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Gas pressurized spacesuits are cumbersome, cause injuries, and are metabolically expensive. Decreasing the gas pressure of the spacesuit is an effective method for improving mobility, but reduction in the total spacesuit pressure also results in a higher risk for decompression sickness (DCS). The risk of DCS is currently mitigated by breathing pure oxygen before the extravehicular activity (EVA) for up to 4 h to remove inert gases from body tissues, but this has a negative operational impact due to the time needed to perform the prebreathe. In this paper, we review and quantify these important trade-offs between spacesuit pressure, mobility, prebreathe time (or risk of DCS), and space habitat/station atmospheric conditions in the context of future planetary EVAs. In addition, we explore these trade-offs in the context of the SmartSuit architecture, a hybrid spacesuit with a soft-robotic layer that, not only increases mobility with assistive actuators in the lower body, but it also applies some level of mechanical counterpressure (MCP). The additional MCP in hybrid spacesuits can be used to supplement the gas pressure (i.e., increasing the total spacesuit pressure), therefore reducing the risk of DCS (or reduce prebreathe time). Alternatively, the MCP can be used to reduce the gas pressure (i.e., maintaining the same total spacesuit pressure), therefore increasing mobility. Finally, we propose a variable pressure concept of operations for the SmartSuit spacesuit. Our framework quantifies critical spacesuit and habitat trade-offs for future planetary exploration and contributes to the assessment of human health and performance during future planetary EVAs. [ABSTRACT FROM AUTHOR]

A personal narrative is presented which explores the author's experience of the first symptom from which the astronaut killed during the spacewalk.

The Biologic Analog Science Associated with Lava Terrains (BASALT) research project is investigating tools, techniques, and strategies for conducting Mars scientific exploration extravehicular activity (EVA). This has been accomplished through three science-driven terrestrial field tests (BASALT-1, BASALT-2, and BASALT-3) during which the iterative development, testing, assessment, and refinement of concepts of operations (ConOps) and capabilities were conducted. ConOps are the instantiation of operational design elements that guide the organization and flow of personnel, communication, hardware, software, and data products to enable a mission concept. Capabilities include the hardware, software, data products, and protocols that comprise and enable the ConOps. This paper describes the simulation quality and acceptability of the Mars-forward ConOps evaluated during BASALT-2. It also presents the level of mission enhancement and acceptability of the associated Mars-forward capabilities. Together, these results inform science operations for human planetary exploration. [ABSTRACT FROM AUTHOR]

Science-driven, human spaceflight missions of the future will rely on regular and interactive communication between Earth- and space-based teams during activity in which astronauts work directly on Mars or other planetary surfaces (extravehicular activity, EVA). The Biologic Analog Science Associated with Lava Terrains (BASALT) project conducted simulated human missions to Mars, complete with realistic one-way light time (OWLT) communication latency. We discuss the modes of communication used by the Mars- and Earth-based teams, including text, audio, video, and still imagery. Real-time communication between astronauts in the field (extravehicular, EV) and astronauts in a communication relay station (intravehicular, IV) was broadcast over OWLT, providing important contextual information to the Science Backroom Team (SBT) in Mission Control. Collaborative communication between the Earth- and Mars-based teams, however, requires active communication across latency via the Mission Log. We provide descriptive statistics of text communication between IV and SBT in a high-fidelity, scientifically driven analog for human space exploration. Over an EVA, the SBT sent an average of ∼23 text messages containing recommendations, requests, and answers to questions, while the science-focused IV crew member (IV2) sent an average of ∼38 text messages. Though patterns varied, communication between the IV and SBT teams tended to be highest during ∼50–150 min into the EVA, corresponding to the candidate sample search and presampling instrument survey phases, and then decreased dramatically after minute ∼200 during the sample collection phase. Generally, the IV2 and SBT used ∼4.6 min to craft a reply to a direct question or comment, regardless of message length or OWLT, offering a valuable glimpse into actual time-to-reply. We discuss IV2-SBT communication within the context of case examples from an EVA during which communication failures affected operations in the field. Finally, we offer recommendations for communication practices for use in future analogs and, perhaps, science-driven human spaceflight. [ABSTRACT FROM AUTHOR]

Biologic Analog Science Associated with Lava Terrains (BASALT) is a science-driven exploration program seeking to determine the best tools, techniques, training requirements, and execution strategies for conducting Mars-relevant field science under spaceflight mission conditions. BASALT encompasses Science, Science Operations, and Technology objectives. This article outlines the BASALT Science Operations background, strategic research questions, study design, and a portion of the results from the second field test. BASALT field tests are used to iteratively develop, integrate, test, evaluate, and refine new concepts of operations (ConOps) and capabilities that enable efficient and productive science. This article highlights the ConOps investigated during BASALT in light of future planetary extravehicular activity (EVA), which will focus on scientific exploration and discovery, and serves as an introduction to integrating exploration flexibility with operational rigor, the value of tactical and strategic science planning and execution, and capabilities that enable and enhance future science EVA operations. [ABSTRACT FROM AUTHOR]

Short-term and long-term science plans were developed as part of the strategic planning process used by the Biologic Analog Science Associated with Lava Terrains (BASALT) science team to conduct two Mars-simulation missions investigating basalt habitability at terrestrial volcanic analog sites in 2016. A multidisciplinary team of scientists generated and codified a range of scientific hypotheses distilled into a Science Traceability Matrix (STM) that defined the set of objectives pursued in a series of extravehicular activity (EVA) campaigns performed across multiple field deployments. This STM was used to guide the pre-deployment selection of sampling stations within the selected Mars analog sites on the Earth based on precursor site information such as multispectral imagery. It also informed selection of hand-held instruments and observational data to collect during EVA to aid sample selection through latency-impacted interaction with an Earth-based Science Support Team. A significant portion of the pre-deployment strategic planning activities were devoted to station selection, ultimately the locations used for sample collection and EVA planning. During development of the EVAs, the BASALT science team identified lessons learned that could be used to inform future missions and analog activities, including the critical need for high-resolution precursor imagery that would enable the selection of stations that could meet the scientific objectives outlined in the STM. [ABSTRACT FROM AUTHOR]

Future human missions to Mars are expected to emphasize scientific exploration. While recent Mars rover missions have addressed a wide range of science objectives, human extravehicular activities (EVAs), including the Apollo missions, have had limited experience with science operations. Current EVAs are carefully choreographed and guided continuously from Earth with negligible delay in communications between crew and flight controllers. Future crews on Mars will be expected to achieve their science objectives while operating and coordinating with a science team back on Earth under communication latency and bandwidth restrictions. The BASALT (Biologic Analog Science Associated with Lava Terrains) research program conducted Mars analog science on Earth to understand the concept of operations and capabilities needed to support these new kinds of EVAs. A suite of software tools (Minerva) was used for planning and executing all BASALT EVAs, supporting text communication across communication latency, and managing the collection of operational and scientific EVA data. This paper describes the support capabilities provided by Minerva to cope with various geospatial and temporal constraints to support the planning and execution phases of the EVAs performed during the BASALT research program. The results of this work provide insights on software needs for future science-driven planetary EVAs. [ABSTRACT FROM AUTHOR]

The construction of future technological systems in work domains that do not yet exist, known as the envisioned world problem, is an increasingly important topic for designers, particularly given the rapid rate of technological advancement in the modern era. This paper first discusses the theoretical underpinnings of using cognitive work analysis (CWA) for developing a decision support system (DSS) situated within the envisioned world problem and recasts the problem as pathway-dependent processes. Using this pathwaydependent framework, each stage of the envisioning process is described to reveal how human factors experts can link existing work domains to envisioned instances. Finally, a case study example of the envisioning process that incorporates CWA modelling is demonstrated as it pertains to the advancement of the human spaceflight domain. As a result, this paper provides a unified treatment of the envisionedworld problemwith an endto- end example of one approach to designing future technologies for future work domains. [ABSTRACT FROM AUTHOR]

Purpose The purpose of this paper is to investigate the time optimal trajectory of the multi-tethered robot (MTR) on a large spinning net structures in microgravity environment.Design/methodology/approach The MTR is a small space robot that uses several tethers attached to the corner-fixed satellites of a spinning net platform. The transition of the MTR from a start point to any arbitrary designated points on the platform surface can be achieved by controlling the tethers’ length and tension simultaneously. Numerical analysis of trajectory optimization problem for the MTR is implemented using the pseudospectral (PS) method.Findings The globally time optimal trajectory for MTR on a free-end spinning net platform can be obtained through the PS method.Research limitations/implications The analysis in this paper is limited to a planar trajectory and the effects caused by attitude of the MTR will be neglected. To make the problem simple and to see the feasibility in the general case, in this paper, it is assumed there are no any limitations of mechanical hardware constraints such as the velocity limitation of the robot and tether length changing constraint, while only geometrical constraints are considered.Practical implications The optimal solution derived from numerical analysis can be used for a path planning, guidance and navigation control. This method can be used for more efficient on-orbit autonomous self-assembly system or extravehicular activities supports which using a tether-controlled robot.Originality/value This approach for a locomotion mechanism has the capability to solve problems of conventional crawling type robots on a loose net in microgravity. [ABSTRACT FROM AUTHOR]

Human extravehicular activity (EVA) is essential to space exploration and involves risk of decompression sickness (DCS). On Earth, the effect of microgravity on physiological systems is simulated in an experimental model where subjects are confined to a 6° head-down bed rest (HDBR). This model was used to investigate various resting and exercise regimen on the formation of venous gas emboli (VGE), an indicator of decompression stress, post-hyperbaric exposure. Eight healthy male subjects participating in a bed rest regimen also took part in this study, which incorporated five different hyperbaric exposure (HE) interventions made before, during and after the HDBR. Interventions i–iv were all made with the subjects lying in 6° HD position. They included (C1) resting control, (C2) knee-bend exercise immediately prior to HE, (T1) HE during the fifth week of the 35-day HDBR period, (C3) supine cycling exercise during the HE. In intervention (C4), subjects remained upright and ambulatory. The HE protocol followed the Royal Navy Table 11 with 100 min spent at 18 m (280 kPa), with decompression stops at 6 m for 5 min, and at 3 m for 15 min. Post-HE, regular precordial Doppler audio measurements were made to evaluate any VGE produced post-dive. VGE were graded according to the Kisman Masurel scale. The number of bubbles produced was low in comparison to previous studies using this profile [Kisman integrated severity score (KISS) ranging from 0–1], and may be because subjects were young, and lay supine during both the HE and the 2 h measurement period post-HE for interventions i–iv. However, the HE during the end of HDBR produced significantly higher maximum bubble grades and KISS score than the supine control conditions (p < 0.01). In contrast to the protective effect of pre-dive exercise on bubble production, a prolonged period of bed rest prior to a HE appears to promote the formation of post-decompression VGE. This is in contrast to the absence of DCS observed during EVA. Whether this is due to a difference between hypo- and hyperbaric decompression stress, or that the HDBR model is a not a good model for decompression sensitivity during microgravity conditions will have to be elucidated in future studies. [ABSTRACT FROM AUTHOR]

Hand dexterity is an important index to assess whether extravehicular activity (EVA) gloves are appropriately designed. Pressurized gloves and low temperature environments can both cause a decrease in hand dexterity. However, due to the difficulty in performing tests under extreme conditions, there has been no report on dexterity tests with gloves under pressure and low temperature. To fill this gap, we performed a dexterity test of EVA gloves with twelve male volunteers involved under the extreme conditions, which were created in the low-pressure simulation cabin with vaporized liquid nitrogen used to cool it down. A total of nine conditions were designed. Purdue pegboard test and nut fastening test were improved before being applied in a hand dexterity test. Completion times for both tests, finger temperatures and cold feeling of the hand were recorded and analyzed. Results showed that the completion times for both tests increased either as the temperature decreased or as the pressure increased. Furthermore, a combined effect of low temperature and pressure was observed. The study provides evidence in support of astronaut training and optimization of EVA glove productivity. [ABSTRACT FROM AUTHOR]

Astronauts training for extravehicular activity (EVA) operations can spend many hours submerged underwater in a pressurized suit, called an extravehicular mobility unit (EMU), exposed to pressures exceeding 2 atmospheres absolute (ATA). To minimize the risk of decompression sickness (DCS) a 46% nitrox mixture is used. This limits the nitrogen partial pressure, decreasing the risk of DCS. The trade-off with using a 46% nitrox mixture is the increased potential for oxygen toxicity, which can lead to severe neurologic symptoms including seizures. Suited runs, which typically expose astronauts of 0.9-1.1 ATA for longer than six hours, routinely exceed the recommendation for central nervous system oxygen toxicity limits (CNSOTL) published by the National Oceanic and Atmospheric Administration (NOAA). Fortunately, in over 50,000 hours of suited training dives spanning 20 years of EVA training operations at NASA's Neutral Buoyancy Laboratory (NBL) there has never been an occurrence of oxygen toxicity. This lends support to anecdotal sentiment among certain members of the hyperbaric community that the NOAA CNSOTL recommendations might be overly conservative, at least for the oxygen pressure and time regime in which NBL operates. The NOAA CNSOTL recommendations are the result of expert consensus with a focus on safety and do not necessarily reflect rigorous experimental evidence. The data from the NBL suited dive operations provide a foundation of evidence that can help inform the expert discussion on dive-related neurologic oxygen toxicity performance and overnight recovery in young, healthy males. [ABSTRACT FROM AUTHOR]

The purpose of this study is to detect mind-wandering in an Extra-Vehicular Activity (EVA) context during a long supervision task. Detection is realized using an electro-cardiogram and measures of heart rate variability. Experienced by everyone, mind-wandering depicts the state of mind where thoughts are not related to the current action. Its deleterious aspect regarding performance suggests a need to take mind-wandering seriously as an impediment to manned space missions' safety. Previous research confirmed the hypothesis according to which several physiological responses can be used to track down mind-wandering. ECG recordings are both easy to obtain and analyze, statistically related to mind-wandering, and easy to record during extra-vehicular activities. Data analyzed in this paper have been recorded during a Mars-analog mission (MDRS 164), from February 20 to March 6, 2016 at the Mars Desert Research Station (Utah). During various cognitive tasks, the subject had his ECG and awareness levels monitored at the same time to see if a correlation between these two measures can be used in a Mars-mission environment. At different time intervals, the subject was interrupted using the thought probe method to inquire about his thoughts. Heart Rate Variability (HRV, which power in high frequencies is related to the parasympathetic system and is expected to vary with mind-wandering) was then computed from recorded data, and its statistical changes during on-task and off-task thoughts were assessed. Although data revealed no significant differences nor coherent trends in HRV-related metrics between the two conditions, results are paving the way towards a better understanding of ECG-recordings and their use during space-analog missions. [ABSTRACT FROM AUTHOR]

Purpose In the future, large space truss structures will be likely to require on-orbit assembly. One of the several proposed methods includes cooperative assembly performed by pressure-suited astronauts during extravehicular activity (EVA) and space robots. An intelligent planning method was presented to generate optimal assembly tasks.Design/methodology/approach Firstly, the inherent hierarchical nature of truss structures allows assembly sequences to be considered from strut level and structural volume element (SVE) level. Then, a serial assembly strategy in human-robot environment was applied. Furthermore, a two-level planning algorithm was presented. At the first-level planning, one ant colony algorithm for assembly sequence planning was improved to adopt assembly direction and time as heuristic information and did not consider assembly tasks. And, at the second-level planning, another novel colony algorithm for assembly task planning mainly considered results of the first-level planning, human-robot interactive information, serial assembly strategy and assembly task distributions.Findings The proposed two-level planning algorithm is very effective for solving the human and robot cooperative assembly of large space truss structures.Research limitations/implications In this paper, the case study is based on the following assumptions: each tetrahedron is assembled by two astronauts; each pentahedron is assembled by three astronauts.Practical implications A case illustrates the results of the two-level planning. From this case study, because of geometrical symmetry nature of large space truss structures, the optimal assembly sequences are not only one.Originality/value The improved ant colony algorithm can deal with the assembly sequence and task planning in human-robot environment more effectively. [ABSTRACT FROM AUTHOR]

Extravehicular activity (EVA) is an inevitable task for astronauts to maintain proper functions of both the spacecraft and the space station. Both experimental research in a microgravity simulator (e.g. neutral buoyancy tank, zero-g aircraft or a drop tower/tube) and mathematical modeling were used to study EVA to provide guidance for the training on Earth and task design in space. Modeling has become more and more promising because of its efficiency. Based on the task analysis, almost 90% of EVA activity is accomplished through upper limb motions. Therefore, focusing on upper limb models of the body and space suit is valuable to this effort. In previous modeling studies, some multi-rigid-body systems were developed to simplify the human musculoskeletal system, and the space suit was mostly considered as a part of the astronaut body. With the aim to improve the reality of the models, we developed an astronauts' upper limb model, including a torque model and a muscle-force model, with the counter torques from the space suit being considered as a boundary condition. Inverse kinematics and the Maggi-Kane's method was applied to calculate the joint angles, joint torques and muscle force given that the terminal trajectory of upper limb motion was known. Also, we validated the muscle-force model using electromyogram (EMG) data collected in a validation experiment. Muscle force calculated from our model presented a similar trend with the EMG data, supporting the effectiveness and feasibility of the muscle-force model we established, and also, partially validating the joint model in kinematics aspect. [ABSTRACT FROM AUTHOR]

During interplanetary flight, after large solar flares, astronauts are subject to the impact of relativistic solar protons. These particles produce an especially strong effect during extravehicular activity or landing on Mars (in the future). The relativistic protons reach the orbits of the Earth and Mars with a delay of several hours relative to solar X-rays and UV radiation. In this paper, we discuss a new opportunity to predict the most dangerous events caused by Solar Cosmic Rays with protons of maximum (relativistic) energy, known in the of solar-terrestrial physics as Ground Level Enhancements or Ground Level Events (GLEs) . This new capability is based on a close relationship between the dangerous events and decrease of Total Solar Irradiance (TSI) which precedes these events. This important relationship is revealed for the first time. [ABSTRACT FROM AUTHOR]

INTRODUCTION: The extravehicular activity suit currently used by the United States in space includes a liquid cooling and ventilation garment (LCVG) that controls thermal conditions. Previously, we demonstrated that self-perspiration for evaporative cooling (SPEC) garment effectively lowers skin temperature without raising humidity in the garment. However, the cooling effect is delayed until a sufficient dose of water permeates and evaporates. In the present study, we hypothesized that wearer-controlled vaporization improves the cooling effect. METHODS: Six healthy subjects rode a cycle ergometer under loads of 30, 60, 90, and 120 W for durations of 3 min each. Skin temperature and humidity on the back were measured continuously. Subjects wore and tested three garments: 1) a spandex garment without any cooling device (Normal); 2) a simulated LCVG (s-LCVG) or spandex garment knitted with a vinyl tube for flowing and permeating water; and 3) a garment that allowed wearer-controlled vaporization (SPEC-W). RESULTS: The use of s-LCVG reduced skin temperature by 1.57 ± 0.14°C during 12 min of cooling. Wearer-controlled vaporization of the SPEC-W effectively and significantly lowered skin temperature from the start to the end of cycle exercise. This decrease was significantly larger than that achieved using s-LCVG. Humidity in the SPEC-W was significantly lower than that in s-LCVG. DISCUSSION: This preliminary study suggests that SPEC-W is effective in lowering skin temperature without raising humidity in the garment. The authors think it would be useful in improving the design of a cooling system for extravehicular activity. [ABSTRACT FROM AUTHOR]

Hypertension is one of the most common chronic diseases in the world: in the United States, it affects one-third of the adult population. Most cases are primary hypertension -- with no identified cause -- and significantly increase risk for cardiovascular disease and stroke. At NASA's Neutral Buoyancy Laboratory (NBL), there is a cadre of professional divers who provide underwater support during extravehicular activity training (EVAs, commonly referred to as "spacewalks") for astronauts. The NBL occupational health program requires regular "work-site" physical exams, including blood pressure checks, on at least a weekly basis. Although some blood pressures measured during such regular checks were elevated, the diagnosis and management of blood pressure was outside the scope of that occupational medicine program. As a result, there was no protocol to analyze and manage asymptomatic elevated blood pressure if and when it warranted physician follow-up. We therefore analyzed the blood pressure data from all divers in 2015, vetted the worksite physical and developed a referral pathway to ensure divers have access to effective management of their blood pressure while minimizing impact of such a program on daily operations. [ABSTRACT FROM AUTHOR]

Future spacecraft and crew habitats are anticipated to use a moderately hypobaric and hypoxic cabin atmosphere to reduce the risk of decompression sickness associated with extravehicular activity. This has raised concerns about potential hypoxia-mediated adverse effects on astronauts. Noninvasive technology for measuring tissue oxygen saturation (StO2) has been developed for clinical use and may be helpful in monitoring oxygenation during spaceflight. We conducted a technical evaluation of a handheld StO2 monitor during a series of parabolic flights, and then undertook a preliminary analysis of the data obtained during the flights from six individuals. The StO2 monitor operated normally in all gravity conditions. There was considerable variability in StO2 between and within individuals. Overall, transition to microgravity was associated with a small decrease in StO2 of 1.1±0.3%. This evaluation has established the basic function of this technology in microgravity and demonstrates the potential for exploring its use in space. [ABSTRACT FROM AUTHOR]

The project Mars-500 was the first long-term simulation of a manned flight to Mars. We examined the ways crew members described their experiences and their life during simulation, what they saw as key episodes and key topics in simulation, as well as key problems and key benefits. The aim of this paper is to present the Mars-500 simulation in its complexity, from beginning to end, as a one narrative story. Method Two weeks after the end of isolation we used narrative qualitative interviews in order to understand the unique experience of the crew members living and working in isolation and confinement. During our ‘Flight Story Interview’ (an adaptation of McAdams´s Life Story Interview) crew members reconstructed a story about their life in a module and revealed important points and processes during simulation: crew members identified and described the peak experience, nadir experience, turning points, important scenes and challenges and other narrative moments that create a story of a simulated flight to Mars. The narratives were subjected to horizontal thematic analysis. The story reconstruction completes quotes from crew member´s diaries published online by the European Space Agency. Results The results showed that for the crew members the peak experiences of simulation were celebrations, video messages from significant others, and the Mars landing, and that the most difficult moments were connected with delay or loss of communication and monotony during the second half of the experiment. The turning points were connected with the Mars episode. Crew members highlighted other crucial scenes and topics of the project Mars-500 in their narratives, and stressed the issues of food, coping strategies, or benefits of cultural heterogeneity in an extreme and confined environment. [ABSTRACT FROM AUTHOR]

Human-robot interaction (HRI) plays an important role in future planetary exploration mission, where astronauts with extravehicular activities (EVA) have to communicate with robot assistants by speech-type or gesture-type user interfaces embedded in their space suits. This paper presents an interactive astronaut-robot system integrating a data-glove with a space suit for the astronaut to use hand gestures to control a snake-like robot. Support vector machine (SVM) is employed to recognize hand gestures and particle swarm optimization (PSO) algorithm is used to optimize the parameters of SVM to further improve its recognition accuracy. Various hand gestures from American Sign Language (ASL) have been selected and used to test and validate the performance of the proposed system. [ABSTRACT FROM AUTHOR]

BACKGROUND: This study aimed to investigate the feasibility of determining the physiological parameters associated with the ability to complete simulated exploration type tasks at metabolic rates which might be expected for lunar and Martian ambulation. METHODS: Running Vo2max and gas exchange threshold (GET) were measured in 21 volunteers.Two simulated extravehicular activity field tests were completed in 1 G in regular athletic apparel at two intensities designed to elicit metabolic rates of ~20.0 and ~30.0 ml • kg-1 • min-1, which are similar to those previously reported for ambulation in simulated lunar- and Martian-based environments, respectively. RESULTS: All subjects were able to complete the field test at the lunar intensity, but 28% were unable to complete the field test at the Martian intensity (non-Finishers). During the Martian field test there were no differences in Vo2 between Finishers and non-Finishers, but the non-Finishers achieved a greater %Vo2max compared to Finishers (78.4 ± 4.6% vs. 64.9 ± 9.6%). Logistic regression analysis revealed fitness thresholds for a predicted probability of 0.5, at which Finishing and non-Finishing are equally likely, and 0.75, at which an individual has a 75% chance of Finishing, to be a Vo2max of 38.4 ml • kg-1 • min-1 and 40.0 ml • kg-1 • min-1 or a GET of 20.1 ml • kg-1 • min"1 and 25.1 ml • kg'1 • min"1, respectively (x2 = 10.2). Logistic regression analysis also revealed that the expected %Vo2max required to complete a field test could be used to successfully predict performance (x2 = 19.3). DISCUSSION: The results of the present investigation highlight the potential utility of Vo2max, particularly as it relates to the metabolic demands of a surface ambulation, in defining successful completion of planetary-based exploration field tests. [ABSTRACT FROM AUTHOR]

INTRODUCTION: Compression garments tend to be difficult to don/doff, due to their intentional function of squeezing the wearer. This is especially true for compression garments used for space medicine and for extravehicular activity (EVA). We present an innovative solution to this problem by integrating shape changing materials-NiTi shape memory alloy (SMA) coil actuators formed into modular, 3D-printed cartridges-into compression garments to produce garments capable of constricting on command. METHODS: A parameterized, 2-spring analytic counterpressure model based on 12 garment and material inputs was developed to inform garment design. A methodology was developed for producing novel SMA cartridge systems to enable active compression garment construction. Five active compression sleeve prototypes were manufactured and tested: each sleeve was placed on a rigid cylindrical object and counterpressure was measured as a function of spatial location and time before, during, and after the application of a step voltage input. RESULTS: Controllable active counterpressures were measured up to 34.3 kPa, exceeding the requirement for EVA life support (29.6 kPa). Prototypes which incorporated fabrics with linear properties closely matched analytic model predictions (4.1%/-10.5% error in passive/active pressure predictions); prototypes using nonlinear fabrics did not match model predictions (errors >100%). Pressure non-uniformities were observed due to friction and the rigid SMA cartridge structure. DISCUSION: To our knowledge this is the first demonstration of controllable compression technology incorporating active materials, a novel contribution to the field of compression garment design. This technology could lead to easy-to-don compression garments with widespread space and terrestrial applications. [ABSTRACT FROM AUTHOR]

Under a collaboration agreement between Space Research and Technology Institute, Bulgarian Academy of Sciences (SRTI-BAS), Institute of Biomedical Problems, Russian Academy of Sciences (IBP-RAS) and S.P. Korolev Rocket and Space Corporation "Energia" an engineering model of new system named "Liulin-ISS-2", for personal dosimetric control of Russian cosmonauts inside and outside ISS, was developed. It is expected that the new system will replace the Liulin-ISS system, launched to ISS in September 2005. The "Liulin-ISS-2" priority is focused on the active measurement with 10 seconds resolution of the dose rate dynamics from Galactic Cosmic Rays (GCR), protons from internal and energetic electrons from external radiation belts, and solar energetic particles (SEP) inside ISS modules and during the extravehicular activity (EVA) of Russian and international cosmonauts. The significance of dose measurements for EVA was formulized during the analysis of the large and rapid variations in space and time of the doses obtained simultaneously at two different locations outside the ISS [1]. Liulin-ISS-2 system consists of 4 portable dosimeters (PD) and interface block (IB) with internal dosimeter. The PD sized 66×56×26 mm is based on the traditional Liulin type DES block diagram with 2 cm² square and 0.3 mm depth PIN diode. The analysis of the obtained deposited energy spectra will be performed according the ideas for intelligent crew personal dosimeter [3] and the new experience obtained during the data analysis from the R3DR2 instrument outside ISS in the period October 2014-January 2016. A SAFT prismatic lithium-Ion rechargeable battery, endorsed for space use, is used in the PD and allows more than 7 days independent work of the PD with 10 sec resolution. Thermostat and manageable heater are implemented to keep the temperature of the PIN diode not lower than -20 °C during EVA when is situated in the cosmonauts' spacesuit pocket. The PD can work independently on ID by using USB connection and special software with any other PC. The interface block (size 265×178×85 mm) is based on a Getac T800 (http://www.getac.com/) fully rugged tablet PC in compliance with the requirements and procedures of MIL-STD-810G, and under Windows-8 operational system. Through eight-port industrial USB hub the tablet PC manages the system and data transfer toward CAN serial interface and/or flash memory stick. Continuously the last 90 minutes of data, obtained with the internal dosimeter, are visualized on the screen of the tablet PC. These data can be used by the cosmonauts and the radiation control personal for fast analysis of the radiation risk for astronauts during solar proton events. [ABSTRACT FROM AUTHOR]

The problem of manipulating objects cooperatively for multi-link multi-degree of freedom space manipulator is very challenging because of the multisource disturbances, including nonlinear coupling, model uncertainties, and external disturbances. To solve this issue, a composite hierarchical control strategy is proposed, which has two layers. In inner layer, uncertainty and disturbance estimator (UDE) is employed to estimate the composite uncertainty that comprises the effect of multisource disturbances and compensate for it, producing the decoupled system. Furthermore, taking the error in UDE estimation into consideration, the chattering–eliminating sliding mode control is designed to suppress it in the outer layer. However, the obtained controller requires the measurement of joint velocities apart from joint positions. To address this issue, a robust velocity observer that employs the UDE-estimated uncertainty is proposed. The notable feature of the proposed design is that it requires neither accurate plant model nor any information about the uncertainty. Also, the design requires only joint position measurements for its implementation. Finally, to demonstrate the effectiveness of the composite hierarchical controller, the simulations of a planar dual-arm manipulator system and the comparisons of the proposed method with the other existing designs are presented. [ABSTRACT FROM AUTHOR]

The Komplast materials experiment was designed by Khrunichev State Research and Production Space Center together with Skobeltsyn Institute of Nuclear Physics, Lomonosov Moscow State University and other Russian scientific institutes, and has been carried out by Mission Control Moscow since 1998. The purpose of this experiment is to study the complex effect of the low Earth orbit environment on samples of various spacecraft materials. On November 20, 1998 the Komplast experiment began with the launch of the first International Space Station module Zarya , or Functional Cargo Block (FGB). Eight Komplast panels with samples of materials and sensors were installed on the outer surface of FGB module. Two of eight experiment panels were retrieved during Russian extravehicular activity in February 2011 after 12 years of space exposure and were subsequently returned to Earth by Space Shuttle “Discovery” on the STS-133/ULF-5 mission in March 2011. The article presents the results obtained from this unique long-duration experiment on board of the International Space Station. [ABSTRACT FROM AUTHOR]

Extravehicular Activity (EVA) is a critical component of human spaceflight, but working in gas-pressurized space suits causes fatigue, excessive energy expenditure, and injury. Relatively little is known about how the astronaut moves and interacts with the space suit, and what factors lead to injury. A wearable pressure sensing system to quantitatively measure areas on the body׳s surface that the space suit impacts during dynamic EVA movement is developed. The system is used to characterize human–suit interaction in the NASA Mark III space suit. Three experienced subjects perform a series of upper body movements: 3 isolated joint movements and 2 functional tasks. Movements are repeated 12 times each and in-suit pressure responses are evaluated both by quantifying peak pressure and full profile responses. Results Sequential sensor activation allows subjects to be indexed inside the space suit during complicated motions to better understand suited biomechanics. Subjectively, subjects generally feel they are consistent for all movements. However, using a nonparametric H -test, 54% of movements are found to be biomechanically inconsistent ( p <0.05). This experiment provides the first “window” inside the space suit to evaluate contact pressures and sequential indexing of the person inside the suit for realistic EVA movement. It cannot be extrapolated how changes in contact pressure would affect a subject׳s propensity for injury as injuries accumulate over long time scales. However, changes in pressure may be due to alterations in biomechanical strategies or fatigue, both of which could be precursors for injury and discomfort. [ABSTRACT FROM AUTHOR]

The article presents the timeline of astronauts conducting a space walk including Russian cosmonaut Alexei Leonov on 18 March 1965 and Alexei Yeliseyev and Yevgeny Khrunov on 16 January 1969 and Dave Scott and Rusty Schweickart on March 1969.

In interplanetary flight, after large solar flares, cosmonauts are subjected to the action of energetic solar protons and electrons. These energetic particles have an especially strong effect during extravehicular activity or (in the future) during residence on the surface of Mars, when they spend an extended time there. Such particles reach the orbits of the Earth and of Mars with a delay of several hours relative to solar X-rays and UV radiation. Therefore, there is always time to predict their appearance, in particular, by means of an X-ray-UV radiometer from the apparatus complex of the Space Solar Patrol (SSP) that is being developed by the co-authors of this paper. The paper discusses the far unexplored biophysical problem of manned flight to Mars, scheduled for the next decade. In long-term manned space flights on the orbital stations “Salyut” Soviet cosmonaut crews from three of the co-authors (cosmonauts V.V. Kovalenok, A.S. Ivanchenkov, and V.P. Savinykh) had repeatedly observed the effect of certain geophysical conditions on the psychological state of each crew. These effects coincide with the increased intensity of global illumination in the upper ionosphere space on flight altitudes (300–360 km). It is important that during all of these periods, most of the geomagnetic pulsations were completely absent. Possible ways to study the synergistic effects of the simultaneous absence of the geomagnetic field, the magnetic pulsations and the microwave radiation of the terrestrial ionosphere are considered for a flight to Mars. [ABSTRACT FROM AUTHOR]

NASA׳s plans for future human exploration missions utilize a new atmosphere of 56.5 kPa (8.2 psia), 34% O 2 , 66% N 2 to enable rapid extravehicular activity (EVA) capability with minimal gas losses; however, existing EVA prebreathe protocols to mitigate risk of decompression sickness (DCS) are not applicable to the new exploration atmosphere. We provide preliminary analysis of a 15-min prebreathe protocol and examine the potential benefits of intermittent recompression (IR) and an abbreviated N 2 purge on crew time and gas consumables usage. A probabilistic model of decompression stress based on an established biophysical model of DCS risk was developed, providing significant ( p <0.0001) prediction and goodness-of-fit with 84 cases of DCS in 668 human altitude exposures including a variety of pressure profiles. DCS risk for a 15-min prebreathe protocol was then estimated under different exploration EVA scenarios. Estimated DCS risk for all EVA scenarios modeled using the 15-min prebreathe protocol ranged between 6.1% and 12.1%. Supersaturation in neurological tissues (5- and 10-min half-time compartments) is prevented and tissue tensions in faster half-time compartments (≤40 min), where the majority of whole-body N 2 is located, are reduced to about the levels (30.0 vs. 27.6 kPa) achieved during a standard Shuttle prebreathe protocol. IR reduced estimated DCS risk from 9.7% to 7.9% (1.8% reduction) and from 8.4% to 6.1% (2.3% reduction) for the scenarios modeled; the penalty of N 2 reuptake during IR may be outweighed by the benefit of decreased bubble size. Savings of 75% of purge gas and time (0.22 kg gas and 6 min of crew time per person per EVA) are achievable by abbreviating the EVA suit purge to 20% N 2 vs. 5% N 2 at the expense of an increase in estimated DCS risk from 9.7% to 12.1% (2.4% increase). A 15-min prebreathe protocol appears feasible using the new exploration atmosphere. IR between EVAs may enable reductions in suit purge and prebreathe requirements, decompression stress, and/or suit operating pressures. Ground trial validation is required before operational implementation. [ABSTRACT FROM AUTHOR]

Space suit simulators are used for extravehicular activities (EVAs) during Mars analog missions. Flight planning and EVA productivity require accurate time estimates of activities to be performed with such simulators, such as experiment execution or traverse walking. We present a benchmarking methodology for the Aouda.X space suit simulator of the Austrian Space Forum. By measuring and comparing the times needed to perform a set of 10 test activities with and without Aouda.X, an average time delay was derived in the form of a multiplicative factor. This statistical value (a second-over-second time ratio) is 1.30 and shows that operations in Aouda.X take on average a third longer than the same operations without the suit. We also show that activities predominantly requiring fine motor skills are associated with larger time delays (between 1.17 and 1.59) than those requiring short-distance locomotion or short-term muscle strain (between 1.10 and 1.16). The results of the DELTA experiment performed during the MARS2013 field mission increase analog mission planning reliability and thus EVA efficiency and productivity when using Aouda.X. Key Words: Extravehicular activity (EVA)-Space suit mobility-Flight planning-Aouda.X-Suited versus unsuited performance-Productivity-Resource optimization-Analog missions-Human factors-Time delay. Astrobiology 15, 283-290. [ABSTRACT FROM AUTHOR]

Extra-Vehicular Activity (EVA) plays such a key role that more and more time is devoted to it in space missions. Nevertheless, EVA presents so many intrinsic critical aspects to result highly hazardous for the human operators. This is why a convenient alternative can be offered by telerobotic manipulations, with multi-fingered robotic hands working in teleoperated mode, to safely and remotely replicate the capabilities of the operator's hands. But at present, remotely controlled robotic hands cannot provide the same dexterity of humans, so this work is intended to experimentally evaluate their feasibility and technological limits when operator's hand gestures are one-to-one mapped directly to a robotic hand device. In particular we demonstrated how state-of-the art sensory gloves, used to measure angles of human finger's joints, can introduce averaged errors of 4.6 degrees in angles, and that these errors increase to 6.5 degrees when remotely replicated by standard anthropomorphic robotic hands. [ABSTRACT FROM AUTHOR]

The spacesuit (SS) donning-on procedure can be viewed as a combination of two kinematic circuits into a single human-spacesuit functional system (HSS) intended for performing extravehicular operations. Optimal human-SS interaction hinges on controllability and coordination of HSS mobile components, as well as SS slaving to the central nervous system (CNS) mediated by the human locomotion apparatus. Analysis of walking patterns in semi-hard and flexible SSs has revealed the direct and feedback connections between the external (SS) and internal (the locomotion apparatus and CNS) circuits of the HSS. An inefficient design of an SS creates difficulties for the direct CNS control of locomotion. Consequently, it is necessary to modify the locomotion command program in order to resolve these difficulties and add flexibility to the CNS control. In addition, the analysis yielded an algorithm of program modifications with the ultimate result of induced (forced) walk optimization. Learning how to walk in a Berkut SS requires no more than 2500 single steps, whereas about 3000 steps should be made to master walking skills in an SKV SS. [ABSTRACT FROM AUTHOR]