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Search indexed NASA NTRS and DOE OSTI research on propulsion, heat transfer, battery materials and energy systems. Follow report and document links to the original sources.

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At least 55 records · Page 3
All sourcesNASA NTRSDOE OSTI
DOE OSTI2025

Divergent evolution of slip banding in CrCoNi alloys

Abstract Metallic materials under high stress often exhibit deformation localization, manifesting as slip banding. Over seven decades ago, Frank and Read introduced the well-known model of dislocation multiplication at a source, explaining slip band formation. Here, we reveal two distinct types of slip bands (confined and extended) in compressed CrCoNi alloys through multi-scale testing and modeling from microscopic to atomic scales. The confined slip band, characterized by a thin glide zone, arises from the conventional process of repetitive full dislocation emissions at Frank–Read source. Contrary to the classical model, the extended band stems from slip-induced deactivation of dislocation sources, followed by consequent generation of new sources on adjacent planes, leading to rapid band thickening. Our findings provide insights into atomic-scale collective dislocation motion and microscopic deformation instability in advanced structural materials.

Science & Technology - Other Topics↗
DOE OSTI2024

Optical pulse-induced ultrafast antiferrodistortive transition in SrTiO 3

The ultrafast dynamics of the antiferrodistortive phase transition in perovskite SrTiO 3 is monitored via time-domain Brillouin scattering. Using femtosecond optical pulses, we initiate a thermally driven tetragonal-to-cubic structural transformation and detect the crystal phase through changes in the frequency of Brillouin oscillations (BO) induced by propagating acoustic phonons. Coupling the measured BO frequency with a spatiotemporal heat diffusion model, we demonstrate that, for a sample kept in the tetragonal phase, deposition of sufficient thermal energy induces a rapid transformation of the heat-affected region to the cubic phase. The initial phase change is followed by a slower reverse cubic-to-tetragonal phase transformation occurring on a timescale of hundreds of picoseconds. Here, we attribute this ultrafast phase transformation in the perovskite to a structural resemblance between atomic displacements of the R-point soft optic mode of the cubic phase and the tetragonal phase, both characterized by anti-phase rotation of oxygen octahedra. The structural relaxation time exhibits a strong temperature dependence consistent with the prediction of the equation of motion describing collective oxygen octahedra rotation based on the energy landscape of the phenomenological Landau theory of phase transitions. Evidence of such a fast structural transition in perovskites can open up new avenues in information processing and energy storage sectors.

36 MATERIALS SCIENCE↗
NASA NTRS2001

Effect of long-duration spaceflight on postural control during self-generated perturbations

This report is the first systematic evaluation of the effects of prolonged weightlessness on the bipedal postural control processes during self-generated perturbations produced by voluntary upper limb movements. Spaceflight impacts humans in a variety of ways, one of which is compromised postflight postural control. We examined the neuromuscular activation characteristics and center of pressure (COP) motion associated with arm movement of eight subjects who experienced long-duration spaceflight (3--6 mo) aboard the Mir space station. Surface electromyography, arm acceleration, and COP motion were collected while astronauts performed rapid unilateral shoulder flexions before and after spaceflight. Subjects generally displayed compromised postural control after flight, as evidenced by modified COP peak-to-peak anterior-posterior and mediolateral excursion, and pathlength relative to preflight values. These changes were associated with disrupted neuromuscular activation characteristics, particularly after the completion of arm acceleration (i.e., when subjects were attempting to maintain upright posture in response to self-generated perturbations). These findings suggest that, although the subjects were able to assemble coordination modes that enabled them to generate rapid arm movements, the subtle control necessary to maintain bipedal equilibrium evident in their preflight performance is compromised after long-duration spaceflight.

NASA Discipline Neuroscience↗
NASA NTRS2014

Low-Speed Dynamic Wind Tunnel Test Analysis of a Generic 53 Degree Swept UCAV Configuration With Controls

Several static and dynamic forced-motion wind tunnel tests have been conducted on a generic unmanned combat air vehicle (UCAV) configuration with a 53deg swept leading edge. These tests are part of an international research effort to assess and advance the state-of-art of computational fluid dynamics (CFD) methods to predict the static and dynamic stability and control characteristics for this type of configuration. This paper describes the dynamic forced motion data collected from two different models of this UCAV configuration as well as analysis of the control surface deflections on the dynamic forces and moments.

Vicroy, Dan D.↗
DOE OSTI2026

A statistical approach to analyzing domain dynamics in ferroelectric crystals using X-ray photon correlation spectroscopy

Ferroelectric materials exhibit strong electromechanical coupling, largely influenced by their domain structures. Numerous microstructural studies indicate that smaller domains with higher domain wall density generally enhance domain wall motion, although some inconsistencies have been reported. In this work, we use X-ray photon correlation spectroscopy (XPCS) to probe dynamic response in Pb(Mg 1/3 Nb 2/3 )O 3 -29PbTiO 3 (PMN-29PT) single crystals under applied electric fields. We introduce a two-field correlation approach, adapted from conventional two-time correlation to quantify dynamics. Statistical analysis reveals that both [001]-oriented direct current (DC) and alternating current (AC) poled samples show Poisson-like behavior within specific electric field regions. The DC-poled samples exhibit more frequent domain wall jump events but with smaller amount of decorrelation per jump event, whereas the AC-poled samples show fewer jump events with larger decorrelation per jump event. This observation aligns with the prevalence of 109° domain walls in the AC-poled samples, which contribute to more domain wall motion. These findings provide experimental evidence of collective domain wall motion and establish a direct connection between mesoscale dynamics and electromechanical response.

36 MATERIALS SCIENCE↗
NASA NTRSDate not supplied

Accuracy of Center of Pressure Determination via Motion Capture

BACKGROUND: This study was conducted to support the stability assessment for tasks in lunar gravity and exercises on a Vibration Isolation and Stabilization (VIS) system in microgravity based on the dynamic feasibility criterion of whether the calculated position of the center of pressure (COP) falls within the base of support (BOS) which outlines the subject’s feet. Motion capture data combined with biomechanical modeling and simulation allows the forces and moments between the human and the VIS platform to be computed and the position of the COP as well as the location and shape of the BOS to be determined. The goal of this study was to assess the accuracy of the COP trajectory calculated using motion capture-based data. METHODS AND RESULTS: To obtain the dynamic quantities from which COP is calculated, motion capture data is first collected in the 1g lab environment by recording the trajectories of passive retroreflective markers placed on a subject during exercise or performance of a given task. The OpenSim [1] inverse kinematics (IK) tool is used to fit a scaled subject model to recorded marker trajectories while minimizing marker error to obtain joint angles. Then, a custom OpenSim plugin [2] is used to determine the subject’s time-varying moment of inertia and its time derivative, center of mass (CM) position, velocity, and acceleration, as well as the angular momentum and its time derivative relative to the subject’s CM. Some of these quantities are not needed for modeling tasks performed on a stationary lunar surface but, due to the moving exercise platform, are needed to model VIS response to the subject’s motion. Hand positions, used in calculating a cable force if present, are recorded as well. These quantities are used to calculate the total force (F ⃗^((plate) )) and moment (M ⃗^((plate) )) exerted by the lunar surface or the VIS plate on the subject’s shoe soles. COP is then calculated from the following equations: r_x^((cop) )= M_z^((plate) )/F_y^((plate) ) and r_z^((cop) )= 〖-M〗_x^((plate) )/F_y^((plate) ), where the y axis is normal to the surface. COP accuracy for feasibility assessments is then determined by whether it falls within the BOS, which is also computed by the plugin. To study the accuracy of COP calculated from motion capture, we first investigated whether COP remained within the BOS, as it must, for exercises performed in the 1g lab environment. Standard exercises such as back squat and deadlift were analyzed, as well as more explosive exercises including hang clean and press. Cases in which the COP exited the BOS indicated that COP accuracy required further investigation. In this study, an exercise device with cables was used, so cable force modeling accuracy should also be considered. In a separate study, we collected motion capture and force plate data for twenty-seven motions not involving an exercise device. About a third were genuine countermeasures exercises (e.g., hang clean and press), some were relevant for lunar tasks (e.g., object pick up), and the rest were of a “unit test” nature (e.g., swaying back and forth or side to side). Motion capture-based COP positions were compared with force plate measured COP. We found that while force plate measured COP remained within the BOS, motion capture-based COP was observed to briefly exit the BOS on occasion. Techniques to mitigate IK artifacts and filtering of calculated data could be used to improve the agreement of calculated and measured results, resolving excursions from the BOS within this dataset. The mean error between calculated and measured COP was found to be less than 6 mm. Additionally, we derived and investigated equations for the COP in terms of the cable force, cable location, as well as the human CM position, acceleration, and angular momentum with respect to the CM, and analyzed them for sensitivity to errors in individual quantities. Several were found, but the most significant one was that when the vertical force on the feet approaches zero, indicating a near-detachment or ‘jump off’ condition, errors are amplified. This is consistent with the observation that in the absence of pressure, the concept of the center of pressure would become meaningless.

C A Bell↗
NASA NTRS2022

Characterization of Infrared Optical Motion Tracking System in NASA's Simulated Lunar Operations (SLOPE) Laboratory

This work characterizes the accuracy of a 16 camera OptiTrack motion tracking system installed in NASA Glenn Research Center's Simulated Lunar Operations (SLOPE) laboratory. The position of a rigid body mounted on a motorized linear stage is compared to its position reported by the motion tracking system as it travels through the facility's 777m$^3$ capture volume of interest. Experiments show that the mean error reported by the motion tracking system for the aggregate capture volume is in-line with independent measurements collected using the motion stage. Error within regions of the capture volume exceed the mean error reported by the motion tracking system, likely due to occlusion, and suggests that additional cameras should be used to increase measurement accuracy in these regions. Overall, results show that error values reported by the motion tracking system are representative of the measurement error in a collected data set and validates the system's use for characterizing the mobility and tractive performance of robots, rovers, and other vehicles for planetary exploration.

Motion capture↗
NASA NTRS2014

Trust Control of VTOL Aircraft Part Deux

Thrust control of Vertical Takeoff and Landing (VTOL) aircraft has always been a debatable issue. In most cases, it comes down to the fundamental question of throttle versus collective. Some aircraft used throttle(s), with a fore and aft longitudinal motion, some had collectives, some have used Thrust Levers where the protocol is still "Up is Up and Down is Down," and some have incorporated both throttles and collectives when designers did not want to deal with the Human Factors issues. There have even been combinations of throttles that incorporated an arc that have been met with varying degrees of success. A previous review was made of nineteen designs without attempting to judge the merits of the controller. Included in this paper are twelve designs entered in competition for the 1961 Tri-Service VTOL transport. Entries were from a Bell/Lockheed tiltduct, a North American tiltwing, a Vanguard liftfan, and even a Sikorsky tiltwing. Additional designs were submitted from Boeing Wichita (direct lift), Ling-Temco-Vought with its XC-142 tiltwing, Boeing Vertol's tiltwing, Mcdonnell's compound and tiltwing, and the Douglas turboduct and turboprop designs. A private party submitted a re-design of the Breguet 941 as a VTOL transport. It is important to document these 53 year-old designs to preserve a part of this country's aviation heritage.

Thrust control↗
NASA NTRS2018

Influence of Load Profile on Biomechanics of the Squat and Deadlift

Long duration space travel will expose astronauts to extended periods of reduced gravity. Since gravity is not present to assist loading, astronauts will use resistive and aerobic exercise regimes for the duration of the space flight to counteract the effect reduced gravity has on the body. Astronauts will exercise on a flywheel based device on the second Orion Exploration Mission (EM2). The effect that the flywheel load profile has on biomechanics is unknown when compared to free weights or a simulated free weight profile. The purpose of this evaluation is to compare the differences in lower body kinematics and kinetics between the flywheel and free weight profile. Test subjects were instrumented with reflective markers for motion capture data collection while exercising on the Device for Aerobic and Resistive Training (DART) prototype developed by TDA Research, Inc. of Wheat Ridge, CO. Exercises performed were either the squat while wearing a harness or deadlift while grasping a T-bar, both of which interfaced with the DART through a rope cable. The DART, a motorized device controlled via software, is capable of producing different load profiles. Profiles include simulated free weights with adjustable eccentric overload capability and flywheel. Test variables included the applied device load and the load profile, both set through the DART software interface. Motion capture data was collected with a 12 camera system (Smart-DX, BTS Bioengineering, Brooklyn, NY). Bilateral ground reaction force data were collected with force plates (P6000, BTS Bioengineering). DART cable force was recorded through an internal load cell. Data was collected from a total of four test subjects. The three repetition maximum was determined for each test subject for both squat and deadlift. High, medium and low loads were determined based on this maximum. The test subject performed five repetitions of each exercise at each load and each test trial was repeated twice. Cadence was controlled during exercising. Biomechanical data were used to drive the models utilizing the OpenSim software platform. Subject specific models were scaled to match the anthropometrics of the test subjects and used to estimate the peak joint angle, joint range of motion, the peak joint moment and the joint moment impulse of the lower extremity joints and the lumbar joint.These are preliminary results because the data analysis is ongoing. There was a lot of inter-subject variability, however, in general, there was a greater peak lumbar flexion angle for the flywheel squat exercise. There was a trend towards a greater range of motion at the hip for the squat exercise with free weight. There was also a greater hip extension, lumbar extension and ankle plantar flexion impulse moment during the squat exercise with free weight. During the deadlift exercise, the peak knee flexion angle and peak knee extension moment were greater when using the free weight profile. For deadlift, the hip extension, lumbar extension and ankle plantar flexion impulse moment tended to be greater with the free weight profile. Overall, the kinematic and kinetic outcomes for the flywheel profile were either statistically the same as free weight profile in many cases, significantly reduced in a few cases, and rarely higher.

Bioengineering↗
NASA NTRS2003

Characterization of the Test Section Walls at the 14- by 22-Foot Subsonic Tunnel

The test section walls of the NASA Langley Research Center 14- by 22-Foot Subsonic Tunnel are known to move under thermal and pressure loads. Videogrammetry was used to measure wall motion during the summer of 2002. In addition, a laser distancemeter was used to measure the relative distance between the test section walls at a single point. Distancemeter and videogrammetry results were consistent. Data were analyzed as a function of temperature and pressure to determine their effects on wall motion. Data were collected between 50 and 100 F, 0 and 0.315 Mach, and dynamic pressures of 0 and 120 psf. The overall motion of each wall was found to be less than 0.25 in. and less than facility personnel anticipated. The results show how motion depends on the temperature and pressure inside the test section as well is the position of the boundary layer vane. The repeatability of the measurements was +/-0.06 in. This report describes the methods used to record the motion of the test section walls and the results of the data analysis. Future facility plans include the development of a suitable wall restraint system and the determination of the effects of the wall motion on tunnel calibration.

Lunsford, Charles B.↗
NASA NTRSDate not supplied

Recent Improvements and Verification of A Full Body Model in Opensim

BACKGROUND: The dynamic feasibility [1,2] criterion, that the subject’s Center of Pressure (COP) be located within the Base of Support (BOS) which outlines the feet, has aided in assessing the stability of human motion recorded on earth while performing the recorded tasks in lunar gravity or as countermeasures exercises on a vibration isolation and stabilization system in microgravity. The convex hull of the BOS on the platform under the subject’s feet was estimated using virtual markers on the feet of the scaled subject model. The COP was calculated using the ground reaction forces and moments determined from motion capture data with biomechanical modeling tools [3]. Occasionally, large-amplitude oscillatory spikes or “artifacts” were observed in the subject’s linear and angular momentum derivatives, affecting some COP data derived from motion capture. The purpose of this investigation was to assess and improve the accuracy of model scaling and BOS estimation as well as to determine the efficacy of model adjustments in mitigating artifacts influencing motion capture-derived ground reaction force and COP results. METHODS: To aid evaluation of proposed process and model updates, motion capture data were collected for two subjects during unit test and range of motion trials, lunar tasks, and countermeasures exercise motions. Markers were added to the full body Plug-in Gait marker set [4] during data collection. New markers were placed on the front, back, sides, and top of the head to improve scaling using distances between marker pairs. Medial elbow markers were added to stabilize the upper arm during OpenSim Inverse Kinematics (IK) [5]. Finally, markers were added on the outer edge of the heels and on the outside edges of the first and last toes on each foot. These additional foot markers were made available to test new automated foot scaling techniques and to calculate the error between the subject’s estimated and recorded BOS. The modified unscaled OpenSim Full Body Rajagopal Model [6,7] was adjusted using some previously investigated techniques [8] to mitigate rapid shifts in joint angles occurring during IK, as these were found to cause the spike artifacts observed in subsequent stages of analysis. Since OpenSim models use Euler angles and rotation sequences, the arm axes of rotation were adjusted, and the pelvis order of rotation was changed to minimize the likelihood of encountering “gimbal lock” during common human motion. The model clavicle, arm, elbow, wrist, pelvis, and ankle angle limits were adjusted to better accommodate the full human range of motion seen in exercise and lunar data. The shoulder joint center was calculated using a “pivoting” algorithm [9], and both shoulder joint center and upper arm markers were included during IK to provide additional shoulder stability on a case-by-case basis. The quality of IK results was assessed by three criteria: minimizing error between recorded motion capture markers and model markers, checking for reasonable rates of change in joint angles between fames (i.e., no IK artifacts), and ensuring the absence of spikes in the inertial forces and angular momentum derivatives calculated using a custom OpenSim plugin [10]. RESULTS: The additional markers placed on the subject during data collection allowed the head and feet to be scaled more accurately using distances between new marker pairs. Scaling with BOS markers placed on the subject and removing the limit on subtalar angle resulted in more accurate BOS determination. Unrealistically large changes in joint angles between frames could be reduced by including clavicle, sternum, and medial elbow markers during IK. In cases with large arm ranges of motion, results could be further improved by running IK using medial elbow and virtual shoulder joint center markers. Model adjustments significantly improved the IK results affecting COP calculation and increased the accuracy of BOS estimation.

C A Bell↗
NASA NTRS2018

Dynamics and Control of a Tethered Enhanced Gravity Tractor Performing Asteroid Deflection

The dynamics and control of an Enhanced Gravity Tractor (EGT) augmented with a tether for deflecting an asteroid are studied. A conventional EGT consists of collected asteroidal mass collocated with the spacecraft. Because of the presence of a tether, the collected mass is placed where the EGT would have been without a tether, and the spacecraft is placed farther away from the asteroid. Doing so improves the fuel efficiency and safety margin of the EGT operation without significantly sacrificing the gravitational attraction between the asteroid and the EGT. The tether is modeled as a series of particles connected by spring-dashpot systems. Physical properties of the tether are selected to be similar to those of the SPECTRA-1000, Kevlar-29, and Kevlar-49 fibers. It is assumed that control is applied only to the spacecraft, and there is no active control associated with the collected mass. A Proportional-Derivative (PD) controller is employed to maintain the spacecraft and the collected mass at desired positions relative to the asteroid. Numerical simulations of tethered EGT operations at 2008 EV5, Itokawa, Apophis, and a fictitious ellipsoidal asteroid are performed. It is demonstrated that a PD controller is capable of accomplishing the control objectives. The gravity gradient and the control force keep the tether stretched throughout a normal tethered EGT operation, and the load on the tether is well within the design limit of the tether material. While including multiple particles in the tether model is essential in capturing details of tether vibration, the number of particles does not significantly affect the motions of the collected mass and the spacecraft. In addition, the distance from the asteroid mass center to the collected mass should be chosen judiciously in the case of a rotating slender asteroid; some distance ranges should be avoided as excessive lateral oscillations can be excited by resonance between the asteroid rotation and tether pendular motion.

Shen, Haijun↗
NASA NTRS2016

Biomechanical Modeling of Split-leg Squat and Heel Raise on the Hybrid Ultimate Lifting Kit (HULK)

Long duration space travel will expose astronauts to extended periods of reduced gravity. Since gravity is not present to aid loading, astronauts will use resistive and aerobic exercise regimes for the duration of the space flight to minimize the loss of bone density, muscle mass and aerobic capacity that occurs during exposure to a reduced gravity environment. Unlike the International Space Station (ISS), the area available for an exercise device in the next generation of spacecraft is limited and therefore compact resistance exercise device prototypes are being developed. The Advanced Resistive Exercise Device (ARED) currently on the ISS is being used as a benchmark for the functional performance of these new devices. Biomechanical data collection and computational modeling aid the device design process by quantifying the joint torques and musculoskeletal forces that occur during exercises performed on the prototype devices. Computational models currently use OpenSim software, an open source code for musculoskeletal modeling, with biomechanical input data from subjects for estimation of muscle and joint loads. Subjects are instrumented with reflective markers for motion capture data collection while exercising on the Hybrid Ultimate Lifting Kit (HULK) prototype device. Ground reaction force data is collected with force plates under the feet and device loading is recorded through load cells internal to the HULK. This data is input into the OpenSim biomechanical model, which has been scaled to match the anthropometrics of the test subject, to calculate the loads on the body. Multiple exercises are performed and evaluated during a test session such as a full squat, single leg squat, heel raise and dead lift. Variables for these exercises include applied device load, narrow or wide foot stance, slow or fast cadence and the harness or long bar interface between the test subject and the device. Data from free weights are compared to the resistively loaded exercise device. The focus of this presentation is to summarize the results from the single-leg squat and heel raise exercises performed during three sessions occurring in 2015. Differences in loading configuration, cadence and stance produce differences in kinematics, joint toques and force and muscle forces.

computational modeling↗
NASA NTRS2016

Squat Biomechanical Modeling Results from Exercising on the Hybrid Ultimate Lifting Kit

Long duration space travel will expose astronauts to extended periods of reduced gravity. Since gravity is not present to aid loading, astronauts will use resistive and aerobic exercise regimes for the duration of the space flight to minimize loss of bone density, muscle mass and aerobic capacity that occurs during exposure to a reduced gravity environment. Unlike the International Space Station (ISS), the area available for an exercise device in the next generation of spacecraft is limited and therefore compact resistance exercise device prototypes are being developed. The Advanced Resistive Exercise Device (ARED) currently on the ISS is being used as a benchmark for the functional performance of these new devices. Biomechanical data collection and computational modeling aid the device design process by quantifying the joint torques and the musculoskeletal forces that occur during exercises performed on the prototype devices. The computational models currently under development utilize the OpenSim software, an open source code for musculoskeletal modeling, with biomechanical input data from test subjects for estimation of muscle and joint loads. The subjects are instrumented with reflective markers for motion capture data collection while exercising on the Hybrid Ultimate Lifting Kit (HULK) prototype device. Ground reaction force data is collected with force plates under the feet and device loading is recorded through load cells internal to the HULK. Test variables include applied device load, narrow or wide foot stance, slow or fast cadence and the harness or long bar interface between the test subject and the device. Data is also obtained using free weights for a comparison to the resistively loaded exercise device. This data is input into the OpenSim biomechanical model, which has been scaled to match the anthropometrics of the test subject, to calculate the body loads. The focus of this presentation is to summarize the results from the full squat exercises across the different test variables.

Bioengineering↗
NASA NTRS2014

Preliminary Sensorimotor and Cardiovascular Results from the Joint Russian/U.S. Pilot Field Test in Preparation for the Full Field Test

Ongoing collaborative research efforts between NASA's Neuroscience and Cardiovascular Laboratories, and the Institute of Biomedical Problems' (IBMP) Sensory-Motor and Countermeasures Laboratories have been measuring functional sensorimotor, cardiovascular and strength responses following bed rest, dry immersion, short-duration (Space Shuttle) and long-duration (Mir and International Space Station [ISS]) space flights. While the unloading paradigms associated with dry immersion and bed rest does serve as acceptable flight analogs, testing of crew responses following the long-duration flights previously has not been possible until a minimum of 24 hours after landing. As a result, it is not possible to estimate the nonlinear trend of the early (<24 hours) recovery process nor is it possible to accurately assess the full impact of the decrements associated with long-duration flight. To overcome these limitations, both the Russian and U.S. programs have implemented testing at the landing site. By joint agreement, this research effort has been identified as the functional Field Test (FT). For practical reasons the FT has been divided into two phases: the full FT and a preliminary pilot version (PFT) of the FT that is reduced in both length and scope. The primary goal of this research is to determine functional abilities in long-duration space-flight crews beginning as soon after landing as possible (< 2 hours) with one to three immediate follow-up measurements on the day of landing. This goal has both sensorimotor and cardiovascular elements, including evaluations of NASA's new anti-orthostatic compression garment and the Russian Kentavr garment. Functional sensorimotor measurements will include, but are not limited to, assessing hand/eye coordination, egressing from a seated position, walking normally without falling, measuring of dynamic visual acuity, discriminating different forces generated with both the hands and legs, recovering from a fall, coordinated walking involving tandem heel-to-toe placement, and determining postural ataxia while standing. The cardiovascular portion of the investigation includes measuring blood pressure and heart rate during a timed stand test in conjunction with postural ataxia testing (quiet stance sway) as well as cardiovascular responses during the other functional tasks. In addition to the immediate post-landing collection of data for the full FT, postflight data will be acquired between one and three more other times within the 24 hours after landing and will continue over the subsequent weeks until functional sensorimotor and cardiovascular responses have returned to preflight normative values. The PFT represents a single trial run comprised of a jointly agreed upon subset of tests from the full FT and relies heavily on IBMP's Sensory-Motor and Countermeasures Laboratories for content and implementation. The PFT has been collected on several ISS missions. Testing included: (1) a sit-to-stand test, (2) recovery from a fall where the crewmember began in the prone position on the ground and then stood for 3 minutes while cardiovascular stability was determined and postural ataxia data were acquired, and (3) a tandem heel-totoe walk test to determine changes in the central locomotor program. Video, cardiovascular parameters (heart rate and blood pressure), data from body-worn inertial sensors, and severity of postflight motion sickness were collected for each test session. In summary, the level of functional deficit is expected to be most profound during the acquisition of gravity loads immediately after landing when the demands for crew intervention in response to emergency operations will be greatest. Clearly measureable performance parameters such as ability to perform a seat egress, recover from a fall or the ability to see clearly when walking, and related physiologic data (orthostatic responses) are required to provide an evidence base for characterizing programmatic risks and the degree of variability among crewmembers for exploration missions where the crew will be unassisted after landing. Overall, these early functional and related physiologic measurements will allow estimation of nonlinear sensorimotor and cardiovascular recovery trends that has not been previously captured in over 50 years of space flight.

Reschke, M. F.↗
NASA NTRS2014

Pilot Sensorimotor and Cardiovascular Results from the Joint Russian/U.S. Field Test

The primary goal of this research is to determine functional abilities associated with long-duration space flight crews beginning as soon after landing as possible (< 2 hours) with an additional two follow-up measurements sessions on the day of landing. This goal has both sensorimotor and cardiovascular elements, including evaluations of NASA's new anti-orthostatic compression garment and the Russian Kentavr garment. Functional sensorimotor measurements will include, but are not limited to, assessing hand/eye coordination, standing from a seated position (sit-to-stand), walking normally without falling, measurement of dynamic visual acuity, discriminating different forces generated with both the hands and legs, recovering from a fall (standing from a prone position), coordinated walking involving tandem heel-to-toe placement, and determining postural ataxia while standing. The cardiovascular portion of the investigation includes measuring blood pressure and heart rate during a timed stand test in conjunction with postural ataxia testing (quiet stance sway) as well as cardiovascular responses during the other functional tasks. In addition to the immediate post-landing collection of data for the full FT, postflight data is being acquired twice more within the 24 hours after landing and will continue over the subsequent weeks until functional sensorimotor and cardiovascular responses have returned to preflight normative values. The PFT represents a initial evaluation of the feasibility of testing in the field, and is comprised of a jointly agreed upon subset of tests from the full FT and relies heavily on Russia's Institute of Biomedical Problems Sensory-Motor and Countermeasures Laboratories for content and implementation. The PFT has been collected on several ISS missions. Testing on the U.S. side has included: (1) a sit-to-stand test, (2) recovery from a fall where the crewmember began in the prone position on the ground and then stood for 3 minutes while cardiovascular stability was determined and postural ataxia data were acquired, and (3) a tandem heel-to-toe walk test to determine changes in the central locomotor program. Video, cardiovascular parameters (heart rate and blood pressure), data from bodyworn inertial sensors, and severity of postflight motion sickness were collected during each test session. Our Russian investigators have added measurements associated with: (a) obstacle avoidance, (b) muscle compliance and (c) postural adjustments to perturbations (push) applied to the subject's chest area. The level of functional deficit observed in the crew tested to date is typically beyond what was expected and is clearly triggered by the acquisition of gravity loads immediately after landing when the demands for crew intervention in response to emergency operations will be greatest. Clearly measureable performance parameters such as ability to perform a seat egress, recover from a fall or the ability to see clearly when walking, and related physiologic data (orthostatic responses) are required to provide an evidence base for characterizing programmatic risks and the degree of variability among crewmembers for exploration missions where the crew will be unassisted after landing. Overall, these early functional and related physiologic measurements will allow the estimation of nonlinear sensorimotor and cardiovascular recovery trends that have not been previously captured

Reschke, M. F.↗
NASA NTRS2016

Sensorimotor Results from the Joint NASA and Russian Pilot Field Test

Testing of crew responses following long-duration flights has not previously been possible until a minimum of 24 hours after landing. As a result, it has not been possible to estimate the nonlinear trend of the early (<24 hours) recovery process, nor has it been possible to accurately assess the full impact of the decrements associated with long-duration flight. To overcome these limitations, both the Russian and U.S. programs have implemented testing at the Soyuz landing site. This research effort has been identified as the Field Test (FT). For operational reasons the FT has been divided into two phases: the full FT and a preliminary pilot version (PFT) of the FT that is reduced in both length and scope. The PFT has now been completed with the landing of the crew of International Space Station Increment 42/43 (Soyuz expedition 41S). RESEARCH: The primary goal of this research was to determine functional abilities associated with long-duration space flight crews beginning as soon after landing as possible (< 2 hours) with an additional two follow-up measurement sessions within 24 hours after landing. This study goal has both sensorimotor and cardiovascular elements. The PFT represented a initial evaluation of the feasibility of testing in the field and was comprised of a jointly agreed upon subset of tests drawn from the full FT and relied heavily on Russia's Institute of Biomedical Problems Sensory-Motor and Countermeasures Department for content and implementation. Data from the PFT was collected following several ISS missions. Testing on the U.S. side has included: (1) a sit-to-stand test, (2) recovery from a fall stand test where the crewmember begins in the prone position on the ground and then stands for 3.5 minutes while cardiovascular performance and postural ataxia data are acquired, and (3) a tandem heel-to-toe walk test to determine changes in the central locomotor program. Video, cardiovascular parameters (heart rate and blood pressure), data from body-worn inertial sensors, and severity of postflight motion sickness were collected during each test session. In addition our Russian investigators have made measurements associated with: (a) obstacle avoidance, (b) muscle compliance, (c) postural adjustments to perturbations (pushes) applied to the subject's chest area and (d) center of mass measurements made across most test objectives with insoles inserted into the subjects' shoes. Data from 18 subjects have been obtained for a majority of the PFT objectives. SUMMARY: The increased level of functional deficit observed in the crewmembers tested with the PFT objectives has been typically greater than previously observed when measurements were collected after the 2 hr window. Significant improvement in crew performance was observed within 24 hours, but full recovery appears to require 6 to 16 days. Clearly measureable performance parameters such as ability to perform a seat egress, recovery from a fall or the ability to see clearly when walking, and related physiologic data (orthostatic responses) are required to provide an evidence base for characterizing programmatic risks and the variability among crewmembers for exploration missions where the crew will be unassisted after landing. Overall, these early functional and related physiologic measurements will allow the estimation of nonlinear sensorimotor and cardiovascular recovery trends that have not been previously captured.

Reschke, Millard↗
NASA NTRS2021

Analysis of Exercise Loads to Inform Vibration Isolation System Design

BACKGROUND: This study was conducted with the primary interest of providing data that would inform Vibration Isolation and Stabilization (VIS) system design and performance for the European Enhanced Exploration Exercise Device (E4D). In preparation for the International Space Station (ISS) in-flight demonstration, a list of critical Human Health Countermeasures (HHC) exercises was compiled [1]. The goal of this study was to assess the ground reaction forces and moments imposed by an exercising subject in each of the six VIS Degrees of Freedom (DOFs) during a comprehensive set of these critical exercises performed on the E4D. METHODS AND RESULTS: The ISS in-flight demonstration list of critical exercises included seated aerobic rowing, bent-over rowing, cycling, front squats, back squats, conventional deadlifts, Romanian deadlifts, heel raises, overhead presses, reverse chops, and power clean presses. At the NASA Johnson Space Center (JSC) Prototype Immersive Technology (PIT) laboratory, motion capture data were collected on critical E4D exercises for six subjects. At the NASA JSC Active Response Gravity Offload System (ARGOS) facility, additional motion capture and load cell data were collected on offloaded trials for four subjects. Select data were extrapolated to represent a 5th percentile female subject and a 95th percentile male subject. A previous investigation comparing the forces obtained from the load cell and from motion capture based data found a satisfactory level of agreement between the two measurements [2]. The motion capture based data were analyzed for this study since it is driven by the subject’s trajectory alone, automatically excluding any forces exerted on the subject by the ARGOS offloading harness. The OpenSim [3, 4] biomechanical simulation inverse kinematics tool was used to calculate the joint angles based on the locations of motion capture markers placed at key positions on the subject’s body. An OpenSim plugin was then used to obtain the forces and moments generated by the subject during each trial, with the moments computed relative to the equilibrium location of the subject’s feet [5]. The force of gravity was also removed to simulate the loads generated by the exercise when performed in microgravity. The load plots for each trial were generated and visually analyzed to obtain the magnitudes of the peak loads for each exercise in each DOF. The typical period of exercise for each trial was also estimated and used to calculate the frequency for each trial. The exercise loads data was then organized in multiple ways to capture different aspects of the data. As a result of this study, we present a summary of the load magnitudes observed during these critical exercises utilizing the E4D.

C A Bell↗