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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 559 records · Page 31
All sourcesNASA NTRSDOE OSTI
NASA NTRS1989

Space station Simulation Computer System (SCS) study for NASA/MSFC. Volume 5: Study analysis report

The Simulation Computer System (SCS) is the computer hardware, software, and workstations that will support the Payload Training Complex (PTC) at the Marshall Space Flight Center (MSFC). The PTC will train the space station payload scientists, station scientists, and ground controllers to operate the wide variety of experiments that will be on-board the Freedom Space Station. The further analysis performed on the SCS study as part of task 2-Perform Studies and Parametric Analysis-of the SCS study contract is summarized. These analyses were performed to resolve open issues remaining after the completion of task 1, and the publishing of the SCS study issues report. The results of these studies provide inputs into SCS task 3-Develop and present SCS requirements, and SCS task 4-develop SCS conceptual designs. The purpose of these studies is to resolve the issues into usable requirements given the best available information at the time of the study. A list of all the SCS study issues is given.

Source record↗
NASA NTRS2013

Space Power Facility-Capabilities for Space Environmental Testing Within a Single Facility

The purpose of this paper is to describe the current and near-term environmental test capabilities of the NASA Glenn Research Center's Space Power Facility (SPF) located at Sandusky, Ohio. The paper will present current and near-term capabilities for conducting electromagnetic interference and compatibility testing, base-shake sinusoidal vibration testing, reverberant acoustic testing, and thermal-vacuum testing. The paper will also present modes of transportation, handling, ambient environments, and operations within the facility to conduct those tests. The SPF is in the midst of completing and activating new or refurbished capabilities which, when completed, will provide the ability to conduct most or all required full-scale end-assembly space simulation tests at a single test location. It is envisioned that the capabilities will allow a customer to perform a wide range of space simulation tests in one facility at reasonable cost.

Sorge, Richard N.↗
NASA NTRS1994

Alpha LAMP Integration Facility

This paper describes the activity recently completed to meet the simulated space environment requirements for the ground-based testing of an integrated Space Based Laser (SBL) system experiment. The need to maintain optical alignment in the challenging dynamic environment of the pressure recovery system required to simulate space dominated the design requirements. A robust system design was established which minimized the total program costs, most notably by reducing the cost of integrating the components of the experiment. The components of the experiment are integrated on an optical bench in a clean area adjacent to the vacuum chamber and moved on air bearings into the chamber for testing.

Oshiro, Richard↗
NASA NTRSDate not supplied

Dual Glovebox Thermal Vacuum Chamber: Testing Capabilities for Spacesuit Arms and Gloves

The development of Extravehicular Activity (EVA) suits and hand mobility EVA tasks are complex, high risk, and difficult to test in a simulated space environment. During the early assembly of the International Space Station, the Crew and Thermal Systems Division at NASA JSC was tasked to design a chamber that could use two Extravehicular Mobility Unit (EMU) arms in a simulated space environment versus testing with a full suit. The Dual Glove Box (DGB) Chamber was built and served to help develop EVA tools and operations to assist with Return to Flight for the Space Shuttle after the Columbia accident. With the recent development of the Exploration Extravehicular Mobility Unit (xEMU) and new commercial suits through the Extravehicular Activities Services (xEVAS) contract, the DGB can support the need to do suit component testing at thermal extremes and EVA operations without the cost of full suit testing. The DGB can simulate realistic delta pressures, vacuum down to 10^-5 Torr with roughing and cryogenic pumps, and a wide range of shroud temperatures achieved via a combination of Liquid Nitrogen (LN2), conditioned Gaseous Nitrogen (GN2), Infrared (IR) lamps, and heater plates. Recent developmental work has verified operational status of the chamber and expanded the capabilities of the DGB to include thermal contact testing of suit gloves through the development of 2 temperature-controlled grab bars. This paper will discuss the history and capabilities of the DGB, and the chamber’s future role in the development of new spacesuit systems.

Extravehicular Activity (EVA) suits↗
NASA NTRS1994

New potentials of NIICHIMMASH's thermal vacuum facilities

The potentialities of existing test facilities as to simulating space environment governing factors for spacecraft successful development thermal vacuum testing are analyzed, ways of modernizing existing test facilities and specific proposals on their redesign are considered. The problem of spacecraft (S/C) ground development in simulated external environments, the solution of which started more than 30 years ago, has not lost its urgency today. Stringent requirements on S/C active lifetime under space conditions, module large dimensions, great number of extension elements and complicated mode of their interaction in long mission do not allow S/C designers to abandon ground tests. S/C thermal modes development is a combination of calculations, thermal vacuum tests and actions on improving S/C design and its thermal control system. Traditionally, tests are carried out by stages from component and end unit level verifications to complex tests of modules and S/C as a whole. In our opinion, sufficient correctness of calculated models and experience gained in organizations designing space systems allow to reduce cost and time of autonomous tests. Unfortunately, this is not true for complex (integrated) thermal vacuum tests. More than that, their recent programs include tasks of verifying other (than thermal control system) systems if S/C for operation under space simulated conditions. The outlined circumstances are the main reason for critical review of the potentialities of the existing test base, and of NIICHIMMASH's two large thermal vacuum chambers, first of all. The reasons for and ways of enlargement of these facilities potentially are analyzed and the results attained are described.

Afanassiev, N. A.↗
NASA NTRSDate not supplied

Dual Glovebox Thermal Vacuum Chamber: Testing Capabilities for Spacesuit Arms and Gloves

The development of Extravehicular Activity (EVA) suits and hand mobility EVA tasks are complex, high risk, and difficult to test in a simulated space environment. During the early assembly of the International Space Station, the Crew and Thermal Systems Division’s Systems Test Branch at NASA JSC was tasked to design a chamber that could use two Extravehicular Mobility Unit (EMU) arms in a simulated space environment versus testing with a full suit. The Dual Glove Box (DGB) Chamber was built and served to help develop EVA tools and operations to assist with Return to Flight for the Space Shuttle after the Columbia accident. With the recent development of the Exploration Extravehicular Mobility Unit (xEMU) and new commercial suits through the Extravehicular Activities Services (xEVAS) contract, the DGB can support the need to do suit component testing at thermal extremes and EVA operations without the cost of full suit testing. The DGB can simulate realistic delta pressures, vacuum down to 10^-5 Torr with roughing and cryogenic pumps, and a wide range of shroud temperatures achieved via a combination of Liquid Nitrogen (LN2), conditioned Gaseous Nitrogen (GN2), and Infrared (IR) lamps. Recent developmental work has verified operational status of the chamber and expanded the capabilities of the DGB to include thermal contact testing of suit gloves through the development of 2 temperature-controlled grab bars. This paper will discuss the history and capabilities of the DGB, and the chamber’s future role in the development of new spacesuit systems.

Kaixin Cui↗
NASA NTRS1989

Computer image generation: Reconfigurability as a strategy in high fidelity space applications

The demand for realistic, high fidelity, computer image generation systems to support space simulation is well established. However, as the number and diversity of space applications increase, the complexity and cost of computer image generation systems also increase. One strategy used to harmonize cost with varied requirements is establishment of a reconfigurable image generation system that can be adapted rapidly and easily to meet new and changing requirements. The reconfigurability strategy through the life cycle of system conception, specification, design, implementation, operation, and support for high fidelity computer image generation systems are discussed. The discussion is limited to those issues directly associated with reconfigurability and adaptability of a specialized scene generation system in a multi-faceted space applications environment. Examples and insights gained through the recent development and installation of the Improved Multi-function Scene Generation System at Johnson Space Center, Systems Engineering Simulator are reviewed and compared with current simulator industry practices. The results are clear; the strategy of reconfigurability applied to space simulation requirements provides a viable path to supporting diverse applications with an adaptable computer image generation system.

Bartholomew, Michael J.↗
NASA NTRS1997

Changes in gravity influence rat postnatal motor system development: from simulation to space flight

Our research examines the role of the environment in postnatal nervous system development. Recently we have been studying the effects of changes in gravity on the motor system of rats from postnatal day (P) 2 to 31 using kinematic analysis of swimming, walking, and righting reflexes. Using the tail suspension model of weightlessness we identified sensitive and critical periods of motor system development corresponding to the time during which a motor skill is first achieved. Motor performance in suspended animals was marked by slow swimming, walking, and air-righting, all of which were characterized by hindlimb extension. (Walton et al, Neurosci. 52,763,1992). The critical periods identified in these studies contributed to determining the age of animals for a small payload, NIH.R3. This 9-day mission (STS-72) included 2 litters at P5, P7, or P15 at launch. The P7-16 and P15-24 groups were studied post-flight. On the landing day (R+0) surface righting, swimming and walking were slower in flight compared to control animals. Differences were more marked in the younger animals and the hindlimbs were more affected than the forelimbs with marked, prolonged extension of, at least, the ankle joint angle. Readaptation to 1G was slower in the P7-16 group with righting reflexes adapting first, walking last. We have shown that gravity is an important factor in postnatal nervous system development and that its affect depends on the age of the animal, duration of the perturbation, and the motor function studied.

Non-NASA Center↗
NASA NTRS1981

Simulation of space plasma phenomena

The importance of computer modeling in investigating physical phenomena is discussed, noting that modern computers can follow the time evolution of systems containing many millions of degrees of freedom, all of which are simultaneously interacting with each other. The two types of models used in simulating plasma, that is, particle and fluid, are described. Attention is given to particle models and some recent results obtained concerning the diffuse aurora. The simulations are shown to give clear evidence that a type of nonlinear cyclotron resonance process for the cold particles is responsible for the saturation observed in these calculations. It is also responsible for the cold electron heating and it is found that at saturation the rate of heating of the cold electrons essentially balances the rate at which energy is fed into unstable waves.

Dawson, J. M.↗
NASA NTRS1989

Simulated space-based Doppler lidar performance in regions of backscatter inhomogeneities

The prospect of obtaining directly measured winds on a global scale has raised questions about the expected quality of the lidar wind measurements and the potential for biases due to sampling patterns and line-of-sight impediments. Extensive computer simulations are ongoing to address these and other issues. One source of measurement bias is found in regions of the atmosphere where gradients in both lidar backscatter and the winds occur together. The potential biases that result are identified and their magnitudes estimated.

Emmitt, G. D.↗
NASA NTRS1973

ATS-F radiant cooler contamination test in a hydrazine thruster exhaust

A test was conducted under simulated space conditions to determine the potential thermal degradation of the ATS-F radiant cooler from any contaminants generated by a 0.44-N(0.1-lbf) hydrazine thruster. The radiant cooler, a 0.44-N(0.1-lbf)hydrazine engine, and an aluminum plate simulating the satellite interface were assembled to simulate their flight configuration. The cooler was provided with platinum sensors for measuring temperature, and its surfaces were instrumented with six quartz crystal microbalance units (QCM) to measure contaminant mass deposits. The complete assembly was tested in the molecular sink vacuum facility (Molsink) at the Jet Propulsion Laboratory. This was the first time that a radiant cooler and a hydrazine engine were tested together in a very-high-vacuum space simulator, and this test was the first successful measurement of detectable deposits from hydrazine rocket engine plumes in a high vacuum. The engine was subjected to an accelerated duty cycle of 1 pulse/min, and after 2-hr of operation, the QCMs began to shift in frequency. The tests continued for several days and, although there was considerable activity in the QCMs, the cooler never experienced thermal degradation.

Chirivella, J. E.↗
NASA NTRS1989

Space station Simulation Computer System (SCS) study for NASA/MSFC. Volume 2: Concept document

The Simulation Computer System (SCS) concept document describes and establishes requirements for the functional performance of the SCS system, including interface, logistic, and qualification requirements. The SCS is the computational communications and display segment of the Marshall Space Flight Center (MSFC) Payload Training Complex (PTC). The PTC is the MSFC facility that will train onboard and ground operations personnel to operate the payloads and experiments on board the international Space Station Freedom. The requirements to be satisfied by the system implementation are identified here. The SCS concept document defines the requirements to be satisfied through the implementation of the system capability. The information provides the operational basis for defining the requirements to be allocated to the system components and enables the system organization to assess whether or not the completed system complies with the requirements of the system.

Source record↗
NASA NTRS1993

New technique for oil backstreaming contamination measurements

Due to the large size and the number of diffusion pumps, space simulation chambers cannot be easily calibrated by the usual test dome method for measuring backstreaming from oil diffusion pumps. In addition, location dependent contamination may be an important parameter of the test. The backstreaming contamination in the Space Power Facility (SPF) near Sandusky, Ohio, the largest space simulation vacuum test chamber in the U.S.A. was measured. Small size clean silicon wafers as contamination sensors placed at all desired measurement sites were used. The facility used diffusion pumps with DC 705 oil. The thickness of the contamination oil film was measured using ellipsometry. Since the oil did not wet uniformly the silicon substrate, two analysis models were developed to measure the oil film: continuous, homogeneous film and islands of oil with the islands varying in coverage fraction and height. In both cases, the contamination film refractive index was assumed to be that of DC 705. The second model improved the ellipsometric analysis quality parameter by up to two orders of magnitude, especially for the low coverage cases. Comparison of the two models for our case shows that the continuous film model overestimates the oil volume by less than 50 percent. Absolute numbers for backstreaming are in good agreement with published results for diffusion pumps. Good agreement was also found between the ellipsometric results and measurements done by x ray photoelectron spectroscopy (XPS) and by scanning electron microscopy (SEM) on samples exposed to the same vacuum runs.

Alterovitz, S. A.↗
NASA NTRS1992

Neutral buoyancy simulation of space telerobotics operations

A number of neutral buoyancy versions of space telerobots have been tested in the Space Research Laboratory to understand the potential roles for telerobotic systems in space operations. Particular attention is given to details of the well-modeled dynamic environment, the existence of sizable data base on EVA operations in neural buoyancy with correlation to flight experience, and routine access to a number of high-fidelity mockups of past and planned operational spacecraft. The compromises necessary for the design and construction of neutral buoyancy telerobotic systems are discussed, and data from a number of past simulations, including correlation of neutral buoyancy structural assembly with EVA flight data, and preliminary tests of telerobotic servicing of Hubble Space Telescope are summarized.

Akin, David L.↗
NASA NTRS1977

Simulation of space radiation effects on polyimide film materials for high temperature applications

Space environment effects on candidate materials for the solar sail film are determined. Polymers, including metallized polyimides that might be suitable solar radiation receivers, were exposed to combined proton and solar electromagnetic radiation. Each test sample was weighted, to simulate the tension on the polymer when it is stretched into near-planar shape while receiving solar radiation. Exposure rates up to 16 times that expected in Earth orbit were employed, to simulate near-sun solar sailing conditions. Sample appearance, elongation, and shrinkage were monitored, noted, and documented in situ. Thermosetting polyimides showed less degradation or visual change in appearance than thermoplastics.

Fogdall, L. B.↗
NASA NTRS1991

A new technique for oil backstreaming contamination measurements

Due to the large size and the number of diffusion pumps, space simulation chambers cannot be easily calibrated by the usual test dome method for measuring backstreaming from oil diffusion pumps. In addition, location dependent contamination may be an important parameter of the test. The backstreaming contamination was measured in the Space Power Facility (SPF) near Sandusky, OH, the largest space simulation vacuum test chamber in the U.S.. Small clean silicon wafers placed at all desired measurement sites were used as contamination sensors. The facility used diffusion pumps with DC 705 oil. The thickness of the contamination oil film was measured using ellipsometry. Since the oil did not wet the silicon substrate uniformly, two analysis models were developed to measure the oil film: (1) continuous, homogeneous film; and (2) islands of oil with the islands varying in coverage fraction and height. In both cases, the contamination film refractive index was assumed to be that of DC 705. The second model improved the ellipsometric analysis quality parameter by up to two orders of magnitude, especially for the low coverage cases. Comparison of the two models shows that the continuous film model overestimates the oil volume by less than 50 percent. Absolute numbers for backstreaming are in good agreement with published results for diffusion pumps. Good agreement was also found between the ellipsometric results and measurements done by x-ray photoelectron spectroscopy (XPS) and by scanning electron microscopy (SEM) on examples exposed to the same vacuum runs.

Alterovitz, S. A.↗
NASA NTRS2012

OVERFLOW Simulations of Space Shuttle Orbiter Reentry Based on As-Built Geometry

The Space Shuttle Orbiters Discovery and Endeavor have been digitally scanned to obtain outer mold line surfaces. Using these scans, the existing overset computational fluid dynamics (CFD) grid system will be modified by projecting the grid points to the scanned geometry. Simulations will be performed using the OVERFLOW solver and the results compared to previous OVERFLOW results on the theoretical geometry and the aerodynamic databook. The "bent airframe" term will be compared between the aerodynamic databook and the computations over a range of reentry conditions.

Ma, Edward C.↗