Engineering Papers⌕ Search

SEARCH · Engineering Papers

Results for “zero-g”

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.

Quote a phrase for an exact phrase match. Source license links do not imply unrestricted reuse.

At least 181 records · Page 10
All sourcesNASA NTRSDOE OSTI
NASA NTRS1981

Design and development of a six degree of freedom hand controller

The design objectives of a six degree of freedom manual controller are discussed with emphasis on a space environment. Details covered include problems associated with a zero-g environment, the need to accommodate both 'shirt sleeve' and space suited astronauts, the combination of both manipulator operation and spacecraft flight control in a single device, and to accommodate restraints in space. A variable configuration device designed as a development tool in which rotational axes can be moved relative to one another, is described and its limitations discussed. Two additional devices were developed for concept testing. Each device combines the need for good quality with its ability achieve a wide range of adjustments.

King, M. L.↗
NASA NTRS1981

The 1981 NASA ASEE Summer Faculty Fellowship Program, volume 2

A collection of papers on miscellaneous subjects in aerospace research is presented. Topics discussed are: (1) Langmuir probe theory and the problem of anisotropic collection; (2) anthropometric program analysis of reach and body movement; (3) analysis of IV characteristics of negatively biased panels in a magnetoplasma; (4) analytic solution to classical two body drag problem; (5) fast variable step size integration algorithm for computer simulations of physiological systems; (6) spectroscopic experimental computer assisted empirical model for the production of energetics of excited oxygen molecules formed by atom recombination shuttle tile surfaces; and (7) capillary priming characteristics of dual passage heat pipe in zero-g.

Robertson, N. G.↗
NASA NTRS1982

Ground- versus spaced-based orbital transfer vehicle

A space based orbital transfer vehicle (SBOTV) and ground based OTV's (GBOTV) are compared for debris protection, space based OTV maintenance provisions, flight performance, onorbit refueling, and launch and return operations. Debris protection has a severe impact on the SBOTV, while the penalty for the GBOTV is much less severe. A key technology issue is the protection capability of composite materials. Onorbit maintenance is critical for SBOTV. Reduction of losses during the various transfers is th maine problem with refueling a SBOTV. Zero-g propellant storage and transfer is an important technology area for SBOTV. A reusable shroud must be developed to return GBOTV's if a Shuttle derivative vehicle is used. The advantage of space basing lies in more efficient use of the launch vehicle. Since most of the mass going to LEO is OTV propellant, and the launches to deliver the SBOTV propellant are generally mass limited, substantially fewer launches are required to support the SBOTV.

Rehder, J.↗
NASA NTRS1982

Spacelab mission 2: Experimental descriptions

The second Spacelab Mission and the 12 multidisciplinary experiments selected to fly on board are described. These experiments include the following: vitamin D metabolities and bone demineralization; interaction of oxygen and gravity influenced lignification; ejectable plasma diagnostics package; plasma depletion experiments for ionospheric and radio astronomical studies; small helium cooled IR telescope; elemental composition and energy spectra of cosmic ray nuclei; hard X-ray imaging of clusters of galaxies and other extended X-ray sources; solar magnetic and velocity field measurement system; solar coronal helium abundance Spacelab experiment; solar UV high resolution telescope and spectroraph; solar UV spectral irradiance monitor; and properties of superfluid helium in zero-G.

Clifton, K. S.↗
NASA NTRS1981

Space transportation - Reflections and projections

The history of U.S. manned spaceflight and the vehicles used is discussed. The programs began with low budgets and handwritten charts, then proceeded through the Redstone Mercury launch in 1961 and the Atlas Mercury orbital mission in 1962, with the decision to begin the Apollo project coming between those flights. Use of a sole source procurement with a nonprofit institution like the MIT Draper Laboratory for the Apollo guidance system is noted to have expedited the speed of paperwork. A lunar orbital rendezvous was chosen in October 1962 for the Saturn CV-launched Apollo. The Gemini capsule, eliminated early as a lunar module, served to expose problems of operation in a zero-g environment. The benefits of humans in space were made apparent in the process of fixing the Skylab solar panels. The Shuttle capabilities are reviewed, and the necessity for a vehicle for access and return from GEO is emphasized. Finally, attention is given to a single stage to orbit vehicle and launch systems for a Solar Power Satellite.

Disher, J. H.↗
NASA NTRS1982

Changes in blood volume and response to vaso-active drugs in horizontally casted primates

Experiments were performed on horizontally casted primates (male rhesus monkeys) in order to note changes in blood volume caused by horizontal restraint, to compare orthostatic tolerance before and after casting using the responses to upright tilting, to begin to uncover the cardiovascular and neural mechanisms involved in deconditioning, and to compare the data with that obtained from bed-rested human subjects and from humans exposed to weightlessness. Bolus injections of norepinephrine of 2.0 microgram/kg, phenylephrine of 4.0 microgram/kg, and nitroprusside of 2.0 microgram/kg were administered; and aortic pressure and heart rate were recorded during the injections. The results indicate that the horizontally casted primate is a valid animal model for studying the effects of simulated zero-G on the human cardiovascular system.

Dickey, D. T.↗
NASA NTRS1982

Fluid dynamic and thermodynamic analysis of a model pertaining to cryogenic fluid management in low gravity environments for a system with dynamically induced settling

The settling behavior of the liquid and gaseous phases of a fluid in a propellant and in a zero-g environment, when such settling is induced through the use of a dynamic device, in this particular case, a helical screw was studied. Particular emphasis was given to: (1) the description of a fluid mechanics model which seems applicable to the system under consideration, (2) a First Law of Thermodynamics analysis of the system, and (3) a discussion of applicable scaling rules.

Rios, J.↗
NASA NTRS1982

The Space Shuttle orbiter payload retention systems

Payloads are secured in the orbiter payload bay by the payload retention system or are equipped with their own unique retention systems. The orbiter payload retention mechanisms provide structural attachments for each payload by using four or five attachment points to secure the payload within the orbiter payload bay during all phases of the orbiter mission. The payload retention system (PRS) is an electromechanical system that provides standarized payload carrier attachment fittings to accommodate up to five payloads for each orbiter flight. The mechanisms are able to function under either l-g or zero-g conditions. Payload berthing or deberthing on orbit is accomplished by utilizing the remote manipulator system (RMS). The retention mechanisms provide the capability for either vertical or horizontal payload installation or removal. The payload support points are selected to minimize point torsional, bending, and radial loads imparted to the payloads. In addition to the remotely controlled latching system, the passive system used for nondeployable payloads performs the same function as the RMS except it provides fixed attachments to the orbiter.

Hardee, J. H.↗
NASA NTRS1983

High effectiveness liquid droplet/gas heat exchanger for space power applications

A high-effectiveness liquid droplet/gas heat exchanger (LDHX) concept for thermal management in space is described. Heat is transferred by direct contact between fine droplets (approx. 100 to 300 micron diameter) of a suitable low vapor pressure liquid and an inert working gas. Complete separation of the droplet and gas media in the zero-g environment is accomplished by configuring the LDHX as a vortex chamber. The large heat transfer area presented by the small droplets permits heat exchanger effectiveness of 0.9 to 0.95 in a compact, lightweight geometry which avoids many of the limitations of conventional plate and fin or tube and shell heat exchangers, such as their tendency toward single point failure. The application of the LDHX in a high temperature Bryaton cycle is discussed to illustrate the performance and operational characteristics of this heat exchanger concept.

Bruckner, A. P.↗
NASA NTRS1982

Spacelab-1: An early space station for science and technology

The scientific capabilities of the Spacelab manned pallet are reviewed, together with the implications of an expansion of the research effectiveness with a free-flying platform. The premier Spacelab flight will carry out earth observations with a metric camera and SAR, atmospheric studies will be performed with imaging spectrometers, and space plasma physics will be examined by injecting particle beams or VLF waves into the near-Shuttle environment. Radiance and spectrum data will be gathered of the sun and UV and X ray information will be recorded from the stars. Experimentation will also be carried out for on-board crystal growth, metallurgy, and glassy material production, as well as the response of biological systems to zero-g conditions and hard space radiation. The telemetry, time, crewmember participation, and on-board controls required for Spacelab operations are outlined. Missions for a space platform for studying the atmosphere/space interface are described.

Knott, K.↗
NASA NTRS1982

Long term storage of cryogens in space

Experimental design procedures leading to the configuration of a space-based cryogenic fluids test system are reported. Large quantities of cryogenic fluids are expected to be required in space for cooling systems, chemical and electrical OTVs, and resupply tankers. The design was guided by the necessity for representative storage and supply systems to be compatible with the Shuttle. Consideration was given to liquid hydrogen, oxygen, methane, and argon containers and concommitant fluid dynamics, thermal, and structural analyses. A 5% initial ullage was included for the liquids, except for methane, which was calculated at 8.9%. The Ar, CH4, and O2 tanks were set at 12.5 cu m, while the H2 tank was 37.4 cu m. The orbital experiment is required to provide actual thermal stabilization lags in a zero-g environment. Details of the Cryogenic Fluid Management Facility test module for flight on board the Shuttle are presented.

Fester, D. A.↗
NASA NTRS1982

Capillary priming characteristics of a high capacity dual passage heat pipe

A parametric study of the forces governing the liquid-vapor interface was performed for the purpose of determining the capillary priming characteristics of Grumman's dual passage monogroove heat pipe when subjected to low-g or zero-g conditions. The static liquid-vapor interface configuration was determined through minimization of the free surface energies and a mathematical model and computer program which describe the time to prime was developed. Modeling predictions confirmed expectations of proper priming action and established the criteria for sizing of the liquid and vapor channels.

Peterson, G. P.↗
NASA NTRS1983

Thermal Canister Experiment on OSS-1

The purpose of the Thermal Canister Experiment carried by the Space Shuttle STS-3 flight was to determine the ability of a device using controllable heat pipes to maintain simulated instruments at selected temperature levels, in zero gravity and under varying internal and external thermal loads. A total of 11 data points were achieved during the flight, including the control of canister walls, of instrument simulators and of temperatures in two different zones, as well as passive thermal control. The set point variation ranged from 5 to 23 C, with power changes of 165-325 watts. Better fluid distribution in the heat pipes during zero-g operation showed improved performance over ground tests, and a temperature stability of + or - 2 C was demonstrated between Orbiter maneuvers in which the cargo bay was shadowed from the sun and those in which full solar exposure of the cargo bay existed.

Ollendorf, S.↗
NASA NTRS1981

Human factors in equipment development for the Space Shuttle - A study of the general purpose work station

The results of a human factors test to assay the suitability of a prototype general purpose work station (GPWS) for biosciences experiments on the fourth Spacelab mission are reported. The evaluation was performed to verify that users of the GPWS would optimally interact with the GPWS configuration and instrumentation. Six male subjects sat on stools positioned to allow assimilation of the zero-g body posture. Trials were run concerning the operator viewing angles facing the console, the console color, procedures for injecting rates with dye, a rat blood cell count, mouse dissection, squirrel monkey transfer, and plant fixation. The trials were run for several days in order to gage improvement or poor performance conditions. Better access to the work surface was found necessary, together with more distinct and better located LEDs, better access window latches, clearer sequences on control buttons, color-coded sequential buttons, and provisions made for an intercom system when operators of the GPWS work in tandem.

Junge, M. K.↗
NASA NTRS1982

Development of electrostatic levitator at JPL

Preliminary results on the design and operation of electrostatic levitators developed at JPL are reported. Particular attention is given to the single-axis levitators for ground-based operation and for operation in the reduced gravity environment. Descriptions are given of the design principles and the performance of final products. A levitator designed for zero-g environment is shown. It is a single-axis system, so there is no active lateral damping. Two ring and two disk electrodes are included. The ring electrodes always maintain a constant voltage difference with respect to the central disk electrodes. This is to ensure that there is always a centering force that does not depend on the voltage difference between the top and bottom electrodes. As the ring-to-disk voltage increases, there is a proportionate increase in the centering force.

Rhim, W.-K.↗
NASA NTRS1983

Etiological factors in space motion sickness

The human susceptibility to motion sickness during exposure to sudden-stop stimulation as a function of gravitoinertial force level is studied. It is determined that susceptibility is greatly enhanced, both with eyes-closed and eyes-open, for zero-g and 2-g conditions in parabolic flight compared with 1-g test conditions. It is argued that this change in susceptibility is related to alterations in vestibulo-occular function which result from variations in gravitoinertial force level, the altered patterns of otolithic activity resulting during variations in gravitoinertial force level, and the altered canal-otolith response synergies that result during exposure to gravitoinertial force levels greater or less than terrestrial levels. These factors are found to be related to the etiology of space motion sickness and to the alterations in performance and vestibular function that are experienced by astronauts during reentry. An explanation is presented for the decrease in susceptibility to motion sickness exhibited by the Skylab astronauts inflight and for some period postflight during exposure to cross-coupled angular accelerations.

Lackner, J. R.↗
NASA NTRS1983

Large space structures raise testing challenges

The testing approaches and techniques necessary for combined ground and space verification for large space structures (LSS) to be deployed and assembled in space are explored. The size of LSS precludes full ground tests, thereby requiring assemblies, components, and their interactions to be examined on orbit. Ground tests involving drop tests and zero-g aircraft flights can be performed with scale models, but need computational compensation to eliminate gravitational and torque effects that do not occur in space. Structural rigidity also varies from ground to space, and can partly be accounted for in ground tests by using cable supports, although numerical modelling must remove the effects of the cables' presence. Long-term funding is recommended for on-orbit tests of components in order to build a data base for later testing and actual construction of LSS.

Hanks, B. R.↗
NASA NTRS1982

Energy balance and the composition of weight loss during prolonged space flight

Integrated metabolic balance analysis, Skylab integrated metabolic balance analysis and computer simulation of fluid-electrolyte responses to zero-g, overall mission weight and tissue losses, energy balance, diet and exercise, continuous changes, electrolyte losses, caloric and exercise requirements, and body composition are discussed.

Leonard, J. I.↗