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Reaching new milestones in space, historically, has been achieved through the execution of a comprehensive developmental test program of increasing complexity, which validates engineering design models and provides operational experience. In this paper, the Red Bull Stratos program, which culminated with Felix Baumgartner's successful space dive on October 14, 2012, has been assessed in order to evaluate the quantitative enhancement to safety by its experimental test program. The analysis is carried out using Probabilistic Risk Assessment (PRA). 1 The PRA is a technique for mature systems to quantify complete system risk. Required inputs include numerical likelihood estimates for each individual failure mode or failure event; accurate results are dependent upon full and complete data sets, derived from the evaluation of mature systems. By contrast, test programs and one-off missions themselves frequently do not have the statistically significant number of past events and thus are not candidates for such evaluations. As such, this analysis is unable to reasonably quantify the absolute risk to the Red Bull Stratos mission. Instead, it is meant to show the relative value of enhancements to safety that were realized through the development program that follows a robust test program of increasing complexity in order to validate design models and reduce risks. The PRA is applied to the experimental test program and compared against the quantified results of the hypothetical test program that would have been performed had the project been completed in a single step, without the developmental test program. In addition to the planned test flights, the Stratos project also benefitted from past experience of other manned stratospheric balloon projects, including Project Manhigh (1955–58), Project Excelsior (1959–60), the Russian Volga (1962) and the Strato Jump project (1965–66). This study is attempting to quantify the safety benefit associated with a developmental test program and shows a marked improvement in quantified safety as a result of implementing lessons learned from testing and prior manned balloon flights. Initially, interest in a stratospheric jump program was from the US Air Force who was focused on the viability for a crew escape system from a reentry vehicle. There is renewed interest on this capability from the commercial industry that is looking to provide suborbital flight and access to Low Earth Orbit.

Background There is a need to develop noninvasive methods to monitor intracranial pressure (ICP). Pupillary reactivity decreases in patients with elevated ICP with demonstrated cerebral edema. We sought to determine whether pupillary reactivity is affected when ICP is elevated in the absence of brain edema. Methods Healthy subjects and individuals with idiopathic intracranial hypertension (IIH) underwent pupillometry in different positions (upright, supine, and head-down tilt) and during different physiological maneuvers. A separate group of healthy subjects were tested in the upright resting position only. The pupillary dynamics were measured with a pupillometer. Results Healthy and IIH subjects were enrolled. In the healthy subjects the change from upright to head-down tilt led to a Neurological Pupil Index (NPI) decrease from 4.30 to 4.12, while maximum pupil size and minimum pupil size increased from 4.74 to 5.19 and 3.04 to 3.44, respectively. In the IIH group the maximum pupil size, minimum pupil size, and latency increased in magnitude with a decline in head tilt. The mean NPI of IIH subjects, 4.37, was greater than the healthy mean, 4.25. Also, the mean IIH Max and Min, 5.02 and 3.25, were greater than the healthy mean, 4.62 and 2.92. Discussion We observed changes in the pupillary reactivity in all subjects based on changes in position and task. There were also differences between the healthy and IIH subjects. This is consistent with our hypothesis that elevated intracranial pressure may result in decreased pupillary reactivity even in the absence of brain edema.Soeken TA, Alonso A, Grant A, Calvillo E, Gutierrez-Flores B, Clark J, Donoviel D, Bershad EM. Quantitative pupillometry for detection of intracranial pressure changes during head-down tilt. Aerosp Med Hum Perform. 2018; 89(8):717-723.

Astronauts aboard the International Space Station (ISS) have exhibited hyperopic shifts, posterior eye globe flattening, dilated optic nerve sheaths, and even optic disk swelling from spaceflight. Elevated intracranial pressure (ICP) consequent to cephalad fluid shifts is commonly hypothesized as contributing to these ocular changes. Head-down tilt (HDT) is frequently utilized as an Earth-based analog to study similar fluid shifts. Sealed environments like the ISS also exhibit elevated CO2, a potent arteriolar vasodilator that could further affect cerebral blood volume (CBV) and cerebral blood flow, intracranial compliance, and ICP. A collaborative pilot study between the National Space Biomedical Research Institute and the German Aerospace Center tested the hypotheses that 1) HDT and elevated CO2 physiologically interact and 2) cerebrovascular pulsatility is related to HDT and/or elevated CO2. In a double-blind crossover study ( n = 6), we measured CBV pulsatility via near-infrared spectroscopy, alongside noninvasive ICP and intraocular pressure (IOP) during 28-h −12° HDT at both nominal (0.04%) and elevated (0.5%) ambient CO2. In our cohort, CBV pulsatility increased significantly over time at cardiac frequencies (0.031 ± 0.009 μM/h increase in total hemoglobin concentration pulsatility amplitude) and Mayer wave frequencies (0.019 ± 0.005 μM/h increase). The HDT-CO2 interaction on pulsatility was not robust but rather driven by one individual. Significant differences between atmospheres were not detected in ICP or IOP. Further work is needed to determine whether individual differences in pulsatility responses to CO2 relate to visual changes in space. NEW & NOTEWORTHY Cerebral blood volume (CBV) pulsatility—as measured by near-infrared spectroscopy—increases over time during −12° head-down tilt at both cardiac and Mayer wave frequencies. CBV pulsatility appeared to increase more under elevated (0.5%) CO2 at Mayer wave frequencies in some individuals. If similar dynamic pulsatility increases occur in astronauts, there is the potential to initiate vascular and possibly other remodeling processes that lead to symptoms associated with sustained increases in intracranial pressure.

Wolbachia are intracellular prokaryotic endosymbionts associated with a wide distribution of arthropod and nematode hosts. Their association ranges from parasitism to mutualism, and there is growing evidence that Wolbachia can have dramatic effects on host reproduction, physiology, and immunity. Although all Wolbachia are currently considered as single species, W. pipientis, phylogenetic studies reveal about a dozen monophyletic groups, each designated as a supergroup. This study uses 16S rRNA gene sequences to examine the genetic diversity of Wolbachia present in three species of Great Salt Lake brine flies, Cirrula hians, Ephydra gracilis, and Mosillus bidentatus. The brine fly Wolbachia sequences are highly similar, with an average nucleotide sequence divergence among the three species of 0.00174. The brine fly Wolbachia form a monophyletic group that is affiliated with a subset of supergroup B, indicating that this supergroup may be more diverse than previously thought. These findings expand the phylogenetic diversity of Wolbachia and extend their host range to taxa adapted to a hypersaline environment.

During long duration space missions, crewmembers are exposed to a variety of incessant noises and acoustic conditions, as well as brief, but very loud, sound levels during launch, descent, and possible abort scenarios. Some common sources of these sounds are payloads (science experiments), ventilation fans, thermal control systems, and equipment within the limited confines of spacecraft (Goodman and Grosveld. Acoustics and noise control in space crew compartments. National Aeronautics and Space Administration, Houston; 2015). Crewmembers have reported that the monotony of adverse acoustic conditions can degrade habitability, especially with inadequate acoustic respite during long duration missions. More specifically, the impact of acoustics on human health and performance during space flight has been associated with disruptions of sleep, interference with speech communications, reduced audible detection of caution or warning alarms, and reduced human performance in demanding tasks. Because excessive noise conditions may also be a risk for temporary or permanent hearing loss, crewmembers must frequently wear hearing protection. In an effort to prevent hearing loss and improve habitability during space missions, multidisciplinary teams have been established to control acoustical noise using hardware design and reviews, acoustical measurements, noise controls, and hearing conservation practices. This chapter offers a summary of the impact of spacecraft noise on human health and performance, as well as options for remediation and crew protection.

Space applications have evolved to play a significant role in disaster relief by providing services including remote sensing imagery for mitigation and disaster damage assessments; satellite communication to provide access to medical services; positioning, navigation, and timing services; and data sharing. Common issues identified in past disaster response and relief efforts include lack of communication, delayed ordering of actions (eg, evacuations), and low levels of preparedness by authorities during and after disasters. We briefly summarize the Space for Health (S4H) Team Project, which was prepared during the Space Studies Program 2014 within the International Space University. The S4H Project aimed to improve the way space assets and experiences are used in support of public health during disaster relief efforts. We recommend an integrated solution based on nano-satellites or a balloon communication system, mobile self-contained relief units, portable medical scanning devices, and micro-unmanned vehicles that could revolutionize disaster relief and disrupt different markets. The recommended new system of coordination and communication using space assets to support public health during disaster relief efforts is feasible. Nevertheless, further actions should be taken by governments and organizations in collaboration with the private sector to design, test, and implement this system. (Disaster Med Public Health Preparedness. 2015;9:319-328)

This chapter explores both the physical and psychological components of airsickness, reviews the operational importance of motion sickness for flight, gives some guidelines for flight crews susceptible to airsickness and outlines the psychological and pharmacological interventions used to eliminate or ameliorate motion sickness. It describes the special cases of motion sickness related to aviation including space motion sickness, high-acceleration environments and virtual aviation systems. Motion sickness is a condition that can be provoked by movement of the human head in a gravity field or by moving visual fields. Theories of motion sickness have to link two seemingly disparate phenomena: gastric distress, with its concomitant nausea and stomach peristalsis, and motion imparted to the body and particularly to the head. As many a college student can attest, two things can occur: the bed-spins and vomiting. The malfunctioning inner ear induces the spinning sensation and then motion sickness, nausea, and vomiting occur.

Background Ultrasound (U/S) and MRI measurements of the optic nerve sheath diameter (ONSD) have been proposed as intracranial pressure measurement surrogates, but these methods have not been fully evaluated or standardized. The purpose of this study was to develop an ex-vivo model for evaluating ONSD measurement techniques by comparing U/S and MRI measurements to physical measurements. Methods The left eye of post mortem juvenile pigs (N = 3) was excised and the subdural space of the optic nerve cannulated. Caliper measurements and U/S imaging measurements of the ONSD were acquired at baseline and following 1 cc saline infusion into the sheath. The samples were then embedded in 0.5% agarose and imaged in a 7 Tesla (7T) MRI. The ONSD was subsequently measured with digital calipers at locations and directions matching the U/S and direct measurements. Results Both MRI and sonographic measurements were in agreement with direct measurements. U/S data, especially axial images, exhibited a positive bias and more variance (bias: 1.318, 95% limit of agreement: 8.609) compared to MRI (bias: 0.3156, 95% limit of agreement: 2.773). In addition, U/S images were much more dependent on probe placement, distance between probe and target, and imaging plane. Conclusions This model appears to be a valid test-bed for continued scrutiny of ONSD measurement techniques. In this model, 7T MRI was accurate and potentially useful for in-vivo measurements where direct measurements are not available. Current limitations with ultrasound imaging for ONSD measurement associated with image acquisition technique and equipment necessitate further standardization to improve its clinical utility.

Background Nontraumatic, nonhydrocephalic increases in intracranial pressure (ICP) are often difficult to diagnose and may underlie spaceflight-related visual changes. This study looked at the utility of a porcine animal model of increasing cephalic venous pressure to mimic acute changes in ICP and optic nerve sheath diameter (ONSD) from cephalic venous fluid shifts observed during spaceflight. Methods Anesthetized juvenile piglets were assigned to groups of either naive (N = 10) or elevated superior vena cava pressure (SVCP; N = 20). To elevate SVCP, a 6F custom latex balloon catheter was inserted and inflated to achieve SVCP of 20 and 40 mmHg for 1 h at each pressure. In both groups, serial measurements of ICP, internal jugular pressure (IJP), and external jugular pressure (EJP) were made hourly for 3 h, and ONSD of the right eye was measured hourly by ultrasound (US). Results There was a significant linear correlation between IJP and ICP (slope: 0.9614 +/- 0.0038, r = 0.9683). With increasing SVCP, resulting ONSD was also well correlated with the ICP (slope: 0.0958 +/- 0.0061, r = 0.7841). The receiver operating characteristic curve for ONSD in diagnosing elevated ICP had an area under the curve of 0.9632 with a sensitivity and specificity of 92% and 91%, respectively, for a cutoff of 5.45 mm. Conclusions Increases in SVCP result in ICP changes that are well correlated with alteration in ONSD. These changes are consistent with observed ONSD changes monitored during spaceflight.

INTRODUCTION: Red Bull Stratos was a commercial program that brought a test parachutist protected by a full pressure suit to 127,852 ft (38,964 m), via a stratospheric balloon with a pressurized capsule, from which he free fell and subsequently parachuted to the ground. In light of the uniqueness of the operation and the medical threats faced, medical protocols specific to distinctive injury patterns were developed. One unique threat was that of a flat spin during free fall with resultant exposure to -Gz (toe-to-head) acceleration. In preparation for stratospheric free fall, the medical team conducted a review of the literature on the spectrum of human and animal injury patterns attributable to -Gz exposures. Based on the findings, an emergency medical field response protocol was developed for the rapid assessment, diagnosis, and treatment of individuals suspected of -Gz injury. METHODS: A systematic review was conducted on available literature on human and animal studies involving significant -Gz exposure, with subsequent development of an applicable field treatment protocol. RESULTS: The literature review identified pathophysiologic processes and mitigation strategies that were used to develop a prevention and treatment protocol, outlining appropriate interventions using current best medical practices. A medical field treatment protocol was successfully established for the high-altitude balloon program. DISCUSSION: Available literature provided insight into best medical practices for the prevention and treatment of significant -Gz exposures during high-altitude parachute activity. Using the protocol developed for the field medical response, injuries from sustained -Gz exposure can be effectively managed in similar high-altitude and space operations. Language: en

INTRODUCTION: Red Bull Stratos was a commercial program designed to bring a test parachutist protected by a full-pressure suit via a stratospheric balloon with a pressurized capsule to 120,000 ft (36,576 m), from which he would freefall and subsequently parachute to the ground. On March 15, 2012, the Red Bull Stratos program successfully conducted a preliminary manned balloon test flight and parachute jump, reaching a final altitude of 71,581 ft (21,818 m). In light of the uniqueness of the operation and medical threats faced, a comprehensive medical plan was needed to ensure prompt and efficient response to any medical contingencies. This report will serve to discuss the medical plans put into place before the first manned balloon flight and the actions of the medical team during that flight. METHODS: The medical operations developed for this program will be systematically evaluated, particularly, specific recommendations for improvement in future high-altitude and commercial space activities. RESULTS: A multipronged approach to medical support was developed, consisting of event planning, medical personnel, equipment, contingency-specific considerations, and communications. DISCUSSION: Medical operations were found to be highly successful when field-tested during this stratospheric flight, and the experience allowed for refinement of medical operations for future flights. The lessons learned and practices established for this program can easily be used to tailor a plan specific to other aviation or spaceflight events.

In spaceflight beyond low Earth's orbit, medical conditions requiring surgery are of a high level of concern because of their potential impact on crew health and mission success. Whereas surgical techniques have been thoroughly studied in spaceflight analogues, the research focusing on anesthesia is limited. To provide safe anesthesia during an exploration mission will be a highly challenging task. The research objective is thus to describe specific anesthesia procedures enabling treatment of pre-identified surgical conditions. Among the medical conditions considered by the NASA Human Research Program Exploration Medical Capability element, those potentially necessitating anesthesia techniques have been identified. The most appropriate procedure for each condition is thoroughly discussed. The substantial cost of training time necessary to implement regional anesthesia is pointed out. Within general anesthetics, ketamine combines the unique advantages of preservation of cardiovascular stability, the protective airway reflexes, and spontaneous ventilation. Ketamine side effects have for decades tempered enthusiasm for its use, but recent developments in mitigation means broadened its indications. The extensive experience gathered in remote environments, with minimal equipment and occasionally by insufficiently trained care providers, confirms its high degree of safety. Two ketamine-based anesthesia protocols are described with their corresponding indications. They have been designed taking into account the physiological changes occurring in microgravity and the specific constraints of exploration missions. This investigation could not only improve surgical care during long-duration spaceflights, but may find a number of terrestrial applications in isolated or austere environments.

Introduction Flights to high altitude can lead to exposure and unique pathology not seen in normal commercial aviation. Methods This paper assesses the potential for point-of-care ultrasound to aid in management and disposition of injured crewmembers from a high altitude incident. This was accomplished through a systematic literature review regarding current diagnostic and therapeutic uses of ultrasound for injuries expected in high altitude free fall and parachuting. Results While current research supports its utility in diagnostics, therapeutic procedures, and triage decisions, little research has been done regarding its utility in high altitude specific pathology, but its potential has been demonstrated. Discussion An algorithm was created for use in high altitude missions, in the event of an emergency descent and traumatic landing for an unconscious and hypotensive pilot, to rule out most life threatening causes. Each endpoint includes disposition, allowing concise decision-making.Galdamez LA, Clark JB, Antonsen EL. Point-of-care ultrasound utility and potential for high altitude crew recovery missions. Aerosp Med Hum Perform. 2017; 88(2):128-136.

Introduction Ebullism is the spontaneous evolution of liquid water in tissues to water vapor at body temperature when the ambient pressure is 47 mmHg or less. While injuries secondary to ebullism are generally considered fatal, some reports have described recovery after exposure to near vacuum for several minutes. The objectives of this article are to review the current literature on ebullism and to present prevention and treatment recommendations that can be used to enhance the safety of high altitude activities and space operations. Methods A systematic review was conducted on currently available information and published literature of human and animal studies involving rapid decompression to vacuum and ebullism, with subsequent development of an applicable treatment protocol. Results Available research on ebullism in human and animal subjects is extremely limited. Literature available identified key pathophysiologic processes and mitigation strategies that were used for treatment protocol design and outlining appropriate interventions using current best medical practices and technologies. Discussion Available literature suggests that the pathophysiology of ebullism leads to predictable and often treatable injuries, and that many exposures may be survivable. With the growing number of high altitude and space-related activities, more individuals will be at risk for ebullism. An integrated medical protocol can provide guidance for the prevention and treatment of ebullism and help to mitigate this risk in the future.

Background Noninvasive intracranial pressure (ICP) measurement would represent a major advance for patients with neurological problems. The Vittamed ICP meter is an ultrasound-based device reported to have high agreement with lumbar puncture cerebrospinal fluid (CSF) pressure measurement. However, previous studies included mostly patients with normal levels of ICP. The purpose of our study was to perform an independent clinical validation study of a transcranial Doppler-based noninvasive ICP meter in patients anticipated to have a wide range of ICP. Methods In a prospective cross-sectional design, we simultaneously measured ICP with the Vittamed device and the invasive lumbar CSF pressure. The operator of each procedure was blinded to the result of the other method. Data were analyzed using Bland-Altman plots, Pearson correlation coefficients, and receiver operator characteristic curves. Results Twenty-four independent paired measurements of Vittamed and lumbar CSF pressure were obtained; with mean absolute difference between paired measures of 4.5 mmHg (standard deviation 3.1). The 95% limits of agreement were −10.5 to +11.0. The systematic bias (mean of paired differences) was negligible at 0.25 mmHg. The sensitivity, specificity, and area under the curve for ICP >20 mmHg were 0.73, 0.77, and 0.71, respectively. Conclusions The Vittamed ICP meter had fair agreement with lumbar CSF pressure measurement. The wide limits of agreement would preclude using this version of the device as a stand-alone method for ICP determination, but may be useful if combined with other ICP screening methods. Ongoing improvements to the Vittamed hardware and software may lead to improvements in accuracy and clinical utility of this device.

This study investigates the use of a mathematical model for thermoregulation as a tool in safety-of-flight issues and proposed solutions for mission operations of the Space Shuttle and the International Space Station. Specifically, this study assesses the effects of elevated cabin temperature and metabolic loads on astronauts wearing the Advanced Crew Escape Suit (ACES) and the Liquid Cooled Ventilation Garment (LCVG). The 225-node Wissler model is validated by comparison with two ground-based human subject tests, firefighters, and surrogate astronauts under anomalous conditions that show good agreement. Subsequent simulations indicate that the performance of the ACES/LCVG is marginal. Increases in either workload or cabin temperature from the nominal will increase rectal temperature, stored heat load, heart rate, and sweating leading to possible deficits in the ability of the astronauts to perform cognitive and motor tasks that could affect the safety of the mission, especially the safe landing of the Shuttle. Specific relationships are given between cabin temperature and metabolic rate that define the threshold for decreased manual dexterity and loss of tracking skills. Model results indicate that the most effective mitigation strategy would be to decrease the LCVG inlet temperature. Methods of accomplishing this are also proposed.

Hand and upper-extremity overuse and repetitive injuries in astronauts have been and continue to be a common problem in the space program. The demands on upper-extremity use in the astronaut training program, the zero-gravity environment, the extreme temperature conditions of space, the effects of space travel on human physiology/anatomy, and the constraints and pressures of space suits and gloves all can negatively impact upper-extremity function in ways that can result in overuse/repetitive injuries. Future plans for space exploration include endeavors that will continue and even increase the demands on the hand and upper extremity.

Objectives The study goal was to determine whether a single Space Shuttle mission can induce decrements in astronaut hearing. Study design We retrospectively compared audiogram information obtained from Space Shuttle astronauts at 10 days preflight, day of return (R + 0), 3 days after landing return (R + 3), and at a mean delayed postflight follow-up of 8 months. Results Temporary threshold shift (mean, 4.6 dB) was noted in R + 0 versus preflight conditions (P < 0.01). Small permanent threshold shifts (mean, 0.83 dB) were found at R + 3 and postflight follow-up compared with preflight in the lower frequencies (500 to 2000 Hz), and corresponding pure tone average (P < 0.001). Conclusions and significance The data indicate that a single Shuttle flight can induce a substantial temporary threshold shift and a small but statistically significant permanent threshold shift, particularly in the frequencies involved in speech reception. Although single-mission effects are small, cumulative effects over several missions may ultimately produce clinically significant hearing loss.

IntroductionRed Bull Stratos was a commercial program that brought a test parachutist, protected by a full-pressure suit, in a stratospheric balloon with pressurized capsule to over 127,582 ft (38,969 m), from which he free fell and subsequently parachuted to the ground. Given that the major risks to the parachutist included ebullism, negative Gz (toe-to-head) acceleration exposure from an uncontrolled flat spin, and trauma, a comprehensive plan was developed to recover the parachutist under nominal conditions and to respond to any medical contingencies that might have arisen. In this report, the project medical team describes the experience of providing emergency medical support and crew recovery for the manned balloon flights of the program.MethodsThe phases of flight, associated risks, and available resources were systematically evaluated.ResultsSix distinct phases of flight from an Emergency Medical Services (EMS) standpoint were identified. A Medical Support Plan was developed to address the risks associated with each phase, encompassing personnel, equipment, procedures, and communications.DiscussionDespite geographical, communications, and resource limitations, the medical team was able to implement the Medical Support Plan, enabling multiple successful manned balloon flights to 71,615 ft (21,828 m), 97,221 ft (29,610 m), and 127,582 ft (38,969 m). The experience allowed refinement of the EMS and crew recovery procedures for each successive flight and could be applied to other high altitude or commercial space ventures.BlueRS, NortonSC, LawJ, PattariniJM, AntonsenEL, GarbinoA, ClarkJB, TurneyMW. Emergency medical support for a manned stratospheric balloon test program. Prehosp Disaster Med. 2014;29(5):1-6.

Recent studies suggest that elevated intracranial pressure (ICP), created by hydrocephalus, can alter the lower limit of cerebrovascular autoregulation (LLA). Our objective in the present study was to determine if ICP elevation from cerebral venous outflow obstruction would result in comparable alterations in the LLA.Anesthetized juvenile pigs were assigned to one of two groups: naïve ICP (n = 15) or high ICP (20 mmHg; n = 20). To elevate ICP through venous obstruction, a modified 5F esophageal balloon catheter was inserted via the right external jugular vein into the superior vena cava (SVC) and inflated to maintain an ICP of20 mmHg. To calculate the LLA, gradual hypotension was induced by continuous hemorrhage from a catheter in the femoral vein. The LLA was determined by monitoring cortical laser Doppler flux (LDF).The naïve and high ICP groups had LLAs of 45 mmHg (95% CI: 41-49 mmHg) and 71 mmHg (95% CI: 66-77 mmHg) respectively by LDF. The LLA was significantly different between the two groups and correlated significantly with ICP.Elevated ICP from cephalic venous engorgement leads to an increase in the LLA. These findings suggest that pathologic processes resulting in cephalic venous outflow obstruction and intracranial venous congestion can acutely elevate ICP and may place the brain at risk for impaired cerebrovascular autoregulation.

INTRODUCTION: The Red Bull Stratos Project consisted of incremental high altitude parachute jumps [maximum altitude 127,852 ft (38,969 m)] from a pressurized capsule suspended from a stratospheric helium-filled balloon. A physiological monitoring system was worn by the parachutist to provide operational medical and acceleration data and to record a unique set of data in a supersonic environment. METHODS: Various physiological parameters, including heart rate (HR), respiratory rate (RR), skin temperature, and triaxial acceleration, were collected during the ascent, high altitude float, free fall, and parachute opening and descent stages of multiple low- and high altitude jumps. Physiologic data were synchronized with global positioning system (GPS) and audiovisual data for a comprehensive understanding of the environmental stressors experienced. RESULTS: HR reached maximum during capsule egress and remained elevated throughout free fall and landing. RR reached its maximum during free fall. Temperature data were unreliable and did not provide useful results. The highest accelerations parameters were recorded during parachute opening and during landing. During each high altitude jump, immediately after capsule egress, the parachutist experienced a few seconds of microgravity during which some instability occurred. Control was regained as the parachutist entered denser atmosphere. DISCUSSION: The high altitude environment resulted in extremely high vertical speeds due to little air resistance in comparison to lower altitude jumps with similar equipment. The risk for tumbling was highest at initial step-off. Physiological responses included elevated HR and RR throughout critical phases of free fall. The monitoring unit performed well despite the austere environment and extreme human performance activities. Language: en

Sequences homologous to the P transposable element have been identified in Musca domestica. Sequence analysis of a genomic clone (Md-P1) indicates that, although the house fly P element has lost its coding capacity, the basic general structure of drosophilid P elements is present. The house fly P element sequence shares a number of structural features with that from the blow fly, Lucilia cuprina, including a large intron separating exons 1 and 2, two additional introns interrupting exon 2 and the apparent absence of inverted repeat termini. Within a relatively well-conserved central region, the house fly sequence shows 59% similarity to the D. melanogaster P element, but distal regions are more diverged. Southern blot analysis of several strains indicated the presence of at least four P element copies.

Nucleotide sequences from two nuclear loci, alcohol dehydrogenase and internal transcribed spacer-1 of the nuclear ribosomal DNA repeats, and two mitochondrial genes, cytochrome oxidase I and cytochrome oxidase II, were determined from nine species in the Drosophila saltans species group. The partition homogeneity test and partitioned Bremer support were used to measure incongruence between phylogenetic hypotheses generated from individual partitions. Individual loci were generally congruent with each other and consistent with the previously proposed morphological hypothesis, although they differed in level of resolution. Since extreme conflict between partitions did not exist, the data were combined and analyzed simultaneously. The total evidence method gave a more resolved and highly supported phylogeny, as indicated by bootstrap proportions and decay indices, than did any of the individual analyses. The cordata and elliptica subgroups, considered to have diverged early in the history of the D. saltans group, were sister taxa to the remainder of the saltans group. The sturtevanti subgroup, represented by D. milleri and D. sturtevanti, occupies an intermediate position in this phylogeny. The saltans and parasaltans subgroups are sister clades and occupy the most recently derived portion of the phylogeny. As with previous morphological studies, phylogenetic relationships within the saltans subgroup were not satisfactorily resolved by the molecular data.

Red Bull Stratos was a commercial program that brought a test parachutist protected by a full pressure suit to 127,852 ft (38,964 m), via a stratospheric balloon with a pressurized capsule, from which he free fell and subsequently parachuted to the ground. In light of the uniqueness of the operation and the medical threats faced, medical protocols specific to distinctive injury patterns were developed. One unique threat was that of a flat spin during free fall with resultant exposure to -Gz (toe-to-head) acceleration. In preparation for stratospheric free fall, the medical team conducted a review of the literature on the spectrum of human and animal injury patterns attributable to -Gz exposures. Based on the findings, an emergency medical field response protocol was developed for the rapid assessment, diagnosis, and treatment of individuals suspected of -Gz injury.A systematic review was conducted on available literature on human and animal studies involving significant -Gz exposure, with subsequent development of an applicable field treatment protocol.The literature review identified pathophysiologic processes and mitigation strategies that were used to develop a prevention and treatment protocol, outlining appropriate interventions using current best medical practices. A medical field treatment protocol was successfully established for the high-altitude balloon program.Available literature provided insight into best medical practices for the prevention and treatment of significant -Gz exposures during high-altitude parachute activity. Using the protocol developed for the field medical response, injuries from sustained -Gz exposure can be effectively managed in similar high-altitude and space operations.

Long duration spaceflight, permanent human presence on the Moon, and future human missions to Mars will require autonomous medical care to address both expected and unexpected risks. An integrated non-invasive visual field test & diagnosis system is presented for the identification, characterization, and automated classification of visual field defects caused by the spaceflight environment. This system will support the onboard medical provider and astronauts on space missions with an innovative, non-invasive, accurate, sensitive, and fast visual field test. It includes a database for examination data, and a software package for automated visual field analysis and diagnosis. The system will be used to detect and diagnose conditions affecting the visual field, while in space and on Earth, permitting the timely application of therapeutic countermeasures before astronaut health or performance are impaired. State-of-the-art perimetry devices are bulky, thereby precluding application in a spaceflight setting. In contrast, the visual field test & diagnosis system requires only a touchscreen-equipped computer or touchpad device, which may already be in use for other purposes (i.e., no additional payload), and custom software. The system has application in routine astronaut assessment (Clinical Status Exam), pre-, in-, and post-flight monitoring, and astronaut selection. It is deployable in operational space environments, such as aboard the International Space Station or during future missions to or permanent presence on the Moon and Mars.

In 1998 Patel et al searched for Earth-Mars free-return trajectories that leave Earth, fly by Mars, and return to Earth without any deterministic maneuvers after Trans-Mars Injection. They found fast trajectory opportunities occurring two times every 15 years with a 1.4-year duration, significantly less than most Mars free return trajectories, which take up to 3.5 years. This paper investigates these fast trajectories. It also determines the launch and life support feasibility of flying such a mission using hardware expected to be available in time for an optimized fast trajectory opportunity in January, 2018.

As directed by the Council of the Aerospace Medical Association, the Commercial Spaceflight Working Group has developed the following position paper concerning medical issues for commercial suborbital spaceflight crewmembers. This position paper has been approved by the AsMA Council to become a policy of the AsMA.

Background Astronauts are exposed to toxic ionizing radiation sources, including galactic cosmic radiation and solar particle events (SPE). Exposure to these radiation sources can lead to cataracts, heritable genetic mutations, cancer, acute life-threatening physiological compromise, and death. Current countermeasures focus on spacecraft shielding and creation of heavily shielded safe havens. At issue is the extraordinarily high cost of launching these heavy structures into space and their inability to provide adequate shielding from heavy ions at a feasible shield thickness. Pharmacological enhancement of cellular radiation resistance, an alternative method to limiting radiation toxicity, has received less attention. Methods We have conducted an extensive literature review and critical evaluation of the scientific data pertaining to this field of study. Publications for review were identified through a Medline search using relevant terms, including radiotherapeutics, galactic cosmic radiation, radiopharmacology, radioprotectants, radiation countermeasures, solar particles, solar flares, radiation toxicity, and radiotoxicity. Results We identified 15 agents with significant radiation dose reduction factors, ranging from 1.1 to 2.4, in experimental models. Of these, only amifostine is FDA approved for use in treating radiation toxicity. Conclusions Current data do not support the use of radiopreventive agents in the treatment of low-level ionizing radiation exposures. However, pharmacological countermeasures should be instituted for life-threatening, high-level radiation exposures, as occur with SPE. Given the catastrophic effects of SPE, the risk of toxicity from radioprotective agents is warranted. The current data supports treatment with high-dose amifostine (at 910 mg m(-2)) 30 min prior to radiation exposure.

Background Sequences homologous to the gypsy retroelement from Drosophila melanogaster are widely distributed among drosophilids. The structure of gypsy includes an open reading frame resembling the retroviral gene env, which is responsible for the infectious properties of retroviruses. Results In this study we report molecular and phylogeny analysis of the complete env gene from ten species of the obscura group of the genus Drosophila and one species from the genus Scaptomyza. Conclusion The results indicate that in most cases env sequences could produce a functional Env protein and therefore maintain the infectious capability of gypsy in these species.

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.

Background Orbiter landing data show decrements in pilot performance following spaceflight compared to preflight simulated landings. This study aimed to characterize pilot head-eye coordination during simulated orbiter landings, and relate findings to microgravity-related spatial disorientation. Methods Orbiter landings were simulated in an A340-300 simulator flown by six pilots. Turns about the Heading Alignment Circle (HAC) to align the orbiter with the runway were simulated by 45 degrees banking turns. Final approach was simulated with an 11 degrees glide slope from an altitude of 4267 m, with preflare at 610 m and touchdown at 200 kn. Orbiter landings were also performed in the Vertical Motion Simulator (VMS) at NASA Ames by a NASA test pilot. Results A340: During the HAC maneuver the head and eyes rolled toward the visual horizon with a combined gain of 0.14 of bank angle. Pilots alternated fixation between the instruments and the runway during final approach, almost exclusively focusing on the runway after preflare. Optokinetic nystagmus was observed during rollout. VMS: Head and eye roll tilt when rounding the HAC were of similar magnitude to that observed in the A340. During final approach the Heads-Up Display (HUD) reduced pitch head and eye movement. Conclusions Roll tilt of the head and eyes during the HAC tended to align the retina with the visual horizon. Overlaying critical flight information and the approaching runway with the HUD reduced pitch head and eye movement during orbiter final approach in the VMS relative to the A340 (no HUD installed).

Transposable elements are characterized by their ability to spread within a host genome. Many are also capable of crossing species boundaries to enter new genomes, a process known as horizontal transfer. Focusing mostly on animal transposable elements, we review the occurrence of horizontal transfer and examine the methods used to detect such transfers. We then discuss factors that affect the frequency of horizontal transfer, with emphasis on the mechanism and regulation of transposition. An intriguing feature of horizontal transfer is that its frequency differs among transposable element families. Evidence summarized in this review indicates that this pattern is due to fundamental differences between Class I and Class II elements. There appears to be a gradient in the incidence of horizontal transfer that reflects the presence of DNA intermediates during transposition. Furthermore, horizontal transfer seems to predominate among families for which copy number is controlled predominantly by self-regulatory mechanisms that limit transposition. We contend that these differences play a major role in the observed predominance of horizontal transfer among Class II transposable elements.

Hypoxia poses a documented threat to aerospace and diving operations in healthy people and is a component of many clinical conditions. Practical training for aircrew, and research on clinically relevant hypoxic conditions frequently rely exclusively on large, expensive hypobaric chambers.Here we describe and report the efficacy of a compact, economical, closed-loop rebreather-type reduced-oxygen breathing device (ROBD) for hypoxia induction in humans.Subjects were four healthy student Naval flight surgeons. During baseline, subjects breathed normoxic air (21% O2, equivalent to sea-level). Baseline was followed by an altitude period, during which participants were exposed to hypoxic air (about 10% O2, approximating 5,486 m [18,000 ft mean sea-level]) for 30 min followed by a normoxic recovery period. Subjects' peripheral arterial oxygen saturation (SpO2), BP, impedance cardiography, cardiac output, and systemic vascular resistance served as dependent measures along with the fraction of inspired oxygen (FiO2).Circuit FiO2 and subjects' SpO2 were significantly lower during the altitude period than the baseline and recovery periods. HR and cardiac output were significantly higher, and systemic vascular resistance was significantly lower, during hypoxic air exposure than during baseline or recovery.These data support the closed-loop ROBD as a potentially useful device for training and research involving acute hypoxia in healthy and clinical populations.

Publisher Summary This chapter reviews the evidence for P element horizontal transfer that has accumulated during the past two decades. There are two main advantages of using P elements for studying horizontal transfer. First, the P element is one of the best described eukaryotic transposable elements, and provided one of the earliest reports of transposable element horizontal transfer and subsequent invasion of a naive contemporary species. Second, the evolutionary history of the genus Drosophila has been well-studied and reasonable estimates exist for species divergence times. This provides a context to evaluate the timing of horizontal transfer events. It reviews evidence for the multiple instances of horizontal transfer of the P transposable element in Drosophila and related genera. Evidence for the horizontal transfer of a number of transposable element families has accumulated during the past two decades. Prominent among these are several members of the Class II elements, which transpose by means of a DNA intermediate. This group of elements includes P elements, mariner elements, and hobo elements.