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Search indexed NASA NTRS and DOE OSTI research on propulsion, heat transfer, battery materials and energy systems. Follow report and document links to the original sources.

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At least 595 records · Page 33
All sourcesNASA NTRSDOE OSTI
NASA NTRS2016

Development of a Protocol to Test Proprioceptive Utilization as a Predictor for Sensorimotor Adaptability

Astronauts returning from space flight show significant inter-subject variations in their abilities to readapt to a gravitational environment because of their innate sensory weighting. The ability to predict the manner and degree to which each individual astronaut will be affected would improve the effectiveness of countermeasure training programs designed to enhance sensorimotor adaptability. We hypothesize participant's ability to utilize individual sensory information (vision, proprioception and vestibular) influences adaptation in sensorimotor performance after space flight. The goal of this study is to develop a reliable protocol to test proprioceptive utilization in a functional postural control task. Subjects "stand" in a supine position while strapped to a backpack frame holding a friction-free device using air-bearings that allow the subject to move freely in the frontal plane, similar to when in upright standing. The frame is attached to a pneumatic cylinder, which can provide different levels of a gravity-like force that the subject must balance against to remain "upright". The supine posture with eyes closed ensures reduced vestibular and visual contribution to postural control suggesting somatosensory and/or non-otolith vestibular inputs will provide relevant information for maintaining balance control in this task. This setup is called the gravity bed. Fourteen healthy subjects carried out three trials each with eyes open alternated with eyes closed, "standing" on their dominant leg in the gravity bed environment while loaded with 60 percent of their body weight. Subjects were instructed to: "use your sense of sway about the ankle and pressure changes under the foot to maintain balance." Maximum length of a trial was 45 seconds. A force plate underneath the foot recorded forces and moments during the trial and an inertial measurement unit (IMU) attached on the backpack's frame near the center of mass of the subject recorded upper body postural responses. Series of linear and non-linear analyses were carried out on several force plate and IMU data including stabilogram diffusion analysis on the center of pressure (COP) to find a subset of parameters that were sensitive to detect differences in postural performance between eyes open and closed conditions. Results revealed that seven parameters (root mean square (RMS) of medio-lateral (ML) COP, range of ML COP, RMS of roll moment, range of trunk roll, minimum time-to-boundary (TTB), integrated TTB, and critical mean square planar displacement (delta r (sup 2) (sub c)) were significantly different between eyes open and closed conditions. We will present data to show the efficacy of using performance in single leg stance with eyes closed on the gravity bed to assess individuals' ability to utilize proprioceptive information in a functional postural control task to predict re-adaptation for sensorimotor and functional performance.

Goel, R.↗
NASA NTRS2016

High Performance Torso Cooling Garment

The concept proposed in this paper is to improve thermal efficiencies of the liquid cooling and ventilation garment (LCVG) in the torso area, which could facilitate removal of LCVG tubing from the arms and legs, thereby increasing suited crew member mobility. EVA space suit mobility in micro-gravity is challenging, and it becomes even more challenging in the gravity of Mars. By using shaped water tubes that greatly increase the contact area with the skin in the torso region of the body, the heat transfer efficiency can be increased. This increase in efficiency could provide the required liquid cooling via torso tubing only; no arm or leg LCVG tubing would be required. Benefits of this approach include increased crewmember mobility, reduced LCVG mass, enhanced evaporation cooling, increased comfort during Mars EVA tasks, and easing of the overly dry condition in the helmet associated with the Advanced Extravehicular Mobility Unit (EMU) ventilation loop currently under development. This report describes analysis and test activities performed to evaluate the potential improvements to the thermal performance of the LCVG. Analyses evaluated potential tube shapes for improving the thermal performance of the LCVG. The analysis results fed into the selection of flat flow strips to improve thermal contact with the skin of the suited test subject. Testing of small segments was performed to compare thermal performance of the tubing approach of the current LCVG to the flat flow strips proposed as the new concept. Results of the testing is presented along with recommendations for future development of this new concept.

Conger, Bruce↗
NASA NTRS2015

High Performance Mars Liquid Cooling and Ventilation Garment Project

EVA space suit mobility in micro-gravity is enough of a challenge and in the gravity of Mars, improvements in mobility will enable the suited crew member to efficiently complete EVA objectives. The idea proposed is to improve thermal efficiencies of the liquid cooling and ventilation garment (LCVG) in the torso area in order to free up the arms and legs by removing the liquid tubes currently used in the ISS EVA suit in the limbs. By using shaped water tubes that greatly increase the contact area with the skin in the torso region of the body, the heat transfer efficiency can be increased to provide the entire liquid cooling requirement and increase mobility by freeing up the arms and legs. Additional potential benefits of this approach include reduced LCVG mass, enhanced evaporation cooling, increased comfort during Mars EVA tasks, and easing of the overly dry condition in the helmet associated with the Advanced Extravehicular Mobility Unit (EMU) ventilation loop currently under development.

Terrier, Douglas↗
NASA NTRS2016

High Performance Torso Cooling Garment

The concept proposed in this paper is to improve thermal efficiencies of the liquid cooling and ventilation garment (LCVG) in the torso area, which could facilitate removal of LCVG tubing from the arms and legs, thereby increasing suited crew member mobility. EVA space suit mobility in micro-gravity is challenging, and it becomes even more challenging in the gravity of Mars. By using shaped water tubes that greatly increase the contact area with the skin in the torso region of the body, the heat transfer efficiency can be increased. This increase in efficiency could provide the required liquid cooling via torso tubing only; no arm or leg LCVG tubing would be required. Benefits of this approach include increased crewmember mobility, enhanced evaporation cooling, increased comfort during Mars EVA tasks, and easing of the overly dry condition in the helmet associated with the Advanced Extravehicular Mobility Unit (EMU) ventilation loop currently under development. This report describes analysis and test activities performed to evaluate the potential improvements to the thermal performance of the LCVG. Analyses evaluated potential tube shapes for improving the thermal performance of the LCVG. The analysis results fed into the selection of flat flow strips to improve thermal contact with the skin of the suited test subject. Testing of small segments was performed to compare thermal performance of the tubing approach of the current LCVG to the flat flow strips proposed as the new concept. Results of the testing is presented along with recommendations for future development of this new concept.

Conger, Bruce↗
NASA NTRS2015

Modeling and Simulation of Vehicle Dynamics on the Surface of Phobos

In this paper we analyze the dynamics of a spacecraft in proximity of Phobos by developing the equations of motion of a test mass in the Phobos rotating frame using a model based on circularly-restricted three body problem, and by analyzing the dynamics of a ATHLETE hopper vehicle interacting with the soil under different soil-interaction conditions. The main conclusion of the numerical studies is that the system response is dominated by the stiffness and damping parameters of the leg springs, with the soil characteristics having a much smaller effect. The system simulations identify ranges of parameters for which the vehicle emerges stably (relying only on the passive viscoelastic damper at each leg) or unstably (needing active attitude control) from the hop. The implication is that further experimental and possibly computational modeling work, as well as site characterization (from precursor missions) will be necessary to obtain validated performance models.

soil-structure interaction↗
NASA NTRS2017

Non-Intrusive Velocity Measurements with MTV During DCC Event in the HTTF

Velocity profiles are measured using molecular tagging velocimetry (MTV) in the high temperature test facility (HTTF) at Oregon State University during a depressurized conduction cooldown (DCC) event. The HTTF is a quarter scale electrically heated nuclear reactor simulator designed to replicate various accident scenarios. During a DCC, a double ended guillotine break results in the reactor pressure vessel (RPV) depressurizing into the reactor cavity and ultimately leading to air ingress in the reactor core (lock-exchange and gas diffusion). It is critical to understand the resulting buoyancy-driven flow to characterize the reactor self-cooling capacity through natural circulation. During tests conducted at ambient pressure and temperature, the RPV containing helium is opened (via the hot and cold legs) to a large vessel filled with nitrogen to simulate the atmosphere. The velocity profile on the hot leg pipe centerline is recorded at 10 Hz with MTV based on NO tracers. The precision of the velocimetry was measured to be 0.02 m/s in quiescent flow prior to the tests. A helium flow from the RPV is initially observed in the top quarter of the pipe. During the first 20 seconds of the event, helium flows out of the RPV with a maximum velocity below 2 m/s. The velocity profile transitions from parabolic to linear in character and decays slowly over the rest of the recording; peak velocities of 0.2 m/s are observed after 30 min. A counter-flow of nitrogen is also observed intermittently, which occurs at lower velocities (>0.1 m/s).

Andre, M. A.↗
NASA NTRS2017

Low Excess Speed Triple Cyclers of Venus, Earth, and Mars

Ballistic cycler trajectories which repeatedly encounter Earth and Mars may be invaluable to a future transportation architecture ferrying humans to and from Mars. Such trajectories which also involve at least one flyby of Venus are computed here for the first time. The so-called triple cyclers are constructed to exhibit low excess speed on Earth-Mars transit legs, and thereby reduce the cost of hyperbolic rendezvous. Numerous solutions are identified with average transit leg excess speed below 5 kilometers per second, independent of encounter epoch. The energy characteristics are lower than previously documented cyclers not involving Venus, but the repeat periods are generally longer.

Jones, Drew Ryan↗
NASA NTRS2020

Current State of the Electrodynamic Dust Shield for Mitigation

The Electrodynamic Dust Shield (EDS) has been developed as a means to lift, transport and remove dust from surfaces for over 18 years in the Electrostatics and Surface Physics Laboratory at NASA Kennedy Space Center. Resent advances in the technology have allowed large-scale EDSs to be fabricated using roll-to-roll techniques for quick efficient processing. The aim of the current research is to demonstrate the 3-dimensional (3-D) version of the EDS and its applicability to various surfaces of interest throughout the Artemis program that require dust mitigation. The conventional two dimensional (2-D) EDS has been comprised of interdigitated electrodes across a surface of alternating polarity to setup non-uniform electric fields in the location of interest for which the particles need to be removed. The 2-D system can be designed to accommodate various phases. For example, the two phase EDS is comprised of two electrodes 180˚ out of phase, while the 3-phase EDS is 120˚ out of phase with the adjacent leg. 4-phase EDS configurations are also possible but for each square wave a high voltage signal is applied to each leg.

Buhler, C. R.↗
NASA NTRSDate not supplied

TPSAS-NF1676L-32084-DND

We present aerosol and cloud observations obtained from the satellite-, aircraft- and ship-based measurements of the North Atlantic Aerosols and Marine Ecosystems Study (NAAMES). The data span three seasons (November 2015, May 2016, and September 2017), which correspond to substantial variation in ocean ecosystem characteristics, continental long-range transport, and local aerosol-cloud microphysics and meteorology. For example, below-cloud aerosol number concentrations in November 2015 were of order 10-50 cm-3, while concentrations observed in May and September were of order 100-500 cm-3. Here, we focus on 20 cloud sampling flight modules carried out during NAAMES, which encompass approximately 27 flight hours of the more than 220 NAAMES project flight hours. The nominal cloud module pattern consists of a series of 5-6 vertically-stacked, horizontal flight legs of 10-15 minute duration (~50-90 km in length) that profile the near-surface (300 ft. altitude) and below-cloud aerosol characteristics, the cloud properties near cloud base and top, the aerosol properties above cloud, and finally a high-altitude remote sensing leg that characterizes the cloud top and above-cloud atmosphere. Ship-based aerosol and ceilometer measurements provide the below-cloud context over time, while GOES satellite imagery and cloud retrieval products fill in the above-cloud story.

Richard H Moore↗
NASA NTRS2020

Material Remodelling and Unconventional Gaits Facilitate Locomotion of a Robophysical Rover Over Granular Terrain

Autonomous robots and vehicles must occasionally recover from locomotion failure in loosely consolidated granular terrain. Recent mobility challenges led NASA Johnson Space Center to develop a prototype robotic lunar rover Resource Prospector 15 (RP15) capable of wheeled, legged, and crawling behavior. To systematically understand performance of such a device, we developed a scaled-down rover robot and studied its locomotion on slopes of dry and wet granular media. Addition of a cyclic legged gait to the robot’s wheel spinning action changes the robot dynamics from that of a wheeled vehicle to a locomotor paddling through frictional fluid. Granular drag force measurements and modified Resistive Force Theory facilitate modeling of such dynamics. A peculiar gait strategy that agitates and cyclically reflows grains under the robot allows it to ‘swim’ up loosely consolidated hills. Whereas substrate disturbance typically hinders locomotion in granular media, the multi-mode design of RP15 and a diversity of possible gaits facilitate formation of self-organized localized frictional fluids that enable effective robust transport.

Siddharth Shrivastava↗
NASA NTRS2017

Semi-analytic preliminary design of low-thrust missions

Using generalized logarithmic spirals to approximate low-thrust trajectories, a new strategy for the design of low-thrust gravity-assist transfers has been developed. Each transfer leg is defined by a semi-analytic model, and its solution is equivalent to a hybrid Lambert’s problem. The method is suitable for approximating both flyby and rendezvous transfer legs. A branch and prune algorithm is used to generate a collection of initial guesses for further optimization. The analytic nature of the low-thrust model simplifies the pruning step, since dynamical and operational constraints (like maximum thrust or total v) can be imposed easily. The solutions obtained with the global search algorithm can be post-processed, filtered, and ranked according to various criteria. This is where the versatility of the method resides, because changing the selection criteria does not require a new search. Selected candidates are then optimized further, in order to generate actual low-thrust orbits. Two mission design examples are presented: an asteroid deflection mission using a kinetic impactor, and a rendezvous mission to Jupiter. These examples are used to analyze the convergence of the optimization stage, in particular how far from the optimal solution the initial guesses are.

Park, Ryan S.↗
NASA NTRS2021

Pneumatic Sampler (P-Sampler) for the Martian Moons Exploration (MMX)

A Pneumatic Sampler (P-SMP)is being provided by Honeybee Robotics with support from NASA Planetary Missions Program Office (PMPO)for JAXA’s Martian Moons eXploration (MMX) mission. The goal of this mission is to closely survey the Martian moons Deimos and Phobos, and then to collect regolith from Phobos and return it to Earth. The P-SMP will be mounted to a leg of the lander and will be responsible for collecting surface regolith alongside the JAXA provide Core Sampler (C-SMP). The Sampling Funnel of the P-SMP utilizes two sets of sampling nozzles: one set of nozzles pointed directly at the surface to kick-up and loft material into the sampling head, and a second set of nozzles to direct the oncoming material into the sample return canister further up the lander leg. A robotic arm mounted underneath the lander will then remove the sample canister and place it inside the sample return capsule for Earth return. Several iterations of the P-Sampler have been designed and tested inside a vacuum chamber with Phobos regolith simulant. In all tests, the P-Sampler successfully acquired the sample, even in an extreme scenario where the sampling head was mounted 10 cm above a surface covered with gravel.

Dylan Van Dyne↗
NASA NTRSDate not supplied

Free-Flight Dynamics of an Aeroshell/Drogue Parachute System

A free-flight test of a subscale aeroshell/drogue parachute model was conducted at the NASA Langley Research Center Vertical Spin Tunnel. Mass properties for the aeroshell model were dynamically scaled. This test simulated the flight of the Dragonfly mission spacecraft at an altitude of 18.4 km above the surface of Titan (Saturn’s largest moon). The aeroshell/drogue parachute model exhibited bimodal oscillatory behavior with sustained small- and large-amplitude modes depending on initial conditions. The effects of drogue parachute size, bridle geometry, and bridle rigidity on the aeroshell/drogue parachute dynamics were investigated. The large-amplitude oscillations seemed to be driven by the aeroshell aerodynamics, with bridle leg collapse being an enabling factor. If the bridle legs were rigid, large-amplitude oscillations were not sustainable.

Parachute↗
NASA NTRS2022

Kink Oscillation of a Flux Rope During a Failed Solar Eruption

We report a decaying kink oscillation of a flux rope during a confined eruptive flare, observed off the solar limb by SDO/AIA, that lacked a detectable white-light coronal mass ejection. The erupting flux rope underwent kinking, rotation, and apparent leg–leg interaction during the event. The oscillations were observed simultaneously in multiple AIA channels at 304, 171, and 193 Å, indicating that multithermal plasma was entrained in the rope. After reaching the overlying loops in the active region, the flux rope exhibited large-amplitude, decaying kink oscillations with an apparent initial amplitude of 30 Mm, period of about 16 min, and decay time of about 17 min. We interpret these oscillations as a fundamental standing kink mode of the flux rope. The oscillation polarization has a clear vertical component, while the departure of the detected waveform from a sinusoidal signal suggests that the oscillation could be circularly or elliptically polarized. The estimated kink speed is 1080 km s−1, corresponding to an Alfv'en speed of about 760 km s−1. This speed, together with the estimated electron density in the rope from our DEM analysis, ne ≈ (1.5–2.0) ×109 cm−3, yields a magnetic field strength of about 15 G. To the best of our knowledge, decaying kink oscillations of a flux rope with non-horizontal polarization during a confined eruptive flare have not been reported before. These oscillations provide unique opportunities for indirect measurements of the magnetic-field strength in low-coronal flux ropes during failed eruptions.

Pankaj Kumar↗
NASA NTRSDate not supplied

Design of A Transition-Edge-Sensor-Based Thermal Stabilization Stage

Electrothermal feedback in a transition edge sensor suppresses thermal fluctuations in the TES and regions in close thermal contact. We designed a heavily-metallized, leg-isolated membrane with a TES which serves as a thermal stabilization stage that can be lithographically integrated with other devices. Through modeling, fabrication and test of prototype devices, we examine whether the noise reduction in this stage can reduce thermal fluctuations (e.g. 1/f noise) in the other components by providing a more stable base temperature. In one implementation, a leg-isolated TES bolometer of higher superconducting transition temperature (Tc) is encircled by a second membrane region which is metallized and thermally stabilized by a second, lower-Tc TES. We present fabrication results on the dual-Tc design and testing of the simultaneous biasing of a two-stage, two-TES device. We explore varied heat capacity of the thermally stabilized stage in the single pixel design. We also present other designs to evaluate the use of an outer thermal stabilization stage for multiple pixel arrangements.

Rachel Borrelli↗
NASA NTRS2023

Plasmoids, Flows, and Jets During Magnetic Reconnection in a Failed Solar Eruption

We report a detailed analysis of a failed eruption and flare in active region 12018 on 2014 April 3 using multiwavelength observations from the Solar Dynamics Observatory/Atmospheric Imaging Assembly, IRIS, STEREO, and Hinode/Solar Optical Telescope. At least four jets were observed to emanate from the cusp of this small active region (large bright point) with a null-point topology during the 2 hr prior to the slow rise of a filament. During the filament slow rise multiple plasma blobs were seen, most likely formed in a null-point current sheet near the cusp. The subsequent filament eruption, which was outside the IRIS field of view, was accompanied by a flare but remained confined. During the explosive flare reconnection phase, additional blobs appeared repetitively and moved bidirectionally within the flaring region below the erupting filament. The filament kinked, rotated, and underwent leg–leg reconnection as it rose, yet it failed to produce a coronal mass ejection. Tiny jet-like features in the fan loops were detected during the filament slow rise/preflare phase. We interpret them as signatures of reconnection between the ambient magnetic field and the plasmoids leaving the null-point sheet and streaming along the fan loops. We contrast our interpretation of these tiny jets, which occur within the large-scale context of a failed filament eruption, with the local nanoflare-heating scenario proposed by Antolin et al.

Sun: jets↗
NASA NTRS2023

Spatially-Coordinated Airborne Data and Complementary Products for Aerosol, Gas, Cloud, and Meteorological Studies: the Nasa Activate Dataset

The NASA Aerosol Cloud meTeorology Interactions oVer the western ATlantic Experiment (ACTIVATE) produced a unique dataset for research into aerosol–cloud–meteorology interactions, with applications extending from process-based studies to multi-scale model intercomparison and improvement as well as to remote-sensing algorithm assessments and advancements. ACTIVATE used two NASA Langley Research Center aircraft, a HU-25 Falcon and King Air, to conduct systematic and spatially coordinated flights over the northwest Atlantic Ocean, resulting in 162 joint flights and 17 other single-aircraft flights between 2020 and 2022 across all seasons. Data cover 574 and 592 cumulative flights hours for the HU-25 Falcon and King Air, respectively. The HU-25 Falcon conducted profiling at different level legs below, in, and just above boundary layer clouds (< 3 km) and obtained in situ measurements of trace gases, aerosol particles, clouds, and atmospheric state parameters. Under cloud-free conditions, the HU-25 Falcon similarly conducted profiling at different level legs within and immediately above the boundary layer. The King Air (the high-flying aircraft) flew at approximately ∼ 9 km and conducted remote sensing with a lidar and polarimeter while also launching dropsondes (785 in total). Collectively, simultaneous data from both aircraft help to characterize the same vertical column of the atmosphere. In addition to individual instrument files, data from the HU-25 Falcon aircraft are combined into “merge files” on the publicly available data archive that are created at different time resolutions of interest (e.g., 1, 5, 10, 15, 30, 60 s, or matching an individual data product's start and stop times). This paper describes the ACTIVATE flight strategy, instrument and complementary dataset products, data access and usage details, and data application notes. The data are publicly accessible through https://doi.org/10.5067/SUBORBITAL/ACTIVATE/DATA001 (ACTIVATE Science Team, 2020).

Aerosol Cloud meTeorology Interactions oVer the we↗
NASA NTRS2024

Unveiling the Journey of A Highly Inclined CME: Insights from the March 13, 2012, Event With 110° Longitudinal Separation

Context. A fast (∼2000 km s -1 ) and wide (>110°) coronal mass ejection (CME) erupted from the Sun on March 13, 2012. Its interplanetary counterpart was detected in situ two days later by STEREO-A and near-Earth spacecraft, such as ACE, Wind, and Cluster. We suggest that at 1 au the CME extended at least 110° in longitude, with Earth crossing its east flank and STEREO-A crossing its- west flank. Despite their separation, measurements from both positions showed very similar in situ CME signatures. The solar source region where the CME erupted was surrounded by three coronal holes (CHs). Their locations with respect to the CME launch site were east (negative polarity), southwest (positive polarity) and west (positive polarity). The solar magnetic field polarity of the area covered by each CH matches that observed at 1 au in situ. Suprathermal electrons at each location showed mixed signatures with only some intervals presenting clear counter streaming flows as the CME transits both locations. The strahl population coming from the shortest magnetic connection of the structure to the Sun showed more intensity. Aims. The aim of this work is to understand the propagation and evolution of the CME and its interaction with the surrounding CHs, to explain the similarities and differences between the observations at each spacecraft, and report what one of the most longitudinal expanded CME structures measured in situ would be. Methods. Known properties of the large-scale structures from a variety of catalogues and previous studies were used to have a better overview of this particular event. In addition, multipoint observations were used to reconstruct the 3D geometry of the CME and determine the context of the solar and heliospheric conditions before the CME eruption and during its propagation. The graduated cylindrical shell model (GCS) was used to reproduce the orientation, size and speed of the structure with a simple geometry. Also, the Drag-Based Model (DBM) was utilised to understand the conditions of the interplanetary medium better in terms of the drag undergone by the structure while propagating in different directions. Finally, a comparative analysis of the different regions of the structure through the different observatories was carried out in order to directly compare the in situ plasma and magnetic field properties at each location. Results. The study presents important findings regarding the in situ measured CME on March 15, 2012, detected at a longitudinal separation of 110° in the ecliptic plane despite its initial inclination being around 45° when erupted (March 13). This suggests that the CME may have deformed and/or rotated, allowing it to be observed near its legs with spacecraft at a separation angle greater than 100°. The CME structure interacted with high-speed streams generated by the surrounding CHs. The piled-up plasma in the sheath region exhibited an unexpected correlation in magnetic field strength despite the large separation in longitude. In situ observations reveal that at both locations there was a flank encounter – where the spacecraft crossed the first part of the CME – then encountered ambient solar wind, and finally passed near the legs of the structure. Conclusions. A scenario covering all evidence is proposed for both locations with a general view of the whole structure and solar wind conditions. Also, the study shows the necessity of having multipoint observations of large-scale structures in the heliosphere.

methods: data analysis↗