthalmic issues associated with spaceflight operations. Current vision standards for space flight, methods of vision correction for spaceflight crewmembers, and vision demographics are discussed, followed by clinical conditions that could affect spaceflight duties and common ocular emergencies that could occur during space operations. The current medical selection and retention standards ensure that space crewmembers are generally healthy, free of significant chronic disease, and are not taking medication on a long-term basis. This chapter focuses primarily on ocular abnormalities that might be expected in healthy subjects during exposure to microgravity. [ABSTRACT FROM AUTHOR]

The effects of radiation on the cell, the fundamental unit of a biological system, can be compared with its effects on the electronic system equivalent, the integrated circuit. In the terminology of electronics, incident radiation could cause a "single event upset" that might go completely unnoticed but could also trigger an undesirable software response, shut down that component, or devastate the hardware through a short circuit or power surge, depending on the location and activity of the component that was hit. The same is true of ionizing radiation events in the cell. The ionized molecule could be immediately neutralized by a cytoplasmic antioxidant molecule, or it could produce a nuclear DNA point mutation in a non-coding region of the genome. It could trigger a chain reaction of ionization events or a DNA single-strand break (SSB) that might lead to mutation or a double-strand break (DSB) leading to cell death. The uncertainties associated with the effects of ionizing radiation and its risks to human health are still quite high. This chapter will review how the space environment differs from that on the surface of Earth and review current knowledge of space radiation. Also included are descriptions of the key areas of research needed to reduce the level of uncertainty associated with space travel and strategies to mitigate the inherent risks associated with human exposure to space radiation. [ABSTRACT FROM AUTHOR]

This chapter reviews atmospheric standards with particular attention to pathophysiology and operational issues associated with pressure, temperature, humidity, and trace contaminants. Next follows a discussion of the physiologically relevant atmospheric gases oxygen and carbon dioxide along with their associated clinical conditions (e.g., hypoxia and hypercarbia). The chapter concludes with a review of the environmental control systems found on board past and present spacecraft. [ABSTRACT FROM AUTHOR]

Safe air for breathing is the most immediate resource required by spaceflight crews. Clearly, gross parameters of the breathing atmosphere, such as temperature, pressure, O2 tension, and water vapor content, must be maintained within physiologically acceptable ranges. Even if these properties are well controlled, exposure to the trace contaminants and particles in the atmosphere confers a significant health risk. This chapter describes strategies for minimizing toxicologic risks to crew health, outlines how toxic exposures can be recognized in the crew and the space environment, and describes how crews and their environment can be restored to healthy conditions after accidental exposure to a toxic compound. [ABSTRACT FROM AUTHOR]

This chapter reviews the stressors and countermeasures that affect crew behavioral health and performance during space flight. This review is based on the experiences of crewed space flight in both the Russian and U.S. programs, including Space Shuttle flights lasting from 1 to 3 weeks, Mir space station flights lasting longer than 1 year, and findings from analog environments that are similar in terms of isolation and other features to the in-flight environments on the Space Shuttle and on the Mir and International Space Stations (ISS). Significant physical and psychosocial stressors challenge crews during mission training, space flight, and mission recovery. In fact, at least one crew has been dissolved before a longduration flight because of incompatibility [1]. Severe stress experienced by crews during Mir and NASA-Mir flights probably contributed to mission-limiting cardiac dysrhythmias and the appearance of emotional symptoms among crewmembers [2,3]. Fatigue and overwork conditions have also affected longduration crews. Journalists have identified these conditions as important factors contributing to the depressurization accident on the Mir space station in 1997 [4]. Psychological stressors known to have affected long-duration crews include the death of a family member; significant interpersonal frictions, both between crewmembers and between space crews and ground crews; overwork and "underwork"; and life-threatening "nearevacuation" events on board a spacecraft, which to date have included fire, depressurization, and loss of power. Although Russian space mission aborts were officially related to diagnoses of intractable headaches, chronic prostatitis, and cardiac dysrhythmias, behavioral conditions were equally important in the early termination of these missions [5,6]. [ABSTRACT FROM AUTHOR]

Early in the history of human space flight, scientists realized that several factors in the space environment might adversely affect human function and performance. Potential disturbances in circadian rhythms and the consequences of such disturbances on performance efficiency and the well-being of space crewmembers were among the principal concerns expressed [1]. In addition to environmental changes—e.g., microgravity and ultrashort light-dark cycles—several operational reasons were cited for the possible development of sleep disturbances and fatigue during space flight [2,3], including an abnormally long working period (the high-workload effect), continuing deviations in the sleep-wake schedule duration (the "migrating day" effect), phase shifting of sleep periods relative to Earthbased sleep time (the shift-work effect), and cyclic noise disturbances. The safety hazards associated with sleepiness and fatigue may have serious consequences for astronauts and cosmonauts as well as their supporting ground crews. In the current space flight environment, imposed 24-h schedules often conflict with physiological and psychological rhythms of space crews, thereby changing their work-rest periods from their accustomed ground-based sleep-wake cycles. Although the consequences of this change remain largely unknown, this chapter is intended to provide a "snapshot" of trends in the assessment of sleep and fatigue, performance implications in space flight, and methods of monitoring and managing sleep and fatigue in operational settings. Also addressed are specific space flight issues related to risk assessment and to sleep and fatigue management strategies for current and future long-duration space flights. [ABSTRACT FROM AUTHOR]

Among other functions, the neurological and neurovestibular systems serve to support positional awareness and motor control. Because gravitational cues and visual references play a role in this support, it is not surprising that the spaceflight environment profoundly influences static and dynamic positional sense and subsequent motor function. Human adaptation to this unique environment is being investigated to understand how performance may be optimized in every flight phase. Proper neurovestibular function ensures spaceflight crew safety in the complex and unfamiliar visual and motion milieu of microgravity and because of reliance on mechanical display information, enhances ability to operate a vehicle safely. The neurovestibular system creates a consistent, conscious map of head and body orientation as well as an internal orientation reference that will correct for absent or erroneous visual and somatosensory systems. It primarily stabilizes the eyes (the visual system) by means of (1) the vestibular ocular reflex, which is related to maintaining a stable world during movement; and (2) the vestibular spinal reflex, which preserves body alignment and establishes an appropriate relationship between the head and body. The character of the vestibular and visual systems' interaction depends on a specific task or relevant operational requirement. For example, whereas a crewmember depends on the visual vestibular ocular reflex to track a stationary target while turning, that same individual suppresses the vestibular ocular reflex when tracking a headfixed target, such as a head-mounted display, while turning. A person's pursuit system (slow eye movement) is used to track and identify moving objects, and the saccade system (fast eye movement) is necessary to acquire objects in the peripheral visual field and scan instruments. Visually induced optokinetic nystagmus occurs when a person views a moving background. This adds to the optical data that generates a sense of speed over terrain. [ABSTRACT FROM AUTHOR]

The human immune system is composed of a complex set of specialized cells, chemicals, and organ systems that interact to protect the host from pathogenic challenge and aberrant tissue growth. The immune system consists of two major elements: innate immunity and acquired immunity. The innate or nonspecific immunity includes the phagocytes and natural killer cells as well as chemical factors (lysozyme, complement, etc.) that act to control extra-cellular pathogens. Resistance of this system to pathogenic entities is not adaptive and is not increased by repeated exposure. The acquired immune system itself consists of two functional components: humoral immunity and cell-mediated immunity. These elements adapt and become more responsive with repeated exposure to pathogens. Simplistically, the humoral immune system encompasses protein factors (antibodies) that bind and neutralize their antigen targets and the specific cells (B cells) that produce the antibodies. The cell-mediated immune system includes the T cells which regulate many aspects of overall immune response and directly provide self vs. non-self discrimination. This system is critical to the control of intracellular pathogens (such as viruses) and the containment and elimination of malignant cells. These elements interact to protect the host from a broad range of medical threats. Defects in immune function can result in three distinct failure modes: (1) immunodeficiency, where the immune system fails to contain infections, (2) autoimmunity, an inappropriate response to self antigens that damages the host, and (3) hypersensitivity, an over-reaction of the immune system to innocuous foreign antigens. Any of these failures can have a significant medical impact on crewmembers during space flight. Precise regulation of immune function is critical because an overly active immune system can be just as damaging as an unresponsive one. Finally, the interplay of immune changes and environmental exposures in space flight (e.g., radiation, chemical exposures) can also induce long-term health risks for the crewmember. [ABSTRACT FROM AUTHOR]

Long- and short-term exposure to microgravity significantly alters the cardiovascular system [1-9]. In this chapter, we describe the cardiovascular changes and the strategies used to manage problems in operational space medicine that arise as a consequence of those changes. Most descriptions of the effects of microgravity on the cardiovascular system have focused mainly on the physiological mechanisms that contribute to cardiovascular changes. Flight surgeons need to understand these important physiological effects on the human cardiovascular system so that they can place them within the operational context of a space mission. Crewmembers may also have subclinical cardiac abnormalities that could be exacerbated by the adaptive responses of the cardiovascular system to microgravity. To help readers of this text understand the cardiovascular issues facing space medicine flight surgeons, this chapter uses an operational approach and considers issues that arise during each phase of a space mission, beginning with crew selection and proceeding through launch, on-orbit activities, atmospheric reentry, and postflight recovery. Both the U.S. and the Russian space programs have implemented extensive research programs to understand the alterations in cardiovascular physiology that are induced by exposure to microgravity, changes that may eventually manifest themselves in the form of impaired cardiovascular performance such as postflight orthostatic intolerance, decreased exercise capacity, or on-orbit cardiac arrhythmias [8-10]. The current literature has devoted little attention to the various clinical complications and operational problems that can arise from the deleterious effects of microgravity on the cardiovascular system [11]. The focus here is on two of the primary goals of operational space medicine: (1) to prevent the occurrence of cardiovascular illness or impaired performance in space flight and (2) to rehabilitate or treat impaired cardiovascular function in a manner that minimizes the effect on the mission while maximizing crew health and performance. [ABSTRACT FROM AUTHOR]

This chapter will focus on the effects of microgravity on the structural integrity of bone, muscle, and connective tissue, with an emphasis on the biomechanical changes, both as cause and effect. Countermeasures to these adverse effects will be discussed. Functional musculoskeletal disorders that occur as a result of adaptation to microgravity and subsequent return to Earth are also described. Further discussion of biochemical markers of bone and muscle turnover can be found in Chaps. 27 and 13. [ABSTRACT FROM AUTHOR]

Genitourinary (GU) disorders are pervasive in the adult population and broadly include the diagnoses of 15-20% of patients who are discharged from hospitals in the United States. The percentage is higher for ambulatory visits. Along with susceptibility to the common disorders of the general population, the GU system of astronauts is additionally vulnerable to spaceflight- related stresses, both in flight as well as immediately preflight and postflight. These stresses may include rigorous exercise, microgravity, dietary changes, limited availability of drinking water, thermal stress, effects of other spaceflightrelated disorders such as space motion sickness, and influence of medications used to treat other spaceflight-related disorders. Some of these conditions may increase the risk of occurrence of genitourinary disorders or complicate their presentation. Exposure to microgravity causes a number of metabolic and physiological changes. Fluid volume, electrolyte levels, and bone and muscle undergo changes as the human body adapts to weightlessness. Changes in urinary chemical composition occurring as a part of this adaptation process may lead to the potentially serious consequences of renal stone formation. With the length of human exposure to microgravity extending as we maintain a permanent presence on the International Space Station (ISS), the probability of GU-related illnesses such as renal stones or infections will undoubtedly increase. Exploration-class lunar missions for long-duration settlement and missions to Mars will pose even greater challenges for GU diagnosis and management as immediate return to Earth will not be possible. This chapter reviews spaceflight influences on GU function and disorders that might arise involving this system and describes treatment methods and countermeasures. [ABSTRACT FROM AUTHOR]

The three maladies to be discussed in this chapter—decompression sickness, arterial gas embolism, and ebullism—all arise from changes in ambient atmospheric pressure, which is the pressure of the gas immediately surrounding an individual. In space flight, the largest planned change in ambient atmospheric pressure is associated with extravehicular activities (EVAs) that take place as the crew moves back and forth between the crew cabin and the environment outside, where they wear pressurized suits. The cabin atmospheric pressure in all current spacecraft typically approximates the atmospheric pressure found at sea level, namely 1 atm absolute pressure (ata) (or 101 kPa). From a strictly physiological point of view, this design specification is probably not optimal, but it serves other interests such as simplifying the conduct of biomedical research. Selected space suit pressures represent a compromise between engineering concerns, which dictate that the internal pressure of a space suit be low to maximize flexibility, and physiological risks. (The space suit used in the current U.S. space program, the extravehicular mobility unit, is pressurized to 30 kPa (4.3 psia); the Orlan suit, used in the current Russian space program, is pressurized to 38 kPa (5.5 psia).) Consequently, crewmembers performing EVAs experience substantial shifts in ambient atmospheric pressure. Unplanned crew cabin or space suit decompressions are also possible while living and working in the hard vacuum of space. The pathophysiological consequences of such exposures are the subject of this chapter [1]. [ABSTRACT FROM AUTHOR]

The physiological zone from sea level to 3,048 m (10,000 ft) encompasses the pressure to which humans are well adapted, although if appropriately acclimated they can survive the summit of Earth's highest mountain (Mt. Everest at 4,448 m/29,028 ft) without supplemental oxygen. Continuing to altitudes above this, artificial systems are required to supply needed oxygen and, eventually, sufficient ambient pressure. The most effective means of preventing physiological problems in aircraft and spacecraft is to provide cabin pressurization so that occupants are never exposed to pressures outside the physiological zone. Failure of structures, hardware, or procedures may unfortunately lead to unwanted and hazardous decompression events. This chapter will review cabin pressurization schemes, events that might lead to loss of pressure, and two major medical concerns of decompression: barotrauma and altitude sickness. [ABSTRACT FROM AUTHOR]

One of the most significant clinical and operational challenges experienced by spaceflight crews during the first few days in microgravity is space motion sickness (SMS) [1-3]. SMS was among the first adverse medical conditions encountered by humans as they ventured outside of Earth's gravity. Because of SMS, decreased human performance is the main risk during the critical first days of space flight. Activities typically performed early that may be disrupted include payload activation, satellite deployment, rendezvous, and docking. SMS symptoms—particularly malaise, loss of initiative, and nausea—can range from being mildly distracting to physically debilitating. Physiologic systems operate effectively by maintaining homeostasis across a broad range of physiologic functions in Earth's 1-G environment. Exposure to the microgravity environment of space flight elicits a large collection of physiologic changes and symptoms (including headward fluid shifts, headaches, back pain, and cardiovascular, bone, and muscle changes) that is collectively referred to as space adaptation syndrome. SMS may be considered a component of space adaptation syndrome. Over time, individuals adapt to the weightless environment, and many initial physiologic changes return to normal 1-G values. SMS is not a sickness as such, but it is generally thought to be a natural response to the adaptation of the neurosensory and perceptual systems to microgravity [4]. Individuals who exhibit symptoms of SMS should therefore not be viewed as abnormal. The next four subsections are a review of the signs, symptoms, laboratory findings, epidemiology, and neurophysiology of SMS and EMS. Next, theories of etiology and possible mechanisms involved in motion sickness are briefly discussed. Finally, the last two sections describe the diagnosis and treatment of SMS and EMS. [ABSTRACT FROM AUTHOR]

The advent of human space flight has brought about the need for physicians to remotely monitor space crews for signs of mission—impacting medical problems. Some of these early space biomedical systems were developed before similar technological advancements for terrestrial medicine were even considered [2]. Presently, the technological level of terrestrial health care has surpassed biomedical systems originally developed for space programs, and the challenge to space medicine is to determine which terrestrial medical technology should be adapted for space use and when that should occur. Spaceflight medical risks have become more apparent with long duration missions to low Earth orbit (LEO) aboard space stations such as Skylab, Mir, and the International Space Station (ISS) [3,4]. Under these circumstances, crewmembers with any existing subclinical deviations from the norm are in space for a fairly long period where the weightless environment presents a number of novel and potentially exacerbating factors. Although the crews are trained and equipped to handle minor medical conditions, a serious event could rapidly overwhelm the modest onboard medical capability and would almost certainly qualify as a medical emergency. Many of the conditions that could occur in space might present significant diagnostic and therapeutic challenges to even the most modern terrestrial health care facility. These factors conspire to limit the ability of a flight surgeon to make difficult decisions, such as discerning between initiating a medical evacuation back to Earth or remaining on orbit for treatment and additional observation. Obviously, these critical decisions should be based, if possible, on objective information and scientific, evidence-based approaches so that the best possible outcome is achieved with minimal impact to the mission. [ABSTRACT FROM AUTHOR]

Experience with human space flight has taught us that serious illnesses can occur during missions. The crew medical officer (CMO) who is assessing the seriously ill or injured crewmember faces several challenges. The CMO not only must correctly diagnose the problem so as to prevent either a premature end to the mission or an increase in crewmember morbidity from delaying return, but also must work with limited resources in an extreme environment, the effects of which on humans are poorly understood. This chapter summarizes the experience gained in diagnosing and treating acute medical problems in space and provides recommendations for treating expected problems in future space flights. [ABSTRACT FROM AUTHOR]

Providing adequate medical care for spaceflight crews requires that appropriate diagnostic tools and treatment modalities be available to them throughout their mission. The challenge for mission planners is deciding what medical capability to provide and then packaging it in a way that meets the many unique constraints of space flight. Crews also must receive adequate training that will help them to make correct diagnoses and administer the appropriate level of care to an ill or injured crewmember. As discussed in Chap. 7, identification of appropriate levels of medical care is driven by the risks that have been identified in space flight. One practical way of identifying such risks is by studying risks among analogous populations, such as military pilots, submarine crews, and Antarctic winter-over research teams. From these groups, which undergo medical screening processes similar to those of spaceflight crews, the probabilities and risks of illness occurring during a mission can be estimated. Review of reported illnesses in U.S. and Russian spaceflight crews also can be useful, although such data were not available to medical mission planners in the earliest days of space flight. The duration of a space mission and the number of high-risk activities associated with it (e.g., extravehicular activities) will also influence decisions concerning the content of onboard medical systems. Mission planners must also consider environmental factors that are unique to the space environment—factors that include microgravity, radiation, toxicology, microbiology, and purity of reclaimed water. Finally, the unique physiological responses to space flight must also be examined—space adaptation syndrome, cardiovascular deconditioning, and bone demineralization, among others. Only by accounting for all of these factors can the best possible care and facilities be provided to spaceflight crews. [ABSTRACT FROM AUTHOR]

Although no surgical procedures have been performed on humans during space flight, the risk of a problem arising that requires surgical intervention is nonetheless real. From a timeweighted standpoint, until the advent of long-duration missions in the U.S. Skylab program and the Russian Salyut and Mir programs, the probability of an in-flight problem arising that would require a surgical solution was small; thus clinical experience and expertise in performing surgery on humans in microgravity remained quite limited. The lack of on-site surgical expertise was keenly felt when Russian space program officials were faced with the possible medical evacuation of a Salyut 7 cosmonaut who was experiencing abdominal pain thought to be due to appendicitis. Although that episode turned out to have been caused by probable ureterolithiasis rather than appendicitis—the cosmonaut recovered and did not require an early return to Earth—this experience nonetheless underscored a pressing need in space flight. With further increases in crew size and mission duration projected in the near future for the International Space Station (ISS) and the exploration-class missions that will follow, the likelihood of events occurring in space flight that will require surgery will also increase. Moreover, the probability of trauma (including penetrating trauma, lacerations, crush injuries, and thermal and electrical burns) occurring will increase as astronauts and cosmonauts conduct ISS construction-related extravehicular activities that involve manipulation of highmass hardware. A surgical need could also be precipitated by exercise countermeasures, which may lead to minor and major orthopedic injuries. Routine surgical diseases such as appendicitis and cholecystitis can occur indiscriminately at seemingly random times. The physiological changes and deconditioning effects of prolonged weightlessness will influence surgical diseases and treatment in predictable as well as unknown ways. Finally, the possibility of previously unknown surgical problems in the unexplored long-duration microgravity environment must be considered. [ABSTRACT FROM AUTHOR]

This chapter will examine key aspects of present-dayterrestrial and spaceflight medical transport and evacuation, enumerate current challenges, and suggest possible solutions for future spaceflight activities [3-5]. We will discuss present and future standards of care on the ISS, and current vehicles including the Russian Soyuz and the U.S. Space Shuttle. We will also address programs such as the NASA-JSC X-38, and the Orbital Space Plane (OSP) [6-9]. These concepts are applicable to the development of future platforms such as the CEV (Crew Exploration Vehicle). Topics addressed will include: 1.Likelihood and types of spaceflight medical events requiring evacuation [10]2.Standards of spaceflight medical care and projected capabilities for LEO space stations, lunar exploration, and inter-planetary missions [11]3.Physiological de-conditioning of astronauts returning from long duration microgravity exposure4.Psychological aspects of crew performance in medical emergencies after long duration space flight5.Inherent risks associated with spaceflight medical evacuation due to the microgravity environment and the dynamics of reentry and landing [12,13]6.Medical requirements and capabilities of an LEO transport and return vehicle [14,15]7.Human factors for crew work stations in vehicles such as the crew return vehicle (CRV)8.Ethical issues and medical standards for evacuation from LEO and other space environments where return to definitive medical care is delayed or impossible (such as a Mars surface station). [ABSTRACT FROM AUTHOR]

This chapter presents a comprehensive framework for understanding the experience and clinico-physiological response of human beings to space flight. This is purposely not an exhaustive physiology review, but rather an overview of consistent and predictable changes that are clinically relevant. These changes include outward symptoms and effects on health and performance as well as laboratory values and test results deemed important for understanding the clinical norms associated with space flight. Further physiological details are included in the subsequent system-oriented chapters; interested readers are also referred to the more detailed work in the Handbook of Physiology [1] and the recent text Space Physiology by Buckey [2]. By way of introduction, this chapter offers a brief history of human space flight to provide a context for the current state of knowledge of space medicine. [ABSTRACT FROM AUTHOR]

Aviation medicine, diving medicine, and space medicine all involve pressure excursions, operational changes in body attitude and position, controlled breathing sources, and critical dependence on supportive mechanisms and protective equipment. Many of the basic problems of space medicine—hypoxia, dysbarism, thermal support, moderate levels of acceleration, response to unusual altitudes—had been studied over the course of decades of aviation and high-altitude balloon flight and were fairly well understood before the first human space flight ever took place. A basic working knowledge of aviation medicine and physiology remains required of the space medicine specialist. A review of these basics or of atmospheric science is beyond the scope of this chapter; the interested reader is referred to the sources in the Suggested Readings section at the end of this chapter. This book focuses on the unique medical circumstances and clinical problems associated with excursions outside of Earth's atmosphere. These circumstances include a wide range of acceleration forces, adaptive processes and problems associated with weightlessness and partial gravity fields, radiation, excursions to other planetary bodies, and biotechnical problems associated with life support systems in enclosed environments. This chapter provides an overview of the basic physics of space flight and physical conditions faced by human space travelers that influence their physiologic responses and adaptation. [ABSTRACT FROM AUTHOR]