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NASA NTRSDate not supplied

Increasing Cognitive Ability/Reserve Using Software – Pilot (ICARUS-Pilot)

BACKGROUND This research study was competitively awarded under the 2022 JSC Innovation Charge Account (ICA) program administered by NASA Johnson Space Center’s Joint Technology Working Group. Study period of performance was May through September 2022, with a maximum allowed procurement budget of $10K. The study sought to quantify and assess the potential benefit of using commercial-off-the-shelf (COTS) cognitive training software to improve cognitive performance in an astronaut-like terrestrial population. METHODS Five volunteer research participants were recruited from the JSC employee population to mimic certain demographic characteristics of the NASA astronaut population (age, education/discipline). Participant cognitive performance was assessed before and after executing eighteen sessions of remote cognitive training executed nominally three times per week using six exercises within an adaptive app-based COTS software package (BrainHQ, Posit Science) on study-provided tablets. Pre- and post-training cognitive performance was measured using internal assessments in BrainHQ as well as Cognition Test Battery (CTB) version ISS B01 v3 (3.0.9-201710021500), an independent software test developed specifically for NASA and used currently in research studies on astronauts. BrainHQ exercises were posited to map well or partially to several CTB sub-tests. Participants provided feedback on their study experience formally via semi-structured interview at the conclusion of testing and informally throughout the study if they encountered issues. RESULTS The enrolled ICARUS-Pilot study participants generally matched Artemis crew demographic characteristics. Four of five participants have completed study training and assessment activities as of the writing of this abstract. These test participants complied well with desired training session frequency and duration yielding an average cumulative active training duration of 15 hours over an average of 45 days; participants showed 78% average improvement in metric performance for the six trained exercises, with an associated overall 33%ile ranking increase against performance of the entire BrainHQ subscribing population for internal pre/post assessment, agreeing with post-study survey self-reported performance increases. CTB overall feedback scoring, not corrected for learning effects, showed an average of 19% performance improvement across its 10 performance measures over the training period for the completed participants. Detailed analyses will be conducted once participant data collection for the study is complete and the resulting dataset is fully populated. DISCUSSION These preliminary results provide a positive trend for the effectiveness of the training approach, but further analysis will be needed to establish significance, investigate far transfer, and suggest the needed participant pool size for subsequent efforts to achieve statistically significant outcomes given similar results. The pilot study has already been helpful by allowing the study team to learn a great deal about the capabilities and limitations of the COTS software package that will be reflected in future proposals along with revised timelines for study execution and test participant management. From participant feedback, one common thread regarding the COTS training was that it felt overly repetitive – future proposals should reassess overall training duration, available levels for each trained exercise, and the behavior of the BrainHQ internal scheduler in determining which exercises should be trained and for how long. If the final analysis of this feasibility study ultimately supports it, the study team will recommend further investigation to fully evaluate this potential countermeasure and optimize its implementation. Future proposals would cite this feasibility study’s outcome and would seek to refine the training protocol and obtain statistically significant results for cognitive performance increases as well as retention data.

cognitive training↗
NASA NTRSDate not supplied

Increasing Cognitive Ability/Reserve Using Software – Pilot (ICARUS-Pilot)

Background: This research study was competitively awarded under the 2022 JSC Innovation Charge Account (ICA) program administered by NASA Johnson Space Center’s Joint Technology Working Group. Study period of performance was May through September 2022, with a maximum allowed procurement budget of $10K. The study sought to quantify and assess the potential benefit of using commercial-off-the-shelf (COTS) cognitive training software to improve cognitive performance in an astronaut-like terrestrial population. Methods: Five volunteer research participants were recruited from the JSC employee population to mimic certain demographic characteristics of the NASA astronaut population (age, education/discipline). Participant cognitive performance was assessed before and after executing eighteen sessions of remote cognitive training executed nominally three times per week using six exercises within an adaptive app-based COTS software package (BrainHQ, Posit Science) on study-provided tablets. Pre- and post-training cognitive performance was measured using internal assessments in BrainHQ as well as Cognition Test Battery (CTB) version ISS B01 v3 (3.0.9-201710021500), an independent software test developed specifically for NASA and used currently in research studies on astronauts. BrainHQ exercises were posited to map well or partially to several CTB sub-tests. Participants provided feedback on their study experience formally via semi-structured interview at the conclusion of testing and informally throughout the study if they encountered issues. Results: The enrolled ICARUS-Pilot study participants generally matched Artemis crew demographic characteristics. Four of five participants have completed study training and assessment activities as of the writing of this abstract. These test participants complied well with desired training session frequency and duration yielding an average cumulative active training duration of 15 hours over an average of 45 days; participants showed 78% average improvement in metric performance for the six trained exercises, with an associated overall 33%ile ranking increase against performance of the entire BrainHQ subscribing population for internal pre/post assessment, agreeing with post-study survey self-reported performance increases. CTB overall feedback scoring, not corrected for learning effects, showed an average of 19% performance improvement across its 10 performance measures over the training period for the completed participants. Detailed analyses will be conducted once participant data collection for the study is complete and the resulting dataset is fully populated. Discussion: These preliminary results provide a positive trend for the effectiveness of the training approach, but further analysis will be needed to establish significance, investigate far transfer, and suggest the needed participant pool size for subsequent efforts to achieve statistically significant outcomes given similar results. The pilot study has already been helpful by allowing the study team to learn a great deal about the capabilities and limitations of the COTS software package that will be reflected in future proposals along with revised timelines for study execution and test participant management. From participant feedback, one common thread regarding the COTS training was that it felt overly repetitive – future proposals should reassess overall training duration, available levels for each trained exercise, and the behavior of the BrainHQ internal scheduler in determining which exercises should be trained and for how long. If the final analysis of this feasibility study ultimately supports it, the study team will recommend further investigation to fully evaluate this potential countermeasure and optimize its implementation. Future proposals would cite this feasibility study’s outcome and would seek to refine the training protocol and obtain statistically significant results for cognitive performance increases as well as retention data.

cognitive training↗
NASA NTRS2004

Two-Armed, Mobile, Sensate Research Robot

The Anthropomorphic Robotic Testbed (ART) is an experimental prototype of a partly anthropomorphic, humanoid-size, mobile robot. The basic ART design concept provides for a combination of two-armed coordination, tactility, stereoscopic vision, mobility with navigation and avoidance of obstacles, and natural-language communication, so that the ART could emulate humans in many activities. The ART could be developed into a variety of highly capable robotic assistants for general or specific applications. There is especially great potential for the development of ART-based robots as substitutes for live-in health-care aides for home-bound persons who are aged, infirm, or physically handicapped; these robots could greatly reduce the cost of home health care and extend the term of independent living. The ART is a fully autonomous and untethered system. It includes a mobile base on which is mounted an extensible torso topped by a head, shoulders, and two arms. All subsystems of the ART are powered by a rechargeable, removable battery pack. The mobile base is a differentially- driven, nonholonomic vehicle capable of a speed >1 m/s and can handle a payload >100 kg. The base can be controlled manually, in forward/backward and/or simultaneous rotational motion, by use of a joystick. Alternatively, the motion of the base can be controlled autonomously by an onboard navigational computer. By retraction or extension of the torso, the head height of the ART can be adjusted from 5 ft (1.5 m) to 6 1/2 ft (2 m), so that the arms can reach either the floor or high shelves, or some ceilings. The arms are symmetrical. Each arm (including the wrist) has a total of six rotary axes like those of the human shoulder, elbow, and wrist joints. The arms are actuated by electric motors in combination with brakes and gas-spring assists on the shoulder and elbow joints. The arms are operated under closed-loop digital control. A receptacle for an end effector is mounted on the tip of the wrist and contains a force-and-torque sensor that provides feedback for force (compliance) control of the arm. The end effector could be a tool or a robot hand, depending on the application.

Engelberger, J. F.↗
NASA NTRS1982

Nondestructive evaluation techniques for nickel-cadmium aerospace battery cells

The ac impedance characteristics of Ni-Cd cells as an in-situ, nondestructive means of determining cell lifetime, particularly with respect to the probability of premature failure were evaluated. Emphasis was on evaluating Ni-Cd cell impedance over a wide frequency range (10,000 to 0.0004 Hz) as the cells were subjected to charge/discharge cycle testing. The results indicate that cell degradation is reflected in the low frequency (Warburg) impedance characteristics associated with diffusion processes. The Warburg slope (W) was found to steadily increase as a function of cell aging for completely discharged cells. In addition, based on data for two cells, a high or rapidly increasing value for W signals imminent cell failure by one mechanism. Degradation by another mechanism is apparently reflected in a fall-off (roll-over) of W at lower frequencies. As a secondary result, the frequency dependence of the absolute cell impedance at low frequencies (5 - 500 mHz) was found to be a good indication of the cell state-of-charge.

Haak, R.↗
NASA NTRS2021

NASA Electric Vertical Takeoff and Landing (eVTOL) Aircraft Technology for Public Services – A White Paper

History has shown that our personal life is highly dependent on the technology that people have developed. A strategic scan of the aerospace environment at the beginning of the 21st century strongly suggests that the world might be approaching a new age of airpower—the era of electrified/hybrid aircraft propulsion. Undeniably, starting from the Montgolfier Brothers balloon flight in 1783, to the Wright Brothers piston engine flight in 1903, and the jet engine of the 1960s, or the space age of today, one can say that leaps in propulsion technology have marked the different ages of human flight. The technological advancements, brought at the beginning of 21st century by the revolution in data exchange, computational power, sensors, wireless communication, internet, and autonomy, contributed to the vision of this new age of propulsion we are approaching. Historically, conventional vertical takeoff and landing (VTOL) aircraft have been equipped with propulsion units relying on complex internal combustion machines (turbines, piston engines, for example), and complex mechanical arrangements (gearboxes, shafts, variable pitch propeller). By contrast, electric VTOL aircraft (eVTOL)1 rely on simpler propulsion units (electric motors and in some cases fixed-pitch propellers). This promotes redundancy and improves tolerance to failures, in turn improving safety. The use of simpler electric propulsion units should also allow significant acquisition and operating cost reductions. Whether full-electric (relying solely on batteries) or hybrid-electric (relying on a combination of batteries, fuel-powered engines, and generators.), eVTOLs are also expected to generate less noise and air pollution than conventional aircraft with similar payloads. According to the 2019 Annual Review of IATA (International Air Transport Association) [ref.1], due to an expected increase in air transport traffic by 5% every year and a doubling of air transport passenger numbers to 8.2 billion by 2037 significant challenges are posed to the aviation industry. Furthermore, this report does not factor in the expected demand for short-range (intra-city) air transportation, which is in development and yet to be operational. The increased demand to fly creates a responsibility to expand in a sustainable manner and an endeavor to develop more environmentally-friendly aircraft. eVTOL aircraft, either piloted or autonomous, is gathering considerable interest worldwide. Modern and novel full-electric or hybrid-electric eVTOL configurations enable a new paradigm shift in air transportation as the aviation industry remains committed to its goals of carbon-neutral growth from 2020 onwards and cutting CO2 emissions to half 2005 levels by 2050. While electric power has been used for decades, recent developments in mobile electric/hybrid propulsion coupled with advanced materials and autonomous systems may create the possibility to transition into the next age of air mobility propelled by electric/hybrid VTOL aircraft technology. Although eVTOL aircraft might seem like an incremental improvement or even a counterintuitive regression with regard to past VTOL development, it has in fact the potential to transform air mobility across a wide range of government applications. Previous transformations in aviation generated dramatic leaps in performance, but the cost was commensurate with performance, limiting quantity produced. This next age appears to take a different approach. Performance may not increase, but at this moment technology is poised for future urban mobility that will spawn commercial passenger drone services, that is, autonomous (pilotless) air taxis and thereby add a new dimension to the urban transportation mix of the future [ref. 2]. Advances in electric propulsion, autonomous flight technology, and 5G communication networks will enable this fast new-growing market to become a reality. It is now time to envision the introduction of electric/hybrid eVTOL aircraft for Public Services2. We believe that in the next decades eVTOL aircraft will have the potential to become an essential tool to Public Service agencies around the world in applications such as firefighting, public safety, search and rescue, disaster relief and law enforcement. This is due to several major factors. • First, with the increasing popularity of small, unmanned aircraft vehicles (UAVs) or drones, many companies today are focusing on the development of passenger UAVs designed to accommodate up to five passengers or equivalent cargo payload. Many such configurations are electric or hybrid-electric designs with VTOL capabilities. Several of these projects have started a flight test program and many more are expected to be in the experimental and development phase in 2020. Such revolutionary vehicles could be in commercial operations by 2030. These eVTOL systems could be ready for selected Public Services missions even sooner. • Second, although these advanced eVTOL vehicles under development still need access to fuel (hybrid) and/or electric charging capability, they can take off and land from almost anywhere. Therefore, such vehicles, both manned and unmanned can be successfully integrated for the critical missions of the Public Services with extra deployment flexibilities. • Third, advancement in electric propulsion systems in the automotive industry together with NASA’s leading efforts in electrification of aircraft propulsion systems, FAA’s ongoing active eVTOL certification programs, and EASA’s proposed framework for the certification of electric/hybrid small category VTOL aircraft in Europe [ref. 3] will help accelerate industry electric propulsion system development and integration. • Finally, eVTOL vehicles could be deployed for Public Services sooner than air taxi or other commercial applications, since Public Services missions may be more easily approved based on specific mission criteria, localized airworthiness authority for public-use aircraft3, and are normally operating under centralized airspace management and control by the theater command. Moreover, public perception and acceptance are generally less of a concern when operations save lives and benefit the wider community. The prioritized introduction of eVTOL aircraft in Public Services is ambitious, but we believe it is achievable in the coming decades if fundamental enablers (people and technologies) are engaged in defining the objectives and needs of these missions. The revolution that is currently taking place in eVTOL aircraft represents an unprecedented opportunity to develop a safer, more affordable, more available and more environmentally friendly future of vertical flight. To ensure that these novel aircraft meet the future expectations of Public Services, it is essential to take a collaborative and multi-disciplinary approach to their development, across engineering disciplines, policy-making, program management, business case development, manufacturing, and flight demonstrations. It should be noted that the term eVTOL (in the near term) used throughout this publication implies aircraft capable of transporting up to 5 persons which may or may not include a pilot if operated fully autonomously, assuming an average of 200 pounds (91 kg) per person or equivalent payload and a range up to 60 miles plus a suitable reserve. Hybrid or hydrogen powered eVTOLs would have greater range. For example, a “3-seat” eVTOL aircraft may only be able to carry two fully equipped firemen, and payload capacity is more relevant when used for the supply mission. Moreover, this paper concentrates on the “last-mile” solutions with a deployment time of no more than 6 hours. Although not specifically discussed in this document, it is understood that the future of Transformative Vertical Flight in general and Public Services, in particular, will also involve smaller UAVs that will undoubtedly play a crucial role in future aerial operations. For example, smaller unmanned aircraft may be used to dispatch medical supplies, portable filtration systems or perform the Search task of future Search and Rescue (SAR) operations. Close collaboration between the aircraft industry, the Civil Aviation Authorities (CAA), e.g., Federal Aviation Administration (FAA), European Aviation Safety Agency (EASA), Transport Canada Civil Aviation (TCCA) and the Department of Defense (DoD) certifiers, will help identify Public Services requirements, define expectations and limit development cost and timescales. Take the US Air Force Agility Prime as an example, the majority of the eVTOL application opportunities and mission elements identified are in line with the NASA TVF WG-4 objectives and use cases. Together, it forms a strong partnership to accelerate the development, certification, and practical deployment for public service missions. The US Air Force Agility Prime has been a collaboration partner on this white paper, and provided valuable input and recommendations. Most of the eVTOL public service mission elements discussed in this paper and additional use cases envisioned by the NASA TVF WG-4 team are shared by the Agility Prime program. The focus and efforts of the Agility Prime in product and system development, industry and government partnership, accelerated certifications as well as early test and deployment are totally in sync with the path forward recommended by this white paper. This kind of collaboration and partnership will help enable the practical use of the eVTOL for public service missions, benefit the eVTOL public acceptance, and accelerate the eVTOL industry revolution.

Johnny T. Doo↗
NASA NTRS2020

CloudSat - From the A-Train to the C-Train

The CloudSat satellite was launched from Vandenberg Air Force Base, in California, on April 28, 2006. It was launched with the CALIPSO satellite, a joint mission between the National Aeronautics and Space Administration (NASA) and the Centre National D'Etudes Spatiales (CNES). CloudSat and CALIPSO were designed to fly in formation with each other, to combine their complimentary scientific measurements. The two missions were maneuvered into the Earth Science Afternoon Constellation (A-Train) shortly after launch and have flown in formation together since then. Originally designed to fly for 22 months, the CloudSat satellite has far exceeded expectations. Inflight anomalies on CloudSat necessitated changes to both the daily concept of operations and formation flying operations with CALIPSO. In 2011, a severe battery anomaly restricted CloudSat science data collection and maneuverability to the sunlit portions of the orbit. In 2017, CloudSat suffered a reaction wheel failure, triggering the criteria established to exit the A-Train. CloudSat successfully exited the A-Train in early 2018, suspending formation flying and joint science observations with CALIPSO. The joint CloudSat/CALIPSO science team continued collaboration with discussions focused on resuming joint observations. As both satellites were aging and CALIPSO was nearing the exhaustion of satellite propellant, the decision was made to lower CloudSat to the CALIPSO graveyard orbit, to be joined by CALIPSO as soon as feasible. With NASA’s approval, CloudSat was maneuvered to the lower orbit over the course of several months in mid-2018. Once CloudSat was in place, and with approval from CNES, CALIPSO began the delicate dance of lowering their orbit and re-aligning the satellite ground tracks. CloudSat and CALIPSO resumed formation flying in the newly dubbed C-Train (CloudSat and CALIPSO) orbit in the Fall of 2018. The ingenuity of the CloudSat and CALIPSO teams made the concept of the C-Train a reality. This paper will discuss the decision processes and the operational challenges the CloudSat flight team faced while designing and implementing the C-Train.

Witkowski, M.M.↗
NASA NTRS1994

Intermittent gravity: How much, how often, how long?

Continuous exposure to gravity may not be necessary to prevent the deconditioning effects of microgravity. It is not known, however, what the minimum gravity (G) exposure reguirements are, whether they vary for different physiological systems, or whether passive Gz (gravity in the head-to-toe vector) or activity in a G field is more effective in preventing deconditioning. It is also not known what the optimal characteristics of the G stimulus should be in terms of amplitude, duration, and frequency. To begin to address these questions, a 4-day -6 deg head-down bed rest (HDBR) study was conducted. Nine males (aged 30-50 yr) were subjected, over a period of seven months, to four different +1 Gz exposure protocols (periodic standing or controlled walking each for a total of 2 or 4 hr/day in individual 15-min doses), plus a control (0 Gz) of continuous HDBR. The study consisted of one ambulatory control day, 4 full days of -6 deg HDBR, and a recovery day when subjects were released at the end of HDBR after completion of tests. A battery of tests was selected and standardized in order to evaluate the known early responses to HDBR. Dependent variables of interest included orthostatic tolerance (30 min at 60 deg head-up tilt) and hemodynamics during head-up tilt, peak oxygen consumption (VO2(sub peak)) plasma volume (PV), and urinary calcium (Ca). The results were as follows: 4 hr standing completely prevented and 2 hr walking partially prevented post-HDBR orthostatic intolerance. Walking at 3 mi/hr for 4 hr/day provided no additional benefit. Intermittent walking attenuated, but did not prevent, the decrease in VO2(sub peak). Both 4 hr conditions showed less PV loss by the end of HDBR; both 2 hr conditions were without effect. Both 2 and 4 hr walking essentially prevented urinary Ca excretion and were more effective than standing. It is concluded that different physiological systems benefit differentially from passive +1 Gz or activity in +1 Gz, and the intensity of the stimulus may be an important contributing factor.

Vernikos, Joan↗
NASA NTRS2009

Respiratory Toxicity of Lunar Highland Dust

Lunar dust exposures occurred during the Apollo missions while the crew was on the lunar surface and especially when microgravity conditions were attained during rendezvous in lunar orbit. Crews reported that the dust was irritating to the eyes and in some cases respiratory symptoms were elicited. NASA s vision for lunar exploration includes stays of 6 months on the lunar surface hence the health effects of periodic exposure to lunar dust need to be assessed. NASA has performed this assessment with a series of in vitro and in vivo tests on authentic lunar dust. Our approach is to "calibrate" the intrinsic toxicity of lunar dust by comparison to a nontoxic dust (TiO2) and a highly toxic dust (quartz) using intratrachael instillation of the dusts in mice. A battery of indices of toxicity is assessed at various time points after the instillations. Cultures of selected cells are exposed to test dusts to assess the adverse effects on the cells. Finally, chemical systems are used to assess the nature of the reactivity of various dusts and to determine the persistence of reactivity under various environmental conditions that are relevant to a space habitat. Similar systems are used to assess the dissolution of the dust. From these studies we will be able to set a defensible inhalation exposure standard for aged dust and predict whether we need a separate standard for reactive dust. Presently-available data suggest that aged lunar highland dust is slightly toxic, that it can adversely affect cultured cells, and that the surface reactivity induced by grinding the dust persists for a few hours after activation.

James, John T.↗
NASA NTRSDate not supplied

A Notional Artemis Lunar Surface Exploration Package (ArLSEP) based on the Gandalf Staff Platform

Introduction: The Artemis program is planning to deliver crew and cargo to the lunar surface, but there is no current package for supporting lunar in-struments and experiments similar to the Apollo Lunar Surface Exploration Package (ALSEP). This abstract provides a possible concept for such a package using the Gandalf Staff Platform as a common core. Gandalf Staff: The Gandalf Staff is an early prototype system developed over FY’21/FY’22 using NASA Science Technology Mission Directorate (STMD) Center Information Fund (CIF) grants to de-sign, build and test “proof-of-concept” components. These components include a 24v battery powered monopole that powers a suite of subsystems, including a Graphical User Interface (GUI) for crew, surface voice and data communications, Lunar Search and Rescue (LunaSAR) navigation and communications, LiDAR, field site external lighting, 360-degree camera, and a geothermal instrument for measuring sub-surface temperature gradient. The staff can be carried independently by an Extra-Vehicular Activity (EVA) astronaut, or can be mounted into a tripod for “hands free” support at a surface site being investigated. The staff can be attached to an external solar array and power storage system for long-duration operations. [1,2] ALSEP: An ASLEP flew on each mission Apollo 12 to Apollo 17. For Apollo 11, a simplified packaged called the Early Apollo Scientific Experiments Pack-age (EASEP) was flown. Each package included a “Central Station” that provided the power and communications connected to a variety of instruments and sensors. The power was provided by a Radioisotope Thermoelectric Generator (RTG) fueled by Plutoni-um-238 generating 70 watts of power (initially, decayed over time) [3]. The communications system provide for direct to Earth data transfer from the lunar surface. Each pack-age was stowed externally in the Lunar Module (LM) Scientific Equipment (SEQ) bay with a mass up to 163 kg (Apollo 17). The crew unloaded the ALSEP from the LM and deployed the instruments on the lunar surface. Although designed to operate for only 1 year, many sites operated for up to 8 years successfully [4]. The Active Seismic Experiment (ASE) included 3 geophones for detecting seismic waves created by mortars and thumpers deployed by the crew. Other active experiments measured the lunar atmosphere, the heat flow in the subsurface, the lunar gravity and potential gravity waves, the lunar magnetic field, the solar wind and plasma interactions in cislunar space. Passive experiments included collectors for dust and cosmic rays, and retroreflectors for precise measurements of distance using a laser from Earth. The ALSEP program continues to generate insights into lunar formation and evolution. ArLSEP Concepts: The lunar surface science package for the Artemis program will hopefully exceed the capability of the ALSEP. There are multiple issues for discussion leading to the design of a new ArLSEP, needing requirements definition from the science community, NASA mission architecture, and NASA budget planners. 1. Delivery Mechanism Two possible projects currently provide capability to deliver scientific cargo to the lunar surface: 1) the Commercial Lunar Payload Services (CLPS) [5] and the Human Landing System (HLS) [6, 7]. Each project is controlled by a different organization within NASA and budgeted with different criteria although both support lunar exploration. The HLS system delivers crew (and potentially cargo) to human landing sites. If an ArLSEP is “predeployed” to such a site, the design must include power (either from the vehicle or independently) to keep the electronics functioning until deployed by the crew. If an ArLSEP is delivered on a vehicle after the crew is present on the lunar surface, safety protocols require adequate distance from the humans for impact from descent propelled sur-face regolith ejecta. This distance can not exceed the capability of the crew to walk (if no rover) to the vehicle for ArLSEP deployment. 2. Overall Guidelines The general design of ArLSEP will likely follow the ALSEP with a common system for communications and power; however, significant architecture differences between Apollo and Artemis exist. Power: The RTG will not be available for early Artemis missions nor likely follow-on Lunar Exploration Transportation Services (LETS) missions [8]. Thus, ArLSEP power must be supplied by solar arrays with sufficient battery capability to “keep alive” necessary electronics during any lunar surface eclipse period. Communication: The Artemis program is developing a series of communications satellites for lunar orbit to provide surface transmission of data and voice to Earth. Called “LunaNET”, this network is component useful for ArLSEP since south polar locations may not always have direct “line-of-sight” to Earth [9]. 3. Concept of Operations (ConOps) The general ConOps for ArLSEP is to deliver the package to lunar surface before the crew arrives, and then have the crew deploy the package after some period of time. This requires coordinated design (for power systems) and launch window (for schedule) on both the cargo and crew missions. Once the ArLSEP is deployed, it will operate autonomously for a number of years. It should be designed to be EVA compatible for crew maintenance and upgrade. 4. Notional Design (for discussion purpose only) The landing site near the South Pole is expected to have no eclipse cycle exceeding 5 days, so the “keep alive” power is 144 hours (6 days to include margin). A 12v ArLSEP will use rechargeable LiFePO4 cells, which are common in the Electric Vehicle (EV) industry. With a current of 5 amps and a 125 watt system, the mass is about 90kg. The comm. system and structure adds another 10kg, thus the “Central Station” is approximately 100kg. The solar power is collected on four arrays (each 2m above the surface), and the entire ArLSEP is designed to stow in a 2m x 1m x 1m volume. The experiment and instrument design will vary for each installation and add mass to the total (although they are expected to fit within the 2m3 volume). Seismic wave generation will likely not be provided with mortars, thus an electric “thumper” will be required. Active instruments such as imaging systems and sensing instruments will benefit from the additional power and communication capability provided by ArLSEP. Passive systems such as retroreflectors, witness plates, and cosmic dust collectors can be added to either the landing vehicle and/or the ArLSEP. With repeated HLS missions to the same human site, the ArLSEP can be expanded and easily maintained for long duration science collection on the lunar surface.

ALSEP↗
NASA NTRS2011

Identification of Cardiometabolic Vulnerabilities Caused by Effects of Synergistic Stressors that are Commonly Encountered During Space Missions

Microgravity is a physiologically challenging state even when at rest. Astronauts experience additional physical and mental stresses, such as prolonged exertion, sleep loss and circadian misalignment, that could impact cardiovascular function. The main goals of this four year NASA project are to characterize the independent and synergistic effects on cardiovascular and immune function of: (1) circadian misalignment; (2) sleep loss; and (3) varied physical and mental stressors, mimicking some of the synergistic stressors experienced by astronauts. Sixteen healthy volunteers, aged 35-55 years, will be studied with standardized behavioral stressors occurring across all circadian phases, both with and without accruing sleep loss, achieved via two 11-day "forced desynchrony" protocols performed in each subject (randomized, within-subject design), where wake periods are advanced 4-h each "day" (i.e. recurring 20-h "days"). One protocol permits 8.33 h sleep opportunity per 20-h "day" (=10 h sleep per 24-h), and the other permits 5 h sleep per 20-h "day" (=6 h sleep per 24-h; matching the reported sleep duration of astronauts). In both protocols, subjects will perform a standardized stress battery including a cognitively challenging task; bicycle exercise, and passive 60deg head up tilt. Outcome variables include blood pressure, heart rate, arrhythmia frequency, cardiac vagal tone (from heart rate variability), sympathetic activity (catecholamines), and endothelial function. Additional measures of cardiac function (echocardiography), responses to a passive 80deg head up tilt, maximal oxygen uptake, and immune function will be assessed at the beginning and at the end of each protocol (i.e., without and with sleep loss, and before and after circadian misalignment). We hope to identify the relative impact on cardiovascular risk markers of varied behavioural stressors while subjects experience circadian misalignment and sleep loss, mimicking some of the synergistic stressors experienced by astronauts. Supported by NASANNX1 OAR 1 OG.

Ruger, M.↗
NASA NTRS2005

Fatigue Behavior and Deformation Mechanisms in Inconel 718 Superalloy Investigated

The nickel-base superalloy Inconel 718 (IN 718) is used as a structural material for a variety of components in the space shuttle main engine (SSME) and accounts for more than half of the total weight of this engine. IN 718 is the bill-of-material for the pressure vessels of nickel-hydrogen batteries for the space station. In the case of the space shuttle main engine, structural components are typically subjected to startup and shutdown load transients and occasional overloads in addition to high-frequency vibratory loads from routine operation. The nickel-hydrogen battery cells are prooftested before service and are subjected to fluctuating pressure loads during operation. In both of these applications, the structural material is subjected to a monotonic load initially, which is subsequently followed by fatigue. To assess the life of these structural components, it is necessary to determine the influence of a prior monotonic load on the subsequent fatigue life of the superalloy. An insight into the underlying deformation and damage mechanisms is also required to properly account for the interaction between the prior monotonic load and the subsequent fatigue loading. An experimental investigation was conducted to establish the effect of prior monotonic straining on the subsequent fatigue behavior of wrought, double-aged, IN 718 at room temperature. First, monotonic strain tests and fully-reversed, strain-controlled fatigue tests were conducted on uniform-gage-section IN 718 specimens. Next, fully reversed fatigue tests were conducted under strain control on specimens that were monotonically strained in tension. Results from this investigation indicated that prior monotonic straining reduced the fatigue resistance of the superalloy particularly at the lowest strain range. Some of the tested specimens were sectioned and examined by transmission electron microscopy to reveal typical microstructures as well as the active deformation and damage mechanisms under each of the loading conditions. In monotonically strained specimens, deformation during the subsequent fatigue loading was mainly confined to the deformation bands initiated during the prior monotonic straining. This can cause dislocations to move more readily along the previously activated deformation bands and to pile up near grain boundaries, eventually making the grain boundaries susceptible to fatigue crack initiation. The mechanisms inferred from the microstructural investigation were extremely valuable in interpreting the influence of prior monotonic straining on the subsequent fatigue life of Inconel 718 superalloy.

Source record↗
NASA NTRS2005

Advanced Joining Technology: Simple, Strong, and Secure

The space-age materials that NASA employs in its spacecraft and satellites have different attributes than the building materials that can work for Earthly uses. These materials do not behave like the typical construction materials, and therefore, require new methods for construction. Work done at NASA s Langley Research Center in the realm of active solder joining has led to a new, self-bonding solder that enables high conductivity, as well as the metallic joining of carbon and ceramic materials to a wide range of metals. The original work involved evaluating high- and low-temperature joining technologies for joining carbon composite structures for use in thermal management and reusable launch vehicles. The initial plan for this innovation was to lower the weight of battery packs in satellites. It was a success. NASA scientists found use for this technology in fabricating a thermal management package for battery compartments in the Earth Observing System (EOS) satellites, but it is also being used by the Agency for space radiator panels. Because it is light, simple to use, and economical, NASA will likely find other uses for this solder, just as outside of the Space Agency, this unique bond is finding many practical applications.

Source record↗
NASA NTRS2011

Comparison of Ocular Outcomes in Two 14-Day Bed Rest Studies

Reports of astronauts visual changes raised concern about ocular health during long-duration spaceflight. Some of these findings included hyperopic shifts, choroidal folds, optic disc edema, retinal nerve fiber layer (RNFL) thickening, and cotton wool spots. While the etiology remains unknown, hypotheses speculate that hypertension in the brain caused by cephalad fluid shifts during spaceflight is a possible mechanism for these ocular changes. Head-down tilt (HDT) bed rest is a spaceflight analog that induces cephalad fluid shifts. In addition, previous studies of the HDT position demonstrated body fluid shifts associated with changes in intraocular pressure (IOP). For these reasons, vision monitoring of HDT bed rest subjects was implemented for NASA bed rest studies. Subjects selected for these studies were healthy adults (14 males and 5 females). Average age was 37.5 plus or minus 9.1 years, weight was 77.4 plus or minus 11.3 Kg, and height was 173.4 plus or minus 7.2 14 cm. Controlled conditions followed for all NASA bed rest studies were implemented. These conditions included factors such as eating a standardized diet, maintaining a strict sleep wake cycle, and remaining in bed for 24 hours each day. In one study, subjects maintained a horizontal (0 degree) position while in bed and were exercised six days per week with an integrated resistance and aerobic training (iRAT) program. In the other study, subjects were placed at 6 degrees HDT while in bed and did not engage in exercise. All subjects underwent pre- and post bed rest vision testing. While the battery of vision tests for each study was not identical, measures common to both studies will be presented. These measures included IOP and measures that provided an indication of optic disc swelling as derived from optical coherence tomography (OCT) testing: average retinal nerve fiber layer (RNFL) thickness (millimeters), disc area (square millimeters), rim area (square millimters), and average cup to disc (C/D) ratio. For all measures, there was no significant difference between subject groups for pre-bed rest testing. Post bed rest values also remained similar between groups. Comparison of pre- to post bed rest testing within each group did not demonstrate any statistical differences. These preliminary results from 14-day bed rest studies suggest that the combination of exercise and horizontal bed rest as compared to 6 degrees HDT bed rest did not produce differences in the ocular response with regard to IOP and optic disc parameters. The ocular measures reported here only included pre- and post bed rest time points. Further investigation is needed to examine both the acute response and long term adaptation of structural and functional ocular parameters in the bed rest platform and determine its usefulness for studying spaceflight phenomena. From a clinical perspective, the ability to study ocular responses in the controlled environment of the bed rest platform can provide valuable information for the care of patients restricted to bed rest.

Cromwell, R. L.↗
NASA NTRS2012

Solid State Multinuclear Magnetic Resonance Investigation of Electrolyte Decomposition Products on Lithium Ion Electrodes

Solid electrolyte interphase (SEI) formation in lithium ion cells prepared with advanced electrolytes is investigated by solid state multinuclear (7Li, 19F, 31P) magnetic resonance (NMR) measurements of electrode materials harvested from cycled cells subjected to an accelerated aging protocol. The electrolyte composition is varied to include the addition of fluorinated carbonates and triphenyl phosphate (TPP, a flame retardant). In addition to species associated with LiPF6 decomposition, cathode NMR spectra are characterized by the presence of compounds originating from the TPP additive. Substantial amounts of LiF are observed in the anodes as well as compounds originating from the fluorinated carbonates.

Li-ion battery electrolytes↗
NASA NTRS2007

Thermal Characterization Study of Lithium-Ion Cells

The primary challenge in designing a full scale lithium-ion (Li-ion) battery system is safety under both normal operating as well as abusive conditions. The normal conditions involve expected charge/discharge cycles and it is known that heat evolves in batteries during those cycles. This is a major concern in the design for high power applications and careful thermal management is necessary to alleviate this concern. An emerging thermal measurement technology, such as the electrochemical calorimetric of batteries, will aid in the development of advanced, safe battery system. To support this technology, several "commercial-off-the-shelf" (COTS) Li-ion cells with different chemistries and designs are being evaluated for different cycling regimes at a given operating temperature. The Accelerated Rate Calorimeter (ARC)-Arbin cycler setup is used to measure the temperature, voltage, and current of the cells at different charge/discharge rates. Initial results demonstrated good cell cyclability. During the cycle testing, the cell exhibited an endothermic cooling in the initial part of the charge cycle. The discharge portion of the cycle is exothermic during the entire discharge period. The presence of an endothermic reaction indicates a significant entropy effect during the beginning of charge cycle. Further studies will be performed to understand the thermal characteristics of the Li-ion cells at the different operating conditions. The effects on the thermal response on cell aging and states-of-charge will also be identified.

Britton, Doris L.↗
NASA NTRS2002

Optimal Charging of Nickel-Hydrogen Batteries for Life Extension

We are exploring the possibility of extending the cycle life of battery systems by using a charging profile that minimizes cell damage. Only nickel-hydrogen cells are discussed at this time, but applications to lithium-ion cells are being considered. The process first requires the development of a fractional calculus based nonlinear dynamic model of the specific cells being used. The parameters of this model are determined from the cell transient responses. To extend cell cycle life, an instantaneous damage rate model is developed. The model is based on cycle life data and is highly dependent on cell voltage. Once both the cell dynamic model and the instantaneous damage rate model have been determined, the charging profile for a specific cell is determined by numerical optimization. Results concerning the percentage life extension for different charging strategies are presented. The overall procedure is readily adaptable to real-time implementations where the charging profile can maintain its minimum damage nature as the specific cell ages.

Hartley, Tom T.↗
NASA NTRSDate not supplied

Evaluating Sensory Augmentation as A Non-Pharmaceutical Tool to Mitigate Motion Sickness and Enhance Sensorimotor Task Performance: A Pilot Study Using Simulated Capsule Wave Motion

Wave motion during capsule recovery operations can result in motion sickness and performance decrements exacerbating reentry sickness following long duration spaceflight. The purpose of this pilot study was (1) to validate a capsule wave motion simulation as a platform to evaluate motion sickness countermeasures and (2) to evaluate a sensory augmentation belt providing vibrotactile feedback of gravitational upright. Ten healthy subjects ages 38.0 ± 10.1 (6M|4F) were exposed to complex wave motions on a six degree-of-freedom platform that included pitch, roll, and heave at provocative stimulus frequencies (0.1-0.25 Hz) while seated in an illuminated cabin deprived of external visual cues. Subjects reported acute symptoms for up to three consecutive 15 min trials or until they reached a motion sickness endpoint of 8 pts on the Pensacola Diagnostic Index (PDI). Five subjects were randomly assigned to the Sensory Augmentation (SA) group while the other five served as controls (CN group). Based on a Motion Sickness Susceptibility Questionnaire, the two groups had similar motion sickness histories (susceptibility percentile ranking of CN group = 27.5 ± 63.6 in the CN group versus 27.5 ± 37.0 in the SA group, median ± IQR). The vibrotactile feedback consisted of a single array of 8 electromechanical tactors positioned around the torso on an adjustable belt (Engineering Acoustics, Inc) that utilized an integrated inertial measurement unit (IMU) to indicate the direction of upright (e.g., subject’s back tactor on during forward tilt). During each wave motion trial subjects performed a battery of four different tasks: tracking Earth vertical using a joystick with and without a secondary task (Paced Auditory Serial Addition Test), an eye-hand target acquisition task on a cabin-fixed tablet, and the psychomotor vigilance test (PVT). All ten subjects reported varying levels of motion sickness with 6 of 10 reaching a symptom endpoint. Interestingly, subjects anecdotally reported that engagement in the joystick tracking task was less provocative than tasks involving the cabin-fixed tablet or periods of no activity. Sensory augmentation appeared to delay symptom onset, with 2 of 5 subjects reaching an endpoint within the first 15 min trial in the CN group versus none in the SA group (PDI after 15 min = 6.0 ± 2.5 in the CN group versus 3.4 ± 2.5 in the SA group, mean ±std). Sensory augmentation also improved performance on the joystick tracking task at lower stimulus frequencies (0.1 Hz in roll and 0.2 Hz in pitch). Both CN and SA groups maintained a consistent level of performance on the eye-hand target acquisition and PVT throughout the baseline (no motion) and wave motion periods. Our results validated that the simulated capsule wave motion paradigm provides an effective motion sickness stressor. This paradigm is currently being used to investigate the efficacy of intranasal scopolamine to mitigate motion sickness. Sensory augmentation using vibrotactile feedback appears to improve spatial awareness and delay symptom onset during complex passive motion. One advantage of this portable belt design is that it incorporates all tactor drive and IMU circuitry and therefore could continue to be worn by crewmembers and serve as a balance aid during egress and ambulation with recovery operations.

A M Bollinger↗
NASA NTRS2001

Application of multivariate statistics to vestibular testing: discriminating between Meniere's disease and migraine associated dizziness

Meniere's disease (MD) and migraine associated dizziness (MAD) are two disorders that can have similar symptomatologies, but differ vastly in treatment. Vestibular testing is sometimes used to help differentiate between these disorders, but the inefficiency of a human interpreter analyzing a multitude of variables independently decreases its utility. Our hypothesis was that we could objectively discriminate between patients with MD and those with MAD using select variables from the vestibular test battery. Sinusoidal harmonic acceleration test variables were reduced to three vestibulo-ocular reflex physiologic parameters: gain, time constant, and asymmetry. A combination of these parameters plus a measurement of reduced vestibular response from caloric testing allowed us to achieve a joint classification rate of 91%, independent quadratic classification algorithm. Data from posturography were not useful for this type of differentiation. Overall, our classification function can be used as an unbiased assistant to discriminate between MD and MAD and gave us insight into the pathophysiologic differences between the two disorders.

NASA Discipline Neuroscience↗