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All sourcesNASA NTRSDOE OSTI
NASA NTRS2015

Menstrual Cycle Control in Female Astronauts and the Associated Risk of Venous Thromboembolism

Venous thromboembolism (VTE) is a common and serious condition affecting approximately 1‐2 per 1000 people in the USA every year. There have been no documented case reports of VTE in female astronauts during spaceflight in the published literature. Some female astronauts use hormonal contraception to control their menstrual cycles and it is currently unknown how this affects their risk of VTE. Current terrestrial risk prediction models do not account for the spaceflight environment and the physiological changes associated with it. We therefore aim to estimate a specific risk score for female astronauts who are taking hormonal contraception for menstrual cycle control, to deduce whether they are at an elevated risk of VTE. A systematic review of the literature was conducted in order to identify and quantify known terrestrial risk factors for VTE. Studies involving analogues for the female astronaut population were also reviewed, for example, military personnel who use the oral contraceptive pill for menstrual suppression. Well known terrestrial risk factors, for example, obesity or smoking would not be applicable to our study population as these candidates would have been excluded during astronaut selection processes. Other risk factors for VTE include hormonal therapy, lower limb paralysis, physical inactivity, hyperhomocysteinemia, low methylfolate levels and minor injuries, all of which potentially apply to crew members LSAH data will be assessed to identify which of these risk factors are applicable to our astronaut population. Using known terrestrial risk data, an overall estimated risk of VTE for female astronauts using menstrual cycle control methods will therefore be calculated. We predict this will be higher than the general population but not significantly higher requiring thromboprophylaxis. This study attempts to delineate what is assumed to be true of our astronaut population, for example, they are known to be a healthy fit cohort of individuals, and combine physiological impacts of spaceflight (cephalic fluid shifts, lower limb inactivity) to understand specific risks associated with hormonal contraception.

Jain, Varsha↗
NASA NTRS2014

Prediction of the Arctic Oscillation in Boreal Winter by Dynamical Seasonal Forecasting Systems

This study assesses the skill of boreal winter Arctic Oscillation (AO) predictions with state-of-the-art dynamical ensemble prediction systems (EPSs): GloSea4, CFSv2, GEOS-5, CanCM3, CanCM4, and CM2.1. Long-term reforecasts with the EPSs are used to evaluate how well they represent the AO and to assess the skill of both deterministic and probabilistic forecasts of the AO. The reforecasts reproduce the observed changes in the large-scale patterns of the Northern Hemispheric surface temperature, upper level wind, and precipitation associated with the different phases of the AO. The results demonstrate that most EPSs improve upon persistence skill scores for lead times up to 2 months in boreal winter, suggesting some potential for skillful prediction of the AO and its associated climate anomalies at seasonal time scales. It is also found that the skill of AO forecasts during the recent period (1997-2010) is higher than that of the earlier period (1983-1996).

Arctic Oscillation↗
NASA NTRS2015

Analyses of Magnetic Resonance Imaging of Cerebrospinal Fluid Dynamics Pre and Post Short and Long-Duration Space Flights

Preliminary results are based on analyses of data from 17 crewmembers. The initial analysis compares pre to post-flight changes in total cerebral blood flow (CBF) and craniospinal CSF flow volume. Total CBF is obtained by summation of the mean flow rates through the 4 blood vessels supplying the brain (right and left internal carotid and vertebral arteries). Volumetric flow rates were obtained using an automated lumen segmentation technique shown to have 3-4-fold improved reproducibility and accuracy over manual lumen segmentation (6). Two cohorts, 5 short-duration and 8 long-duration crewmembers, who were scanned within 3 to 8 days post landing were included (4 short-duration crewmembers with MRI scans occurring beyond 10 days post flight were excluded). The VIIP Clinical Practice Guideline (CPG) classification is being used initially as a measure for VIIP syndrome severity. Median CPG scores of the short and long-duration cohorts were similar, 2. Mean preflight total CBF for the short and long-duration cohorts were similar, 863+/-144 and 747+/-119 mL/min, respectively. Percentage CBF changes for all short duration crewmembers were 11% or lower, within the range of normal physiological fluctuations in healthy individuals. In contrast, in 4 of the 8 long-duration crewmembers, the change in CBF exceeded the range of normal physiological fluctuation. In 3 of the 4 subjects an increase in CBF was measured. Large pre to post-flight changes in the craniospinal CSF flow volume were found in 6 of the 8 long-duration crewmembers. Box-Whisker plots of the CPG and the percent CBF and CSF flow changes for the two cohorts are shown in Figure 4. Examples of CSF flow waveforms for a short and two long-duration (CPG 0 and 3) are shown in Figure 5. Changes in CBF and CSF flow dynamics larger than normal physiological fluctuations were observed in the long-duration crewmembers. Changes in CSF flow were more pronounced than changes in CBF. Decreased CSF flow dynamics were observed in a subject with VIIP signs. Study limitations include a slightly longer landing-to-MRI scan period for the short-duration cohort and limited sensitivity of the subjective discrete ordinal CPG scale. This limitation can be overcome by using imaging based parametric measures of VIIP severity such as globe deformation measures.

Alperin, Noam↗
NASA NTRS2012

Factors Contributing to Unsuccessful Re-Proposed Missions

JPL often re-proposes unselected missions after technology advancement and mission concept development. Feedback given as major and minor weaknesses and strengths in prior rounds are addressed in later versions of proposals. This feedback provides insight into the factors that affect perceptions of risk and value. My research involved an in-depth case study of an original mission, Mission-A, and the re-proposed mission, Mission-B, after a multi-year technology development effort.In 2002, Mission-A was rated as Category III, with above average science merit (top score) and High Risk. To reduce risk, NASA invested technology development funds. In 2006 the re-formulated Mission-A mission, renamed Mission-B, was rated Category IV, good to very good science, and Medium Risk. While the risk rating improved from Mission-A to Mission-B, the overall results were worse.

risk↗
NASA NTRS2013

Decadal Prediction Skill in the GEOS-5 Forecast System

A suite of decadal predictions has been conducted with the NASA Global Modeling and Assimilation Office's (GMAO's) GEOS-5 Atmosphere-Ocean general circulation model. The hind casts are initialized every December 1st from 1959 to 2010, following the CMIP5 experimental protocol for decadal predictions. The initial conditions are from a multivariate ensemble optimal interpolation ocean and sea-ice reanalysis, and from GMAO's atmospheric reanalysis, the modern-era retrospective analysis for research and applications. The mean forecast skill of a three-member-ensemble is compared to that of an experiment without initialization but also forced with observed greenhouse gases. The results show that initialization increases the forecast skill of North Atlantic sea surface temperature compared to the uninitialized runs, with the increase in skill maintained for almost a decade over the subtropical and mid-latitude Atlantic. On the other hand, the initialization reduces the skill in predicting the warming trend over some regions outside the Atlantic. The annual-mean Atlantic meridional overturning circulation index, which is defined here as the maximum of the zonally-integrated overturning stream function at mid-latitude, is predictable up to a 4-year lead time, consistent with the predictable signal in upper ocean heat content over the North Atlantic. While the 6- to 9-year forecast skill measured by mean squared skill score shows 50 percent improvement in the upper ocean heat content over the subtropical and mid-latitude Atlantic, prediction skill is relatively low in the sub-polar gyre. This low skill is due in part to features in the spatial pattern of the dominant simulated decadal mode in upper ocean heat content over this region that differ from observations. An analysis of the large-scale temperature budget shows that this is the result of a model bias, implying that realistic simulation of the climatological fields is crucial for skillful decadal forecasts.

Decadal Prediction↗
NASA NTRS1961

Spacecraft

In this twentieth century, we are privileged to witness the first steps toward realization of an age-old dream: the exploration of space. Already, in the first few years of the Space Age, man has been able to penetrate the layer of atmosphere which surrounds his planet and to venture briefly into space. Scores of man-made objects have been thrust into space, some of them to roam the solar system forever. Behind each space mission are years of patient research, thousands of man-hours of labor, and large sums of money. Because the sums involved are so enormous, the question is frequently asked, "Is it worth it?" Many people want to know what return this huge investment will bring to mankind. The return on the investment is knowledge. The accumulation of knowledge over the centuries has made possible our advanced way of life. As we unlock more and more of the secrets of the universe through space exploration, we add new volumes to the encyclopedia of man's knowledge. This will be applied to the benefit of mankind. For the practical-minded, there are concrete benefits to our way of life. Although we are still in the Stone Age of space exploration, a number of immediate applications of space technology are already apparent. For instance, imagine the benefits of an absolutely perfect system of predicting the weather. Or, going a step further, even changing the weather. And wouldn't it be fascinating to watch the next Olympic games, telecast from Tokyo, on your TV set? These are just a few of the practical benefits made possible by space technology.

Clark, John F.↗
NASA NTRS2015

The Integrated Medical Model: A Probabilistic Simulation Model Predicting In-Flight Medical Risks

The Integrated Medical Model (IMM) is a probabilistic model that uses simulation to predict mission medical risk. Given a specific mission and crew scenario, medical events are simulated using Monte Carlo methodology to provide estimates of resource utilization, probability of evacuation, probability of loss of crew, and the amount of mission time lost due to illness. Mission and crew scenarios are defined by mission length, extravehicular activity (EVA) schedule, and crew characteristics including: sex, coronary artery calcium score, contacts, dental crowns, history of abdominal surgery, and EVA eligibility. The Integrated Medical Evidence Database (iMED) houses the model inputs for one hundred medical conditions using in-flight, analog, and terrestrial medical data. Inputs include incidence, event durations, resource utilization, and crew functional impairment. Severity of conditions is addressed by defining statistical distributions on the dichotomized best and worst-case scenarios for each condition. The outcome distributions for conditions are bounded by the treatment extremes of the fully treated scenario in which all required resources are available and the untreated scenario in which no required resources are available. Upon occurrence of a simulated medical event, treatment availability is assessed, and outcomes are generated depending on the status of the affected crewmember at the time of onset, including any pre-existing functional impairments or ongoing treatment of concurrent conditions. The main IMM outcomes, including probability of evacuation and loss of crew life, time lost due to medical events, and resource utilization, are useful in informing mission planning decisions. To date, the IMM has been used to assess mission-specific risks with and without certain crewmember characteristics, to determine the impact of eliminating certain resources from the mission medical kit, and to design medical kits that maximally benefit crew health while meeting mass and volume constraints.

Risk Analysis↗
NASA NTRS2015

Selection of Leafy Green Vegetable Varieties for a Pick-and-Eat Diet Supplement on ISS

Several varieties of leafy vegetables were evaluated with the goal of selecting those with the best growth, nutrition, and organoleptic acceptability for ISS. Candidate species were narrowed to commercially available cultivars with desirable growth attributes for space (e.g., short stature and rapid growth). Seeds were germinated in controlled environment chambers under conditions similar to what might be found in the Veggie plant growth chamber on ISS. Eight varieties of leafy greens were grown: 'Tyee' spinach, 'Flamingo' spinach, 'Outredgeous' Red Romaine lettuce, 'Waldmann's Dark Green' leaf lettuce, 'Bull's Blood' beet, 'Rhubarb' Swiss chard, 'Tokyo Bekana' Chinese cabbage, and Mizuna. Plants were harvested at maturity and biometric data on plant height, diameter, chlorophyll content, and fresh mass were obtained. Tissue was ground and extractions were performed to determine the tissue elemental content of Potassium (K), Magnesium (Mg), Calcium (Ca) and Iron (Fe). Following the biometric/elemental evaluation, four of the eight varieties were tested further for levels of anthocyanins, antioxidant (ORAC-fluorescein) capacity, lutein, zeaxanthin, and Vitamin K. For sensory evaluation, 'Outredgeous' lettuce, Swiss chard, Chinese cabbage, and Mizuna plants were grown, harvested when mature, packaged under refrigerated conditions, and sent to the JSC Space Food Systems Laboratory. Tasters evaluated overall acceptability, appearance, color intensity, bitterness, flavor, texture, crispness and tenderness. All varieties received acceptable scores with overall ratings greater than 6 on a 9-point hedonic scale. Chinese cabbage was the highest rated, followed by Mizuna, 'Outredgeous' lettuce, and Swiss chard. Based on our results, the selected varieties of Chinese cabbage, lettuce, Swiss chard and Mizuna seem suitable for a pick-and-eat scenario on ISS with a ranking based on all factors analyzed to help establish priority.

Nutrition↗
NASA NTRS2015

Multidimensional Risk Analysis: MRISK

Multidimensional Risk (MRISK) calculates the combined multidimensional score using Mahalanobis distance. MRISK accounts for covariance between consequence dimensions, which de-conflicts the interdependencies of consequence dimensions, providing a clearer depiction of risks. Additionally, in the event the dimensions are not correlated, Mahalanobis distance reduces to Euclidean distance normalized by the variance and, therefore, represents the most flexible and optimal method to combine dimensions. MRISK is currently being used in NASA's Environmentally Responsible Aviation (ERA) project o assess risk and prioritize scarce resources.

McCollum, Raymond↗
NASA NTRS2016

Recommended Methods for Monitoring Skeletal Health in Astronauts to Distinguish Specific Effects of Prolonged Spaceflight

NASA uses areal bone mineral density (aBMD) by dual-energy X-ray absorptiometry (DXA) to monitor skeletal health in astronauts after typical 180-day spaceflights. The osteoporosis field and NASA, however, recognize the insufficiency of DXA aBMD as a sole surrogate for fracture risk. This is an even greater concern for NASA as it attempts to expand fracture risk assessment in astronauts, given the complicated nature of spaceflight-induced bone changes and the fact that multiple 1-year missions are planned. In the past decade, emerging analyses for additional surrogates have been tested in clinical trials; the potential use of these technologies to monitor the biomechanical integrity of the astronaut skeleton will be presented. OVERVIEW: An advisory panel of osteoporosis policy-makers provided NASA with an evidence-based assessment of astronaut biomedical and research data. The panel concluded that spaceflight and terrestrial bone loss have significant differences and certain factors may predispose astronauts to premature fractures. Based on these concerns, a proposed surveillance program is presented which a) uses Quantitative Computed Tomography (QCT) scans of the hip to monitor the recovery of spaceflight-induced deficits in trabecular BMD by 2 years after return, b) develops Finite Element Models [FEM] of QCT data to evaluate spaceflight effect on calculated hip bone strength and c) generates Trabecular Bone Score [TBS] from serial DXA scans of the lumbar spine to evaluate the effect of age, spaceflight and countermeasures on this novel index of bone microarchitecture. SIGNIFICANCE: DXA aBMD is a widely-applied, evidence-based predictor for fractures but not applicable as a fracture surrogate for premenopausal females and males <50 years. Its inability to detect structural parameters is a limitation for assessing changes in bone integrity with and without countermeasures. Collective use of aBMD, TBS, QCT, and FEM analysis for astronaut surveillance could accommodate NASA's aggressive schedule for risk definition and inform a NASA-developed model which assesses the probability of overloading bones during mechanically-loaded mission tasks and possibly for physical activities after return to Earth.

Vasadi, Lukas J.↗
NASA NTRS2015

Recommendations on Future Science and Engineering Studies for Ocean Color

The Ocean Health Index measured Ecological Integrity as the relative condition of assessed species in a given location. This was calculated as the weighted sum of the International Union for Conservation of Natures (IUCN) assessments of species. Weights used were based on the level of extinction risk following Butchart et al.2007: EX (extinct) 0.0, CR (critically endangered) 0.2, EN (endangered) 0.5, VU (vulnerable) 0.7, NT (not threatened) 0.9, and LC (least concern) 0.99. For primarily coastal goals, the spatial average of these per pixel scores was based on a 3nmi buffer; for goals derived from all ocean waters, the spatial average was computed for the entire EEZ.

Geo-Cape↗
NASA NTRS2016

Development of an Objective Space Suit Mobility Performance Metric Using Metabolic Cost and Functional Tasks

Existing methods for evaluating EVA suit performance and mobility have historically concentrated on isolated joint range of motion and torque. However, these techniques do little to evaluate how well a suited crewmember can actually perform during an EVA. An alternative method of characterizing suited mobility through measurement of metabolic cost to the wearer has been evaluated at Johnson Space Center over the past several years. The most recent study involved six test subjects completing multiple trials of various functional tasks in each of three different space suits; the results indicated it was often possible to discern between different suit designs on the basis of metabolic cost alone. However, other variables may have an effect on real-world suited performance; namely, completion time of the task, the gravity field in which the task is completed, etc. While previous results have analyzed completion time, metabolic cost, and metabolic cost normalized to system mass individually, it is desirable to develop a single metric comprising these (and potentially other) performance metrics. This paper outlines the background upon which this single-score metric is determined to be feasible, and initial efforts to develop such a metric. Forward work includes variable coefficient determination and verification of the metric through repeated testing.

Norcross, J. R.↗
NASA NTRS2015

Videopanorama Frame Rate Requirements Derived from Visual Discrimination of Deceleration During Simulated Aircraft Landing

In order to determine the required visual frame rate (FR) for minimizing prediction errors with out-the-window video displays at remote/virtual airport towers, thirteen active air traffic controllers viewed high dynamic fidelity simulations of landing aircraft and decided whether aircraft would stop as if to be able to make a turnoff or whether a runway excursion would be expected. The viewing conditions and simulation dynamics replicated visual rates and environments of transport aircraft landing at small commercial airports. The required frame rate was estimated using Bayes inference on prediction errors by linear FRextrapolation of event probabilities conditional on predictions (stop, no-stop). Furthermore estimates were obtained from exponential model fits to the parametric and non-parametric perceptual discriminabilities d' and A (average area under ROC-curves) as dependent on FR. Decision errors are biased towards preference of overshoot and appear due to illusionary increase in speed at low frames rates. Both Bayes and A - extrapolations yield a framerate requirement of 35 < FRmin < 40 Hz. When comparing with published results [12] on shooter game scores the model based d'(FR)-extrapolation exhibits the best agreement and indicates even higher FRmin > 40 Hz for minimizing decision errors. Definitive recommendations require further experiments with FR > 30 Hz.

deceleration perception↗
NASA NTRS2015

The Integrated Medical Model: A Probabilistic Simulation Model for Predicting In-Flight Medical Risks

The Integrated Medical Model (IMM) is a probabilistic model that uses simulation to predict mission medical risk. Given a specific mission and crew scenario, medical events are simulated using Monte Carlo methodology to provide estimates of resource utilization, probability of evacuation, probability of loss of crew, and the amount of mission time lost due to illness. Mission and crew scenarios are defined by mission length, extravehicular activity (EVA) schedule, and crew characteristics including: sex, coronary artery calcium score, contacts, dental crowns, history of abdominal surgery, and EVA eligibility. The Integrated Medical Evidence Database (iMED) houses the model inputs for one hundred medical conditions using in-flight, analog, and terrestrial medical data. Inputs include incidence, event durations, resource utilization, and crew functional impairment. Severity of conditions is addressed by defining statistical distributions on the dichotomized best and worst-case scenarios for each condition. The outcome distributions for conditions are bounded by the treatment extremes of the fully treated scenario in which all required resources are available and the untreated scenario in which no required resources are available. Upon occurrence of a simulated medical event, treatment availability is assessed, and outcomes are generated depending on the status of the affected crewmember at the time of onset, including any pre-existing functional impairments or ongoing treatment of concurrent conditions. The main IMM outcomes, including probability of evacuation and loss of crew life, time lost due to medical events, and resource utilization, are useful in informing mission planning decisions. To date, the IMM has been used to assess mission-specific risks with and without certain crewmember characteristics, to determine the impact of eliminating certain resources from the mission medical kit, and to design medical kits that maximally benefit crew health while meeting mass and volume constraints.

Risk Analysis↗
NASA NTRS2016

Dynamic Visual Acuity and Landing Sickness in Crewmembers Returning from Long-Duration Spaceflight

Long-term exposure to microgravity causes sensorimotor adaptations that result in functional deficits upon returning to a gravitational environment. At landing the vestibular system and the central nervous system, responsible for coordinating head and eye movements, are adapted to microgravity and must re-adapt to the gravitational environment. This re-adaptation causes decrements in gaze control and dynamic visual acuity, with astronauts reporting oscillopsia and blurred vision. Dynamic visual acuity (DVA) is assessed using an oscillating chair developed in the Neuroscience Laboratory at JSC. This chair is lightweight and easily portable for quick deployment in the field. The base of the chair is spring-loaded and allows for manual oscillation of the subject. Using a metronome, the chair is vertically oscillated plus or minus 2 cm at 2 Hz by an operator, to simulate walking. While the subject is being oscillated, they are asked to discern the direction of Landolt-C optotypes of varying sizes and record their direction using a gamepad. The visual acuity thresholds are determined using an algorithm that alters the size of the optotype based on the previous response of the subject using a forced-choice best parameter estimation that is able to rapidly converge on the threshold value. Visual acuity thresholds were determined both for static (seated) and dynamic (oscillating) conditions. Dynamic visual acuity is defined as the difference between the dynamic and static conditions. Dynamic visual acuity measures will be taken prior to flight (typically L-180, L-90, and L-60) and up to eight times after landing, including up to 3 times on R plus 0. Follow up measurements will be taken at R plus 1 (approximately 36 hours after landing). Long-duration International Space Station crewmembers will be tested once at the refueling stop in Europe and once again upon return to Johnson Space Center. In addition to DVA, subjective ratings of motion sickness will be recorded throughout the testing. Using the chair as a portable and reliable way to test DVA, we aim to test returning astronauts to assess the amount of retinal slip that they experience. By comparing these measurements to their motion sickness scores (using a scale of 1 to 20 where 20 is vomiting), we will correlate the amount of retinal slip to the level of motion sickness experienced. In addition to testing this in returning astronauts, we will perform ground-based studies to determine the effectiveness of stroboscopic goggles in reducing retinal slip and improving DVA. Finally, we will employ stroboscopic goggles in the field to astronauts experiencing high levels of motion sickness to minimize retinal slip and reduce their symptoms.

Rosenberg, M.J.F↗
NASA NTRS2016

Pilot Field Test: Performance of a Sit-to-Stand Test After Long-Duration Space Flight

BACKGROUND: Astronauts returning from the International Space Station are met by a team of recovery personnel typically providing physical assistance and medical support immediately upon landing. That is because long-duration spaceflight impacts astronauts' functional abilities. Future expeditions to planets or asteroids beyond the low Earth orbit, however, may require crewmembers to egress the vehicle and perform other types of physical tasks unassisted. It is therefore important to characterize the extent and longevity of functional deficits experienced by astronauts in order to design safe exploration class missions. Pilot Field Test (PFT) experiment conducted with participation of ISS crewmembers traveling on Soyuz expeditions 34S - 41S comprised several tasks designed to study the recovery of sensorimotor abilities of astronauts during the first 24 hours after landing and beyond. METHODS: The first test in the PFT battery sequence, and also the least demanding one from the sensorimotor perspective, was a Sit-to-Stand test. Test subjects were seated in the chair and had to stand up on command and remain standing for ten seconds. The subjects were instructed to stand up unassisted as quickly as they were able to, while maintaining postural control. Synchronized wireless inertial sensors mounted on the head, chest, lower back, wrists, and ankles were used to continuously log body kinematics. Crewmembers' blood pressure and heart rate were monitored and recorded with the Portapres and Polar systems. Each session was recorded with a digital video camera. During data collections occurring within the 24-hour postflight period, crewmembers were also asked to (1) evaluate their perceived motion sickness symptoms on a 20-point scale before and after completion of the test and (2) estimate how heavy they felt compared to their normal (preflight) body weight. Consent to participate in PFT was obtained from 18 crewmembers (11 US Orbital Segment [USOS] astronauts and 7 Russian cosmonauts). For 10 subjects, the first set of data was collected in the medical tent in Soyuz landing zone (1-2 hours after landing); the other 8 subjects were tested at the Kazakhstan deployment airport (4-5 hours after landing). 8 of the 11 astronauts were tested twice more within the first 24 hours postflight, at a refueling stop on the way to Houston (approximately 13 hours after landing) and at the Johnson Space Center (approximately 24 hours after landing). Later postflight data were collected in the first two weeks on some crewmembers. Finally, 6 astronauts were tested 60+ days after landing to establish a delayed baseline. RESULTS/DISCUSSION: Two of the 18 PFT participants felt too ill to attempt any tests in Kazakhstan (at either the landing zone or deployment airport). The remaining test subjects completed the Sit-to-Stand test and their reported motion sickness scores were unaffected by this task. The task completion times and body kinematics data analysis are currently underway. Preliminary analysis of astronaut data shows a steep improvement in the time to complete the task on the second data take, and in some cases, the trend continues through day six postflight. Head and trunk pitch angles and pitch rates were also examined and increases in all measures are evident throughout the observed recovery period (60+ days postflight). Interesting patterns of head and trunk pitch coordination have also emerged. One of the data analysis objectives is comparison of initial postflight performance and recovery of experienced crewmembers and first-time fliers. Another one - possible differences in performance between USOS and Russian crewmembers.

Kofman, I. S.↗
NASA NTRS2016

Development and Provision of Functional Foods to Promote Health on Long-Duration Space Missions

During long-duration NASA space missions, such as proposed missions to Mars, astronauts may experience negative physiological effects such as bone loss. Functional foods such as high-lycopene, high-flavonoids and high-omega-3 products and fruits and vegetables may mitigate the negative effects of spaceflight on physiological factors including the bone health of crewmembers. Previous studies showed that current ISS provisions provide high-lycopene and high-omega-3 food items but the variety is limited, which could promote menu fatigue. Bioactive compounds can degrade like other chemical compounds and lose functionality. The native concentrations and stability of bioactive compounds have never been determined in spaceflight foods, and adequate information is not available for commercial products for the storage durations required for space exploration (5 years). The purpose of this task is to develop new spaceflight foods that are high in omega-3 fatty acids, lycopene, or flavonoids, identify commercial products with these bioactive compounds that meet spaceflight requirements, and define the stability of these nutrients in storage to enable purposeful functional food incorporation into the space food system. The impact of storage temperature on the stability of lutein, lycopene, beta-carotene, omega-3 fatty acids, phenolics, anthocyanins and sterols is being studied in 12 ISS menu items stored at three different temperatures (4, 21, 35 degree C) over 2 years. Additionally, nutrient and quality stability are being assessed on a larger food set stored at 21 degree C over 2 years that contains twelve newly developed foods, 10 commercial products repackaged to spaceflight requirements, and another 5 current ISS menu items expected to be good sources of omega-3 fatty acids, lycopene, or flavonoids. All items were shipped overnight to the Linus Pauling Institute at Oregon State University (Corvalis, OR) after processing and 1-year of storage and analyzed for bioactive compound concentrations. Sensory evaluation was conducted on the newly developed functional foods and commercial products with untrained panelists (n is greater than or equal to 25) using a 9-point Hedonic scale to test sensory attributes and overall acceptability after processing and 1-year of storage (21 degree C). Repeat nutritional and sensory analyses will be conducted in the same foods after the 2-year storage period is completed. The stability of bioactive compounds in the selected foods was dependent on storage temperature and food matrix. Omega-3 showed excellent stability in the analyzed products after 1-year of storage, regardless of the storage temperature; phenolic compounds also showed good stability. Lycopene was more stable in oil-based products rather than water-based products because of the protection that lipids offer to lycopene molecules. Also, lycopene was more stable in freeze-dried products than in high moisture foods. The 12 newly developed functional foods showed good overall acceptability in sensory attributes after processing (average score 7.2 out of 9.0) and maintained sensory quality through 1-year (21 degree C); the overall acceptability was on average 7.1 after storage. Similar behavior was observed for the 10 commercial products after 1 year. The developed products are good sources of omega-3 (both plant and marine), vegetables (7 vegetable-based products), and good sources of carotenoids, such as the Curry Pumpkin Soup and the Sweet and Savory Kale. Nine of the new products, such as Mango Salad, Pickled Beets, and Braised Red Cabbage, are rich in phenolic compounds. Stability of most of the studied nutrients seems to be adequate after 1-year of storage in most of the tested foods. However, storage temperature of the food must be considered during long-duration space missions to achieve stability of all nutrients. Likewise, more information is needed regarding nutrient retention after 2-years of storage to identify nutritional gaps that may be expected over the 5-year shelf life required for a Mars mission. New developed products will be filling a gap in the current space food system to minimize menu fatigue, provide specific nutrients to reduce the negative effects of long-duration space missions and maintain crew members' health. Information about bioactive compounds in developed products after 1-year and 2-year of storage will provide the knowledge base for further product development.

Bermudez-Aguirre, D.↗
NASA NTRS2016

Development of an Objective Space Suit Mobility Performance Metric Using Metabolic Cost and Functional Tasks

Existing methods for evaluating EVA suit performance and mobility have historically concentrated on isolated joint range of motion and torque. However, these techniques do little to evaluate how well a suited crewmember can actually perform during an EVA. An alternative method of characterizing suited mobility through measurement of metabolic cost to the wearer has been evaluated at Johnson Space Center over the past several years. The most recent study involved six test subjects completing multiple trials of various functional tasks in each of three different space suits; the results indicated it was often possible to discern between different suit designs on the basis of metabolic cost alone. However, other variables may have an effect on real-world suited performance; namely, completion time of the task, the gravity field in which the task is completed, etc. While previous results have analyzed completion time, metabolic cost, and metabolic cost normalized to system mass individually, it is desirable to develop a single metric comprising these (and potentially other) performance metrics. This paper outlines the background upon which this single-score metric is determined to be feasible, and initial efforts to develop such a metric. Forward work includes variable coefficient determination and verification of the metric through repeated testing.

McFarland, Shane M.↗