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NASA NTRS2013

An Evidence Base for Human Spaceflight Risks in Wikipedia

NASA's Human Research Program (HRP) is focused on understanding and mitigating thirty two risks to crew health and performance in exploration missions beyond low Earth orbit. The HRP has developed an evidence report for each of the risks. Most evidence reports are a brief review article describing the evidence related to a specified risk, written at a level appropriate for the scientifically educated, non‐specialist reader. Each evidence report captured the current state of knowledge from both research and operations. Two limitations of the evidence reports have become apparent: 1) they are updated infrequently and 2) they do not take full advantage of the expertise available in other space agencies and in related fields of terrestrial research. Therefore, the HRP is experimenting with the use of Wikipedia articles as a repository for evidence. Wikipedia's accessibility to the international space flight community and researchers in related terrestrial fields creates the opportunity to generate a more timely and comprehensive evidence base. Initial Wikipedia articles were populated for seven risks using a subset of the information in the HRP‐approved evidence reports: Fatigue and Sleep Loss, Treating An Ill or Injured Crew Member, Radiation Carcinogenesis, Visual Impairment and Intracranial Pressure, Renal Stone Formation, Team Cohesion, and Intervertebral Disc Damage. Since the initial articles were created, there have been additions to these Wikipedia articles, including content from sources outside the HRP, and editorial changes to the pages. We will report on the nature of the contributions made after the initial articles were created, the comprehensiveness of the resulting Wikipedia articles, and the effort required to maintain quality control of the content. The Wikipedia approach will also be compared to wiki efforts that exert more traditional editorial control of content prior to posting.

Kundrot, Craig↗

NASA NTRS1996

The Effects of Promethazine on Human Performance, Mood States, and Motion Sickness Tolerance

Intramuscular (IM) injections of promethazine in 25 mg or 50 mg dosages are commonly used to treat space motion sickness in astronauts. The present study examined the effects of IM injections of promethazine on neuropsy-chological performance, mood states, and motion sickness tolerance in humans. Twelve men, mean age 36 plus or minus 3.1 participated in one training (no injections) and three treatment conditions: a 25 mg injection of promethazine, a 50 mg injection of promethazine, and a placebo injection of sterile saline. Each condition, spaced at 7 day intervals, required an 8-10 hr session in which subjects were given four repetitions of 12 performance tasks, and one rotating chair motion sickness test. On the training day subjects were trained on each task to establish stability and proficiency. On treatment days, the order in which the drug or placebo was assigned to subjects was counter-balanced and a double-blind technique was used. Statistically significant decrements in performance were observed on 10 of 12 tasks when subjects were given 25 mg or 50 mg of promethazine as compared to the placebo. Performance decrements were associated with mean blood alcohol dose equivalency levels of 0.085% for 25 mg and 0. 1 37% for 50 mg dosages. The mood scale results showed significant changes in individual subjective experiences with maximum deterioration in the arousal state and fatigue level. When compared to placebo significant increases in motion sickness tolerance were found for both dosages of promethazine. These data suggest that effective dosages of promethazine currently used to counteract motion sickness in astronauts may significantly impair task components of their operational performance.

Cowings, Patricia S.↗

NASA NTRS1999

Motion sickness and proprioceptive aftereffects following virtual environment exposure

To study the potential aftereffects of virtual environments (VE), tests of visually guided behavior and felt limb position (pointing with eyes open and closed) along with self-reports of motion sickness-like discomfort were administered before and after 30 min exposure of 34 subjects. When post- discomfort was compared to a pre-baseline, the participants reported more sickness afterward (p < 0.03). The change in felt limb position resulted in subjects pointing higher (p < 0.038) and slightly to the left, although the latter difference was not statistically significant (p = 0.08). When findings from a second study using a different VE system were compared, they essentially replicated the results of the first study with higher sickness afterward (p < 0.001) and post- pointing errors were also up (p < 0.001) and to the left (p < 0.001). While alternative explanations (e.g. learning, fatigue, boredom, habituation, etc.) of these outcomes cannot be ruled out, the consistency of the post- effects on felt limb position changes in the two VE implies that these recalibrations may linger once interaction with the VE has concluded, rendering users potentially physiologically maladapted for the real world when they return. This suggests there may be safety concerns following VE exposures until pre-exposure functioning has been regained. The results of this study emphasize the need for developing and using objective measures of post-VE exposure aftereffects in order to systematically determine under what conditions these effects may occur.

NASA Discipline Neuroscience↗

NASA NTRS2005

Rotordynamic Analysis and Feasibility Study of a Disk Spin Test Facility for Rotor Health Monitoring

Recently, National Aeronautics and Space Administration (NASA) initiated a program to achieve the significant improvement in aviation safety. One of the technical challenges is the design and development of accelerated experiments that mimic critical damage cases encountered in engine components. The Nondestructive Evaluation (NDE) Group at the NASA Glenn Research Center (GRC) is currently addressing the goal concerning propulsion health management and the development of propulsion system specific technologies intended to detect potential failures prior to catastrophe. For this goal the unique disk spin simulation system was assembled at NASA GRC, which allows testing of rotors with the spinning speeds up to 10K RPM, and at the elevated temperature environment reaching 540 C (1000 F). It is anticipated that the facility can be employed for detection of Low Cycle Fatigue disk cracking and further High Cycle Fatigue blade vibration. The controlled crack growth studies at room and elevated temperatures can be conducted on the turbine wheels, and various NDE techniques can be integrated and assessed as in-situ damage monitoring tools. Critical rotating parts in advanced gas turbine engines such as turbine disks frequently operate at high temperature and stress for long periods of time. The integrity of these parts must be proven by non-destructive evaluation (NDE) during various machining steps ranging from forging blank to finished shape, and also during the systematic overhaul inspections. Conventional NDE methods, however, have unacceptable limits. Some of these techniques are time-consuming and inconvenient for service aircraft testing. Almost all of these techniques require that the vicinity of the damage is known in advance. These experimental techniques can provide only local information and no indication of the structural strength at a component and/or system level. The shortcomings of currently available NDE methods lead to the requirement of new damage detection techniques that can provide global information on the rotating components/system, and, in addition, they do not require direct human access to the operating system. During this period of research considerable effort was directed towards the further development of experimental facility and development of the vibration-based crack detection methodology for rotating disks and shafts. A collection of papers and reports were written to describe the results of this work. The attached captures that effort and represents the research output during the grant period.

Sawicki, Jerzy T.↗

NASA NTRSDate not supplied

Monitoring Human Performance on Future Deep Space Missions Abstract

NASA and the commercial spacecraft community are working diligently to put the first woman on the moon in the 2024 timeframe. At the same time, NASA researchers are thinking about how to solve the even larger challenges that future deep space missions will bring. Space travel itself is difficult, but astronauts on deep space missions will face obstacles and unknowns never before experienced. In addition to the altered gravity and hostile/closed environment of a spacecraft, deep space crews will face increased radiation, isolation, and distance from Earth. During Extravehicular Activity (EVA, or “spacewalk”) operations, crew will experience increased physical and cognitive workload due to extended types, frequencies and durations of tasks performed on exploration missions in partial gravity environments. All of these stressors will impact crew physical and mental health and performance in difficult-to-anticipate ways. Crew autonomy may be one of the biggest challenges faced. Communication delays and blackouts will occur, and in those situations, the crew may not have access to the Mission Control Center (MCC). They may be forced to be solely dependent on each other and the available information onboard to stay alive, healthy, and achieve the mission. The only conceivable way to meet the challenges of Earth independence is to enable the crew to monitor their own health and performance -- preferably unobtrusively as they perform their duties. Technologies and techniques must be developed to aid the crew in these assessments. A deep space mission is expected to have relatively short periods of high cognitive demand, stress, and fatigue, alongside potentially long periods of cognitive underload during the transit, where boredom, loneliness, and depression can set in. Both ends of this spectrum are dangerous. Crew must be made aware when their task performance drops significantly, when their cognitive workload is too high, when they have lost situation awareness, or when they are too stressed or too fatigued to perform well. They must be able to identify these risks, and then mitigate them with countermeasures available onboard. A number of self-monitoring technologies are presently being explored by NASA to advance crew state determination capabilities. These range from real-time, physiological workload and situation awareness assessments, to crew health measurements determining physical and mental fitness for duty, to task performance metrics such as suit resource expenditures. For EVA tasks during surface exploration missions, biomedical information such as metabolic rate may be provided to crewmembers for situational awareness related to task performance efficiency. In addition, translation distances, hydration, nutrition, inspired CO2 exposure and other consumables usage rates may be useful input metrics for modeling individualized performance during tasks to inform crew or provide estimates of work efficiency. Oculomotor metrics such as gaze dwell time, pupilometry, and eye tracking collected in advanced helmet mounted displays could potentially be used to characterize crew situation awareness. This paper highlights some of these projects, and provides broader discussion about the need for advanced monitoring and smart technologies, as NASA takes the leap into the next generation of space exploration.

Kritina Holden↗

NASA NTRSDate not supplied

Behavioral Health and Performance Operations and Research in Human Spaceflight

There are two distinct functions of the Behavioral Health and Performance (BHP) specialists at NASA Johnson Space Center (JSC), with a shared goal of promoting optimal performance during all mission phases, beginning with selection to the NASA Astronaut Corps through training for and completing a spaceflight mission. The BHP Operations team is active in areas such as selection, training, routine behavioral healthcare services, and work-rest schedule. The BHP Laboratory is engaged in research in space and analog platforms to address the risks and other challenges associated with future deep space missions. Their research focuses on topics that align with the NASA Human Research Program’s Human Factors Behavioral Performance Element goals. This panel will provide details of recent work by BHP Operations and the BHP Laboratory at NASA JSC, and will demonstrate their shared goals, and contributions toward, optimizing performance and maintaining the behavioral health and well-being of astronauts during all mission phases.In 2020-2021, NASA engaged another astronaut applicant screening process to identify its 23rd group of astronaut candidates. The BHP Operations team completed a significant amount of work to evaluate applicants and provide valuable input to the Astronaut Selection Board and the Aerospace Medical Board. One presentation will provide an overview of the work completed by BHP; and one presentation will discuss a critical competency important for successful job performance of the astronauts – Team Orientation. The former will summarize aspects of BHP’s Select-in and Select-out process and provide lessons learned for future selection cycles; the latter will briefly discuss the competencies of BHP’s applicant screening work, with focus on the importance of Team Orientation and the challenges of its measure. A third presentation will provide an overview of BHP’s current fatigue management work with astronauts and mission-critical operators at JSC (e.g., flight directors, pilots), and provide a look at the direction these fatigue management services may take in future exploration missions. Two other presentations will focus on the research completed by the BHP Lab to measure in a standardized way the critical aspects of behavioral health and well-being. One of the presentations will provide an overview of the Exploration Measures being collected during all space and analog missions, and the importance these objective measures have for future research and operations. The final presentation will summarize analyses completed with these measures, as they have been harmonized across both ISS and Analog missions.

Gary Beven↗

NASA NTRS2000

Isometric handgrip training reduces arterial pressure at rest without changes in sympathetic nerve activity

The purpose of this study was to determine whether isometric handgrip (IHG) training reduces arterial pressure and whether reductions in muscle sympathetic nerve activity (MSNA) mediate this drop in arterial pressure. Normotensive subjects were assigned to training (n = 9), sham training (n = 7), or control (n = 8) groups. The training protocol consisted of four 3-min bouts of IHG exercise at 30% of maximal voluntary contraction (MVC) separated by 5-min rest periods. Training was performed four times per week for 5 wk. Subjects' resting arterial pressure and heart rate were measured three times on 3 consecutive days before and after training, with resting MSNA (peroneal nerve) recorded on the third day. Additionally, subjects performed IHG exercise at 30% of MVC to fatigue followed by muscle ischemia. In the trained group, resting diastolic (67 +/- 1 to 62 +/- 1 mmHg) and mean arterial pressure (86 +/- 1 to 82 +/- 1 mmHg) significantly decreased, whereas systolic arterial pressure (116 +/- 3 to 113 +/- 2 mmHg), heart rate (67 +/- 4 to 66 +/- 4 beats/min), and MSNA (14 +/- 2 to 15 +/- 2 bursts/min) did not significantly change following training. MSNA and cardiovascular responses to exercise and postexercise muscle ischemia were unchanged by training. There were no significant changes in any variables for the sham training and control groups. The results indicate that IHG training is an effective nonpharmacological intervention in lowering arterial pressure.

NASA Discipline Neuroscience↗

NASA NTRS2016

Initial Work Toward a Robotically Assisted EVA Glove

The Space Suit RoboGlove is a device designed to provide additional grasp strength or endurance for an EVA crew member since gloved hand performance is a fraction of what the unencumbered human hand can achieve. There have been past efforts to approach this problem by employing novel materials and construction techniques to the glove design, as well as integrating powered assistance devices. This application of the NASA/GM RoboGlove technology uses a unique approach to integrate the robotic actuators and sensors into a Phase VI EVA glove. This design provides grasp augmentation to the glove user while active, but can also function as a normal glove when disabled. Care was taken to avoid adding excessive bulk to the glove or affecting tactility by choosing low-profile sensors and extrinsically locating the actuators. Conduits are used to guide robotic tendons from linear actuators, across the wrist, and to the fingers. The second generation of the SSRG includes updated electronics, sensors, and actuators to improve performance. The following discusses the electromechanical design, softgoods integration, and control system of the SSRG. It also presents test results from the first integration of a powered mobility element onto a space suit, the NASA Mark III. Early results show that sensor integration did not impact tactile feedback in the glove and the actuators show potential for reduction in grasp fatigue over time.

Rogers, J.↗

NASA NTRSDate not supplied

Behavioral Indicators in Air Traffic Controllers: How Do You Know When You Are Working at The Edge of Performance?

Air traffic controllers are responsible for the safety and efficiency of air traffic and therefore must maintain a consistently high standard of performance. However, performance can be negatively affected by factors such as workload and fatigue, potentially leading to performance decline and performance-related incidents. Real-time identification of negative influences would facilitate timely implementation of supportive strategies prior to performance decline. The current study aimed to explore the concept of ‘behavioral indicators’ to identify when a controller was reaching a performance limit. A second aim was to capture behavioral indicators associated with performance influencing factors. A total of 65 controllers spanning Tower, Approach and Enroute facilities across the United States of America were interviewed. Findings revealed that controllers were familiar with the concept of behavioral indicators, and that indicators were associated with specific performance-influencing factors. Implications for implementing behavioral indicators training in control environments are discussed.

behavioral indicators↗

NASA NTRS1996

Relation of systemic and local muscle exercise capacity to skeletal muscle characteristics in men with congestive heart failure

OBJECTIVES. The present study was undertaken to further characterize changes in skeletal muscle morphology and histochemistry in congestive heart failure and to determine the relation of these changes to abnormalities of systemic and local muscle exercise capacity. BACKGROUND. Abnormalities of skeletal muscle appear to play a role in the limitation of exercise capacity in congestive heart failure, but information on the changes in muscle morphology and biochemistry and their relation to alterations in muscle function is limited. METHODS. Eighteen men with predominantly mild to moderate congestive heart failure (mean +/- SEM New York Heart Association functional class 2.6 +/- 0.2, ejection fraction 24 +/- 2%) and eight age- and gender-matched sedentary control subjects underwent measurements of peak systemic oxygen consumption (VO2) during cycle ergometry, resistance to fatigue of the quadriceps femoris muscle group and biopsy of the vastus lateralis muscle. RESULTS. Peak VO2 and resistance to fatigue were lower in the patients with heart failure than in control subjects (15.7 +/- 1.2 vs. 25.1 +/- 1.5 ml/min-kg and 63 +/- 2% vs. 85 +/- 3%, respectively, both p < 0.001). Patients had a lower proportion of slow twitch, type I fibers than did control subjects (36 +/- 3% vs. 46 +/- 5%, p = 0.048) and a higher proportion of fast twitch, type IIab fibers (18 +/- 3% vs. 7 +/- 2%, p = 0.004). Fiber cross-sectional area was smaller, and single-fiber succinate dehydrogenase activity, a mitochondrial oxidative marker, was lower in patients (both p < or = 0.034). Likewise, the ratio of average fast twitch to slow twitch fiber cross-sectional area was lower in patients (0.780 +/- 0.06 vs. 1.05 +/- 0.08, p = 0.019). Peak VO2 was strongly related to integrated succinate dehydrogenase activity in patients (r = 0.896, p = 0.001). Peak VO2, resistance to fatigue and strength also correlated significantly with several measures of fiber size, especially of fast twitch fibers, in patients. None of the skeletal muscle characteristics examined correlated with exercise capacity in control subjects. CONCLUSIONS. These results indicate that congestive heart failure is associated with changes in the characteristics of skeletal muscle and local as well as systemic exercise performance. There are fewer slow twitch fibers, smaller fast twitch fibers and lower succinate dehydrogenase activity. The latter finding suggests that mitochondrial content of muscle is reduced in heart failure and that impaired aerobic-oxidative capacity may play a role in the limitation of systemic exercise capacity.

Non-NASA Center↗

NASA NTRS2000

Bioavailability and Pharmacodynamics of Promethazine in Human Subjects

Space Motion Sickness (SMS) is often treated in space with promethazine (PMZ). Anecdotal reports indicate that the common side effects of drowsiness and decrements in cognitive performance that are associated with PMZ administration (50 mg IM on the ground, are absent or less pronounced in space suggesting I that-the bioavailability and/or pharmacodynamic behavior of PMZ may be altered during space flight. There are limited flight opportunities available for clinical research in space, the NRA-99, therefore, solicits research required to improve, or answer specific questions about in-flight diagnosis, therapy, and post-flight rehabilitation. We propose here, to establish a noninvasive method for pharmacodynamic and therapeutic assessment of PMZ. The specific objectives of the proposed research are to, 1. Establish a saliva to plasma ratio of PMZ after administration, 2. Estimate the relative bioavailability of the three flight-specific dosage forms of PMZ, and 3. Establish the dose-response relationship of PMZ. We will estimate the bioavailability of intramuscular injection (IM), oral tablets and rectal suppositories in normal subjects during ambulatory and antiorthostatic; bed rest (ABR) conditions using novel stable isotope techniques. Drowsiness, cognitive performance and salivary flow rate will be measured as a function of circulating drug concentrations after administration of three IM doses of PMZ. We will compare and contrast the bioavailability of PMZ during normal and ABR conditions to examine whether or not ABR can simulate changes in drug, absorption and availability similar to those anticipated in a microgravity environment. Results of this study will validate methods for an approved study with this medication awaiting a flight opportunity for manifestation. These data will also provide the much needed information on the dynamics and therapeutic index. of this medication and their implications on crew fatigue and performance in space. Key words: Promethazine, stable isotopes, bioavailability, pharmacodynamics, cognitive performance, antiorthostatic bed rest.

Putcha, Lakshmi↗

NASA NTRS2011

Nutrition Coupled with High-Load Traditional or Low-Load Blood Flow Restricted Exercise During Human Limb Suspension

High-load resistance exercise (HRE) and low-load blood flow restricted (BFR) exercise have demonstrated efficacy for attenuating unloading related muscle atrophy and dysfunction. In recreational exercisers, protein consumption immediately before and/or after exercise has been shown to increase the skeletal muscle anabolic response to resistance training. PURPOSE: To compare the skeletal muscle adaptations when chocolate milk intake was coupled with HRE or low-load BFR exercise [3 d/wk] during simulated lower limb weightlessness. METHODS: Eleven subjects were counterbalanced [based on age and gender] to HRE (31 +/- 14 yr, 170 +/- 13 cm, 71 +/- 18 kg, 2M/3W) or low-load BFR exercise (31 +/- 12 yr, 169 +/- 13 cm, 66 +/- 14 kg, 2M/4W) during 30 days of unilateral lower limb suspension (ULLS). Both HRE and BFR completed 3 sets of single leg press and calf raise exercise during ULLS. BFR exercise intensity was 20% of repetition maximum (1RM) with a cuff inflation pressure of 1.3 systolic blood pressure (143 4 mmHg). Cuff pressure was maintained during all 3 sets including rest intervals (90s). HRE intensity was 75% 1RM and was performed without cuff inflation. Immediately (<10 min) before and after exercise 8 fl oz of chocolate milk (150 kcal, 2.5g total fat, 22g total carbohydrate, 8g protein) was consumed to optimize acute exercise responses in favor of muscle anabolism. ULLS analog compliance was assessed from leg skin temperature recordings and plantar accelerometry. Muscle cross-sectional area (CSA) for knee extensor and plantar flexor muscle groups were determined from analysis of magnetic resonance images using ImageJ software. 1RM strength for leg press and calf raise was assessed on the Agaton exercise system. Muscular endurance during leg press and calf raise was evaluated from the maximal number of repetitions performed to volitional fatigue using 40% of pre-ULLS 1RM. RESULTS: Steps detected by plantar acceleometry declined by 98.9% during ULLS relative to an ambulatory control period. Average skin temperature of the unloaded calf declined from 27.4 C to 26.8 C (-2.1%), while there was a slight increase (+1.1%) in skin temperature in the loaded calf (27.6 C to 27.9 C). Collectively, these measures indicate strong subject compliance with the ULLS analog. Unloaded limb work performed during leg press (1514 +/- 334 vs. 576 +/- 103) and calf raise (2886 +/- 508 vs. 1233 +/- 153) exercises sessions was greater in HRE vs. BFR, respectively. Leg press training loads were 44 +/- 7 kg in HRE compared to 11 +/- 1 kg in BFR. Similarly, calf raise training loads were 81 +/- 11 kg in HRE and 16 +/- 1 kg in BFR. Pre to post-ULLS training adaptations in the unloaded leg are shown in the table. CONCLUSION: The preliminary results of this investigation suggest when HRE is optimized for muscle anabolism during unloading muscle size and strength are preserved (or enhanced) at the expense of muscle endurance. In contrast, when BFR exercise is optimized for muscle anabolism during unloading muscle endurance is preserved (or enhanced) at the expense of muscle size and strength

Hackney, K. J.↗

NASA NTRS2000

Orthostatic intolerance: a disorder of young women

Orthostatic intolerance (OI) is a cause of significant disability in otherwise healthy women seen by gynecologists. Orthostatic tachycardia is often the most obvious hemodynamic abnormality found in OI patients, but symptoms may include dizziness, visual changes, discomfort in the head or neck, poor concentration, fatigue, palpitations, tremulousness, anxiety, and, in some cases, fainting (syncope). It is the most common disorder of blood pressure regulation after essential hypertension, and patients with OI are traditionally women of childbearing age. Estimates suggest that at least 500,000 Americans suffer from some form of OI, and such patients comprise the largest group referred to centers specialized in autonomic disorders. This article reviews recent advances made in the understanding of this condition, potential pathophysiological mechanisms contributing to orthostatic intolerance, and therapeutic alternatives currently available for the management of these patients.

Review, Tutorial↗

NASA NTRS1994

Neuromuscular adaptation to actual and simulated weightlessness

The chronic "unloading" of the neuromuscular system during spaceflight has detrimental functional and morphological effects. Changes in the metabolic and mechanical properties of the musculature can be attributed largely to the loss of muscle protein and the alteration in the relative proportion of the proteins in skeletal muscle, particularly in the muscles that have an antigravity function under normal loading conditions. These adaptations could result in decrements in the performance of routine or specialized motor tasks, both of which may be critical for survival in an altered gravitational field, i.e., during spaceflight and during return to 1 G. For example, the loss in extensor muscle mass requires a higher percentage of recruitment of the motor pools for any specific motor task. Thus, a faster rate of fatigue will occur in the activated muscles. These consequences emphasize the importance of developing techniques for minimizing muscle loss during spaceflight, at least in preparation for the return to 1 G after spaceflight. New insights into the complexity and the interactive elements that contribute to the neuromuscular adaptations to space have been gained from studies of the role of exercise and/or growth factors as countermeasures of atrophy. The present chapter illustrates the inevitable interactive effects of neural and muscular systems in adapting to space. It also describes the considerable progress that has been made toward the goal of minimizing the functional impact of the stimuli that induce the neuromuscular adaptations to space.

Non-NASA Center↗

NASA NTRS2002

Cerebral blood flow velocity declines before arterial pressure in patients with orthostatic vasovagal presyncope

OBJECTIVES: We studied hemodynamic changes leading to orthostatic vasovagal presyncope to determine whether changes of cerebral artery blood flow velocity precede or follow reductions of arterial pressure. BACKGROUND: Some evidence suggests that disordered cerebral autoregulation contributes to the occurrence of orthostatic vasovagal syncope. We studied cerebral hemodynamics with transcranial Doppler recordings, and we closely examined the temporal sequence of changes of cerebral artery blood flow velocity and systemic arterial pressure in 15 patients who did or did not faint during passive 70 degrees head-up tilt. METHODS: We recorded photoplethysmographic arterial pressure, RR intervals (electrocardiogram) and middle cerebral artery blood flow velocities (mean, total, mean/RR interval; Gosling's pulsatility index; and cerebrovascular resistance [mean cerebral velocity/mean arterial pressure, MAP]). RESULTS: Eight men developed presyncope, and six men and one woman did not. Presyncopal patients reported light-headedness, diaphoresis, or a sensation of fatigue 155 s (range: 25 to 414 s) before any cerebral or systemic hemodynamic change. Average cerebral blood flow velocity (CBFV) changes (defined by an iterative linear regression algorithm) began 67 s (range: 9 to 198 s) before reductions of MAP. Cerebral and systemic hemodynamic measurements remained constant in nonsyncopal patients. CONCLUSIONS: Presyncopal symptoms and CBFV changes precede arterial pressure reductions in patients with orthostatic vasovagal syncope. Therefore, changes of cerebrovascular regulation may contribute to the occurrence of vasovagal reactions.

Non-NASA Center↗

NASA NTRS2023

Modeling and Simulation of the Angel Upper Limb Offload Device: Branching Into New Methods

BACKGROUND: The Active Response Gravity Offload System (ARGOS) provides an analog environment for extravehicular activity (EVA) testing and training. Discomfort has been observed during longer suited test sessions. While the subject’s core is offloaded during surface EVA evaluations, his/her arms experience full Earth gravity and can become overly fatigued, especially during suited tests which involve reaching and prolonged arm extensions. A device (ARGOS Negation of Gravitational Effects on the Limbs: ANGEL) to offload the weight of the arms and suit sleeves is being developed by JSC’s Flight Systems Branch of the Software, Robotics, and Simulation Division. Previously we have shared preliminary modeling of that device and kinematics based on motion capture data. Here we present an alternative approach to determine device kinematics by calculating ANGEL component angles with an OpenSim plugin. We compare calculated angles to inverse kinematics (IK) derived ones with the goal of validating the model. This new method can be further informative for device design and analytically testing different configurations to achieve desired reduced gravity conditions (e.g., lunar gravity (Lg) or Martian gravity (Mg)). We have compared calculated angles with IK-derived angles in tests with a shirt-sleeve subject positioned in a test stand with a Mark-III Hard Upper Torso (HUT) and Portable Life Support System (PLSS) mockup and arm weights to emulate the weight of the suit sleeve as well as a suited subject in ARGOS with a Mark-III suit. A variety of upper body tasks were completed in the former and full-body tasks in the latter. METHODS AND RESULTS: To model the offload device, we augment the OpenSim human model topology with the offload mechanism components and joints, using CAD models to represent the mechanism graphically. The joint angles of the device are calculated in the OpenSim plugin by modeling how the components configure themselves under the offloading spring tension given a particular IK-derived arm position. There are four ANGEL components with a total of 5 degrees of freedom (DOFs), each component has a single DOF except for the cuff which is modeled as 2 DOFs. The sickle/yaw bracket and cuff rotation angles are determined statically based on the assumptions that the sickle will track the attachment point of the cuff and that the cuff will rotate such that the attachment point is at its highest point. The cuff tilt, linker and V-bracket angles are then determined by optimizing their positions to approach a mechanical equilibrium. The calculated linker angle is compared to three different methods of determining the linker line-of-force kinematically (from V-bracket to center-cuff, cuff highest point or marker-derived position). Given the joint angles of the device, the spring force and resulting force on the arm is computed by the plugin and applied as an external load in inverse dynamics (ID) to enable study of overall shoulder joint torques as well as offload achieved. We verify the calculated joint angles by using the inverse kinematic data. The average difference in angles is the smallest for the V-bracket and linker, around 1 to 5 degrees for most trials. The resulting offload and shoulder torque are comparable between calculated and IK-derived angles. In summary, we have developed a method to calculate the joint angles of an exoskeleton-like upper limb offloading device currently in development. We have also developed a custom plugin which will be a valuable tool to optimize device configurations for a desired gravitational environment, probe the offload achieved for motions recorded outside of our test suite, and inform future design improvements.

L B Nilsson↗

NASA NTRS2023

Modeling and Simulation of The Angel Upper Limb Offload Device: Branching into New Methods

L B Nilsson↗

NASA NTRSDate not supplied

Vacuum Sealable Container (VSC) and Astronaut Lunar Drill (ALD) for Artemis

Introduction: NASA’s Artemis Program is under development to send first woman and next man to the Moon. Artemis will utilize a suite of new technology for Lunar exploration, including new space vehicles, new space suits, and new Astronaut Tools. Honeybee Robotics has been working with NASA JSC to develop a new Vacuum Sealable Container (VSC) and new Astronaut Lunar Drill (ALD) for the upcoming Artemis missions. Vacuum Sealable Container: Sample return continues to be the “Holy Grail” of space exploration, allowing for the analysis of materials using Earth-based laboratories instead of needing to miniaturize and ruggedize instrumentation for space. The Apollo missions to the Moon had several kinds of Sealable Containers which brought back Lunar samples for analysis [1]. These samples are still being analyzed, fifty years later. The VSC requirements are different from that for Apollo containers and as such, new development was required. One major difference between Artemis samples and those from Apollo is the desire to bring back volatiles which may be part of lunar regolith. The VSC is designed to withstand a high-pressure differential caused by sublimating volatiles. Because of the new, stricter sealing requirements, additional features have been added to the VSC. For example, the seal on the container is required to be more robust, thus required more force to actuate, and the seal must be locked in place with a secondary mechanism. Astronaut Lunar Drill: The ALD is designed to be a multi-functional platform for Lunar sample acquisition. The drill builds on lessons learned from the Apollo Lunar Surface Drill (ALSD), as well as Honeybee’s long history of mechanized sample acquisition devices for space [2]. The main functionality of the ALD is Deep Core Regolith Drilling. Additional functionality includes Surface Rock Coring (SRC), and GeoTech Tools (GTT). The ALD is a rotary-percussive drill designed with deep drilling in mind. The ALD is currently designed to have decoupled rotary and percussion subsystems to allow for maximum battery life and reduced fatigue on the crewmember. Honeybee drill technology will automatically engage the percussion when needed to drill at maximum efficiency. The mechanized drill stand helps improve drilling efficiency; the system utilizes advanced drilling algorithms which only require the crewmember to hold a single switch. Additionally, the stand aids in extraction of deep cores, something which was a problem on Apollo. The SRC functionality of the ALD utilizes Honeybee’s Eccentric Tube Core Breakoff technology to collect and retain rock core samples. This technology has also been infused into the Perseverance rover mission. The ALD is removable from the stand to allow crewmembers to collect samples from large boulders. Bringing back rock cores samples instead of full rocks allows for a wider variety of samples to be returned to Earth for study and puts them in a uniform form-factor for effective sealing and analysis. SRC bits will utilize the power of the drill’s percussion system to drill hard Lunar rocks and expedite sample acquisition. The mechanized stand on the ALD allows for additional attachments for taking geotechnical measurements with a Static Cone Penetrometer (SCP) and a Shear Vane (SV). With the stand, the ALD can take SCP measurements with the touch of a button, storing data for return to Earth. SV measurements utilize the ALD’s Rotary motor to spin the vanes in a controlled manner, getting clean data untampered by human error. References: [1] Bar Cohen and Zacny (2009), Drilling in Extreme Environments - Penetration and Sampling on Earth and Other Planets, Wiley. [2] Bar-Cohen and Zacny, Advances in Terrestrial and Extraterrestrial Drilling, CRC Press. [3] Myrick (2003), Core Break-off Mechanism. US Patent No. 6,550,549 Acknowledgements: This work has been supported by NASA via SBIR Phase 3.

Artemis↗