Commercial Spaceflight: Progress and Challenges in Expanding Human Access to Space

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Commercial access to space travel for private individuals is a near-term reality. Compared to the few professional astronauts, cosmonauts, and taikonauts who have flown in space through government programs in the past six decades, the number of these new spaceflight participants (SFPs) will rapidly expand. The SFP cohort will have a much greater age range than traditional astronauts and may also have a much greater prevalence of medical problems. To date, regulation regarding medical screening, certification, or guidelines for suborbital and orbital SFPs has been relegated to the commercial space companies. However, many organizations, ranging from space advocacy groups to academic institutions to the Federal Aviation Administration (FAA), have offered input and recommendations for medical screening of SFPs for the industry’s consideration. Simultaneously, governmental space agencies have made progress in defining appropriate preflight medical testing and medical standards and for those commercial providers that plan to provide access to the International Space Station (ISS). There is limited information available with regard to the effect of spaceflight-related stressors like acceleration, microgravity, and altered atmospheric pressure and breathing gas mixtures on individuals with medical conditions. To date, most research on humans exposed to challenging or extreme environments has focused on a healthy, young, and predominately male population. However, recent studies funded in part by the FAA and conducted by university programs have examined the effect of certain medical problems like cardiovascular disease, diabetes, and back problems in the acceleration environment. While the numbers are small, the early data from these studies examining the effects of acceleration are reassuring. There is still much for space medicine providers to learn from this new cohort of individuals that will soon be participating in commercial space activities. With appropriate training and treatment or stabilization of medical liabilities, most of those who desire to fly in space will be able to safely accomplish their dream.

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... The physiological and clinical implications of this dynamic flight environment in such a diverse population have yet to be established. 1,8 According to U.S. regulations, commercial spaceflight crew must demonstrate an ability to withstand the stresses of spaceflight, including high acceleration, but there is no regulatory requirement for centrifuge-based training or experience for prospective suborbital passengers. 8,38 Spacecraft occupants are usually reclined in a supine position during launch and re-entry phases so that acceleration is experienced in the chest-to-back direction (+G x ). ...
... 1,8 According to U.S. regulations, commercial spaceflight crew must demonstrate an ability to withstand the stresses of spaceflight, including high acceleration, but there is no regulatory requirement for centrifuge-based training or experience for prospective suborbital passengers. 8,38 Spacecraft occupants are usually reclined in a supine position during launch and re-entry phases so that acceleration is experienced in the chest-to-back direction (+G x ). This reduces the likelihood of loss of consciousness compared with the headto-foot direction when seated upright (+G z , experienced by fast-jet pilots), but instead causes chest compression that has been commonly likened to an 'elephant sitting on the chest' . ...
... Most individuals with well-controlled medical conditions are expected to be capable of safely tolerating the hypergravity phases of suborbital spaceflight. 8 Centrifuge-simulated suborbital acceleration profiles conducted under normoxic conditions have been tolerated by many volunteers of widely varying ages and with minor and stable medical conditions, 7,9,10 although physical symptoms and problematic anxiety were quite common and approximately 5% of volunteers were unable to complete the exposures, possibly related in part to a sensation of difficulty breathing. 8,26 Limited measurements of arterial oxygen saturation (S p O 2 ) in some individuals indicated desaturation as low as 89% that was not associated with adverse sequelae. ...
BACKGROUND: Members of the public will soon be taking commercial suborbital spaceflights with significant G x (chest-to-back) acceleration potentially reaching up to 6 G x . Pulmonary physiology is gravity-dependent and is likely to be affected, which may have clinical implications for medically susceptible individuals. METHODS: During 2-min centrifuge exposures ranging up to 6 G x , 11 healthy subjects were studied using advanced respiratory techniques. These sustained exposures were intended to allow characterization of the underlying pulmonary response and did not replicate actual suborbital G profiles. Regional distribution of ventilation in the lungs was determined using electrical impedance tomography. Neural respiratory drive (from diaphragm electromyography) and work of breathing (from transdiaphragmatic pressures) were obtained via nasoesophageal catheters. Arterial blood gases were measured in a subset of subjects. Measurements were conducted while breathing air and breathing 15 oxygen to simulate anticipated cabin pressurization conditions. RESULTS: Acceleration caused hypoxemia that worsened with increasing magnitude and duration of G x . Minimum arterial oxygen saturation at 6 G x was 86 1 breathing air and 79 1 breathing 15 oxygen. With increasing G x the alveolar-arterial (A-a) oxygen gradient widened progressively and the relative distribution of ventilation reversed from posterior to anterior lung regions with substantial gas-trapping anteriorly. Severe breathlessness accompanied large progressive increases in work of breathing and neural respiratory drive. DISCUSSION: Sustained high-G acceleration at magnitudes relevant to suborbital flight profoundly affects respiratory physiology. These effects may become clinically important in the most medically susceptible passengers, in whom the potential role of centrifuge-based preflight evaluation requires further investigation. Pollock RD, Jolley CJ, Abid N, Couper JH, Estrada-Petrocelli L, Hodkinson PD, Leonhardt S, Mago-Elliott S, Menden T, Rafferty G, Richmond G, Robbins PA, Ritchie GAD, Segal MJ, Stevenson AT, Tank HD, Smith TG. Pulmonary effects of sustained periods of high-G acceleration relevant to suborbital spaceflight . Aerosp Med Hum Perform. 2021; 92(7):633641.
... These include reducing bias and increasing efficiency by using analysis of covariance instead of "change from baseline" analyses, using longitudinal data (analysis of repeated measurements) as opposed to change score analysis to potentially reduce sample size, and using composite endpoints to increase statistical power. Establishing a robust pharmacovigilance system dedicated to monitoring adverse events and drug problems encountered in space would also benefit our understanding on the alterations to pharmacokinetics and pharmacodynamics (Blue et al., 2017). It would be interesting to be able to predict changes in the pharmacokinetics or in the safety of drugs using pharmacokinetic modelling tools currently available. ...
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Recent advancements in next generation spacecrafts have reignited public excitement over life beyond Earth. However, to safeguard the health and safety of humans in the hostile environment of space, innovation in pharmaceutical manufacturing and drug delivery deserves urgent attention. In this review/commentary, the current state of medicines provision in space is explored, accompanied by a forward look on the future of pharmaceutical manufacturing in outer space. The hazards associated with spaceflight, and their corresponding medical problems, are first briefly discussed. Subsequently, the infeasibility of present-day medicines provision systems for supporting deep space exploration is examined. The existing knowledge gaps on the altered clinical effects of medicines in space are evaluated, and suggestions are provided on how clinical trials in space might be conducted. An envisioned model of on-site production and delivery of medicines in space is proposed, referencing emerging technologies (e.g. Chemputing, synthetic biology, and 3D printing) being developed on Earth that may be adapted for extra-terrestrial use. This review concludes with a critical analysis on the regulatory considerations necessary to facilitate the adoption of these technologies and proposes a framework by which these may be enforced. In doing so, this commentary aims to instigate discussions on the pharmaceutical needs of deep space exploration, and strategies on how these may be met.
... Despite the demands of spacefaring, space travel involves a set of complicated protocols, because the tourists must ensure that they receive extensive training, such as underwater training in order to satisfy criteria for medical screening, learn and follow safety protocols, which includes mandatory quarantining, and gaining prior experience about dealing with weightlessness and high velocities (Blue et al., 2017;Reddy et al., 2012). The service providers must prepare the tourists physiologically and psychologically to behave and react in the outer space environment properly (Pletser et al., 2019). ...
Space travel involves complicated processes, and the potential tourists may avoid these trips at any stage due to various risks and costs. The avoidance intention has serious implications for both the tourists and the services. Applying a push-pull-mooring (PPM) framework, we modelled space tourist's avoidance intention. We developed a model that investigates the direct effect of the push, pull, and mooring factors on avoidance intention. We evaluated the moderation role of the mooring factor with the associations of the push and pull factors with the avoidance intention. We also assessed the necessity of the push, pull, and mooring factors with avoiding space tourism. Using configurational modelling, we explored algorithms that explain the conditions where tourists avoid space tourism. Space tourism avoidance intention is increased by the push factor and decreased by the push and mooring factors. The mooring factor moderates the impact of the pull factor on the avoidance intention.
Health issues typical of the expected commercial space tourism (CST) population are considered manageable, but less is known about the impact of psychological conditions on spaceflight participant (SFP) wellbeing and safety during spaceflight. Plans to detect and prepare SFP for potential effects of psychological conditions emerging during spaceflight are unknown and may be inadequate. This purpose of this integrative literature review was to identify CST operators’ plans for SFP psychological assessment and training. Forty-four (44) articles met inclusion criteria and were largely composed of grey and popular literature sourced online. Plans for SFP psychological assessment and training prior to CST were not found, although vague descriptions of training for specific CST opportunities and limited medical assessment information was located. An undisclosed or possibly non-existent psychological support approach will likely be insufficient to ensure SFP safety and optimal performance during emergencies. Instead, detailed and focused intentional screening of SFP should be completed by appropriate members of a transdisciplinary healthcare team at various phases of the spaceflight experience. Following assessment, collaborative decision making to develop training, interventions, and mitigation strategies in support of the individual SFP psychological needs should occur before, during and after spaceflight. The strategies should align with standards of care and inform urgently-needed SFP research. Knowledge gained from future research will contribute to appropriate, effective SFP psychological assessments, intervention and training development, testing, and implementation, and overall management of SFP programs and strategy development aimed at optimizing the CST experience and goals.
New findings: This review focuses on the main physiological challenges associated with exposure to acceleration in the Gx, Gy and Gz direction in addition to microgravity. Our current understanding of the physiology of these environments and latest strategies to protect against them are discussed in light of the limited knowledge we have in some of these areas. Abstract: The desire to go higher, faster and further has taken us to environments where the accelerations placed on our body far exceed, or are much lower, than that due to Earth's gravity. While on the ground racing drivers of the fastest cars are exposed to high degrees of lateral acceleration (Gy) during cornering. In the air, while within the confines of the lower reaches of earth's atmosphere, fast jet pilots are routinely exposed to high levels of acceleration in the head-foot direction (Gz). During launch and re-entry of sub-orbital and orbital spacecraft astronauts and spaceflight participants are exposed to high levels of chest-back acceleration (Gx) while once in space the effects of gravity are all but removed (termed microgravity; μG). Each of these environments have profound effects on the homeostatic mechanisms within the body and can have a serious impact not only for those with underlying pathology but also healthy individuals. This review will provide an overview of the main challenges associated with these environments and our current understanding of the physiological and pathophysiological adaptations to them. Where relevant protection strategies will be discussed with the implications of our future exposure to these environments considered. This article is protected by copyright. All rights reserved.
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Human spaceflight presents new challenges for traditional approaches to risk assessment. From the onset human, spaceflight has been recognized as an inherently dangerous activity. Consequently, U.S. laws and regulations have grown in tandem with space launch activities and operations to protect public health and safety. The recent development of the commercial space transportation industry is now seeing the burden of risk shift from government and government-sponsored missions to private commercial entities and individuals, and yet ethical frameworks are lacking for the private space sector. Opening access to space to the public inherently raises novel concerns for increased risk awareness, communication, and management among commercial entities and voluntary participants. This also highlights the need for evaluating and clarifying social perspectives on issues of risk, uncertainty, and standardization. This article offers a multidisciplinary analysis in ethics, law, and business organization to support responsible decision-making and risk assessment for commercial spaceflight activities.
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This document provides general guidance for operators of manned commercial aerospace flights (suborbital and orbital) in the medical assessment of prospective passengers. This guidance is designed to identify those individuals who have medical conditions that may result in an inflight medical emergency or inflight death, or may compromise in any other way the health and safety of any occupants (crew members and passengers) onboard a commercial aerospace vehicle. Space flight exposes individuals to an environment that is far more hazardous than what is experienced by passengers who fly onboard current airline transports. With orbital and suborbital flights, pre-existing medical conditions can be aggravated or exacerbated by exposure to environmental and operational stressors such as acceleration, microgravity, and solar/cosmic radiation, among others.
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Medical knowledge of the human body in microgravity and hypergravity is based upon studies of healthy individuals well-conditioned for such environments. Little data exist regarding the effects of spaceflight on untrained commercial passengers. We examined the responses of potential spaceflight participants (SFP) to centrifuge G-force exposure. There were 77 individuals (65 men, 12 women), 22-88 yr old, who underwent 6 centrifuge runs over 48 h. Day 1 consisted of two +Gz runs (peak = 3.5+Gz, run 2) and two +Gx runs (peak = 6.0+Gx, run 4). Day 2 consisted of two runs approximating a suborbital spaceflight profile. Data included blood pressure, electrocardiogram, and postrun questionnaires regarding motion sickness, disorientation, greyout, and other symptoms. Of the 77 participants, average age was 50.4 +/- 12.7 yr. Average heart rate (HR) varied by sex and direction of G-exposure (+Gz: F 150 +/- 19, M 123 +/- 27; +Gx: F 135 +/- 30, M 110 +/- 27). Age and peak HR were inversely related (HR < 120 bpm: 60.2 +/- 12.2 yr, HR > 120: 47.1 +/- 10.9 yr). HR during peak G-exposure for the final run was associated with post-run imbalance (no imbalance: HR 126 +/- 26, imbalance: HR 145 +/- 21); no other significant hemodynamic change, sex, or age variation was associated with imbalance. Age and greyout were inversely associated; there was no association between greyout and vital sign change, sex, or G-force magnitude. Baseline/pretrial mean arterial pressure (MAP) was not associated with any symptoms. The results suggest that most individuals with well-controlled medical conditions can withstand acceleration forces involved in launch/landing profiles of commercial spaceflight vehicles. Further investigation will help refine which conditions present significant risk during suborbital flight and beyond.
Introduction: Hypergravitational exposures during human centrifugation are known to provoke dysrhythmias, including sinus dysrhythmias/tachycardias, premature atrial/ventricular contractions, and even atrial fibrillations or flutter patterns. However, events are generally short-lived and resolve rapidly after cessation of acceleration. This case report describes a prolonged ectopic ventricular rhythm in response to high G exposure. Case report: A previously healthy 30-yr-old man voluntarily participated in centrifuge trials as a part of a larger study, experiencing a total of 7 centrifuge runs over 48 h. Day 1 consisted of two +Gz runs (peak +3.5 Gz, run 2) and two +Gx runs (peak +6.0 Gx, run 4). Day 2 consisted of three runs approximating suborbital spaceflight profiles (combined +Gx and +Gz). Hemodynamic data collected included blood pressure, heart rate, and continuous three-lead electrocardiogram. Following the final acceleration exposure of the last Day 2 run (peak +4.5 Gx and +4.0 Gz combined, resultant +6.0 G), during a period of idle resting centrifuge activity (resultant vector +1.4 G), the subject demonstrated a marked change in his three-lead electrocardiogram from normal sinus rhythm to a wide-complex ectopic ventricular rhythm at a rate of 91-95 bpm, consistent with an accelerated idioventricular rhythm (AIVR). This rhythm was sustained for 2 m, 24 s before reversion to normal sinus. The subject reported no adverse symptoms during this time. Discussion: While prolonged, the dysrhythmia was asymptomatic and self-limited. AIVR is likely a physiological response to acceleration and can be managed conservatively. Vigilance is needed to ensure that AIVR is correctly distinguished from other, malignant rhythms to avoid inappropriate treatment and negative operational impacts.Suresh R, Blue RS, Mathers C, Castleberry TL, Vanderploeg JM. Sustained accelerated idioventricular rhythm in a centrifuge-simulated suborbital spaceflight. Aerosp Med Hum Perform. 2017; 88(8):789-793.
Introduction: In commercial spaceflight, anxiety could become mission-impacting, causing negative experiences or endangering the flight itself. We studied layperson response to four varied-length training programs (ranging from 1 h-2 d of preparation) prior to centrifuge simulation of launch and re-entry acceleration profiles expected during suborbital spaceflight. We examined subject task execution, evaluating performance in high-stress conditions. We sought to identify any trends in demographics, hemodynamics, or similar factors in subjects with the highest anxiety or poorest tolerance of the experience. Methods: Volunteers participated in one of four centrifuge training programs of varied complexity and duration, culminating in two simulated suborbital spaceflights. At most, subjects underwent seven centrifuge runs over 2 d, including two +Gz runs (peak +3.5 Gz, Run 2) and two +Gx runs (peak +6.0 Gx, Run 4) followed by three runs approximating suborbital spaceflight profiles (combined +Gx and +Gz, peak +6.0 Gx and +4.0 Gz). Two cohorts also received dedicated anxiety-mitigation training. Subjects were evaluated on their performance on various tasks, including a simulated emergency. Results: Participating in 2-7 centrifuge exposures were 148 subjects (105 men, 43 women, age range 19-72 yr, mean 39.4 ± 13.2 yr, body mass index range 17.3-38.1, mean 25.1 ± 3.7). There were 10 subjects who withdrew or limited their G exposure; history of motion sickness was associated with opting out. Shorter length training programs were associated with elevated hemodynamic responses. Single-directional G training did not significantly improve tolerance. Discussion: Training programs appear best when high fidelity and sequential exposures may improve tolerance of physical/psychological flight stressors. The studied variables did not predict anxiety-related responses to these centrifuge profiles.Blue RS, Bonato F, Seaton K, Bubka A, Vardiman JL, Mathers C, Castleberry TL, Vanderploeg JM. The effects of training on anxiety and task performance in simulated suborbital spaceflight. Aerosp Med Hum Perform. 2017; 88(7):641-650.
In 2010, the Federal Aviation Administration (FAA) announced the institution of a Center of Excellence for Commercial Space Transportation (COE CST), a partnership of multiple academic institutions assembled to address the numerous challenges involved in the commercial spaceflight industry. The University of Texas Medical Branch in Galveston, Texas, was included in this collaboration to provide medical insight into the human challenges of commercial spaceflight. This article will serve to outline the human spaceflight research tasks as designated by the FAA COE CST, and to discuss the research that has been conducted to address many of the risks and challenges involved in human commercial spaceflight.
Introduction: Future commercial spaceflight participants (SFPs) with conditions requiring personal medical devices represent a unique challenge. The behavior under stress of cardiac implanted devices (CIDs) such as pacemakers is of special concern. No known data currently exist on how such devices may react to the stresses of spaceflight. We examined the responses of two volunteer subjects with CIDs to G forces in a centrifuge to evaluate how similar potential commercial SFPs might tolerate the forces of spaceflight. Case report: Two subjects, 75- and 79-yr-old men with histories of atrial fibrillation and implanted dual-lead, rate-responsive pacemakers, underwent seven centrifuge runs over 2 d. Day 1 consisted of two +Gz runs (peak = +3.5 Gz, run 2) and two +Gx runs (peak = +6.0 Gx, run 4). Day 2 consisted of three runs approximating suborbital spaceflight profiles (combined +Gx/+Gz). Data collected included blood pressures, electrocardiograms, pulse oximetry, neurovestibular exams, and postrun questionnaires regarding motion sickness, disorientation, greyout, and other symptoms. Despite both subjects' significant medical histories, neither had abnormal physiological responses. Post-spin analysis demonstrated no lead displacement, damage, or malfunction of either CID. Discussion: Potential risks to SFPs with CIDs include increased arrhythmogenesis, lead displacement, and device damage. There are no known prior studies of individuals with CIDs exposed to accelerations anticipated during the dynamic phases of suborbital spaceflight. These cases demonstrate that even individuals with significant medical histories and implanted devices can tolerate the acceleration exposures of commercial spaceflight. Further investigation will determine which personal medical devices present significant risks during suborbital flight and beyond.
Introduction: Historically, space has been the venue of the healthy individual. With the advent of commercial spaceflight, we face the novel prospect of routinely exposing spaceflight participants (SPFs) with multiple comorbidities to the space environment. Preflight screening procedures must be developed to identify those individuals at increased risk during flight. We examined the responses of volunteers to centrifuge accelerations mimicking commercial suborbital spaceflight profiles to evaluate how potential SFPs might tolerate such forces. We evaluated our screening process for medical approval of subjects for centrifuge participation for applicability to commercial spaceflight operations. Methods: All registered subjects completed a medical questionnaire, physical examination, and electrocardiogram. Subjects with identified concerns including cardiopulmonary disease, hypertension, and diabetes were required to provide documentation of their conditions. Results: There were 335 subjects who registered for the study, 124 who completed all prescreening, and 86 subjects who participated in centrifuge trials. Due to prior medical history, five subjects were disqualified, most commonly for psychiatric reasons or uncontrolled medical conditions. Of the subjects approved, four individuals experienced abnormal physiological responses to centrifuge profiles, including one back strain and three with anxiety reactions. Discussion: The screening methods used were judged to be sufficient to identify individuals physically capable of tolerating simulated suborbital flight. Improved methods will be needed to identify susceptibility to anxiety reactions. While severe or uncontrolled disease was excluded, many subjects successfully participated in centrifuge trials despite medical histories of disease that are disqualifying under historical spaceflight screening regimes. Such screening techniques are applicable for use in future commercial spaceflight operations.
Introduction: U.S. astronauts undergo extensive job-related screening and medical examinations prior to selection in order to identify candidates optimally suited for careers in spaceflight. Screening medical standards evolved over many years and after extensive spaceflight experience. These standards assess health-related risks for each astronaut candidate, minimizing the potential for medical impact on future mission success. This document discusses the evolution of the Shuttle-era medical selection standards and the most common reasons for medical dis-qualification of applicants. Methods: Data for astronaut candidate finalists were compiled from medical records and NASA archives from the period of 1978 to 2004 and were retrospectively reviewed for medically disqualifying conditions. Results: During Shuttle selection cycles, a total of 372 applicants were disqualified due to 425 medical concerns. The most common disqualifying conditions included visual, cardiovascular, psychiatric, and behavioral disorders. During this time period, three major expert panel reviews resulted in refinements and alterations to selection standards for future cycles. Discussion: Shuttle-era screening, testing, and specialist evaluations evolved through periodic expert reviews, evidence-based medicine, and astronaut medical care experience. The Shuttle medical program contributed to the development and implementation of NASA and international standards, longitudinal data collection, improved medical care, and occupational surveillance models. The lessons learned from the Shuttle program serve as the basis for medical selection for the ISS, exploration-class missions, and for those expected to participate in commercial spaceflight.
Introduction: We examined responses of volunteers with known medical disease to G forces in a centrifuge to evaluate how potential commercial spaceflight participants (SFPs) might tolerate the forces of spaceflight despite significant medical history. Methods: Volunteers were recruited based upon suitability for each of five disease categories (hypertension, cardiovascular disease, diabetes, lung disease, back or neck problems) or a control group. Subjects underwent seven centrifuge runs over 2 d. Day 1 consisted of two +G(z) runs (peak = +3.5 G(z), Run 2) and two +G(x), runs (peak = +6.0 G(x), Run 4). Day 2 consisted of three runs approximating suborbital spaceflight profiles (combined +G(x) and +G(z), peak = +6.0 G(x)/+4.0 G(z)). Data collected included blood pressure, electrocardiogram, pulse oximetry, neurovestibular exams, and post-run questionnaires regarding motion sickness, disorientation, grayout, and other symptoms. Results: A total of 335 subjects registered for participation, of which 86 (63 men, 23 women, age 20-78 yr) participated in centrifuge trials. The most common causes for disqualification were weight and severe and uncontrolled medical or psychiatric disease. Five subjects voluntarily withdrew from the second day of testing: three for anxiety reasons, one for back strain, and one for time constraints. Maximum hemodynamic values recorded included HR of 192 bpm, systolic BP of 217 mmHg, and diastolic BP of 144 mmHg. Common subjective complaints included grayout (69%), nausea (20%), and chest discomfort (6%). Despite their medical history, no subject experienced significant adverse physiological responses to centrifuge profiles. Discussion: These results suggest that most individuals with well-controlled medical conditions can withstand acceleration forces of launch and re-entry profiles of current commercial spaceflight vehicles.
As planning continues for commercial spaceflight, attention is turned to NASA to assess whether its human system risk management approach can be applied to mitigate the risks associated with commercial suborbital and orbital flights. NASA uses a variety of methods to assess the risks to the human system based on their likelihood and consequences. In this article, we review these methods and categorize the risks in the system as "definite," "possible," or "least" concern for commercial spaceflight. As with career astronauts, these risks will be primarily mitigated by screening and environmental control. Despite its focus on long-duration exploration missions, NASA's human system risk management approach can serve as a preliminary knowledge base to help medical planners prepare for commercial spaceflights.
The first private-sector flight to the International Space Station will open up myriad opportunities for science, says Alan Stern.
Commercial spaceflight is expected to rapidly develop in the near future. This will begin with sub-orbital missions and then progress to orbital flights. Technical informed consent of spaceflight participants is required by the commercial spaceflight operator for regulatory purposes. Additionally, though not required by regulation, the aerospace medicine professional involved in the medical screening of both spaceflight participants and crewmembers will be asked to assist operators in obtaining medical informed consent for liability purposes. The various federal and state regulations regarding informed consent for sub-orbital commercial spaceflight are evolving and are unfamiliar to most aerospace medical professionals and are reviewed and discussed.
Background: Commercial spaceflight participants on orbital flights typically are older than career astronauts and they often have medical conditions that have not been studied at high g or in microgravity. This is a case report of a 56-yr-old orbital spaceflight participant with essential tremor and frequent premature ventricular contractions that occurred at rates up to 7000 per day. Before training and spaceflight, he was required to complete extensive clinical investigations to demonstrate normal cardiac structures and the absence of cardiac pathology. The evaluation included signal averaged ECG, transthoracic stress echocardiography, exercise tolerance tests, electrophysiological studies, cardiac MRI, electron beam CT, Holter monitoring, and overnight oximetry. While no cardiac pathology was demonstrated, the Russian medical team required that the PVCs be treated prior to training and spaceflight. For the initial flight, a selective beta-1 receptor beta blocker was used and for the second a calcium channel blocker was used in combination with a nonselective beta blocker for tremor control. Analogue environment testing assured that this combination of medications was compatible. Conclusion: The spaceflight participant's PVCs were incompletely suppressed with a low-dose selective beta-1 blocker, but were well suppressed by a calcium channel blocker. He tolerated in-flight periodic use of a nonselective beta blocker in combination with a calcium channel blocker. In-flight ECG and blood pressure monitoring results were normal, and an ECG obtained midmission and on landing day showed successful PVC suppression. He did not have any cardiac difficulty with launch, on-orbit operations, entry, or recovery
Commercial spaceflight participants are typically older than traditional astronauts and often have medical conditions that make medical certification for flight difficult. This case report considers a 43-yr-old spaceflight participant who planned a short-duration Soyuz flight to the International Space Station (ISS). While he participated in many hazardous activities such as parachuting, hang gliding, scuba diving, Antarctic and jungle exploration, and deep sea submersible operations, he knew that several of his medical conditions precluded serving as a career astronaut. At the time of his initial spaceflight prescreen examination, he was known to have previous bilateral photorefractive keratectomy (PRK) for myopia and a cross-fused left ectopic kidney that would be disqualifying for a career astronaut. During the evaluation for the left single cross-fused ectopic kidney, a giant hepatic hemangioma was also discovered. In order to medically qualify for flight, the giant hepatic hemangioma was surgically removed. This case summary investigat*es the implications of a single cross-fused left ectopic kidney and the decision process and treatment implications for spaceflight medical certification in an individual with an asymptomatic giant hepatic hemangioma.
BACKGROUND: A total of eight commercial spaceflight participants have launched to the International Space Station (ISS) on Soyuz vehicles. Based on an older mean age compared to career astronauts and an increased prevalence of medical conditions, spaceflight participants have provided the opportunity to learn about the effect of space travel on crewmembers with medical problems. The 12-d Soyuz TMA-13/12 ISS flight of spaceflight participant Richard Garriott included medical factors that required preflight intervention, risk mitigation strategies, and provided the opportunity for medical study on-orbit. Equally important, Mr. Garriott conducted extensive medical, scientific, and educational payload operations during the flight. These included 7 medical experiments and a total of 15 scientific projects such as protein crystal growth, Earth observations/photography, educational projects with schools, and amateur radio. The medical studies included the effect of microgravity on immune function, sleep, bone loss, corneal refractive surgery, low back pain, motion perception, and intraocular pressure. CONCLUSION: The overall mission success resulted from non-bureaucratic agility in mission planning, cooperation with investigators from NASA, ISS, International Partners, and the Korean Aerospace Research Institute, in-flight support and leadership from a team with spaceflight and Capcom experience, and overall mission support from the ISS program. This article focuses on science opportunities that suborbital and orbital spaceflight participant flights offer and suggests that the science program on Richard Garriott's flight be considered a model for future orbital and suborbital missions. The medical challenges are presented in a companion article.
It now appears likely that commercial entities will carry paying passengers on suborbital spaceflights in this decade. The stresses of spaceflight, the effects of microgravity, and the limited capability for medical care onboard make it advisable to develop a system of medical clearance for such space tourists. The Aerospace Medical Association, therefore, organized a Space Passenger Task Force whose first report on medical guidelines was published in 2001. That report consisted of a list of conditions that would disqualify potential passengers for relatively long orbital flights. The Task Force reconvened in 2002 to focus on less stringent medical screening appropriate for short duration suborbital flights. It was assumed that such commercial flights would involve: 1) small spacecraft carrying 4-6 passengers; 2) a cabin maintained at sea-level "shirt-sleeve" condition; 3) maximum accelerations of 2.0-4.5 G; 4) about 30 min in microgravity. The Task Force addressed specific medical problems, including space motion sickness, pregnancy, and medical conditions involving the risk of sudden incapacitation. The Task Force concluded that a medical history should be taken from potential passengers with individualized follow-up that focuses on areas of concern.
Candidates for commercial spaceflight may be older than the typical astronaut and more likely to have medical problems that place them at risk during flight. Since the effects of microgravity on many medical conditions are unknown, physicians have little guidance when evaluating and certifying commercial spaceflight participants. This dynamic new era in space exploration may provide important data for evaluating medical conditions, creating appropriate medical standards, and optimizing treatment alternatives for long-duration spaceflight. A 57-yr-old spaceflight participant for an ISS mission presented with medical conditions that included moderately severe bullous emphysema, previous spontaneous pneumothorax with talc pleurodesis, a lung parenchymal mass, and ventricular and atrial ectopy. The medical evaluation required for certification was extensive and included medical studies and monitoring conducted in analogue spaceflight environments including altitude chambers, high altitude mixed-gas simulation, zero-G aircraft, and high-G centrifuge. To prevent recurrence of pneumothorax, we performed video-assisted thoracoscopic pleurodesis, and to assess lung masses, several percutaneous or direct biopsies. The candidate's 10-d mission was without incident. Non-career astronauts applying for commercial suborbital and orbital spaceflight will, at least in the near future, challenge aerospace physicians with unknowns regarding safety during training and flight, and highlight important ethical and risk-assessment problems. The information obtained from this new group of space travelers will provide important data for the evaluation and in-flight treatment of medical problems that space programs have not yet addressed systematically, and may improve the medical preparedness of exploration-class missions.
Introduction: The medical community of the International Space Station (ISS) has developed joint medical standards and evaluation requirements for Space Flight Participants ("space tourists") which are used by the ISS medical certification board to determine medical eligibility of individuals other than professional astronauts (cosmonauts) for short-duration space flight to the ISS. These individuals are generally fare-paying passengers without operational responsibilities. Material and context: By means of this publication, the medical standards and evaluation requirements for the ISS Space Flight Participants are offered to the aerospace medicine and commercial spaceflight communities for reference purposes. It is emphasized that the criteria applied to the ISS spaceflight participant candidates are substantially less stringent than those for professional astronauts and/or crewmembers of visiting and long-duration missions to the ISS. Conclusions: These medical standards are released by the government space agencies to facilitate the development of robust medical screening and medical risk assessment approaches in the context of the evolving commercial human spaceflight industry.
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