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NASA NTRS1977

Comparison of dynamic stall phenomena for pitching and vertical translation motions

Test data for vertical translation motions of the V0012 and V23010-1.58 airfoils were compared with force pitch and oscillation data to determine qualitative differences in dynamic stall behavior. Chordwise differential pressure variations were examined in detail for the test conditions displaying dynamic stall. The comparison revealed a number of differences both in the onset of stall and in the progression separation as a function of the type of motion. The evidence of secondary stall events following the recovery from initial stall were found to be dependent on the type of motion, but additional data will be needed to incorporate vertical translation effects into the empirical approximation of dynamic stall.

Fukushima, T.↗

NASA NTRSDate not supplied

Vertical Translation System for the Common Habitat Architecture

The Common Habitat is a large, long-duration habitat that uses an SLS core stage Liquid Oxygen (LOX) tank as its primary structure. Measuring 8.4 meters in diameter and 15 meters in length, it is manufactured as a habitat and launched as such into space. It is intended for use on the Moon as part of a permanently occupied outpost, on Mars as part of an outpost that will be occupied for hundreds of days at a time, and in deep space as part of the Deep Space Exploration Vehicle where it will support crewed missions up to 1200 days in duration. A study of internal orientation and crew size resulted in a Common Habitat configuration sized for a crew of eight with a three-deck horizontal orientation. The Common Habitat Vertical Translation System provides a means for transporting crew and cargo between decks in a Common Habitat spacecraft in gravity levels varying from 0g to 1g. A crowdsourcing campaign was conducted through the GrabCAD platform to initially solicit ideas for restraints and mobility aids, including vertical translation. Four of the five top responses repeated ideas that would be incorporated into features of the Vertical Translation System. The first was a safety barrier (to prevent falls into the opening between decks) that could collapse to form a floor surface covering the opening when not in use. The second idea was a folding ladder that could be stowed in the ceiling when not in use. The third idea was an elevator platform that could traverse the ladder. Several key driving requirements were established for the Vertical Translation System: it may not penetrate into or through the lower deck; it must work on the Earth, Moon, Mars, and in microgravity; it must be easy to operate; it must enable translation of any item that can fit through the Common Habitat’s 40” x 60” hatches, inclusive of suited and unsuited crew with any degree of incapacitation and any equipment or cargo item; and it must include three component systems – deploying floor / safety barriers, a deployable ladder, and an elevator platform. Additional requirements were established for each of the component systems. The safety barriers must form a roughly 40-inch tall, complete wall enclosure on all four sides when deployed; it must include an easy to open gate that allows access to/from the ladder when deployed; and when retracted, the safety barrier must form a smooth, load-bearing floor that can be walked on, and wheeled objects can be rolled across in gravity, without being a trip hazard. The deployable ladder must be composed of multiple ladders that work together; it must stow in the ceiling when not in use; and it must not penetrate into the 40” x 60” vertical passage corridor. The elevator platform must work with the deployable ladder system; it must be able to bridge any gap in ladders between decks; it must stop at each deck flush with the deck surface; it must be capable of transporting an incapacitated crew member as a single rescuer operation; it must be capable of transporting a full-size subsystems pallet; it must function as an elevator for a crew member carrying large objects; it must have safety functions to prevent falls from the platform, or crew/cargo collisions with edges of hatch openings, or entanglement with ladder rungs/structure; it must stow when not in use; and it must autonomously both connect itself to the ladder and deploy itself to any deck where needed when called (e.g., a crew member on any deck can call for the platform and it must connect itself to the ladders without assistance and translate to the requestor’s deck). These requirements were developed into a system concept with the assistance of a NASA Pathways Intern who also added the requirement to size the design based on the use of commercial components, using existing motors and other mechanisms to ensure that the resulting system could be inexpensively produced. The Floor and Safety Barrier consists of four panels, two roughly 40 inches long and two roughly 60 inches long that can fold into the floor on top of each other when not in use. The uppermost panel is load bearing and acts as the floor surface. When deployed, they connect with each other to form a rigid barrier surrounding the vertical passageway. One of the panels contains a hinged gate that can be opened when deployed to allow for access to/from the passageway. The Deploying Ladder consists of two ladder segments, one mounted on the ceiling of the lower deck and the other mounted on the ceiling of the mid deck. A rotating mechanism is mounted on the ladder to allow it to rotate into a horizontal position against the ceiling for stowage, or down to a vertical position for use. A second rotating mechanism is built into the ladder, allowing the rungs to rotate. A toothed surface intended to work with the elevator platform covers the front of the ladder rails and the top and bottom of the rails are designed to be flush when aligned with another ladder segment. The elevator platform is essentially a motorized, self-propelled deck. It has a mechanism that holds it in contact with the ladder rails and drives itself against the toothed surface. This mechanism allows the elevator platform to ascend or descend the ladder. In order to stow the platform when not in use, a set of short ladder rails (without rungs) are mounted to the ceiling of the mid deck. When the mid deck ladder is stowed, it is flush with these rails and the platform can drive itself onto those short rails for stowage. An additional mechanism on the platform can pitch its deck surface 90 degrees, such that when the ladder is to be stowed, the platform can fold up against the ceiling. As a consequence of the ladder and elevator platform design, the opening between decks in the Common Habitat was enlarged to ensure that the elevator platform can accept a payload up to 40”x60” in dimension.

Human Centered Design↗

NASA NTRS2016

Vestibulo-Ocular Responses to Vertical Translation using a Hand-Operated Chair as a Field Measure of Otolith Function

The translational Vestibulo-Ocular Reflex (tVOR) is an important otolith-mediated response to stabilize gaze during natural locomotion. One goal of this study was to develop a measure of the tVOR using a simple hand-operated chair that provided passive vertical motion. Binocular eye movements were recorded with a tight-fitting video mask in ten healthy subjects. Vertical motion was provided by a modified spring-powered chair (swopper.com) at approximately 2 Hz (+/- 2 cm displacement) to approximate the head motion during walking. Linear acceleration was measured with wireless inertial sensors (Xsens) mounted on the head and torso. Eye movements were recorded while subjects viewed near (0.5m) and far (approximately 4m) targets, and then imagined these targets in darkness. Subjects also provided perceptual estimates of target distances. Consistent with the kinematic properties shown in previous studies, the tVOR gain was greater with near targets, and greater with vision than in darkness. We conclude that this portable chair system can provide a field measure of otolith-ocular function at frequencies sufficient to elicit a robust tVOR.

Wood, S. J.↗

NASA NTRSDate not supplied

Configuration and Projected Capabilities of the Common Habitat Medical Care Facility

The Common Habitat is a large, long-duration habitat being explored as part of a conceptual study (not an active NASA program) that uses an SLS core stage Liquid Oxygen (LOX) tank as its primary structure. It is intended for use on the Moon as part of a permanently occupied outpost, on Mars as part of an outpost that will be occupied for hundreds of days at a time, and in deep space as part of the Deep Space Exploration Vehicle where it will support crewed missions up to 1200 days in duration. A study of internal orientation and crew size resulted in a Common Habitat configuration sized for a crew of eight with a three-deck horizontal orientation. Additional work outside the scope of this paper is developing a vertical translation system, a crew mobility aids system based on wearable gecko-derived grippers, and a crew seating/restraint system. These systems are all assumed for use in conjunction with the Medical Care Facility, which is needed to maintain crew well-being during these missions, where distance from Earth precludes the possibility of evacuation to Earth. This paper describes recent improvements in the Common Habitat Medical Care Facility and associated benefits for crew survivability in long duration missions beyond Earth orbit. These improvements were made with the assistance of a NASA Pathways intern whose experience includes a tour of duty in Afghanistan as an Army combat medic with the 691st GHOST-T, attached to the 1st and 7th US Special Forces Groups as part of Operation Freedom’s Sentinel, where he helped provide far-forward surgical capabilities in austere combat environments. The initial baseline Medical Care Facility was developed working in conjunction with University of Houston Space Architecture graduate students. The facility was placed on the upper deck of the Common Habitat in a location that provided privacy, operational volume, and was close to the vertical translation pathway. The notional outfitting repurposed component CAD models from unrelated studies and notionally indicated a level of care roughly equivalent to that aboard the International Space Station. The CAD modeling provided notional stowage volumes, a deployable surface, some fixed equipment, an ultrasound, and a potentially reconfigurable treatment table. While this facility is clearly a competent arrangement, it was desired to leverage available expertise and upgrade the station given the vast distances from Earth to be experienced by the Common Habitat. Key driving requirements applied to the upgrade included to provide Medical Level of Care V, offer enhanced telemedicine capabilities, provide patient physical accommodation, provide caregiver access to the patient from all sides, include sliding pocket doors for access to hygiene and to the Vertical Translation System, and to add any additional capability possible for the best achievable medical care. The first step in the facility upgrade was to quantify the current medical inventory on the International Space Station and ensure that sufficient stowage volume was present for this purpose. To that end, the ISS medical kits were reviewed, and eight full size mid deck lockers were placed in the facility. A number of additional devices were also added, based on the intern’s combat medic experience. Also, two fixed shelves and one horizontal work surface were added to the Medical Care Facility, with the shelves providing storage space for the additional devices and the work surface providing a location for the caregiver to work or stage equipment. Four display monitors were added to the wall above the horizontal work surface, supporting data display, telemedicine, conferencing, or other needs. The existing treatment table was replaced with a mobile surgical stretcher-chair. Two additional doors were added to the Medical Care Facility. One leads directly to the hygiene compartment, allowing it to support medical operations in addition to providing galley/wardroom support. The other door leads directly into the Vertical Translation System. The wall adjacent to the subsystems bay was moved, adding additional volume to the Medical Care Facility. This improved caregiver access to the patient and allowed for a larger number of caregivers to be present. It also provided options for relocation of support equipment relative to the patient as needed. In the upgraded Medical Care Facility, the Surgical Stretcher-Chair and the Vertical Translation System can work together to provide incapacitated crew member transport from a site of injury on any deck of the Common Habitat to the Medical Care Facility. It can also support patient treatment in a variety of positions including a variety of sitting postures and a supine posture at a variety of pitch angles. The facility can also support caregiver office work for review of examination results, private consultation, inventory and maintenance, and a variety of other purposes. A forward activity will be to conduct evaluations of the Medical Care Facility with different medical scenarios. Additionally, ambient and task lighting selections remain as forward work. The eight mid deck lockers can be augmented to use as portable equipment carts, similar to a manner in which maintenance facility stowage was used as portable carts during the NASA Desert Research and Technology Studies in the Constellation Program. Trash accommodation will also need forward work to assess, including provision for wet trash, dry trash, and biological waste. It will be important to assess a redesign of the surgical stretcher-chair. The commercial version used in the upgrade can only enable vertical translation in the seated configuration, requiring the patient to bend both hips and knees. A possible redesign of the chair will allow for vertical translation without requiring any bending at the hip or knees. Also, the commercial version is wheeled, making it mobile in gravity but unanchored in microgravity. Work will be needed to adapt the chair for gravity-independent performance. The hygiene compartment can be redesigned for dual-use medical scrub and galley handwash facility. Pending sufficient volume, it may also be possible to place sanitation equipment in this location to clean medical tools. Finally, most space architectures have never allowed for more than one incapacitated crew member, but several scenarios could potentially injure two or more crew in the same incident. This facility could be assessed to determine its present ability to address two or more injured crew in parallel and determine the potential upper limit for number of treatable crew in a multi-crew injury scenario, or to treat polytrauma of a single patient.

Habitat↗

NASA NTRSDate not supplied

Configuration and Projected Capabilities of the Common Habitat Medical Care Facility

The Common Habitat is a large, long-duration habitat being explored as part of a conceptual study (not an active NASA program) that uses an SLS core stage Liquid Oxygen (LOX) tank as its primary structure. It is intended for use on the Moon as part of a permanently occupied outpost, on Mars as part of an outpost that will be occupied for hundreds of days at a time, and in deep space as part of the Deep Space Exploration Vehicle where it will support crewed missions up to 1200 days in duration. A study of internal orientation and crew size resulted in a Common Habitat configuration sized for a crew of eight with a three-deck horizontal orientation. Additional work outside the scope of this paper is developing a vertical translation system, a crew mobility aids system based on wearable gecko-derived grippers, and a crew seating/restraint system. These systems are all assumed for use in conjunction with the Medical Care Facility, which is needed to maintain crew well-being during these missions, where distance from Earth precludes the possibility of evacuation to Earth. This paper describes recent improvements in the Common Habitat Medical Care Facility and associated benefits for crew survivability in long duration missions beyond Earth orbit. These improvements were made with the assistance of a NASA Pathways intern whose experience includes a tour of duty in Afghanistan as an Army combat medic with the 691st GHOST-T, attached to the 1st and 7th US Special Forces Groups as part of Operation Freedom’s Sentinel, where he helped provide far-forward surgical capabilities in austere combat environments. The initial baseline Medical Care Facility was developed working in conjunction with University of Houston Space Architecture graduate students. The facility was placed on the upper deck of the Common Habitat in a location that provided privacy, operational volume, and was close to the vertical translation pathway. The notional outfitting repurposed component CAD models from unrelated studies and notionally indicated a level of care roughly equivalent to that aboard the International Space Station. The CAD modeling provided notional stowage volumes, a deployable surface, some fixed equipment, an ultrasound, and a potentially reconfigurable treatment table. While this facility is clearly a competent arrangement, it was desired to leverage available expertise and upgrade the station given the vast distances from Earth to be experienced by the Common Habitat. Key driving requirements applied to the upgrade included to provide NASA’s Medical Level of Care V, offer enhanced telemedicine capabilities, provide patient physical accommodation, provide caregiver access to the patient from all sides, include sliding pocket doors for access to hygiene and to the Vertical Translation System, and to add any additional capability possible for the best achievable medical care. The first step in the facility upgrade was to quantify the current medical inventory on the International Space Station and ensure that sufficient stowage volume was present for this purpose. To that end, the ISS medical kits were reviewed, and eight full size mid deck lockers were placed in the facility. A number of additional devices were also added, based on the co-author’s combat medic experience. Also, two fixed shelves and one horizontal work surface were added to the Medical Care Facility, with the shelves providing storage space for the additional devices and the work surface providing a location for the caregiver to work or stage equipment. Four display monitors were added to the wall above the horizontal work surface, supporting data display, telemedicine, conferencing, or other needs. The existing treatment table was replaced with a mobile surgical stretcher-chair. Two additional doors were added to the Medical Care Facility. One leads directly to the hygiene compartment, allowing it to support medical operations in addition to providing galley/wardroom support. The other door leads directly into the Vertical Translation System. The wall adjacent to the subsystems bay was moved, adding additional volume to the Medical Care Facility. This improved caregiver access to the patient and allowed for a larger number of caregivers to be present. It also provided options for relocation of support equipment relative to the patient as needed. In the upgraded Medical Care Facility, the Surgical Stretcher-Chair and the Vertical Translation System can work together to provide incapacitated crew member transport from a site of injury on any deck of the Common Habitat to the Medical Care Facility. It can also support patient treatment in a variety of positions including a variety of sitting postures and a supine posture at a variety of pitch angles. The facility can also support caregiver office work for review of examination results, private consultation, inventory and maintenance, and a variety of other purposes. A forward activity will be to conduct evaluations of the Medical Care Facility with different medical scenarios. Additionally, ambient and task lighting selections remain as forward work. The eight middeck lockers can be augmented to use as portable equipment carts, similar to a manner in which maintenance facility stowage was used as portable carts during the NASA Desert Research and Technology Studies in the Constellation Program. Trash accommodation will also need forward work to assess, including provision for wet trash, dry trash, and biological waste. It will be important to assess a redesign of the surgical stretcher-chair. The commercial version used in the upgrade can only enable vertical translation in the seated configuration, requiring the patient to bend both hips and knees. A possible redesign of the chair will allow for vertical translation without requiring any bending at the hip or knees. Also, the commercial version is wheeled, making it mobile in gravity but unanchored in microgravity. Work will be needed to adapt the chair for gravity-independent performance. The hygiene compartment can be redesigned to serve both as a medical scrub facility and for galley hand washing. Pending sufficient volume, it may also be possible to place sanitation equipment in this location to clean medical tools. Finally, most space architectures have never allowed for more than one incapacitated crew member, but several scenarios could potentially injure two or more crew in the same incident. This facility could be assessed to determine its present ability to address two or more injured crew in parallel and determine the potential upper limit for number of treatable crew in a multi-crew injury scenario, or to treat polytrauma of a single patient.

Common Habitat↗

NASA NTRS1975

A study of moving base simulation motion cues utilizing washout technique

The present study was conducted to derive data on non-visual motion thresholds utilizing washout technique, and to develop specific threshold values for use as washout parameters. It describes the results of acceleration detection studies carried out using the NASA MSFC General Purpose Simulator which provides six degree-of-freedom cab motion. A series of experiments was performed to test the hypothesis that constant velocity visual cues might suppress non-visual deceleration sensitivity. The psychophysical method employed was the forced-choice procedure which theoretically yields a pure sensitivity measure. The MSFC General Purpose Simulator was programmed to provide velocity ramps in three axes - pitch, fore-aft translation, and vertical translation. Data were collected with and without a constant velocity visual input. Comparison of the current results with classical data suggested significantly greater sensitivity of the human observer to fore-aft accelerations than has generally been reported, sensitivity tending to depend on motion direction and sign of velocity change.

Kirkpatrick, M., III↗

NASA NTRSDate not supplied

Internal Architecture of the Common Habitat

The core stage liquid oxygen tank of the Space Launch System can be manufactured as a habitat instead of as a propellant tank, with a common design such that it is equally suitable for use in 0g, 1/6g, 3/8g, 1g, or variable artificial gravity. This Common Habitat can be the central element of a human spaceflight architecture that encompasses the Moon, Mars, and other destinations within the inner solar system. The Common Habitat is specifically used within an alternative architecture study (that is not part of the current NASA baseline) as the core habitation element within a Lunar Basecamp, Mars Basecamp, and the Deep Space Exploration Vehicle. The Common Habitat internal architecture applies a design philosophy to separate crew functions according to deck. The lower deck is reserved for private functions. It includes eight private crew quarters and four waste and hygiene clusters – each with a private waste management compartment, private full body hygiene compartment, and foyer/clothes changing area. The mid deck is primarily allocated to mission-related working functions. It includes an exercise facility, fabrication / maintenance / repair facility, physical science laboratory (physics, geology, and astronomy), and life science laboratory (biology and human research). The mid deck also has four external hatches, clocked one every 90 degrees, centered on the vehicle vertical centerline. Each hatch has a 60-inch tall by 40-inch wide opening with the mid deck floor 16 inches below the bottom lip of the hatch opening. The upper deck is primarily allocated to group or social functions. It includes a large galley, wardroom with projector and display screen, plant growth chambers, bulk stowage, command and control station, medical facility, hygiene compartment, and vehicle subsystems. A Vertical Translation System, based in part on results from a GrabCAD public challenge, enables crew and equipment traverse between habitat decks in 0g, 1/6g, 3/8g, and 1g. A 40-inch by 60-inch vertical translation corridor ensures that anything that can fit through the external hatches can also be moved from deck to deck. The system includes three component systems: a deploying floor to safety barrier system that folds down to become a traversable floor when vertical translation is not in use and deploys to become a safety barrier during vertical translations; a folding ladder that stows in the ceiling when not in use; and an elevator platform that can attach to the ladder for cargo or incapacitated crew member transport. This system is complemented by a Horizontal Translation System, also based in part on the same GrabCAD challenge, provides for horizontal crew translation in microgravity but requires no vehicle reconfiguration for fractional or whole gravity operation. It relies primarily on gecko-inspired grippers, originally developed at Stanford and NASA JPL, attached to footwear to enable crew to emulate walking. Some handrails are also strategically placed throughout the Common Habitat to aid translation in both gravity and microgravity environments.

Common Habitat↗

NASA NTRS1974

The use of an aircraft test stand for VTOL handling qualities studies

The VTOL flight tests stand for testing control concepts on the X-14B VSS aircraft in hover, is described. This stand permits realistic and safe piloted evaluation and checkout of various control systems and of parameter variations within each system to determine acceptability to the pilot. Pilots can use it as a practical training tool to practice procedures and flying techniques and become familiar with the aircraft characteristics. Some examples of test experience are given. The test stand allows the X14B to maneuver in hover from centered position + or - 9.7 deg in roll and + or - 9.3 deg in pitch, about + or - 6 deg in yaw, and + or - 15 cm in vertical translation. The unique vertical free flight freedom enables study of liftoffs and landings with power conditions duplicated. The response on the stand agrees well with that measured in free hovering flight, and pilot comments confirm this.

Pauli, F. A.↗

NASA NTRS2002

Identifying head-trunk and lower limb contributions to gaze stabilization during locomotion

The goal of the present study was to determine how the multiple, interdependent full-body sensorimotor subsystems respond to a change in gaze stabilization task constraints during locomotion. Nine subjects performed two gaze stabilization tasks while walking at 6.4 km/hr on a motorized treadmill: 1) focusing on a central point target; 2) reading numeral characters; both presented at 2 m in front at the level of their eyes. While subjects performed the tasks we measured: temporal parameters of gait, full body sagittal plane segmental kinematics of the head, trunk, thigh, tibia and foot, accelerations along the vertical axis at the head and the tibia, and the vertical forces acting on the support surface. We tested the hypothesis that with the increased demands placed on visual acuity during the number recognition task, subjects would modify full-body segmental kinematics in order to reduce perturbations to the head in order to successfully perform the task. We found that while reading numeral characters as compared to the central point target: 1) compensatory head pitch movement was on average 22% greater despite the fact that the trunk pitch and trunk vertical translation movement control were not significantly changed; 2) coordination patterns between head and trunk as reflected by the peak cross correlation between the head pitch and trunk pitch motion as well as the peak cross correlation between the head pitch and vertical trunk translation motion were not significantly changed; 3) knee joint total movement was on average 11% greater during the period from the heel strike event to the peak knee flexion event in stance phase of the gait cycle; 4) peak acceleration measured at the head was significantly reduced by an average of 13% in four of the six subjects. This was so even when the peak acceleration at the tibia and the transmission of the shock wave at heel strike (measured by the peak acceleration ratio of the head/tibia and the time lag between the tibial and head peak accelerations) remained unchanged. Taken together these results provide further evidence that the full body contributes to gaze stabilization during locomotion, and that its different functional elements can be modified online to contribute to gaze stabilization for different visual task constraints.

NASA Center JSC↗

NASA NTRS2003

Identifying Head-Trunk and Lower Limb Contributions to Gaze Stabilization During Locomotion

The goal of the present study was to determine how the multiple, interdependent full-body sensorimotor subsystems respond to a change in gaze stabilization task constraints during locomotion. Nine subjects performed two gaze stabilization tasks while walking at 6.4 km/hr on a motorized treadmill: 1) focusing on a central point target; 2) reading numeral characters; both presented at 2m in front at the level of their eyes. While subjects performed the tasks we measured: temporal parameters of gait, full body sagittal plane segmental kinematics of the head, trunk, thigh, shank and foot, accelerations along the vertical axis at the head and the shank, and the vertical forces acting on the support surface. We tested the hypothesis that with the increased demands placed on visual acuity during the number recognition task, subjects would modify full-body segmental kinematics in order to reduce perturbations to the head in order to successfully perform the task. We found that while reading numeral characters as - compared to the central point target: 1) compensatory head pitch movement was on average 22% greater despite the fact that the trunk pitch and trunk vertical translation movement control were not significantly changed; 2) coordination patterns between head and trunk as reflected by the peak cross correlation between the head pitch and trunk pitch motion as well as the peak cross correlation between the head pitch and vertical trunk translation motion were not significantly changed; 3) knee joint total movement was on average 11% greater during the period from the heel strike event to the peak knee flexion event in stance phase of the gait cycle; 4) peak acceleration measured at the head was significantly reduced by an average of 13% in four of the six subjects. This was so even when the peak acceleration at the shank and the transmissibility of the shock wave at heel strike (measured by the peak acceleration ratio of the head/shank) remained unchanged. Taken together these results provide further evidence that the full body contributes to gaze stabilization during locomotion, and that its different functional elements can be modified online to contribute to gaze stabilization for different visual task constraints.

Mulavara, Ajitkumar P.↗

NASA NTRS2004

The Formation Control Testbed

This paper describes the design and construction of the Formation Control Testbed. The FCT consists of three robots navigating on an air bearing floor, propelled by cold gas thrusters. Each robot contains an attitude platform supported on a spherical air bearing which provides three rotational degrees of freedom. The sixth degree of freedom, vertical translation, will be provided by a powered vertical stage, actively controlled to provide a simulated zero-g environment for the attitude platform.

Singh, Gurkirpal↗

NASA NTRS1989

Simulation evaluation of transition and hover flying qualities of a mixed-flow, remote-lift STOVL aircraft

Using a generalized simulation model developed for piloted evaluations of STOVL aircraft, an initial fixed-base simulation of a mixed-flow, remote-lift configuration has been completed. Objectives were to evaluate the integration of the aircraft's flight and propulsion controls to achieve good flying qualities throughout the low-speed flight envelope; to determine control power used during transition, hover, and vertical landing; and to evaluate the transition flight envelope considering the influence of thrust deflection of the remote-lift component. Pilots' evaluations indicated that Level 1 flying qualities could be achieved for deceleration to hover in instrument conditions, for airfield landings, and for recovery to a small ship when attitude and velocity stabilization and command augmentation control modes were provided. Level 2 flying qualities were obtained for these same tasks when only the attitude command mode was used, leaving the pilot to perform the task of thrust management required to control the flight-path and speed in transition and the horizontal and vertical translational velocities in hover. Thrust margins were defined for vertical landing as a function of ground effect and hot-gas ingestion.

Franklin, James A.↗

NASA NTRS2017

Validation of a Manually Oscillating Chair for In-The-Field Assessment of Dynamic Visual Acuity on Crewmembers Within Hours of Returning From Long-Duration Spaceflight

Long-duration spaceflight results in sensorimotor adaptations, which cause functional deficits during gravitational transitions, such as landing on a planetary surface after long-duration microgravity exposure. Both the vestibular system and the central nervous system are affected by gravitational transitions. These systems are responsible for coordinating head and eye movements via the vestibulo-ocular reflex (VOR) and go through an adaptation period upon exposure to microgravity. Consequently, they must also re-adapt to Earth's gravitational environment upon landing. This re-adaptation causes decrements in gaze control and dynamic visual acuity, with crewmembers reporting oscillopsia and blurred vision caused by retinal slip, or the inability to keep an image focused on their retina. This is thought to drive motion sickness symptoms experienced by most crewmembers following landing. Retinal slip can be estimated by dynamic visual acuity (DVA); visual acuity while in motion. Previously, DVA has been assessed in the laboratory where subjects walked at 6.4 km/hr on a motorized treadmill. Using this method, Peters et al. (2011) found that DVA is worsened in astronauts by an average of 0.75 eye-chart lines one day after landing. However, it is believed that re-adaptation occurs quickly and that DVA might be worse immediately upon re-exposure to a gravitational environment. Since many crewmembers are unable to walk safely upon landing, it was necessary to develop a method for replicating the vertical head movements associated with walking. In addition, the use of a chair to imitate the head displacement caused by walking isolates eye-head interactions without allowing for trunk and lower-body compensation, as seen with treadmill walking (Mulavara & Bloomberg 2003). Therefore, a modality for assessing DVA in the field within a few hours of landing was developed. In this study, we validated the ability of a manually operated oscillating chair to reproduce the oscillatory frequency of walking on a treadmill. Healthy non-astronaut subjects (n=14) participated in one test session and completed three static (seated) and three dynamic (walking/oscillated) visual acuity tests. DVA was assessed using a motorized treadmill, an automated oscillating chair, and a manually operated chair, both developed in the Neuroscience Laboratory at JSC. The automated chair was motor-driven and set to oscillate vertically at 2 Hz with a vertical displacement of +/- 5 cm to simulate vertical translation while walking. The manually operated chair was oscillated vertically by a test operator to the beat of a metronome at 120 beats/min (2 Hz) and a vertical displacement of approximately +/- 5 cm. As the subject was oscillated, they were asked to discern the direction gap of Landolt-C optotypes of varying sizes and verbally reported the direction while an operator recorded their response using a gamepad. Subjects were outfitted with accelerometers (sampling rate = 128 Hz) on their head, trunk and lumbar spine. A fast Fourier transform was performed on the vertical trunk acceleration to compare the peak and spread of the distribution of oscillation frequencies for each oscillating condition. The spread of the frequency distribution for the manual chair was not significantly different from either the treadmill or the automated chair. However, all three conditions had similar non-zero standard error values, suggesting a variance in head movement frequency which may affect DVA. The average oscillation frequency of the manual chair (1.85 Hz) was significantly different (α=0.05) from that of treadmill walking (2.24 Hz), but not significantly different from that of the automated chair (1.85 Hz) and all three conditions had small standard errors (SEM = 0.04, 0.06, and 0.08 Hz for manual, treadmill, and automated respectively). This implies that both chairs oscillate at a frequency below that of treadmill walking, but are comparable to each other and reproducible across sessions. Additionally, DVA scores did not vary significantly across conditions. The smaller spread values of the oscillating chairs' frequencies indicated mitigation of variation induced by locomotor strategies, which enables better examination of the issue of VOR adaptation. Furthermore, due to the deconditioned state of crewmembers in the initial hours after landing, it is easier to transport a manual bouncing chair into the field and safer to perform a vision test while seated in a chair versus walking on a treadmill. Therefore, the manually oscillating chair has been deemed to meet and exceed the DVA testing capabilities previously obtained by treadmill walking.

Kreutzberg, G. A.↗

DOE OSTI2023

140° Line of Sight (LOS) Mounting Fixture Prototype for ZNeutron Time of Flight (Z-NToF)

The 140° Line of Sight (LOS) Mounting Fixture Prototype for the Z-Neutron Time of Flight diagnostic (Z-NToF) is a prototype support structure for the NToF Jac Black that will be fielded at Sandia’s Z-Machine. The Mounting Fixture will allow the detector to be properly positioned and aligned horizontally from the load, with manual horizontal and vertical translation capabilities, and a limited manual rotation capability. It attaches overhead I-beams at Sandia’s Z machine 140° location approximately 18m from the average source location. The assembly (1011219955) is shown in Figure 1 below. It is capable of rotating ±20° about the vertical axis of the Jac Black detector and translating ±37.5mm horizontally along the Mounting Plate. Vertical adjustments of ±76.2mm can be made using the Lead Screw. Coarser adjustments are possible by changing the number of plates between the I-Beam Hanger Assemblies and the 5in and changing the position of the clamps on the I-beams at Z.

42 ENGINEERING↗

NASA NTRS2009

Video image stabilization and registration--plus

A method of stabilizing a video image displayed in multiple video fields of a video sequence includes the steps of: subdividing a selected area of a first video field into nested pixel blocks; determining horizontal and vertical translation of each of the pixel blocks in each of the pixel block subdivision levels from the first video field to a second video field; and determining translation of the image from the first video field to the second video field by determining a change in magnification of the image from the first video field to the second video field in each of horizontal and vertical directions, and determining shear of the image from the first video field to the second video field in each of the horizontal and vertical directions.

Hathaway, David H.↗

NASA NTRS1999

Helicopter Flight Simulation Motion Platform Requirements

To determine motion fidelity requirements, a series of piloted simulations was performed. Several key results were found. First, lateral and vertical translational platform cues had significant effects on fidelity. Their presence improved performance and reduced pilot workload. Second, yaw and roll rotational platform cues were not as important as the translational platform cues. In particular, the yaw rotational motion platform cue did not appear at all useful in improving performance or reducing workload. Third, when the lateral translational platform cue was combined with visual yaw rotational cues, pilots believed the platform was rotating when it was not. Thus, simulator systems can be made more efficient by proper combination of platform and visual cues. Fourth, motion fidelity specifications were revised that now provide simulator users with a better prediction of motion fidelity based upon the frequency responses of their motion control laws. Fifth, vertical platform motion affected pilot estimates of steady-state altitude during altitude repositioning. Finally, the combined results led to a general method for configuring helicopter motion systems and for developing simulator tasks that more likely represent actual flight. The overall results can serve as a guide to future simulator designers and to today's operators.

Schroeder, Jeffery Allyn↗

DOE OSTI2022

HIDRA-MAT liquid metal droplet injector for liquid metal applications in HIDRA

A liquid metal droplet injector was explicitly designed for the Hybrid Illinois Device for Research and Applications Material Analysis Test-stand (HIDRA-MAT) at the University of Illinois Urbana-Champaign to prepare liquid metal plasma-facing components (PFCs) for plasma exposure. The design goals were to create a compact, reliable, and robust design that could apply liquid metal droplets in-vacuo to a variety of samples. The injector was designed for liquid metal use, and results discussed pertain to lithium. The injector can produce lithium droplets of consistent size by utilizing programmable piston movement. Here, droplet formation data is presented for four different piston step sizes (0.125 mm, 0.25 mm, 0.5 mm, and 1 mm) at three different nozzle temperatures (185 °C, 230 °C, and 270 °C). Droplets are formed on the injector nozzle tip and a linear shift mechanism vertically translates the droplet to the substrate for application. This design prevents the droplet from inadvertently detaching off the nozzle and falling to the sample. Application of the liquid metal droplet ensures placement consistency on the substrate and helps avoid damage to components in HIDRA-MAT that should not interact with liquid metals. A description of the liquid lithium droplet creation and application results is given and provides additional insight into the cooling and oxidation of lithium droplets under vacuum conditions. A second nozzle was fabricated and demonstrated repeatability in droplet diameter creation having a variance of ±0.14 mm for droplets created from the same number of piston steps. The end-use for the injector on HIDRA-MAT is to apply liquid metals to PFCs and expose them to HIDRA's plasma with subsequent intershot in-vacuo surface analysis in HIDRA-MAT for plasma-material interaction studies.

42 ENGINEERING↗

DOE OSTI2020

Design of target irradiation and diagnostic chamber to study ps-laser generated plasma as a source of singly charged ions for external injection into an electron beam ion source

High repetition-rate (~10 kHz) ps-lasers are becoming available on the market with reasonable cost and may offer several advantages compared to ns-lasers by generating nearly continuous beams of singly charged ions appropriate for the “slow” injection mode into the Electron Beam Ion Source (EBIS). To evaluate these advantages, we will perform studies of a ps-laser generated plasma using a laser with a pulse duration of 8 ps and energy up to 5 mJ per pulse. A vacuum chamber equipped with a 3D target positioner, a focusing lens, and a Faraday Cup has been designed and built for this study. Lens-to-target distance variations have been measured using a laser tracker over the whole range of horizontal and vertical translation for all five targets we will use. The variations were found to be within ±150 µm. This level of “target flatness” should be acceptable for our experimental conditions. Ion currents and ion pulse durations of various elements (from Al to Ta) will be measured for different target irradiation conditions (focal spot size and laser pulse energy). The results obtained will allow us to specify all parameters and geometry of a laser ion source based on a ps-laser to provide external ion injection into the relativistic heavy ion collider EBIS

43 PARTICLE ACCELERATORS↗