Crew Mission Research Articles

Long-Duration Space Flight and Bed Rest Effects on Testosterone and Other Steroids

Limited data suggest that testosterone is decreased during space flight, which could contribute to bone and muscle loss. The main objective was to assess testosterone and hormone status in long- and short-duration space flight and bed rest environments and to determine relationships with other physiological systems, including bone and muscle. Blood and urine samples were collected before, during, and after long-duration space flight. Samples were also collected before and after 12- to 14-d missions and from participants in 30- to 90-d bed rest studies. Space flight studies were conducted on the International Space Station and before and after Space Shuttle missions. Bed rest studies were conducted in a clinical research center setting. Data from Skylab missions are also presented. All of the participants were male, and they included 15 long-duration and nine short-duration mission crew members and 30 bed rest subjects. Serum total, free, and bioavailable testosterone were measured along with serum and urinary cortisol, serum dehydroepiandrosterone, dehydroepiandrosterone sulfate, and SHBG. Total, free, and bioavailable testosterone was not changed during long-duration space flight but were decreased (P < 0.01) on landing day after these flights and after short-duration space flight. There were no changes in other hormones measured. Testosterone concentrations dropped before and soon after bed rest, but bed rest itself had no effect on testosterone. There was no evidence for decrements in testosterone during long-duration space flight or bed rest.

Development of Modular Mission Packages Providing Focused Warfighting Capability for the Littoral Combat Ship

The US Navy has been involved in the development of a new class of combatant ship called the Littoral Combat Ship (LCS). The LCS is designed to operate more effectively in the littoral environment by providing enhanced maneuverability through the seaframe's inherent ability to operate at high speeds and in shallow waters. Additionally, to counter the high threat environment of the littorals and to enhance the mission commander's options at reasonable cost, the LCS is designed to augment its core self-defense capability with modular mission packages (MPs) that provide focused warfighting capabilities. The LCS MPs are classified as systems-of-systems (SoSs) as they are made up of: mission systems, support equipment, software, mission crew detachments, and aviation systems; and then integrated into a larger SoS to deliver unique capability. To support the accelerated development schedule, PMS 420 is using an evolutionary acquisition process to provide continuous improvements in warfighting capability over time. The initial MP increments are specifically designed to augment the warfighting areas of Anti-Submarine Warfare (ASW), Mine Countermeasures (MCM), and Surface Warfare (SUW). Modularity, an open business model, and open system architectures are key enablers supporting the future insertion of new technologies into the MP baseline. The paper will provide a brief overview of the LCS seaframe designs as they impact MP development, but will focus on the development and maturation of the MPs as SoSs. A definition of what composes an MP will be presented along with the perceived benefits and challenges of developing focused warfighting capability separate from the seaframe design. The present status of the SUW, ASW, and MCM MPs will be reviewed as well as their respective incremental development plans. The joint developmental relationship between PMS 420 and PMS 501 will be discussed with respect to the definition and management of seaframe-MP interfaces. The techniques and methodologies used by PMS 420 in controlling SoS development and evaluating the technical and programmatic performance of the three MPs will be presented. The extensive use of the government laboratories to fulfill the lead system integration role will be presented and the methodology used by PMS 420 in transitioning technologies developed by PMS 420 and/or other program offices for incorporation into MPs will be reviewed.

High versus low crewmember autonomy in space simulation environments

Given the long distances involved and the kinds of activities planned, crewmembers participating in long-duration exploratory space missions such as an expedition to Mars will have more autonomy than in previous space missions. In order to study the impact of high versus low crew autonomy on crewmembers and the crew–mission control interaction, we conducted a series of pilot studies involving three space simulation settings: NEEMO missions, the Haughton-Mars Project, and the pilot phase of the Mars 500 Program. As in our previous on-orbit studies on the Mir and International Space Station, crew and mission control subjects working in missions involving these three settings completed a weekly study questionnaire that assessed mood and interpersonal interactions using the Profile of Mood States, the Group Environment Scale, and the Work Environment Scale. The Mars 500 pilot study also directly assessed individual and group autonomy. In these studies, high autonomy periods were those where crewmembers planned much of their work schedule, whereas low autonomy periods were those where mission control personnel developed the schedule, much as happens now during actual space flight conditions. Our results suggested that high work autonomy was well-received by the crews, mission goals were accomplished, and there were no adverse effects. During high autonomy periods, crewmember mood was generally reported as being better and creativity was higher, but mission control personnel reported some confusion about their work role. The crewmember group environment in the Mars 500 pilot study was dependent on the nationality mix. Despite scoring lower in work pressure overall, the four Russian crewmembers reported a greater rise in work pressure from low to high autonomy than the two Europeans. In contrast, the European crewmembers reported a greater rise in dysphoric mood in going from low to high autonomy, whereas the Russians’ emotional state remained the same or slightly improved. It is time to study the effects of high autonomy with larger subject samples during actual space missions on-orbit in preparation for future exploratory missions, where high autonomy will be the norm.

A review of trauma patients taken to hospital by air ambulance

Introduction Doctors are being introduced on air ambulance services in the UK. Meaningful assessment of air ambulance services is difficult owing to inter-service variation. County air ambulance (CAA) (rebranded as Midland's Air Ambulance after this article was written) progressively introduced doctors into their service from 2006 providing an opportunity to gather data and quantify the sample size that will be required to assess their impact on patient survival. Method CAA trauma alerts to Selly Oak Hospital (the main receiving hospital for the service) between 1 January 2006-30 June 2007 were reviewed. Crew composition, mission data and patient notes were examined and the abbreviated injury score 98 and injury severity score were used to calculate the probability of survival. Survival outcome was ascertained at 90 days. Data analysis included survival analysis; Cox regression; logistic regression; tests for association (CI 95%, P&lt;0.05). Post-hoc power calculations were undertaken. Results 299 cases were identified, 186 met the inclusion criteria. The probability of survival ranged between 5.56-99.48%. There was no statistically significant association found between crew composition and survival (P=0.355) and post-hoc power calculations showed 54 258 events would be required to assess this. If accepting 80% power and assuming our proportion of 14% mortality ± 5%, 800 events would be required in each arm of future studies. Conclusions Our post-hoc power calculations revealed that a national or multi-centre study is needed to assess this aspect of aircrew composition in order to prove or discount associations between crew composition and survival at 90 days. Now that a power estimate is available, designing adequately powerful studies will be possible; enabling monitoring the increasing deployment of this expensive resource and examining the effect of doctors on air ambulances. This is of increasing importance to assess as medically-led air ambulance missions increase.

Biological component of life support systems for a crew in long-duration space expeditions

Creation of effective life support systems (LSSs) is one of the main tasks of medico-biological support of long-duration space flight. Principles of development of such an LSS will be defined on the basis of number of parameters, including mass-overall and energetic limitations of interplanetary spacecraft, duration of expedition and crew size. It is obvious that including biological subsystems in LSS of long-duration interplanetary space flights will help to form a full-fledged environment for humans in the spacecraft. It would be an appropriate solution for long-term biological needs of humans and important for elimination of possible negative consequences of their long stay under artificial (abiogenous) environment. Experiments with higher plants, conducted on board “MIR” orbital complex and Russian segment of ISS, showed that plant organisms are capable of long-duration normal growth, full development and reproduction without deviations under real space flight environment. These results allow us to assume that greenhouses are potential candidates to be a biological subsystem to be included in the LSS for interplanetary space flight. Inclusion of greenhouse equipment in the spacecrafts will require a number of corrective actions in functional schemes of the existing LSS, i.e. it will lead to redistribution of material streams inside an LSS and increase in functional load of authorized systems. Furthermore, involvement of greenhouse in an LSS of an interplanetary spacecraft requires a number of technical tasks to be cleared. In the present review, we discuss the constructive, technological and mass-transfer characteristics of greenhouse as a component part of the LSS for crews of long-term interplanetary missions, in particular, Mars expedition.

The measurements of light high-energy ions in NINA-2 experiment

Abstract. The flux of energetic light ions at low altitude is both an important input and output for self-consistent calculations of albedo particles resulting from the interaction of trapped and cosmic ray particles, with the upper atmosphere. In addition, data on the flux of light ions are needed to evaluate radiation damages on space-borne instruments and on space mission crews. In spite of that, sources of data on the flux of energetic ions at LEO are roughly limited to the AP-8 model, CREME/CREME96 codes and the SAMPEX, NOAA/TIROS satellites. The existing and operational European SAC-C/ICARE and PROBA-1/SREM instruments could also be potential sources for proton data at LEO. Although AP-8 and SAMPEX/PSB97 may be publicly accessed through the SPENVIS, they exhibit an order of magnitude difference in low altitude proton fluxes and they do not contain helium fluxes. Therefore, improved light ion radiation models are still needed. In this paper we present a procedure to identify and measure the energy of ions that are not stopped in the NINA-2 instrument. Moreover, problems related to particles that cross the instrument in the opposite direction are addressed and shown to be a possible cause of particle misidentification. Measuring fluxes of low abundance elements like energetic helium ions requires a good characterisation of all possible sources of backgrounds in the detector. Hints to determine the several contributions to the background are presented herein and may be applied to extract an order of magnitude of energetic ions fluxes from existing data sets, while waiting for dedicated high performance instruments.

Biological dosimetry in the ENEIDE Mission on the International Space Station

Space radiation represents one of the major health hazards to crews of interplanetary missions. As the duration of space flight increases, according to International Space Station (ISS) and Mars mission programs, the risk associated with exposure to ionizing radiation also increases. Although physical dosimetry is routinely performed in manned space missions, it is generally accepted that direct measurement of biological endpoints (biological dosimetry) is necessary for a precise assessment of radiation risk in extraterrestrial activities. Chromosomal aberrations (CAs) in peripheral blood lymphocytes (PBLs) are particularly suitable to this purpose, as they can provide estimates of both equivalent radiation dose and risk. In this study, cytogenetic analysis was performed on PBL chromosomes of an Italian astronaut involved in two different 10-day missions on the ISS (Marco Polo, April 2002, and ENEIDE, May 2005). Blood samples were collected before and after flights. CAs were evaluated in either mitotic spreads or in prematurely condensed chromosomes (PCC) by Fluorescence in Situ Hybridization (FISH). In addition, blood samples were exposed to graded doses of X-rays in vitro before and after the flight and cytogenetic damage evaluated to investigate whether the space environment alters the sensitivity of human cells to ionizing radiation. The yield of baseline chromosomal aberrations was not modified following Marco Polo and ENEIDE mission. This is consistent with the low dose absorbed in these short-term space missions. Preliminary results from Marco Polo mission suggested a significant increase in intrinsic radiosensitivity of lymphocytes after landing compared to pre-flight and follow-up (6 months after landing) samples. However, this effect was not observed during the ENEIDE mission. The results suggest that intra-indi-vidual variations in radiosensitivity are significant, but they cannot be related to the space flight.

Rapid hologram updates for real-time volumetric information displays

We have demonstrated that holograms incorporating changes in three-dimensional (3D) scenes can be recalculated in real time to present dynamic updates on information displays. This approach displays 3D information in a compatible format for fast and reliable interpretation of changes in the 3D scenes. The rapid-update algorithm has been demonstrated by real-time computation and transcription of the holograms to our digital micromirror device hologram projection system for visual validation of the reconstruction. The reported algorithm enables full parallax 1024 x 768 pixel holograms of 3D scenes to be updated at a rate of 0.8 s with a 1.8 GHz personal computer. Volumetric information displays that can enhance reliable data assimilation and decrease reaction times for applications such as air-traffic control, cockpit heads-up displays, mission crew stations, and undersea navigation can benefit from this research.

Some approaches to medical support for Martian expedition

Medical support in a Martian expedition will be within the scope of crew responsibilities and maximally autonomous. Requirements to the system of diagnostics in this mission include considerable use of means and methods of visualization of the main physiological parameters, telemedicine, broad usage of biochemical analyses (including “dry” chemistry), computerized collection, measurement, analysis and storage of medical information. The countermeasure system will be based on objective methods of crew fitness and working ability evaluation, individual selection of training regimens, and intensive use of computer controlled training. Implementation of the above principles implies modernization and refinement of the countermeasures currently used by space crews of long-term missions (LTM), and increases of the assortment of active and passive training devices, among them a short-arm centrifuge. The system of medical care with the functions of prevention, clinical diagnostics and timely treatment will be autonomous, too. The general requirements to medical care during the future mission are the following: availability of conditions and means for autonomous urgent and special medical aid and treatment of the most possible states and diseases, “a hospital”, and assignment to the crew of one or two doctors. To ensure independence of medical support and medical care in an expedition to Mars an automated expert system needs to be designed and constructed to control the medical situation as a whole.

Biological dosimetry in Russian and Italian astronauts

Large uncertainties are associated with estimates of equivalent dose and cancer risk for crews of longterm space missions. Biological dosimetry in astronauts is emerging as a useful technique to compare predictions based on quality factors and risk coefficients with actual measurements of biological damage in-flight. In the present study, chromosomal aberrations were analyzed in one Italian and eight Russian cosmonauts following missions of different duration on the MIR and the international space station (ISS). We used the technique of fluorescence in situ hybridization (FISH) to visualize translocations in chromosomes 1 and 2. In some cases, an increase in chromosome damage was observed after flight, but no correlation could be found between chromosome damage and flight history, in terms of number of flights at the time of sampling, duration in space and extra-vehicular activity. Blood samples from one of the cosmonauts were exposed in vitro to 6 MeV X-rays both before and after the flight. An enhancement in radiosensitivity induced by the spaceflight was observed.

Chromosome aberration dosimetry in cosmonauts after single or multiple space flights

Background and aims: Cosmic radiation is one of the main hazards for manned space exploration. Uncertainty in radiation risk estimates for crews of long-term missions are very high, and direct biological measurements are necessary. We measured chromosomal aberrations in peripheral blood lymphocytes from 33 cosmonauts involved in space missions during the past 11 years. Methods: Blood lymphocytes from the cosmonauts were stimulated to grow in vitro and were harvested at their first mitosis. Slides were either stained with Giemsa stain for dicentrics analysis, or painted with whole-chromosome DNA probes for translocation analysis (FISH). Results: A statistically significant increase in the yield of chromosomal aberrations was measured following long-term space missions in lymphocytes from cosmonauts at their first flight. No significant changes in aberration frequencies were observed for short-term taxi flights. The increase in long-term missions was consistent with the values calculated from physical dosimetry data. However, for cosmonauts involved in two or more space flights, the yield of interchromosomal exchanges was not related to the total duration of space sojourn or integral absorbed dose. Indeed, the yield of aberrations at the end of the last mission was generally in the range of background frequencies measured before the first mission. Conclusions: Chromosome aberration dosimetry can detect radiation damage during space flight, and biological measurements support the current risk estimates for space radiation exposure. However, for cosmonauts involved in multiple space missions the frequency of chromosomal aberrations is lower than expected, suggesting that the effects of repeated space flights on this particular endpoint are not simply additive. Changes in the immune system in microgravity and/or adaptive response to space radiation may explain the apparent increase in radioresistance after multiple space flights.

BIOLOGICAL EFFECTS OF COSMIC RADIATION IN LOW-EARTH ORBIT

Space exploration poses health hazards to the crews of manned missions. Exposure to cosmic radiation and loss of bone density are considered the two most important risk factors for long-term missions. Stochastic risk deriving from cosmic radiation exposure can be estimated by physical dosimeters, using appropriate conversion factors. Recent measurements of space radiation fluence and energy spectra will improve current estimates. Biological dosimetry can be used as a tool to determine the risk directly from biological damage. Chromosomal aberrations in astronauts' peripheral blood lymphocytes have been used as a biomarker of cancer risk. In this paper we will also discuss countermeasures to radiation damage, focusing on the problem of shielding in space.

Simultaneous exposure of mammalian cells to heavy ions and X-rays

Crews of space missions are exposed to a mixed radiation field, including sparsely and densely ionizing radiation. To determine the biological effectiveness of mixed high-/low-LET radiation fields, mammalian cells were exposed in vitro simultaneously to X-rays and heavy ions, accelerated at the HIMAC accelerator. X-ray doses ranged from 1 to 11 Gy. At the same time, cells were exposed to either 40Ar (550 MeV/n, 86 keV/μm), 28Si (100 MeV/n, 150 keV/μm), or 56Fe (115 MeV/n, 442 keV/μm) ions. Survival was measured in hamster V79 fibroblasts. Structural aberrations in chromosome 2 were measured by chemical-induced premature chromosome condensation combined with fluorescence in situ hybridization in isolated human lymphocytes. For argon and silicon experiments, measured damage in the mixed radiation field was consistent with the value expected using an additive function for low- and high-LET separated data. A small deviation from a simple additive function is observed with very high-LET iron ions combined to X-rays.

Applications of telemedicine in the United States space program.

Since the beginning of human space flight, NASA has been placing humans in extreme and remote environments. There are many challenges in maintaining humans in outer space, including the provision of life-support systems, radiation shielding, and countermeasures for minimizing the effect of microgravity. Because astronauts are selected for their health, among other factors, disease and illness are minimized. However, it is still of great importance to have appropriate medical care systems in place to address illness and injury should they occur. With the exception of the Apollo program, exploration of space has been limited to missions that are within several hundred miles of the surface of the Earth. At the drawn of the 21st century and the new millennium, human exploration will be focused on operation of the International Space Station (ISS) and preparation for human missions to Mars. These missions will present inherent risks to human health, and, therefore, appropriate plans must be established to address these challenges and risks. Crews of long-duration missions must become more independent from ground controllers. New systems, protocols, and procedures are currently being perfected. Application of emerging technologies in information systems and telecommunications will be critical to inflight medical care. Application of these technologies through telemedicine will provide crew members access to information, noninvasive procedures for assessing health status, and guidance through the integration of sensors, holography, decision-support systems, and virtual environments. These technologies will also serve as a basis to enhance training and medical education. The design of medical care for space flight should lead to a redesign of the practice of medicine on Earth.

Effects of Mission Preparation on Crew Combat Mission Training Performance

Although military doctrine assumes that thorough mission preparation is a prerequisite for mission success, empirical data are lacking. The present study investigated the relationship between mission preparation and mission performance during combat mission training of 11 MC-130P (Combat Shadow) aircrews from USAF Special Operations Forces squadrons. Two observers independently rated crew coordination processes and mission performance based on extensive observations taken both during a planning period and while the crews executed a simulated mission. Statistically, a reliable, strong relationship between preparation and performance was noted, with correlations ranging from .60 to .78. Exceptional preparation behaviors include utilizing personnel effectively, establishing a firm timeline, aggressively questioning a plan's assumptions, and testing a plan's logic against possible contingencies. The paper concludes with a discussion of the characteristics of effective mission preparation and implications of the research for combat mission training.

Human Factors Issues in Night Airborne Mine Countermeasures Operations

The U. S. Navy's Airborne Mine Countermeasures (AMCM) mission, performed by the MH-53E helicopter, is characterized by long duration flight at low altitudes and low airspeeds over the water while towing a variety of devices. This mission imposes substantial demands on the pilots and mission crew. Because of its complexity and potential hazards, the AMCM mission is currently performed only during the daytime. The Navy identified a requirement to perform AMCM operations at night and sponsored research to investigate the system and procedural modifications required to accomplish night AMCM operations safely and effectively. This paper discusses the human factors issues identified as part of this research effort and provides specific examples from the AMCM mission environment. A thorough understanding of these issues and how they will impact night AMCM operations is essential for a successful transition from day to night operations.

Solar modulation and nuclear fragmentation effects in galactic cosmic ray transport through shielding

Crews of manned interplanetary missions may accumulate significant radiation exposures from the galactic cosmic ray (GCR) environment in space. Estimates of how these dose levels are affected by the assumed temporal and spatial variations in the composition of the GCR environment, and by the effects of the spacecraft and body self-shielding on the transported radiation fields are presented. In this work, the physical processes through which shielding alters the transported radiation fields are described. We then present estimates of the effects on model calculations of (1) nuclear fragmentation model uncertainties, (2) solar modulation, (3) variations between solar cycles, and (4) proposed changes to the quality factors which relate dose equivalent to absorbed dose.

Estimates of HZE particle contributions to SPE radiation exposures on interplanetary missions

Estimates of radiation doses resulting from possible HZE (high energy heavy ion) components of solar particle events (SPEs) are presented for crews of manned interplanetary missions. The calculations assume a model spectrum obtained by folding measured solar flare HZE particle abundances with the measured energy spectra of SPE alpha particles. These hypothetical spectra are then transported through aluminum spacecraft shielding. The results, presented as estimates of absorbed dose and dose equivalent, indicate that HZE components by themselves are not a major concern for crew protection but should be included in any overall risk assessment. The predictions are found to be sensitive to the assumed spectral hardness parameters.

An attempt to determine the ideal psychological profiles for crews of long term space missions.

This paper reviews possible psychological criteria for selection at individual level (personality, psychological stability, competence, social skills) as well as at crew level (crew size, gender, compatability, group homeostasis). Once astronauts have been selected an important effort will have to be made pre-flight to prepare the crew to the autonomy necessary for a Mars trip. During the mission psychological support will be important, but probably limited by the mission constraints. At this stage, mission success will probably rely mainly on the capacity of the crew to prevent and manage crises internally. Post-flight psychological support is necessary to help astronauts to readapt to a normal way of life on Earth.

Prediction and evaluation of solar particle events based on precursor information.

Protection from the radiation effects of solar particle events for deep space mission crews requires a warning system to observe solar flares and predict subsequent charged particle fluxes. Such a system relates precursor information observed in each flare to the intensity, delay, and duration of the subsequent Solar Particle Event (SPE) at other locations in the solar system. A warning system of this type is now in operation at the NOAA Space Environment Services Center in Boulder, Colorado for support of space missions. It has been used to predict flare particle fluxes at the earth for flares of Solar Cycle 22. The flare parameters used and the effectiveness of the current warning system, based on Solar Cycle 22 experience, are presented, with an examination of the shortcomings. Needed improvements to the system include more complete observations of solar activity, especially information on the occurrences of solar mass ejections; and consideration of the effects of propagation conditions in the solar corona and interplanetary medium. Requirements for solar observations and forecasting systems on board the spacecraft are discussed.