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NASA NTRS2007

Medical Monitoring during Short Radius Centrifugation in Bed-rested Subjects

The artificial gravity pilot project was designed to investigate the efficacy of daily exposure to a Gz acceleration gradient for counteracting the physiologic decrements induced by prolonged bed rest. A short radius centrifuge was used to produce a Gz gradient such that 1 g was applied at the level of the subject s heart and 2.5 g at the feet. For inclusion in the study, subjects were required to complete a 75-minute screening spin on the centrifuge. During the study, each active treatment subject was scheduled for a 60-minute spin each day for 20 consecutive days. During centrifugation, subjects were continuously monitored by a physician for signs and symptoms of pre-syncope, motion sickness, arrhythmias, joint/muscle pain and any other unanticipated problems. The physician was also present to provide emergency care in the case of a medical emergency. Cameras mounted on the centrifuge were used to provide a means of observing the subject s face and torso. Audio communication was continuously maintained. Other monitoring tools included two-lead EKG tracings, pulse oximetry, intermittent sphygmomanometer readings, lights in the peripheral visual field, and continuous blood pressure readout from a tonometry device. Thirty screening runs were attempted using twenty-seven subjects. Seven of these runs were terminated early for symptoms of pre-syncope, motion sickness, or GI distress. A total of eight subjects completed the active treatment arm of the study. Of the 160 centrifuge runs that were scheduled for these eight treatment subjects, 152 were completed, seven were terminated early, and one was not attempted. Of the seven early terminations, four were related to symptoms of pre-syncope, one to leg pain, one to GI discomfort, and one to equipment failure. Three terminations for adverse symptoms occurred on the first treatment day. Three terminations occurred on day nineteen of treatment and within 24 hours after scheduled soleus and quadriceps muscle biopsies. We have summarized the relative usefulness of the information obtained by the various monitoring modalities in making a decision to terminate a centrifuge run. The video and audio communication information was essential to the decision-making process. Heart rate and EKG tracings are considered valuable, even though no spins were terminated due to significant arrhythmias. The tonometer device was generally not reliable in this application. Our observations suggest that subjects may be less tolerant of centrifugation just after starting bed rest and after invasive procedures.

Reinertson, Randal↗

NASA NTRS2006

Vivid Motor Imagery as an Adaptation Method for Head Turns on a Short-Arm Centrifuge

Artificial gravity (AG) has been proposed as a potential countermeasure to the debilitating physiological effects of long duration space flight. The most economical means of implementing AG may be through the use of a short-radius (2m or less) centrifuge. For such a device to produce gravitational forces comparable to those on earth requires rotation rates in excess of 20 revolutions per minute (rpm). Head turns made out of the plane of rotation at these rates, as may be necessary if exercise is combined with AG, result in cross-coupled stimuli (CCS) that cause adverse side effects including motion sickness, illusory sensations of motion, and inappropriate eye movements. Recent studies indicate that people can adapt to CCS and reduce these side effects by making multiple head turns during centrifuge sessions conducted over consecutive days. However, about 25% of the volunteers for these studies have difficulty tolerating the CCS adaptation paradigm and often drop out due to motion sickness symptoms. The goal of this investigation was to determine whether vivid motor imagery could be used as a pseudostimulus for adapting subjects to this unique environment. Twenty four healthy human subjects (14 males, 10 females), ranging in age from 21 to 48 years (mean 33, sd 7 years) took part in this study. The experimental stimuli were produced using the NASA JSC short-arm centrifuge (SAC). Subjects were oriented supinely on this device with the nose pointed toward the ceiling and head centered on the axis of rotation. Thus, centrifuge rotation was in the body roll plane. After ramp-up the SAC rotated clockwise at a constant rate of 23 rpm, producing a centrifugal force of approximately 1 g at the feet. Semicircular canal CCS were produced by having subjects make yaw head turns from the nose up (NU) position to the right ear down (RED) position and from RED to NU. Each head turn was completed in about one second, and a 30 second recovery period separated consecutive head movements. Participants were randomly assigned to one of three groups (n=8 per group): physical adapters (PA), mental adapters (MA), or a control group (CG). Each subject participated in a one hour test session on each of three consecutive days. Each test session consisted of an initial (preadaptation) period during which the subject performed six CCS maneuvers in the dark, followed by an adaptation period with internal lighting on the centrifuge, and a final (postadaptation) period during which six more CCS maneuvers were performed in the dark. For the PA group, the adaptation period consisted of performing 30 additional CCS maneuvers in the light. For the MA and CG group the centrifuge was ramped down to 0 rpm after the pre-adaptation period and ramped back up to 23 rpm before the post-adaptation period. For the both of these groups, the adaptation period consisted of making 30 CCS maneuvers in the light with the centrifuge stationary (so no cross-coupling occurred). MA group subjects were instructed to vividly imagine the provocative sensations produced by the preadaptation CCS maneuvers in terms of magnitude, duration, and direction of illusory body tilt, as well as any accompanying levels of motion sickness. CG group subjects were asked to answer low imagery content questions (trivial pursuit) during each adaptation period head turn. During the 30 second recovery following each head turn, psychophysical data were collected including self reports of motion sickness, magnitude and direction estimates of illusory body tilt, and the overall duration of these sensations. A multilevel mixed effects linear regression analysis performed on all response variables indicated that all three groups experienced some psychophysical adaptation across the three test sessions. For illusory tilt magnitude, the PA group exhibited the most overall adaptation, followed by the MA group, and the CG group. The slopes of these adaptation trajectories by group over day were significantly diffent from one another. For the perceived duration of sensations, the CG group again exhibited the least amount of adaptation. However, the rates of adaptation of the PA and the MA groups were indistinguishable, suggesting that the imagined pseudostimulus appeared to be just as effective a means of adaptation as the actual stimulus. The MA group's rate of adaptation to motion sickness symptoms was also comparable to the PA group. The use of vivid motor imagery may be an effective method for adapting to the illusory sensations and motion sickness symptoms produced by cross-coupled stimuli. For space-based AG applications, this technique may prove quite useful in retaining astronauts considered highly susceptible to motion sickness as it reduces the number of actual CCS required to attain adaptation.

Newby, N. J.↗

NASA NTRS2011

Technology Applications that Support Space Exploration

Several enabling technologies have been identified that would provide significant benefits for future space exploration. In-Space demonstrations should be chosen so that these technologies will have a timely opportunity to improve efficiencies and reduce risks for future spaceflight. An early window exists to conduct ground and flight demonstrations that make use of existing assets that were developed for the Space Shuttle and the Constellation programs. The work could be mostly performed using residual program civil servants, existing facilities and current commercial launch capabilities. Partnering these abilities with the emerging commercial sector, along with other government agencies, academia and with international partners would provide an affordable and timely approach to get the launch costs down for these payloads, while increasing the derived benefits to a larger community. There is a wide scope of varied technologies that are being considered to help future space exploration. However, the cost and schedule would be prohibitive to demonstrate all these in the near term. Determining which technologies would yield the best return in meeting our future space needs is critical to building an achievable Space Architecture that allows exploration beyond Low Earth Orbit. The best mix of technologies is clearly to be based on our future needs, but also must take into account the availability of existing assets and supporting partners. Selecting those technologies that have complimentary applications will provide the most knowledge, with reasonable cost, for future use The plan is to develop those applications that not only mature the technology but actually perform a useful task or mission. These might include such functions as satellite servicing, a propulsion stage, processing lunar regolith, generating and transmitting solar power, cryogenic fluid transfer and storage and artificial gravity. Applications have been selected for assessment for future consideration and are addressed in this paper. These applications have been made available to the various NASA study groups that are determining the next steps the Agency must take to secure a sound foundation for future space exploration The paper also addresses how follow-on demonstrations, as launch performance grows, can build on the earlier applications to provide increased benefits for both the commercial and scientific communities. The architecture of incrementally building upon previous successes and insights dramatically lowers the overall associated risk for developing and maturing the key enabling technologies. The goal is to establish a potential business case that encourages commercial activity, thereby reducing the cost for the demonstration while using the technology maturation in developing readiness for future space exploration with overall less risk.

Henderson, Edward M.↗

NASA NTRS2005

NASA Tech Briefs, December 2005

Topics covered include: Video Mosaicking for Inspection of Gas Pipelines; Shuttle-Data-Tape XML Translator; Highly Reliable, High-Speed, Unidirectional Serial Data Links; Data-Analysis System for Entry, Descent, and Landing; Hybrid UV Imager Containing Face-Up AlGaN/GaN Photodiodes; Multiple Embedded Processors for Fault-Tolerant Computing; Hybrid Power Management; Magnetometer Based on Optoelectronic Microwave Oscillator; Program Predicts Time Courses of Human/ Computer Interactions; Chimera Grid Tools; Astronomer's Proposal Tool; Conservative Patch Algorithm and Mesh Sequencing for PAB3D; Fitting Nonlinear Curves by Use of Optimization Techniques; Tool for Viewing Faults Under Terrain; Automated Synthesis of Long Communication Delays for Testing; Solving Nonlinear Euler Equations With Arbitrary Accuracy; Self-Organizing-Map Program for Analyzing Multivariate Data; Tool for Sizing Analysis of the Advanced Life Support System; Control Software for a High-Performance Telerobot; Java Radar Analysis Tool; Architecture for Verifiable Software; Tool for Ranking Research Options; Enhanced, Partially Redundant Emergency Notification System; Close-Call Action Log Form; Task Description Language; Improved Small-Particle Powders for Plasma Spraying; Bonding-Compatible Corrosion Inhibitor for Rinsing Metals; Wipes, Coatings, and Patches for Detecting Hydrazines; Rotating Vessels for Growing Protein Crystals; Oscillating-Linear-Drive Vacuum Compressor for CO2; Mechanically Biased, Hinged Pairs of Piezoelectric Benders; Apparatus for Precise Indium-Bump Bonding of Microchips; Radiation Dosimetry via Automated Fluorescence Microscopy; Multistage Magnetic Separator of Cells and Proteins; Elastic-Tether Suits for Artificial Gravity and Exercise; Multichannel Brain-Signal-Amplifying and Digitizing System; Ester-Based Electrolytes for Low-Temperature Li-Ion Cells; Hygrometer for Detecting Water in Partially Enclosed Volumes; Radio-Frequency Plasma Cleaning of a Penning Malmberg Trap; Reduction of Flap Side Edge Noise - the Blowing Flap; and Preventing Accidental Ignition of Upper-Stage Rocket Motors.

Source record↗

NASA NTRS2011

Technology Development to Support Human Health and Performance in Exploration Beyond Low Earth Orbit

In the course of defining the level of risks and mitigating the risks for exploration missions beyond low Earth orbit, NASA s Human Research Program (HRP) has identified the need for technology development in several areas. Long duration missions increase the risk of serious medical conditions due to limited options for return to Earth; no resupply; highly limited mass, power, volume; and communication delays. New space flight compatible medical capabilities required include: diagnostic imaging, oxygen concentrator, ventilator, laboratory analysis (saliva, blood, urine), kidney stone diagnosis & treatment, IV solution preparation and delivery. Maintenance of behavioral health in such an isolated, confined and extreme environment requires new sensory stimulation (e.g., virtual reality) technology. Unobtrusive monitoring of behavioral health and treatment methods are also required. Prolonged exposure to weightlessness deconditions bone, muscle, and the cardiovascular system. Novel exercise equipment or artificial gravity are necessary to prevent deconditioning. Monitoring of the degree of deconditioning is required to ensure that countermeasures are effective. New technologies are required in all the habitable volumes (e.g., suit, capsule, habitat, exploration vehicle, lander) to provide an adequate food system, and to meet human environmental standards for air, water, and surface contamination. Communication delays require the crew to be more autonomous. Onboard decision support tools that assist crew with real-time detection and diagnosis of vehicle and habitat operational anomalies will enable greater autonomy. Multi-use shield systems are required to provide shielding from solar particle events. The HRP is pursuing the development of these technologies in laboratories, flight analog environments and the ISS so that the human health and performance risks will be acceptable with the available resources.

Kundrot, C.E.↗

NASA NTRS2012

Computational Fluid Dynamics Ventilation Study for the Human Powered Centrifuge at the International Space Station

The Human Powered Centrifuge (HPC) is a facility that is planned to be installed on board the International Space Station (ISS) to enable crew exercises under the artificial gravity conditions. The HPC equipment includes a "bicycle" for long-term exercises of a crewmember that provides power for rotation of HPC at a speed of 30 rpm. The crewmember exercising vigorously on the centrifuge generates the amount of carbon dioxide of about two times higher than a crewmember in ordinary conditions. The goal of the study is to analyze the airflow and carbon dioxide distribution within Pressurized Multipurpose Module (PMM) cabin when HPC is operating. A full unsteady formulation is used for airflow and CO2 transport CFD-based modeling with the so-called sliding mesh concept when the HPC equipment with the adjacent Bay 4 cabin volume is considered in the rotating reference frame while the rest of the cabin volume is considered in the stationary reference frame. The rotating part of the computational domain includes also a human body model. Localized effects of carbon dioxide dispersion are examined. Strong influence of the rotating HPC equipment on the CO2 distribution detected is discussed.

Son, Chang H.↗

NASA NTRS2013

Benefits, Consequences, and Uncertainties of Conventional (Exercise) Countermeasure Approaches

This presentation will review the pros, cons, and uncertainties of using exercise countermeasures in hypothetical long duration exploration missions. The use of artificial gravity and exercise will be briefly discussed. One benefit to continued use of exercise is related to our extensive experience with spaceflight exercise hardware and programming. Exercise has been a part of each space mission dating back to the 1960's when simple isometric and bungee exercises were performed in the Gemini capsule. Over the next 50 years, exercise hardware improved cumulating in today's ISS suite of exercise equipment: Cycle Ergometer with Vibration Isolation and Stabilization System (CEVIS), Treadmill (T2) and Advanced Resistive Exercise Device (ARED). Today's exercise equipment is the most robust ever to be flown in space and allows the variety and intensity of exercise that might reasonably be expected to maintain muscle mass and function, bone density and cardiovascular fitness. A second benefit is related to the large body of research literature on exercise training. There is a considerable body of supporting research literature including >40,000 peer reviewed research articles on exercise training in humans. A third benefit of exercise is its effectiveness. With the addition of T2 and ARED to our ISS exercise suite, crew member outcomes on standard medical tests have improved. Additionally exercise has other positive side effects such as stress relief, possible improvement of immune function, improved sleep, etc. Exercise is not without its consequences. The major cons to performance of in‐flight exercise are the time and equipment required. Currently crew are scheduled 2.5 hrs/day for exercise and there is considerable cost to develop, fly and maintain exercise hardware. While no major injuries have been reported on ISS, there is always some risk of injury with any form of exercise There are several uncertainties going forward; these relate mostly to the development of small compact robust effective exercise devices for the next generation of space vehicles. It is becoming increasingly apparent that high intensity exercise is required for maintenance of fitness and functional capability and so future hardware will need to be developed, tested and implemented that allow for a wide variety of exercise, at high intensity while likely involving low mass, volume and power. There are many unanswered issues related to the minimum number and type of exercise devices required for exploration, optimizing exercise prescriptions for these devices, whether a treadmill is absolutely required, and even whether any single countermeasure can adequately protect muscle, bone, cardiovascular and sensorimotor function.

Ploutz-Snyder, Lori↗

NASA NTRS2015

Physiological Health Challenges for Human Missions to Mars

During the next decades, manned space missions are expected to be aiming at the Lagrange points, near Earth asteroids, and Mars flyby and/or landing. The question is therefore: Are we ready to go? To answer this with a yes, we are currently using the International Space Station to develop an integrated human physiological countermeasure suite. The integrated countermeasure suite will most likely encounter: 1) Exercise devices for aerobic, dynamic and resistive exercise training; 2) sensory‐motor computer training programs and anti‐motion sickness medication for preparing EVAs and G‐transitions; 3) lower limb bracelets for preventing and/or treating the VIIP (vision impairment and intracranial pressure) syndrome; 4) nutritional components for maintenance of bone, muscle, the cardiovascular system and preventing oxidative stress and damage and immune deficiencies (e. g. omega‐3 fatty acids, PRO/K, anti‐oxidants and less salt and iron); 5) bisphosphonates for preventing bone degradation.; 6) lower body compression garment and oral salt and fluid loading for landing on a planetary surface to combat orthostatic intolerance; 7) laboratory analysis equipment for individualized monitoring of biomarkers in blood, urine and saliva for estimation of health status in; 8) advanced ultrasound techniques for monitoring bone and cardiovascular health; and 9) computer modeling programs for individual health status assessments of efficiency and subsequent adjustments of countermeasures. In particular for future missions into deep space, we are concerned with the synergistic effects of weightlessness, radiation, operational constraints and other spaceflight environmental factors. Therefore, increased collaboration between physiological, behavioral, radiation and space vehicle design disciplines are strongly warranted. Another venue we are exploring in NASA's Human Research Program is the usefulness of artificial gravity for mitigating the health risks of long duration weightlessness.

Norsk, Peter↗

NASA NTRS2016

Tethered Space Satellite-1 (TSS-1): Wound About a Bolt

In the early 1990's US and Italian scientists collaborated to study the electrodynamics on a long tether between two satellites as it moved through the electrically charged portion of Earth's atmosphere called the ionosphere. Potential uses for the electrical current induced in the long wire include power and thrust generation for a satellite, momentum exchange, artificial gravity, deployment of sensors or antennas, and gravity-gradient stabilization. The Tethered Space Satellite (TSS) was a first-of-its-kind experiment with long tethers in space. It consisted of a satellite with science experiments attached to a 12.5 mile long, very thin (0.10 inch diameter) copper wire assembly wound around a spool in the deployer reel mechanism. The whole mechanism sits on a pallet that is installed into the Shuttle bay. At an altitude of 160 nautical miles above earth, the satellite would be deplodeployed from the Shuttle bay by raising it on a boom facing away from Earth. Once cleared of the bay, the deployer mechanism would slowly feed out the 12-plus miles of tether. Scientific data would be collected throughout the operation, after which the satellite would be reeled back in. A receiver spool to catch the 12.5 mile tether as it was being unwound by the deployer reel mechanism was set up to do the system-level test of deployer real mechanism prior to installing the loaded pallet into the Shuttle bay. The system level tests were required before the pallet could be installed into the Space Shuttle cargo bay. A few months before flight, the system level tests, including unreeling and reeling the tether, were completed at Kennedy Space Center (KSC) and the TSS payload was installed onto the Spacelab pallet. Some of this testing equipment was then shipped back to the contractor, Martin Marietta. Integration with the Shuttle began. Systems-level load analyses, which cannot be run until all information about each payload is finalized, was run in parallel with the physical integration of the hardware into the Shuttle payload bay. An analysis, called Coupled loads analysis, incorporates any updates to the model due to system level tests of all the different payloads, and any changes that were found during integration. Engineering analysis examines the worst case scenarios for the loads the hardware will see. The two times during the mission where the dynamic loads are the worst were 1) the first 10-second portion of Shuttle lift off, and 2) a 2-second time during landing when the landing gears hit the ground. The coupled loads analysis using the final verification loads showed that a single bolt attaching the deployer reel mechanism to the support structure had a "negative margin" - which is an indication that it might fail - during touch down. Hardware certification rules do not allow for hardware to fly with negative margins. A structural failure of one payload could have serious or catastrophic consequences to other payloads, or may significantly damage the Orbiter. The issue had to be resolved before the flight.

O'Connor, Brian↗

NASA NTRS2016

Tethered Space Satellite-1 (TSS-1): Technical Roundabouts

In the early 1990's US and Italian scientists collaborated to study the electrodynamics of dragging a satellite on a tether through the electrically charged portion of Earth's atmosphere called the ionosphere. An electrical current induced in the long wire could be used for power and thrust generation for a satellite. Other tether uses include momentum exchange, artificial gravity, deployment of sensors or antennas, and gravity-gradient stabilization for satellites. Before the Tethered Space Satellite (TSS-1), no long tether had ever been flown, so many questions existed on how it would actually behave. The TSS consisted of a satellite with science experiments attached to a 12.5 mile long, very thin (0.10 inch diameter) copper wire assembly wound around a spool in the deployer reel mechanism. With the Space Shuttle at an altitude of 160 nautical miles above earth, the satellite was to be deployed by raising it from the Shuttle bay on a boom facing away from Earth. Once cleared of the bay, the deployer mechanism was to slowly feed out the 12-plus miles of tether. Scientific data would be collected throughout the operation, after which the satellite would be reeled back in. Pre-flight testing system level tests involved setting up a tether receiver to catch the 12.5 mile tether onto another reel as it was being unwound by the deployer reel mechanism. Testing only the reel mechanism is straightforward. This test becomes more complicated when the TSS is mounted on the flight pallet at Kennedy Space Center (KSC). The system level tests must be passed before the pallet can be installed into the Space Shuttle cargo bay. A few months before flight, the TSS payload had been integrated onto the Spacelab pallet and system level tests, including unreeling and reeling the tether, had been successfully completed. Some of this testing equipment was then shipped back to the contractor Martin Marietta. Systems-level load analyses, which cannot be run until all information about each payload is finalized, was run in parallel with the physical integration of the hardware into the Shuttle payload bay. The coupled loads analysis, as it is called, incorporates any updates to the model due to system level tests, and any changes that were found during integration. The coupled loads analysis revealed that a single bolt attaching the deployer reel mechanism to the support structure had a "negative margin" - which is an indication that it might fail during operation. Hardware certification rules do not allow for hardware to fly with negative margins, so this issue had to be resolved before the flight. Since there is conservatism in engineering analysis, there is an option to "waive" the margin requirement, and fly the experiment as is. On the other hand, a structural failure of one payload could have serious or catastrophic consequences to other payloads and possibly the mission. Minor design changes or fixes might be feasible within the payload bay prior to launch. Any major design changes that required the spooling test to validate the hardware, or for the pallet to be removed, would cause TSS not to be ready for the Shuttle launch.

O'Connor, Brian↗

NASA NTRS2016

Advancing Translational Space Research Through Biospecimen Sharing: Amplified Impact of Studies Utilizing Analogue Space Platforms

Biospecimen Sharing↗

NASA NTRS2017

Advancing Translational Space Research Through Biospecimen Sharing: Amplifying the Impact of Ground-Based Studies

Biospecimen Sharing Programs (BSPs) have been organized by NASA Ames Research Center since the 1960s with the goal of maximizing utilization and scientific return from rare, complex and costly spaceflight experiments. BSPs involve acquiring otherwise unused biological specimens from primary space research experiments for distribution to secondary experiments. Here we describe a collaboration leveraging Ames expertise in biospecimen sharing to magnify the scientific impact of research informing astronaut health funded by the NASA Human Research Program (HRP) Human Health Countermeasures (HHC) Element. The concept expands biospecimen sharing to one-off ground-based studies utilizing analogue space platforms (e.g., Hind limb Unloading (HLU), Artificial Gravity) for rodent experiments, thereby significantly broadening the range of research opportunities with translational relevance for protecting human health in space and on Earth. In this presentation, we will report on biospecimens currently being acquired from HHC Award Head-Down Tilt as a Model for Intracranial and Intraocular Pressures, and Retinal Changes during Spaceflight, and their availability. The BSP add-on to the project described herein has already yielded for HHC-funded investigators more than 4,700 additional tissues that would otherwise have been discarded as waste, with additional tissues available for analysis. Young (3-mo old) male and female rats and Older (9-mo old) male rats are being exposed to HLU for either 7, 14, 28, or 90 days. Additional groups are exposed to 90 days of unloading followed by either 7, 14, 28 days or 90 days of recovery (normal loading). Comparisons are made with non-suspended controls. Unused tissues are: Skin, Lungs, Thymus, Adrenals, Kidneys, Spleen, Hindlimb Muscles (Soleus, Extensor Digitorum Longus, Tibialis Anterior, Plantaris Gastrocnemius), Fat Pads, Reproductive Organs, and Intestines. Tissues are harvested, weighed, preserved then archived (with metadata) using a sample tracking system (CryoTrack). Preservation techniques include snap-freezing and RNALatersnap-freezing. Specimens were weighed at the time of dissection, and organ mass: body mass ratios analyzed to determine unloading effects across conditions and durations. The results corroborate previously reported effects of short-term exposure to microgravity or unloading exposure on various organs, and provide new insights into adaptation to long-duration unloading relevant to sustained spaceflight exposures on ISS. Supported by the Human Research Program (HRP) Human Health Countermeasures (HHC) Element and NASA Grant NNX13AD94G (CAF).

rodent↗

NASA NTRS2017

Digital Cellular Solid Pressure Vessels: A Novel Approach for Human Habitation in Space

It is widely assumed that human exploration beyond Earth's orbit will require vehicles capable of providing long duration habitats that simulate an Earth-like environment - consistent artificial gravity, breathable atmosphere, and sufficient living space- while requiring the minimum possible launch mass. This paper examines how the qualities of digital cellular solids - high-performance, repairability, reconfigurability, tunable mechanical response - allow the accomplishment of long-duration habitat objectives at a fraction of the mass required for traditional structural technologies. To illustrate the impact digital cellular solids could make as a replacement to conventional habitat subsystems, we compare recent proposed deep space habitat structural systems with a digital cellular solids pressure vessel design that consists of a carbon fiber reinforced polymer (CFRP) digital cellular solid cylindrical framework that is lined with an ultra-high molecular weight polyethylene (UHMWPE) skin. We use the analytical treatment of a linear specific modulus scaling cellular solid to find the minimum mass pressure vessel for a structure and find that, for equivalent habitable volume and appropriate safety factors, the use of digital cellular solids provides clear methods for producing structures that are not only repairable and reconfigurable, but also higher performance than their conventionally manufactured counterparts.

Robotics↗

NASA NTRS2017

Computational Modeling of Space Physiology for Informing Spaceflight Countermeasure Design and Predictions of Efficacy

MOTIVATION: Spaceflight countermeasures mitigate the harmful effects of the space environment on astronaut health and performance. Exercise has historically been used as a countermeasure to physical deconditioning, and additional countermeasures including lower body negative pressure, blood flow occlusion and artificial gravity are being researched as countermeasures to spaceflight-induced fluid shifts. The NASA Digital Astronaut Project uses computational models of physiological systems to inform countermeasure design and to predict countermeasure efficacy.OVERVIEW: Computational modeling supports the development of the exercise devices that will be flown on NASAs new exploration crew vehicles. Biomechanical modeling is used to inform design requirements to ensure that exercises can be properly performed within the volume allocated for exercise and to determine whether the limited mass, volume and power requirements of the devices will affect biomechanical outcomes. Models of muscle atrophy and bone remodeling can predict device efficacy for protecting musculoskeletal health during long-duration missions. A lumped-parameter whole-body model of the fluids within the body, which includes the blood within the cardiovascular system, the cerebral spinal fluid, interstitial fluid and lymphatic system fluid, estimates compartmental changes in pressure and volume due to gravitational changes. These models simulate fluid shift countermeasure effects and predict the associated changes in tissue strain in areas of physiological interest to aid in predicting countermeasure effectiveness. SIGNIFICANCE: Development and testing of spaceflight countermeasure prototypes are resource-intensive efforts. Computational modeling can supplement this process by performing simulations that reduce the amount of necessary experimental testing. Outcomes of the simulations are often important for the definition of design requirements and the identification of factors essential in ensuring countermeasure efficacy.

biomedical data↗

NASA NTRS2017

Characterizing the Effects of Chronic 2G Centrifugation on the Rat Skeletal System

During weightlessness, the skeletal system of astronauts is negatively affected by decreased calcium absorption and bone mass loss. Therefore, it is necessary to counteract these changes for long-term skeletal health during space flights. Our long-term plan is to assess artificial gravity (AG) as a possible solution to mitigate these changes. In this study, we aim to determine the skeletal acclimation to chronic centrifugation. We hypothesize that a 2G hypergravity environment causes an anabolic response in growing male rats. Specifically, we predict chronic 2G to increase tissue mineral density, bone volume fraction of the cancellous tissue and to increase overall bone strength. Systemically, we predict that bone formation markers (i.e., osteocalcin) are elevated and resorption markers (i.e., tartrate resistant acid phosphatase) are decreased or unchanged from controls. The experiment has three groups, each with an n8: chronic 2g, cage control (housed on the centrifuge, but not spun), and a vivarium control (normal rat caging). Pre-pubescent, male Long-Evans rats were used to assess our hypothesis. This group was subject to 90 days of 2G via centrifugation performed at the Chronic Acceleration Research Unit (CARU) at University of California Davis. After 90 days, animals were euthanized and tissues collected. Blood was drawn via cardiac puncture and the right leg collected for structural (via microcomputed tomography) and strength quantification. Understanding how counteract these skeletal changes will have major impacts for both the space-faring astronauts and the people living on Earth.

rat↗

NASA NTRS2018

Space Technology Innovation

There is a series of experiments and projects that have been done to support space missions, which we are now utilizing in our daily lives. The advancement of science and technology moves at a fast speed, and many of those technology advancements were thanks to the need that space missions required to make them happen. This presentation will provide information about some of those technologies developed in the international space station, in robotic missions to the moon and mars, and in earth simulations. We will touch on satellite applications, planetary defense from asteroids and meteorites, lunar structures, analog missions, and human systems integration. Similarly, we will touch on some microgravity countermeasures, such as artificial gravity, telemedicine, crew autonomy for scheduling their own activities, within others. During the presentation of each topic, we will provide suggestions on how students and young professionals can get involved to work on similar projects and in this manner be able to contribute to the scientific and technological space research.

Space science↗

NASA NTRS2017

Advancing Translational Space Research Through Biospecimen Sharing: Amplified Impact of Studies Utilizing Analogue Space Platforms

Biospecimen Sharing Programs (BSPs) have been organized by NASA Ames Research Center since the 1960s with the goal of maximizing utilization and scientific return from rare, complex and costly spaceflight experiments. BSPs involve acquiring otherwise unused biological specimens from primary space research experiments for distribution to secondary experiments. Here we describe a collaboration leveraging Ames expertise in biospecimen sharing to magnify the scientific impact of research informing astronaut health funded by the NASA Human Research Program (HRP) Human Health Countermeasures (HHC) Element. The concept expands biospecimen sharing to one-off ground-based studies utilizing analogue space platforms (e.g., Hindlimb Unloading (HLU), Artificial Gravity) for rodent experiments, thereby significantly broadening the range of research opportunities with translational relevance for protecting human health in space and on Earth. In this presentation, we will report on biospecimens currently being acquired from HHC Award Head-Down Tilt as a Model for Intracranial and Intraocular Pressures, and Retinal Changes during Spaceflight, and their availability. The BSP add-on to the project described herein has already yielded for HHC-funded investigators more than 4,700 additional tissues that would otherwise have been discarded as waste, with additional tissues available for analysis. Young (3-mo old) male and female rats and Older (9-mo old) male rats are being exposed to HLU for either 7, 14, 28, or 90 days. Additional groups are exposed to 90 days of unloading followed by either 7, 14, 28 days or 90 days of recovery (normal loading). Comparisons are made with non-suspended controls. Unused tissues are: Skin, Lungs, Thymus, Adrenals, Kidneys, Spleen, Hindlimb Muscles (Soleus, Extensor Digitorum Longus, Tibialis Anterior, Plantaris Gastrocnemius), Fat Pads, Reproductive Organs, and Intestines. Tissues are harvested, weighed, preserved then archived (with metadata) using a sample tracking system (CryoTrack). Preservation techniques include snap-freezing and RNALatersnap-freezing. Specimens were weighed at the time of dissection, and organ mass:body mass ratios analyzed to determine unloading effects across conditions and durations. The results corroborate previously reported effects of short-term exposure to microgravity or unloading exposure on various organs, and provide new insights into adaptation to long-duration unloading relevant to sustained spaceflight exposures on ISS.

biospecimen sharing↗

NASA NTRS2019

Potential NASA Rodent Centrifuge

This presentation is a summary of the continuing effort to determine options for studying artificial gravity with rodents. Results of an engineering trade study are presented and an overview of past and planned short radius centrifugation studies are presented. A leading proposal for a future flight centrifuge capable of housing rodents, the Techshot RCF, is presented in only enough detail as is approved by Techshot for public domain use.

Donovan, Frances↗