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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 505 records · Page 28
All sourcesNASA NTRSDOE OSTI
NASA NTRSDate not supplied

Impact of Sleep Shifting Strategies on the International Space Station

Astronaut crews have historically averaged around six hours of sleep per night, especially during missions that required a high tempo work environment, confined spacecraft without crew quarters, and frequent sleep schedule changes. In recent years, crew aboard the ISS have had much more stable schedules, with a consistent bedtime at 2130 and wake time at 0600 Greenwich Mean Time. Despite these improvements to sleep conditions on the ISS, sleep schedules are disrupted by visiting vehicles that arrive or leave the ISS or when uncontrollable operational events require the crewmembers to shift their sleep. We characterized the approaches to sleep shifting, including shifting sleep earlier and later and split sleep to determine the impact on sleep duration and quality. METHODS Data were gathered though the Spaceflight Standard Measures protocol. These consisted of objective measures of sleep duration (calculated via a wrist-worn accelerometer) collected by 19 crewmembers (7 females; mean age 46 ± 7 years) throughout their tenure aboard the ISS. We first categorized episodes of “split sleep” whereby a person attempts sleep on two separate occasions in a 24-hour period that are similar in length. For example, they might have a 4-hour sleep opportunity followed by a night awake, followed by another 4-hour sleep opportunity the next morning. RESULTS Out of the 19 crewmembers, a total of 8 engaged in 11 episodes of split sleep while inflight. These periods all surrounded visiting vehicle events that interfered with their nominal sleep window, including docking, relocation, and undocking events. The first sleep opportunity typically took place during the afternoon before the disrupting event (all sleep periods were contained between 1151 and 2009), while the second episode took place the following morning (between 0343 and 1325) On average, the time in bed of the first sleep opportunity was shorter than the second (M1=2.89±0.82 vs. M2=4.30±1.41). DISCUSSION Next in our analysis, we will compare the crewmembers’ split sleep outcomes to those from other strategies (e.g., phase delays). We aim to determine which strategies yield the best sleep outcomes and to determine whether the sleep shifting strategy has consequences to subsequent sleep. Understanding these impacts will aid in decision making for future ISS operations and will also help us better understand the impacts of various strategies to adjust sleep and help guide scheduling in future missions where consistent schedules may not be possible.

sleep↗
NASA NTRSDate not supplied

Investigating the Causes and Consequences of Controlled Rest on the Flight Deck

INTRODUCTION: Long and irregular working hours can lead to fatigue in aviation operations. In some regions, a short nap taken on the flight deck (known as controlled rest) can be used as a countermeasure to unexpected in-flight sleepiness. We aimed to investigate the impact of taking controlled rest on self-reported sleepiness at top-of-descent. METHODS: Data from 120 long-haul (> 6 h flight duration), unaugmented flights were analyzed (n = 31 pilots). Pilots wore actigraphs and completed sleep logs before and during trips. At pre-flight and top-of-descent, pilots completed a Karolinska Sleepiness Scale (KSS). A mixed-effects model was used to assess the impact of controlled rest on KSS at top-of-descent. Sleep duration in the 48 hours prior to departure, timing of the flight (day vs. night), and pre-flight KSS scores were included as covariates. RESULTS: Due to missing data, complete data from 83 flights (n = 29 participants) were available in the analyses of the KSS. There were no differences by controlled rest status for KSS scores at top-of-descent (estimated marginal means ± SEM with controlled rest: 5.10 ± 0.22, without controlled rest: 5.37 ± 0.29; p = .45, η2p = 0.01). DISCUSSION: Our results suggest that there is no difference in self-reported sleepiness at top-of-descent on flights in which controlled rest was taken compared to flights without controlled rest. Further research is necessary to determine the impact of controlled rest on objective measures of performance at top-of-descent.

aviation↗
NASA NTRSDate not supplied

Comparison of Daily, Monthly (Lunar), Yearly, Decadal, Quarter-Century, Half-Century, and Centurial Shoreline Change Rates at the Kennedy Space Center, Cape Canaveral, Florida, USA

The Kennedy Space Center (KSC) is North America’s premier spaceport and provides crucial access to space for both government and private entities. The National Aeronautics and Space Administration (NASA) facilities are clustered along a 12 km active shoreline at Cape Canaveral, Florida, USA, with the entire NASA and US Space Force station (SF) shoreline stretching over 32 km (Figure 1). Several Launch Complexes (LC’s) including the modern heavy lift facilities are only a few tens of meters from the active shoreline and are imminently threatened by continued sea level rise and ongoing coastal erosion. The space center was built on the northern part of Cape Canaveral. Images collected in 1943 show that Apollo Heavy Lift Launch Complexes were built in swales on ground that was at or below sea level with Launch Complex 39B constructed on a paleo inlet (Figures 2 and 3). Today the Heavy Lift Launch Complexes are ~220 meters from the shoreline with the area between the complexes retreating at the highest rates along the cape (Figure 4). To better understand the intersection of environmental concerns, limited budgets for shoreline protection, and sheltering critical infrastructure; NASA, The University of Florida, United States Geological Survey (USGS), National Park Service (NPS) and contractors have and continue to conduct numerous studies to characterize and understand the shoreline evolution and rates of change at KSC. This project aims to better understand and visualize the temporal and spatial variability of change along the NASA shoreline beyond a simple point to point solution.

Richard MacKenzie III↗
NASA NTRSDate not supplied

Assessing Potential Geophysical and Environmental Impacts from Frequent Rocket Launch Missions at Kennedy Space Center

Kennedy Space Center (KSC) in Florida has been utilized for space missions over many years with a gradually increasing number of rocket launches. There have been multiple studies where air-coupled acoustic waves and infrasound originating from launched rockets were used for operational purposes, such as locating booster trajectories as a function of changing atmospheric conditions. However, no study has utilized the acoustoelastic waves as a signal source for subsurface seismic investigations. We conducted a dispersion analysis using the seismic energy recorded from the Artemis I rocket launch at KSC in November 2022, and from these results we generated depth-sensitivity kernels at different wave frequencies. The kernels were compared with sedimentary core data to verify boundaries of carbonate layers above the Floridan Aquifer System. Accumulative information of bedrock-sediment boundary across the sedimentary platform could especially provide geo-structural evidence that manifests the configuration of coastal features. Continuous dispersion analysis of seismic recordings from consecutive rocket launches also has potential to identify non-stationary environmental effects, such as reorientation of sedimentary structures and fluctuation of the saltwater/groundwater lens from gravitational tides, which may affect erosional susceptibility of coastal features.

Han Byul Woo↗
NASA NTRSDate not supplied

Space Transport and Fatigue

Space travel presents numerous challenges to fatigue management. Fatigue in space results from many of the same challenges that shiftworkers face on Earth, including inadequate sleep, circadian misalignment, and elevated workload. However, spaceflight also presents unique challenges including circadian misalignment due to non-24- hour light-dark cycles, erratic work schedules due to operational constraints, a microgravity sleep environment, constraints to habitat design, and an isolated and confined living environment. These challenges can be mitigated with fatigue management strategies and countermeasures specifically targeted for space travel. Those strategies can include light interventions, advanced scheduling tools, improved habitat design, and pharmacological countermeasures. What is needed is a future-facing approach to most effectively manage the challenges that may arise as advancements in space travel continue to develop at a rapid pace.

sleep deprivation and performance↗
NASA NTRSDate not supplied

Caffeine Consumption Aboard the International Space Station

INTRODUCTION: Caffeine is the most widely used performance-enhancing drug on Earth and astronaut crews have access to liquid coffee. While caffeine is a potent countermeasure to improve alertness and performance, it can also interfere with sleep. This can lead to performance deficits on the following day, driving a cycle of caffeine use to counter the effects of caffeine-induced sleep disruption. Caffeine availability may be limited during future Artemis and/or Mars missions. Accordingly, it is important that we 1) determine the prevalence of caffeine use among astronauts, 2) characterize the impact of caffeine on performance, and 3) characterize the impact of caffeine on sleep. Our aim in this study is to describe the use of caffeine aboard the ISS and begin to examine the relationship between caffeine use and sleep and performance outcomes. METHODS: Daily caffeine consumption was determined from food and beverage intake tracking for 25 astronauts on 6 month International Space Station (ISS) missions. Data were recorded using the ISS Food Intake Tracker iPad App or other detailed recording technique. On average, crew recorded dietary intake on 179.7±68.6 (mean±SD) days inflight. RESULTS: Astronauts consumed 97±92 mg caffeine per day. All astronauts (25/25) in this study consumed caffeine at some point during flight, though the frequency, amounts, and regularity differed across crewmembers. Approximately a quarter of crewmembers were regular caffeine consumers (6/25), i.e., they ingested at least 90 mg caffeine (equivalent to one cup of coffee) on 90% of inflight days.

fatigue↗
NASA NTRSDate not supplied

Addressing CFM Modeling Gaps for Application into NASA’S Future Cutting Edge Missions

NASA, the US industry, and international partners are crafting frameworks to enable sustaining lunar missions. The ongoing programs, led by the agency, and prominent industry players, encompass plans for the sustained use of cryogenic propellants in lunar landers and in-space propellant refueling depots. NASA’s proactive funding initiatives have fueled the advancement of predictive computational models tailored to enhance the storage and transfer of cryogenic propellant. This paper aims to spotlight the latest advancements in this arena and delve into the collaborative efforts surrounding predictive model development within internal NASA programs as well as current and previous collaborations with industry and international partners. The paper presents an overview of recent advancements in cryogenic fluid management model development, along with their correlation with recent microgravity and large-scale cryogenic ground tests. The tests include key experiments such as the ISS Zero-Boil-Off Tank (ZBOT) series of experiments and the (Robotic Refueling Mission 3) RRM3 test during which liquid methane was stored on-orbit for an extended period of five months. The paper also highlights the anchoring of propellant tank pressurized drain tests involving sloshing that were conducted with liquid methane propellant during the Apollo/Saturn Era. Additionally, the paper discusses model anchoring against more recent sloshing tests carried out with liquid hydrogen propellant. Notable large-scale tests, such as a liquid oxygen propellant transfer test conducted by SpaceX were also used to help correlate a two-phase propellant transfer model using the valuable data measured during the test. The paper further showcases model correlations against a substantial oxygen liquefaction test undertaken by NASA to validate In-Situ-Resource-Utilization (ISRU) technologies that will prove pivotal for a sustained lunar presence.

Low-gravity fluid modeling↗
NASA NTRSDate not supplied

Three-Dimensional Reconstruction of Defects and Structures in Additively Manufactured Parts with Automated Serial Sectioning

Metal additive manufacturing (AM) processes have been demonstrated to be effective at reducing costs and lead times associated with complex components for space flight applications. Laser powderbed fusion (L-PBF) is a commonly used AM technology due to the ability to produce complex parts with fine feature resolution in a wide variety of alloys and applications. L-PBF, like many other manufacturing processes, can produce minor flaws in parts when in nominal operation as well as process-escape defects when process abnormalities occur. The effects of the flaws and methods of detecting the flaws are a subject of interest to understand the difficulties in detecting these flaws with current technology and how much risk the flaws or defects pose to potential flight parts. Using a RoboMet.3D automated serial sectioning system, seeded defects as well as minor process flaws can be imaged and reconstructed in three dimensions to compare to non-destructive evaluation (NDE) techniques, such as x-ray computed tomography (CT), neutron CT, and in-situ monitoring. The RoboMet automates the metallography process by automatically grinding, polishing, and imaging samples in a single system and providing the control data for NDE comparisons to know the real size of defects built into coupons. These comparisons provide an understanding behind the technological limitations of the NDE techniques for different alloys. The same serial sectioning methods have also been utilized to characterize the surfaces of parts to reconstruct the surfaces and take measurements of internal features not easily examined with non-destructive methods. Using the RoboMet, fine lattice structures built with L-PBF have been characterized to determine the actual thicknesses of struts and density of the lattice structures. These structures have been used as finer build supports for the L-PBF process, designs for fine catalysts, and other design considerations for small components. The RoboMet data helps to inform the modeling and design efforts around these fine components.

additive manufacturing↗
NASA NTRSDate not supplied

Caves as Planetary Analogs for GPS Denied, Low-Light Mapping and Navigation in Rugged Environments

KNaCK (Kinematic Navigation and Cartography Knapsack) is a backpack-mounted mobile mapping system. It can map its surroundings in 3 dimensions and localize itself in space using a LiDAR (Light Detection and Ranging) sensor and SLAM (Simultaneous Localization and Mapping) algorithm. The KNaCK team is leveraging caves as a proving ground to refine technology for mapping and navigation on other worlds while simultaneously advancing the State of the Art for terrestrial cave exploration and study.

LiDAR↗
NASA NTRSDate not supplied

Nondestructive Evaluation and In-Situ Monitoring Efforts for Additive Manufacturing

Nondestructive evaluation (NDE) is required to determine the quality of additive manufactured (AM) parts due to the inherent variability of AM processes. In-situ monitoring technologies endeavor to characterize the process and part quality during production. Qualifying an in-situ monitoring technology requires a proven, causal correlation between indications in the monitoring data and flaws in the finished part.

James Mavo↗
NASA NTRSDate not supplied

Metallic Environmentally Resistant Coatings Rapid Innovation Initiative (MERCRII) Mechanism Development and Testing

This project seeks to address the high friction and low wea resistance of lightweight aluminum (Al) and titanium (Ti) alloys to extend the lifetime and sustainability of both lunar and Martian assets missions by developing advanced wear-and radiation-resistant. MERCRII started with 6 candidate coating materials and 3 candidate application methods that were down-selected through pathfinder and 2 phases of testing to one coating configuration: Ti64 with 2%hBN Vacuum Plasma Spray.

dust mitigation↗
NASA NTRSDate not supplied

The Impact of Controlled Rest on Neurobehavioral Outcomes at Top-of-Descent

INTRODUCTION: Long and irregular working hours can lead to fatigue in aviation operations. In some regions, a short nap taken on the flight deck (known as controlled rest) can be used as a countermeasure to unexpected in-flight sleepiness. We aimed to investigate the impact of taking controlled rest on neurobehavioral measures at top-of-descent. METHODS: Data from 120 long-haul (> 6 h flight duration), unaugmented flights were analyzed (n = 31 pilots). Pilots wore actigraphs and completed sleep logs before and during trips. At pre-flight and top-of-descent, pilots completed a 5-minute psychomotor vigilance task (PVT) and Karolinska Sleepiness Scale (KSS). A series of mixed-effects models were conducted to assess the impact of controlled rest on outcome measures at top-of-descent. Sleep duration in the prior 48 hours, timing of the flight, and pre-flight scores for each measure were included as covariates. RESULTS: Due to missing data, complete data from 76 flights (n = 28 participants) were available in the models examining the PVT metrics, and data from 83 flights (n = 29 participants) were available in the analyses of the KSS. Pilots who took controlled rest had faster response speeds at top-of-descent (p = .03, η2p = 0.07; estimated marginal mean [EMM] = 4.19, standard error [SE] = 0.07, 95% CI [4.08, 4.29]) than those who did not take controlled rest (EMM = 4.00, SE = 0.05, 95% CI [3.86, 4.14]). There were no differences by controlled rest status for KSS scores and PVT lapses (p values > .05, η2p values ≤ 0.01). DISCUSSION: Our results suggest that taking controlled rest may improve vigilant attention at critical phases of flight and, thus, may be a useful fatigue management tool during unaugmented flights. Further research is necessary to determine the impact of factors on the decision to take controlled rest (e.g., airline culture, personal preference) and how the controlled rest policy is applied in practice.

aviation↗
NASA NTRSDate not supplied

The Impact of Controlled Rest on Self-Reported Sleepiness at Top-of-Descent

INTRODUCTION: Long and irregular working hours can lead to fatigue in aviation operations. In some regions, a short nap taken on the flight deck (known as controlled rest) can be used as a countermeasure to unexpected in-flight sleepiness. We aimed to investigate the impact of taking controlled rest on self-reported sleepiness at top-of-descent. METHODS: Data from 120 long-haul (> 6 h flight duration), unaugmented flights were analyzed (n = 31 pilots). Pilots wore actigraphs and completed sleep logs before and during trips. At pre-flight and top-of-descent, pilots completed a Karolinska Sleepiness Scale (KSS). A mixed-effects model was used to assess the impact of controlled rest on KSS at top-of-descent. Sleep duration in the 48 hours prior to departure, timing of the flight (day vs. night), and pre-flight KSS scores were included as covariates. RESULTS: Due to missing data, complete data from 83 flights (n = 29 participants) were available in the analyses of the KSS. There were no differences by controlled rest status for KSS scores at top-of-descent (estimated marginal means ± SEM with controlled rest: 5.10 ± 0.22, without controlled rest: 5.37 ± 0.29; p = .45, η2p = 0.01). DISCUSSION: Our results suggest that there is no difference in self-reported sleepiness at top-of-descent on flights in which controlled rest was taken compared to flights without controlled rest. Further research is necessary to determine the impact of controlled rest on objective measures of performance at top-of-descent.

aviation↗
NASA NTRSDate not supplied

Planetary Protection

Explore the source record for details and available documents.

Amy Baker↗
NASA NTRSDate not supplied

Cabin Crew Alertness and Performance During Long-Haul Flights

INTRODUCTION: -Sleep loss and circadian disruption pose a significant risk in aviation. -Previous literature has shown that inflight rest facilities influence alertness and performance among pilots, but few studies have evaluated cabin crew. -The aim of this research was to assess alertness and performance among cabin crew members sleeping in different rest locations during a long-haul out-and-back trip. METHODS: -Twenty-nine cabin crewmembers flew the same long-haul route (outbound and inbound). -Participants were randomly assigned to fly on an aircraft with a bunk in both directions or to fly an aircraft with a bunk in one direction and with a high comfort jump seat (HCJS) in the other direction. -Throughout the study they completed a Karolinska Sleepiness Scale (KSS) and a 5-minute Psychomotor Vigilance Task (PVT) at the beginning and at the end of each flight. RESULTS: -A series of mixed-effects models were performed to assess the changes in KSS and PVT when crewmembers slept in the bunk during both directions of flight (bunk-only) compared to when sleep was obtained in the HCJS during one direction and bunk in the other (bunk + HCJS). -There was no significant difference in KSS alertness between the two conditions. - There were no significant differences in PVT response speed or lapses between the two conditions. CONCLUSIONS: -Limitations: small number of participants. Our study stopped abruptly because of the COVID-19 pandemic which limited our sample size. -Further research is needed to understand how other factors such as duty start time and workload might influence the sleep of cabin crewmembers during long-haul flights.

long-haul↗