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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 325 records · Page 18
All sourcesNASA NTRSDOE OSTI
NASA NTRS2017

Skeletal Responses to Long-Duration Simulated Weightlessness in Rats

Damaging effects due to spaceflight and long-duration weightlessness are seen in the musculoskeletal system, specifically with regards to bone loss, bone resorption, and changes in overall bone structure. These adverse effects are all seen with indicators of oxidative stress and a variation in the levels of oxidative gene expression. Once gravity is restored, however, the recovery is slow and incomplete. Despite this, few reports have investigated the correlation between oxidative damage and general modifications within the bone. In this project, we will make use of a ground-based model of simulated weightlessness (hindlimb unloading, HU) in order to observe skeletal changes in response to induced microgravity due to changes in oxidative pressures. With this model we will analyze samples at 14-day and 90-day time points following HU for the determination of acute and chronic effects, each with corresponding controls. We hypothesize that simulated microgravity will lead to skeletal adaptations including time-dependent activation of pro-oxidative processes and pro-osteoclastogenic signals related to the progression, plateau, and recovery of the bone. Microcomputed tomography techniques will be utilized to measure skeletal changes in response to HU. With the results of this study, we hope to further the understanding of skeletal affects as a result of long-duration weightlessness and develop countermeasures to combat bone loss in spaceflight and osteoporosis on Earth.

hindlimb unloading↗
NASA NTRS2019

Improved Earth Oblateness Rate Reveals Increased Ice Sheet Losses and Mass-Driven Sea Level Rise

Satellite laser ranging (SLR) observations are routinely applied toward the estimation of dynamic oblateness, C(sub 20), which is the largest globally integrated component of Earth's time-variable gravity field. Since 2002, GRACE and GRACE Follow-On have revolutionized the recovery of higher spatial resolution features of global time-variable gravity, with SLR continuing to provide the most reliable estimates of C (sub 20).We quantify the effect of various SLR processing strategies on estimating C(sub 20) and demonstrate better signal recovery with the inclusion of GRACE-derived low-degree gravity information in the forward model. This improved SLR product modifies the Antarctic and Greenland Ice Sheet mass trends by -15.4 and -3.5 Gt/year, respectively, as compared to CSR TN11, and improves global mean sea level budget closure by modifying sea level rise by +0.08 mm/year. We recommend that this new C(sub 20) product be applied to RL06 GRACE data products for enhanced accuracy and scientific interpretation.

Loomis, B. D.↗
NASA NTRSDate not supplied

A Review of Baseline Assumptions and Ersatz Waste Streams for Partial Gravity Habitats and Orbiting Microgravity Habitats

Highly efficient water management and recovery systems will be required to support human missions beyond the low Earth orbit of the International Space Station (ISS).A review of baseline assumptions for the human activities and associated water cycle in surface, partial gravity habitats and orbiting, microgravity habitats is conducted. The paper reviews and updates ersatz formulations and water flow rates for the main liquid water waste streams of urine, humidity condensate, hygiene, and laundry. A framework is provided to coordinate development of water recovery systems for 30-day crew occupancies under partial gravity with longer term, continuous occupancy in orbiting microgravity habitats and the Mars transit habitat.

Water Ersatz Habitat↗
NASA NTRS1949

Spin Investigation of a 1/29-Scale Model of the Republic XF-91 Airplane with a Conventional Tail Installed

An investigation has been conducted in the Langley 20-foot free-spinning tunnel of a 1/29-scale model of the Republic XF-91 airplane with a.conventional-tail arrangement installed. Previously, tests were made on the model with a vee tail installed. The erect spin and recovery characteristics of the model were determined for the normal loading with the wing installed at various amounts of incidence. The spin investigation also included inverted-spin tests, spin-recovery-parachute tests, tests with the center of gravity moved rearward, and tests with external fuel tanks added to the model. In addition, several tail.modifications were tested,on the model in an attempt, to improve the model's spin-recovery characteristics. The results indicate that any fully developed spin obtained on the airplane with the conventional tail installed will be satisfactorily terminated if rudder reversal is accompanied by moving the ailerons with the spin (stick right in a right spin).Decreasing the wing incidence from 6deg to -2deg should have a beneficial effect on the recovery characteristics of the airplane. Recovery characteristics by normal use of controls (full rudder reversal followed by moving the elevators down) will be satisfactory if the wing incidence,of the airplane is -2deg. Installation of external fuel tanks (with or without fuel) will have a somewhat adverse effect on the recovery characteristics of the airplane, but if the recovery technique includes movement of the ailerons to full with the spin, the spin rotation will be terminated rapidly. Varying the position of the center of gravity within the limits indicated to be possible on the airplane should not affect the recovery characteristics.

Klinar, Walter J.↗
NASA NTRS1976

Strategies for estimating the marine geoid from altimeter data

Altimeter data from a spacecraft borne altimeter was processed to estimate the fine structure of the marine geoid. Simulation studies show that, among several competing parameterizations, the mean free air gravity anomaly model exhibited promising geoid recovery characteristics. Using covariance analysis techniques, quantitative measures of the orthogonality properties are investigated.

Argentiero, P.↗
NASA NTRS1989

Overview of the National Aeronautics and Space Administration tether activities

NASA research concerning the use of tethers in space is reviewed, including joint research with the Italian Space Agency. Tether applications under consideration are described, such as a tethered fuel depot and a tethered gravity laboratory platform for the Space Station, providing artificial gravity to and from Mars, payload recovery and waste management, aerothermodynamic magnetospheric physics, and electrodynamic propulsion, braking, and power generation for the Space Shuttle. Also, tether flight demonstrations are examined, including the Small Expendable Deployer System, the Get-Away Tether Experiment, the Tether Elevator Crawler System, and the Kinetic Isolation Tether Experiment.

Penzo, Paul A.↗
NASA NTRS2020

Development and Comparison of an Artificial Gravity Concept for Human Spaceflight

This Internship served as a resource to find specific research about the many facets of artificial gravity. With three main areas to be addressed in detail: the negative health effects of microgravity and how current mitigation methods fall short, the knowns and unknowns of artificial gravity as a countermeasure, and past artificial gravity habitat concepts. This report primarily focuses on the negative health effects of microgravity and how current mitigation methods fall short. Through NASA resources such as the NTRS, and external sources such as the AIAA, research papers were gathered that were pertinent to the topic. Each paper was uploaded to a NASA SharePoint and abstracts were drafted to highlight the important information. The expected results were to build a library of easily accessible information that would allow for Ryan Joyce and Gabe Merrill to easily get up to speed on relevant information. This process should allow for a faster period of understanding with high relevancy material. The ability to quickly reference data will help to build an informed and detailed case for any future proposals on artificial gravity. This also prevents the need to spend many hours searching for relevant documentation, allowing for more time to be dedicated to the creation process. The project has successfully met expectations and is continuing to add pertinent documentation. Current research shows great potential for artificial gravity as a countermeasure on long duration missions. The gravity like forces created in an artificial gravity ship could help to prevent serious problems such as muscle loss, bone fractures, vision loss due to increased intracranial pressure, and would allow for transition to other gravity environments with little to no recovery period. These conditions are highly favorable for long duration missions as current mitigation methods have yet to be proven beyond one year in space and often only slow symptoms instead of preventing them.

Alice Elberfeld↗
NASA NTRS1963

Spin Investigation Of A 1/20-Scale Model Of An Unswept-Wing, Twin-Engine, Observation Airplane

An investigation was conducted in the Langley 20-foot free-spinning tunnel on a 1/20-scale model of an unswept-wing, twin-engine, observation airplane. The effects of control settings and movements on the erect spin and recovery characteristics for the normal loading and the most rearward center-of-gravity loading (external wing tanks full) were determined. Also, tests were made to determine the effect on the spin and recovery characteristics of a large radar store, of empty and full external wing tanks, and of an asymmetrical condition when one empty or one full external wing tank is carried. Spin-recovery parachute tests were also performed. The results of the tests indicate that erect spins obtained on the airplane for the normal loading should be satisfactorily terminated by rudder reversal to full against the spin, ailerons moved to with the spin, followed one-half turn later by forward movement of the stick to neutral. With the radar store, with wing tanks empty, or with an asymmetrical condition when one empty tank is on either wing, satisfactory recoveries can be obtained by using the same technique as for the normal loading. Recoveries for the model with a rearward center-of-gravity loading (external wing tanks full) or with a full tank on the wing inboard of the spin axis will be slow to unsatisfactory with rudder reversal to full against the spin followed by brisk forward stick movement. With a full tank on the wing outboard of the spin axis, the recoveries will be satisfactory. Spins in the landing configuration should be terminated by first retracting the flaps, slats, and landing gear, after which recovery should be attempted immediately by using the recovery technique recommended for the normal loading condition. Inverted spins can be satisfactorily terminated by rudder reversal to full against the spin followed by neutralization of the longitudinal and lateral controls. A 12.7-foot-diameter tail parachute with a towline length of 21.7 feet and a drag coefficient of 0.65 should be satisfactory for recoveries from erect and inverted demonstration spins when used simultaneously with movement of rudder to neutral.

SPIN↗
DOE OSTI2024

Recommendations on setup in simulating atmospheric gravity waves under conventionally neutral boundary layer conditions

Wind farm-induced atmospheric gravity waves have been the subject of recent research as they can impact wind farm performance. Pressure variations associated with gravity waves can contribute to the global blockage effect and wind farm wake recovery. Therefore, accurate numerical simulation of flow fields, where wind-farm-induced gravity waves may be produced, is important. Three main considerations in such simulations are the overall domain size, the use of Rayleigh damping near domain boundaries to dampen gravity waves, and advection damping at the inlet to prevent spurious oscillations. Often these considerations are treated ad hoc rather than systematically. This work aims to test and extend the systematic modelling of internal gravity waves proposed in a preliminary investigation to modelling of both internal and trapped gravity waves. The preliminary study identifies the length scales to set the domain and damping layer sizes and the time scale to configure the Rayleigh damping coefficient but under linearly stratified conditions. Large eddy simulations of flow through a wind farm canopy are performed under conventionally neutral boundary layer (CNBL) conditions to test the validity of proposed setups for CNBL conditions. Background atmospheric parameters, such as Froude number (Fr), inversion height (H i ), and inversion layer Froude number (Fr i ) control most of the atmospheric gravity wave characteristics. We validated for CBNL conditions that the effective wavelengths of the internal gravity waves are the correct length scale to configure the domain size and damping layer thickness. Likewise, the optimum damping coefficient to dampen the internal gravity waves relates to the free atmosphere's buoyancy frequency or buoyant perturbations' time scale. We infer that the damping coefficient in the inversion layer may relate to the inversion buoyancy frequency to effectively dampen the trapped gravity waves. Moreover, the advection damping length is linked to the horizontal wavelength of the trapped gravity waves in the inversion layer to prevent spurious waves at the inlet by retaining wave energy accumulation.

17 WIND ENERGY↗
NASA NTRS1988

Spacecraft Fire-Safety Experiments for Space Station: Technology Development Mission

Definitions, overall descriptions, and preliminary apparatus and instrumentation requirements are presented for three spacecraft fire-safety experiments appropriate for inclusion in a growth-version of the Space Station. The experiments are as follows: 1. Combustion and Flame Spread of Typical Spacecraft Materials in a Low­ Velocity Convective Flow in Low Gravity 2. Fire and Fire-Extinguishant Interactions with Various Fire Scenarios in Low Gravity 3. Smoldering and Deep-Seated Combustion in Low Gravity. The experiments were selected from an assessment of recommendations for advanced technologies for prevention, detection, and control of fires in spacecraft. The experiments and their facilities are intended to constitute a portion of a Spacecraft Fire Safety Technology Development Mission (TDM). Basic requirements for the mission study are that the Space Station is essential for the accomplishment of the experimental objectives and that the technology being developed is appropriate for the growth version of the Space Station. The advantages of these three experiments are that, not only do they explore problems relevant to the Space Station operation and utilization, but also they constitute tests adaptable to two multiuse facilities installed in the Space Station laboratory module, the Combustion Tunnel Facility and the Combustion Facility. Three additional spacecraft fire-safety experiments, essential precursors to the TD M for near-term performance, are also described as follows: 1. Near-Term Testing of Materials for Combustion and Flame Spread 2. Near-Term Extinguishment of Fires in a Low-Gravity Test Bed 3. Post-Fire Recovery of Sensitive Electrical and Electronic Equipment. For all the experiments, the study defines accommodations in terms of first-order space, mass, power, consumables, and crew-time estimates. The study also reviews the key problems to be addressed, namely experiment safety hazards, non-intrusive diagnostics development and waste-products disposal. A preliminary task and time schedule for design, development, and experiment fabrication is proposed.

Youngblood, Wallace W.↗
NASA NTRS2003

Re-Adaptation to 1-G of Pregnant Rats Following Exposure to Spaceflight or Centrifugation

Late-pregnant rat dams were flown on a 9-day Space Shuttle mission or exposed to 1.5, 1.75 or 2-g centrifugation and compared with 1 .O-g vivarium controls. Exposure to altered gravity began on the 11th day and recovery occurred on the 20th day of the dams' 22-day pregnancy. In the 1 st experiment, comparisons were made between Flight (FLT), Synchronous (SYN; identically-housed) and Vivarium (VIV) controls. In the 2nd experiment, comparisons were made between dams centrifuged at 2-G, 1.75-G, 1.5-G, Rotational controls (1.08-G) or Stationary controls (1 G). Within three hours of recovery from either spaceflight or centrifugation, the dams' locomotor behavior was videotaped for 2 min. FLT dams showed dramatically reduced movement relative to both SYN and VIV control conditions, with significantly greater amounts of locomotor activity observed in SYN as compared to VIV dams. Significantly greater locomotor activity was observed in SYN as compared to VIV controls. In the second experiment, no differences were observed between dams exposed either 1, 1.5, 1.75, or 2-G. In both studies, the dams showed similar patterns of hindlimb rearing. Together, these findings provide quantitative evidence for decreased locomotor activity during re-adaptation to 1-g following spaceflight, but not centrifugation.

Johnson, K. E.↗
NASA NTRS1974

Strategies for estimating the marine geoid from altimeter data

In processing altimeter data from a spacecraft borne altimeter to estimate the fine structure of the marine geoid, a problem is encountered. In order to describe the geoid fine structure, a large number of parameters must be employed and it is not possible to simultaneously estimate all of them. Unless the parameterization exhibits good orthogonality in the data, serious aliasing results. From simulation studies it has been found that amongst several competing parameterizations, the mean free air gravity anomaly model (i.e., Stokes' formula) exhibited promising geoid recovery characteristics. Using covariance analysis techniques, this report provides quantitative measures of the orthogonality properties associated with the above mentioned parameterization. It has been determined that a 5 deg x 5 deg area mean free air gravity anomaly can be estimated with an uncertainty of 1 mgal (40 cm undulation) provided that all free air gravity anomalies within a spherical radius of 10 arc degrees are simultaneously estimated.

Argentiero, P.↗
NASA NTRS1986

Design and development of high strength parachutes for recovery of Filament Wound Case Space Shuttle solid rocket boosters

The Filament Wound Case (FWC) solid rocket boosters, developed for Space Shuttle launches from the West coast, are substantially lighter than their steel case counterparts, but present unique recovery system challenges due to their aft center of gravity location. This causes them to re-enter in a tail-first attitude, rather than broadside like the steel case boosters, resulting in much higher dynamic pressure at deployment. This paper outlines the differences in recovery conditions, and describes the design, development, and testing of new parachutes to meet this challenging new requirement.

Corwin, R. A.↗
NASA NTRS1974

Laser network survey and orbit recovery

Simulations were performed for the anticipated GEOS-C laser network stations at Goddard, Bermuda, and Florida to predict how well survey and orbit will be recovered. Lasers were added one at a time at Grand Turk, Antigua, and Panama to estimate the contribution from these additional sites. Time tag biases of 50 microseconds, survey uncertainties of 10 meters in each coordinate, laser range biases and noise estimates of 20 cm each, and conventional gravity uncertainties were included in the simulations. The results indicate that survey can be recovered to about 1 meter and Grand Turk can be recovered better than Antigua or Panama. Reducing the probably pessimistic assumed time tag biases and gravity field uncertainties improves the results. Using these survey recovery estimates, the short arc GEOS-C satellite heights for altimeter intercomparison orbits can be recovered within the calibration area to better than the required two meters.

Berbert, J. H.↗
NASA NTRS1984

On the accuracy of gravimetric geoids and the recovery of oceanographic signals from altimetry

The accuracy of measurements of gravity over the North Atlantic is assessed. The effect of errors due mainly to aliasing, of the distribution of available data, and of the unresolved geoid power on geoidal estimates is determined. A crude estimate of circulation in the North Atlantic is obtained by using the simplest of preconceptions: a reasonable rms value of zeta prime, the component of the surface expression of seawater motion corresponding to the general circulation.

Zlotnicki, V.↗
NASA NTRS1978

The US/USSR Biological Satellite Program: COSMOS 936 Mission Overview

On August 3, 1977, the Soviet Union launched Cosmos 936, an unmanned spacecraft carrying biology and physics experiments from 9 countries, including both the Soviet Union and U.S. The launch marked the second time the Soviet Union has flown U.S. experiments aboard one of its spacecraft, the first being Cosmos 782 launched Nov. 25, 1975, which remained in orbit 19.5 days. Aboard Cosmos 936 were: 30 young male Wistar SPF rats, 20 of which was exposed to hypogravity during flight while the remainder were subjected to a l x g acceleration by continuous configuration; 2) experiments with plants and fruit flies; 3) radiation physics experiments; and 4) a heat convection experiment. After 18.5 days in orbit, the spacecraft landed in central Asia where a Soviet recovery team began experiment operations, including animal autopsies, within 4.5 hr of landing. Half of the animals were autopsied at the recovery site and the remainder returned to Moscow and allowed to readapt to terrestrial gravity for 25 days after which they, too, were autopsied. Specimens for U.S. were initially prepared at the recovery site or Soviet laboratories and transferred to U.S. laboratories for complete analyses. An overview of the mission focusing on preflight, on-orbit, and postflight activities pertinent to the seven U.S. experiments aboard Cosmos 936 will be presented.

Souza, K. A.↗