Effect of environment on thermal control coatings
Ferrocyanide and ferricyanide additives for prevention of optical degradation of coatings by ultraviolet radiation and vacuum
Freund, T.↗
SEARCH · Search NASA
Results for “environment controllers”
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.
Effects of simulated Mars dust erosion environment on thermal control coatings.
Thermal control coatings, windows and mirrors for 1973 Mars Viking Lander vehicles under simulated Martian surface conditions
Adlon, G. L.↗
Effect of environment on thermal control coatings Final report
Thermal control coating degradation under vacuum and ultraviolet radiation by chemical change of photoproduced holes and electrons
Morrison, S. R.↗
Effects of Simulated Mars Dust Erosion Environment on Thermal Control Coatings
Thermal control coatings, windows and mirrors for 1973 Mars Viking Lander vehicles under simulated Martian surface conditions
Adlon, G. L.↗
Generic Ada code in the NASA space station command, control and communications environment
The results of efforts to apply powerful Ada constructs to the formatted message handling process are described. The goal of these efforts was to extend the state-of-technology in message handling while at the same time producing production-quality, reusable code. The first effort was initiated in September, 1984 and delivered in April, 1985. That product, the Generic Message Handling Facility, met initial goals, was reused, and is available in the Ada Repository on ARPANET. However, it became apparent during its development that the initial approach to building a message handler template was not optimal. As a result of this initial effort, several alternate approaches were identified, and research is now on-going to identify an improved product. The ultimate goal is to be able to instantly build a message handling system for any message format given a specification of that message format. The problem lies in how to specify the message format, and one that is done, how to use that information to build the message handler. Message handling systems and message types are described. The initial efforts, its results and its shortcomings are detailed. The approach now being taken to build a system which will be significantly easier to implement, and once implemented, easier to use, is described. Finally, conclusions are offered.
Mcdougall, D. P.↗
Implementation and integration of a counterbalanced CRT-based stereoscopic display for interactive viewpoint control in virtual environment applications
The NASA-Ames Counterbalanced CRT-based Stereoscopic Viewer (CCSV), which is being used as a viewing device for biomechanical CAD environments, is uniquely suited for applications in which the user frequently moves between desk work and virtual environment viewing, or in which high resolution views of the virtual environment are required, or in which the viewing device must be shared among collaborators in a group setting. The CCSV hardware encompasses a dual-CRT-based stereoscopic viewer with wide-angle optics, a video electronics box, a dedicated microprocessor system monitoring joint angles in the linkage, and a host computer interpreting sensor values and running the application which renders the right and left views for reader CRTs.
Mcdowall, I. E.↗
Method for resource control in parallel environments using program organization and run-time support
A system and method for dynamic scheduling and allocation of resources to parallel applications during the course of their execution. By establishing well-defined interactions between an executing job and the parallel system, the system and method support dynamic reconfiguration of processor partitions, dynamic distribution and redistribution of data, communication among cooperating applications, and various other monitoring actions. The interactions occur only at specific points in the execution of the program where the aforementioned operations can be performed efficiently.
Ekanadham, Kattamuri↗
Method for resource control in parallel environments using program organization and run-time support
A system and method for dynamic scheduling and allocation of resources to parallel applications during the course of their execution. By establishing well-defined interactions between an executing job and the parallel system, the system and method support dynamic reconfiguration of processor partitions, dynamic distribution and redistribution of data, communication among cooperating applications, and various other monitoring actions. The interactions occur only at specific points in the execution of the program where the aforementioned operations can be performed efficiently.
Ekanadham, Kattamuri↗
Detecting Controller Malfunctions in Electromagnetic Environments: Design and Analysis of the Detector - Part 2
Verifying the integrity of control computers in adverse operating environments is a key issue in the development, validation, certification, and operation of critical control systems. Future commercial aircraft will necessitate flight-critical systems with high reliability requirements for stability augmentation, flutter suppression, and guidance and control. Operational integrity of such systems in adverse environments must be validated. This paper considers the problem of applying dynamic detection techniques to monitoring the integrity of fault tolerant control computers in critical applications. Specifically, this paper considers the detection of malfunctions in an aircraft flight control computer (FCC) that is subjected to electromagnetic environment (EME) disturbances during laboratory testing. A dynamic monitoring strategy is presented and demonstrated for the FCC from glideslope engaged until flare under clear air turbulence conditions using a detailed simulation of the B737 Autoland. The performance of the monitoring system is analyzed.
Belcastro, Celeste M.↗
Problems in modeling man machine control behavior in biodynamic environments
Reviewed are some current problems in modeling man-machine control behavior in a biodynamic environment. It is given in two parts: (1) a review of the models which are appropriate for manual control behavior and the added elements necessary to deal with biodynamic interfaces; and (2) a review of some biodynamic interface pilot/vehicle problems which have occurred, been solved, or need to be solved.
Jex, H. R.↗
The definition of the low earth orbital environment and its effect on thermal control materials
The LEO environment and its effects on thermal-control materials (TCMs) being evaluated for use in long-term-mission space structures such as the Space Station are characterized, summarizing the results of recent space and laboratory experiments. Factors examined include atomic oxygen (a serious problem out to 600-700 km), ionizing radiation, solar UV radiation, solid particles (manmade debris and micrometeoroids, a significant hazard out to about 1000 km), and synergistic effects. Numerical data on the expected intensity of these effects for the different Space Station components, the resistance of specific TCMs to the effects, and the effectiveness of protective coatings are compiled in extensive tables and illustrated with diagrams, graphs, and micrographs.
Durcanin, J. T.↗
Automated Test Environment for a Real-Time Control System
An automated environment with hardware-in-the-loop has been developed by Rocketdyne Huntsville for test of a real-time control system. The target system of application is the man-rated real-time system which controls the Space Shuttle Main Engines (SSME). The primary use of the environment is software verification and validation, but it is also useful for evaluation and analysis of SSME avionics hardware and mathematical engine models. It provides a test bed for the integration of software and hardware. The principles and skills upon which it operates may be applied to other target systems, such as those requiring hardware-in-the-loop simulation and control system development. Potential applications are in problem domains demanding highly reliable software systems requiring testing to formal requirements and verifying successful transition to/from off-nominal system states.
Hall, Ronald O.↗
SOYCHMBR.I - A model designed for the study of plant growth in a closed chamber
The analytical model SOYCHMBER.I, an update and alteration of the SOYMOD/OARDC model, for describing the total processes experienced by a plant in a controlled mass environment is outlined. The model is intended for use with growth chambers for examining plant growth in a completely controlled environment, leading toward a data base for the design of spacecraft food supply systems. SOYCHMBER.I accounts for the assimilation, respiration, and partitioning of photosynthate and nitrogen compounds among leaves, stems, roots, and potentially, flowers of the soybean plant. The derivation of the governing equations is traced, and the results of the prediction of CO2 dynamics for a seven day experiment with rice in a closed chamber are reported, together with data from three model runs for soybean. It is concluded that the model needs expansion to account for factors such as relative humidity.
Reinhold, C.↗
Plants and somatic embryos in space: what have we learned?
Space provides a unique environment that can affect the interplay between cell cycle controls and environment and can thus modify the processes of cell division, development and growth. It is proposed that the chromosomal and nuclear abnormalities frequently encountered in cells of various plants exposed to space are due to a combination of factors including the biological status of the systems and the way in which they are grown, exposed to, and ultimately, the way in which they experience multiple stresses. The extent to which space-specific changes become manifest is dependent on the extent of pre-existing stresses in the system. This has become evident in a variety of plant species grown in space but has been particularly amenable to study using in vitro systems, especially in developing embryoids. The following observations allow us to harmonize disparate results from a variety of space experiments:- (a) the more completely developed a system, the less likely it is to show cell stress during growth; the less morphologically complex, the greater the vulnerability; (b) the size/"packaging" of the genome (karyotype) are significant experimental variables; plants with larger genomes (e.g. polyploids) seem to be more space-stress tolerant; (c) a single space-associated stress is inadequate to produce a significant adverse response unless the stress is severe, or a biological parameter necessary to 'amplify' it exists. On this view, an appropriate "stress match" with other non-equilibrium determinants, much like a 'tug of war', can result in genomic variations in space. All this emphasizes that fastidiously-controlled growing environments must be devised if one is to resolve the matter of direct versus indirect effects of space. Better understanding of the novel physico-chemical equilibrium phenomena associated with space will allow those interested in space cell and developmental biology to pick and choose procedures best suited to their exploitation for specific objectives.
Flight Experiment↗
Investigating Dual Electrospinning as a Means of Enhancing Passive Thermal Control Coatings for Cryogenic Propellant Storage in Extraterrestrial Environments
Passive thermal control is necessary as space exploration becomes increasingly widespread. Materials with superior optical properties (high solar reflectance and infrared emittance) are critical for passive thermal control because they can reject most of the incident solar radiation and promote thermal emission from cryogenic propellant storage tanks, enabling the extraterrestrial storage of cryogens. We have demonstrated in previous studies that electrospun nanofibers exhibit exceptional optical properties, offering significant benefits for passive radiative cooling in space. Particularly, electrospun polyvinylidene fluoride-co-hexafluoropropylene PVDF-HFP nanofibers demonstrate exceptionally high solar reflectance (>99%) and strong thermal emittance (measured at ~300 K). However, they exhibit nanostructural changes in the presence of atomic oxygen, which is prevalent in Low Earth Orbit. This study focuses on creating a unique blend of polymeric (PVDF-HFP) and ceramic-based (silica) nanofibers by leveraging the chemical stability and atomic oxygen resistance of silica, using the dual electrospinning manufacturing method. This approach aims to preserve the structural properties of the polymeric counterpart without compromising its optical performance, thereby providing an innovative method for manufacturing environmentally resilient passive thermal control nanofibers with desirable optical and thermal control functionalities for extraterrestrial storage of cryogenic propellants.
Chieloka Ibekwe↗
Corrosion control at the Cape - Environment at Cape Kennedy ideal for corrosion.
Material corrosion control techniques, considering initial structure design, coatings application and protective coatings specifications
PROTECTIVE COATING↗
Minitron II system for precise control of the plant growth environment
The Minitron II system which accommodates hydroponic culture and separate control of atmospheric composition in individual chambers is used to measure gas-exchange by small crop canopies in the undisturbed plant growth environment. It is concluded that the system is capable of providing separate controlled environments for multiple small plants with adequate precision and at relatively low cost when coupled with appropriate control systems.
Knight, Sharon L.↗
Assessment of shuttle payloads gaseous environment contamination and its control
A prediction is given of the in-orbit gaseous environment and the contamination it could produce on cryogenic and room temperature surfaces of payloads in the shuttle bay. The time varying environment was obtained by the superposition of the calculated shuttle environment for a discrete time and payload induced environments measured in large space chambers. Representative contaminant surface accretions were calculated for flights 1 week and 1 month long for payloads having the largest source of outgassing and an orbit of 200 km. A number of calculations were based on the magnitude of the sources, the molecular natures, the decay rate with time, the sticking coefficients, the view factors, and the temperatures of the surfaces being contaminated. Significant results are reported.
Scialdone, J. J.↗