Engineering Papers⌕ Search

SEARCH · Engineering Papers

Results for “Fire Systems”

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 1,027 records · Page 57
All sourcesNASA NTRSDOE OSTI
NASA NTRSDate not supplied

Autonomous Control for Arbitrary Thruster Configurations and Mass Properties in Special Euclidean Group SE(3)

Most current methods for determining maneuvers and thrust firing sequences depend on explicit and predetermined commands generated by a combination of on-board systems and ground-based human-in-the-loop methods. For spacecraft and space structures with changing mass properties and thruster configurations, such as the Deep Space Gateway as it changes configurations throughout its lifetime, determining these commands can be time-consuming and computationally intensive. However, recent work within the Lie group SE(3) has offered ways of autonomously determining the location, power, precision, and capabilities of thrusters in any arbitrary position. Furthermore, a method for determining thruster firing sequences based on an arbitrary control input (both translational and rotational in a coupled, 6-element vector) and arbitrary thruster configurations has also recently been developed. When combining these methods, any spacecraft with any mass properties and thruster configurations can be understood in terms of controllability limits and thruster firing sequences can be generated quickly and with low computational load, thus extending the autonomous capabilities of deep space missions. In this work, this method is presented and explored in terms of convergence time to the desired pose. The capabilities of this method are also examined in the case of the Deep Space Gateway both in fully controllable configurations and uncontrollable configurations.

SE(3)↗
NASA NTRSDate not supplied

Human-Autonomy Teaming Assistant to Support Small Uncrewed Aircraft Systems for Wildland Firefighting Operations

An exploratory human-in-the-loop simulation was conducted to investigate and characterize a Human-Autonomy Teaming (HAT) Assistant to support a remote operator of multiple small Uncrewed Aircraft Systems (sUAS) using a ground control station (GCS) in the context of a wildland fire surveillance mission. Operator performance using the GCS with the HAT Assistant (Assisted Mode) was compared to operator performance using the GCS without the HAT Assistant (Unassisted Mode) during two types of contingency-event scenarios (Low and High Complexity). In the Assisted Mode, the HAT Assistant provided updates to the level of risk to the mission along with recommendations for risk mitigation, which were not provided in the Unassisted Mode. No significant differences in objective performance and subjective ratings of workload, situation awareness, and trust in automation between the Assisted and Unassisted Modes were detected, however there were indications that participants preferred the Assisted GCS over the Unassisted GCS and directions for further development were explored. Additional work is necessary to further refine the HAT Assistant and better characterize its effects on remote operator performance while managing multiple sUAS assets. Future work is recommended to optimize the implementation of an assistant to support operator performance during different missions and across vehicle classes.

Human-Autonomy Teaming↗
NASA NTRS1990

Preliminary simulations of the large-scale environment during the FIRE cirrus IFO

Large scale forcing (scales greater than 500 km) is the dominant factor in the generation, maintenance, and dissipation of cirrus cloud systems. However, the analyses of data acquired during the first Cirrus IFO have highlighted the importance of mesoscale processes (scales of 20 to 500 km) to the development of cirrus cloud systems. Unfortunately, Starr and Wylie found that the temporal and spatial resolution of the standard and supplemental rawinsonde data were insufficient to allow an explanation of all of the mesoscale cloud features that were present on the 27 to 28 Oct. 1986. It is described how dynamic initialization, or 4-D data assimilation (FDDA) can provide a method to address this problem. The first steps towards application of FDDA to FIRE are also described.

Westphal, Douglas L.↗
NASA NTRS1972

Development of moldable carbonaceous materials for ablative rocket nozzles.

Description of a materials system developed for use as low-cost ablative nozzles for NASA's 260-in. solid rocket motor. Petroleum coke and carbon black fillers were employed; high density was achieved by controlling particle size distribution. An alumina catalyzed furfuryl ester resin which produced high carbon residues after pyrolysis was employed as the binder. Staple carbon fibers improved the strength and crack resistance of molded bodies. In static firing tests of two subscale nozzles, this material compared favorably in erosion rate with several other ablative systems.

Lockhart, R. J.↗
NASA NTRS1978

Status of NO sub x control for coal-fired power plants

The status of technologies for controlling emissions of oxides of nitrogen (NOx) from coal-fired power plants is reviewed. A discussion of current technology as well as future NOx control approaches is presented. Advanced combustion approaches are included as well as post-combustion alternatives such as catalytic and noncatalytic ammonia-bases systems and wet scrubbing. Special emphasis is given to unresolved development issues as they relate to practical applications on coal-fired power plants.

Teixeira, D. P.↗
NASA NTRS1990

CLIPS: A tool for corn disease diagnostic system and an aid to neural network for automated knowledge acquisition

This paper describes the building of a corn disease diagnostic expert system using CLIPS, and the development of a neural expert system using the fact representation method of CLIPS for automated knowledge acquisition. The CLIPS corn expert system diagnoses 21 diseases from 52 symptoms and signs with certainty factors. CLIPS has several unique features. It allows the facts in rules to be broken down to object-attribute-value (OAV) triples, allows rule-grouping, and fires rules based on pattern-matching. These features combined with the chained inference engine result to a natural user query system and speedy execution. In order to develop a method for automated knowledge acquisition, an Artificial Neural Expert System (ANES) is developed by a direct mapping from the CLIPS system. The ANES corn expert system uses the same OAV triples in the CLIPS system for its facts. The LHS and RHS facts of the CLIPS rules are mapped into the input and output layers of the ANES, respectively; and the inference engine of the rules is imbedded in the hidden layer. The fact representation by OAC triples gives a natural grouping of the rules. These features allow the ANES system to automate rule-generation, and make it efficient to execute and easy to expand for a large and complex domain.

Wu, Cathy↗
NASA NTRS1995

Flight test of a low-altitude helicopter guidance system with obstacle avoidance capability

Military aircraft regularly conduct missions that include low-atltitude, near-terrain flight in order to increase covertness and payload effectiveness. Civilian applications include airborne fire fighting, police surveillance, search and rescue, and helicopter emergency medical service. Several fixed-wing aircraft now employ terrain elevation maps and forward-pointed radars to achieve automated terrain following or terrain avoidance flight. Similar systems specialized to helicopters and their flight regime have not received as much attention. A helicopter guidance system relying on digitized terrain elevation maps has been developed that employs airborne navigation, mission requirements, aircraft performance limits, and radar altimeter returns to generate a valley-seeking, low-altitude trajectory between waypoints. The guidance trajectory is symbolically presented to the pilot on a helmet mounted display. This system has been flight tested to 150 ft (45.7 m) above ground level altitude at 80 kts, and is primarily limited by the ability of the pilot to perform manual detection and avoidance of unmapped hazards. In this study, a wide field of view laser radar sensor has been incorporated into this guidance system to assist the pilot in obstacle detection and avoidance, while expanding the system's operational flight envelope. The results from early flight tests of this system are presented. Low-altitude missions to 100 ft (30.5 m) altitude at 80n kts in the presence of unmapped natural and man-made obstacles were demonstrated while the pilot maintained situational awareness and tracking of the guidance trajectory. Further reductions in altitude are expected with continued flight testing.

Zelenka, Richard E.↗
NASA NTRS1989

Flammability and sensitivity of materials in oxygen-enriched atmospheres; Proceedings of the Fourth International Symposium, Las Cruces, NM, Apr. 11-13, 1989. Volume 4

The present volume discusses the ignition of nonmetallic materials by the impact of high-pressure oxygen, the promoted combustion of nine structural metals in high-pressure gaseous oxygen, the oxygen sensitivity/compatibility ranking of several materials by different test methods, the ignition behavior of silicon greases in oxygen atmospheres, fire spread rates along cylindrical metal rods in high-pressure oxygen, and the design of an ignition-resistant, high pressure/temperature oxygen valve. Also discussed are the promoted ignition of oxygen regulators, the ignition of PTFE-lined flexible hoses by rapid pressurization with oxygen, evolving nonswelling elastomers for high-pressure oxygen environments, the evaluation of systems for oxygen service through the use of the quantitative fault-tree analysis, and oxygen-enriched fires during surgery of the head and neck.

Stoltzfus, Joel M.↗
NASA NTRS2005

Designing For Human Presence in Space: An Introduction to Environmental Control and Life Support Systems (ECLSS)

Human exploration and utilization of space requires habitats to provide appropriate conditions for working and living. These conditions are provided by environmental control and life support systems (ECLSS) that ensure appropriate atmosphere composition, pressure, and temperature; manage and distribute water, process waste matter, provide fire detection and suppression; and other functions as necessary. The tables in appendix I of NASA RP 1324 "Designing for Human Presence in Space" summarize the life support functions and processes used onboard U.S. and U.S.S.R/Russian space habitats. These tables have been updated to include information on thermal control methods and to provide additional information on the ECLS systems.

Wieland, P. O.↗
NASA NTRS2010

Space Operations for a New Era of Exploration Launch Vehicles

NASA's Constellation Program is depending on the Ares Projects to deliver the crew and cargo launch capabilities needed to send human explorers to the Moon and beyond. Ares I and V will provide the core space launch capabilities needed to continue providing crew and cargo access to the International Space Station (ISS), and to build upon the U.S. history of human space exploration. Since 2005, Ares has made substantial progress on designing, developing, and testing the Ares I crew launch vehicle and has continued its in-depth studies of the Ares V cargo launch vehicles. The combined Ares I/Ares V architecture has been designed to reduce the complexity and labor intensity of ground operations for America's next journeys beyond low-Earth orbit (LEO). A deliberate effort is being made to ensure a high level of system operability to significantly increase safety and system availability as well as reduce recurring costs for this new launch vehicle. The Ares Projects goal is to instill operability as part of the vehicles requirements development, design, and operations. This simplicity will come from using simpler, proven engine designs, as in the case of the J-2X upper stage engine and RS-68 engine; improving existing hardware, as in the case of the Shuttle-heritage 5-segment solid rocket motor; and using common propulsion and instrument unit elements between Ares I and Ares V. Furthermore, lessons learned while developing Ares I will be applied directly to Ares V operations. In 2009, the Ares Projects plan to conduct the first flight test of Ares I, designated Ares I-X. Ares I-X preparations have already prompted changes to the vehicle stacking and launch infrastructure at Kennedy Space Center (KSC), including removing Shuttle-specific fixtures from the Vehicle Assembly Building (VAB) to accommodate Ares I-style stacking operations, new firing room computers and infrastructure in the VAB Launch Control Center, and new lightning protection system towers at Launch Complex 39B to accommodate the greater height of Ares I-X. In addition to lessons learned from the stacking of Ares I-X, the flight test itself promises to yield important data and operations lessons for assembling, launching, and flying Ares I.

Cook, Stephen A.↗
NASA NTRS1999

The Mars Pathfinder Mission and Science Results

Mars Pathfinder, the first low-cost, quick Discovery class mission to be completed, successfully landed on the surface of Mars on July 4, 1997, deployed and navigated a small rover, and collected data from 3 science instruments and 10 technology experiments. The mission operated on Mars for 3 months and returned 2.3 Gbits of new data, including over 16,500 lander and 550 rover images, 16 chemical analyses of rocks and soil, and 8.5 million individual temperature, pressure and wind measurements. The rover traversed 100 m clockwise around the lander, exploring about 200 square meters of the surface. The mission captured the imagination of the public, and garnered front page headlines during the first week. A total of about 566 million internet "hits" were registered during the first month of the mission, with 47 million "hits" on July 8th alone, making the Pathfinder landing by far the largest internet event in history at the time. Pathfinder was the first mission to deploy a rover on Mars. It carried a chemical analysis instrument, to characterize the rocks and soils in a landing area over hundreds of square meters on Mars, which provided a calibration point or "ground truth" for orbital remote sensing observations. The combination of spectral imaging of the landing area by the lander camera, chemical analyses aboard the rover, and close-up imaging of colors, textures and fabrics with the rover cameras offered the potential of identifying rocks (petrology and mineralogy). With this payload, a landing site in Ares Vallis was selected because it appeared acceptably safe and offered the prospect of analyzing a variety of rock types expected to be deposited by catastrophic floods, which enabled addressing first-order scientific questions such as differentiation of the crust, the development of weathering products, and the nature of the early Martian environment and its subsequent evolution. The 3 instruments and rover allowed seven areas of scientific investigation: the geology and geomorphology of the surface, mineralogy and geochemistry of rocks and soils, physical properties of surface materials, magnetic properties of airborne dust, atmospheric science including aerosols, and rotational and orbital dynamics of Mars. Scientists were assembled into 7 Science Operations Groups that were responsible for requesting measurements by the 3 instruments, rover and engineering subsystems for carrying out their scientific investigations and for analyzing the data and reporting on their findings. The spacecraft was launched on December 4, 1996 and had a 7 month cruise to Mars, with four trajectory correction maneuvers. The vehicle entered the atmosphere directly following cruise stage separation. Parachute deployment, heatshield and lander separation, radar ground acquisition, airbag inflation and rocket ignition all occurred before landing at 2:58 AM true local solar time (9:56:55 AM PDT). The lander bounced at least 15 times up to 12 in high without airbag rupture, demonstrating the robustness of this landing system. Reconstruction of the final landing sequence indicates that the parachute/backshel1/1ander was tilted due to a northwest directed wind and wind shear, which resulted in the lander bouncing about I km to the northwest and initially downhill about 20 m from where the solid rockets fired. Two anomalously bright spots located in the lander scene are likely the heatshield, which continued in a ballistic trajectory about 2 km downrange (west southwest), and the backshell/parachute, which stayed nearer to where the rockets fired. Unconnected disturbed soil patches in the scene indicate that the final few bounces of the lander were from the east-southeast and were followed by a gentle roll to the west before coming to rest on the base petal. The location of the lander away from where the solid rockets fired and considerations of the exhaust products used to inflate the airbags and their fate, indicate that the Pathfinder landing system is one of the cleanest designed leaving the local area essentially contaminant free. The radio signal from the low-=gain antenna was received at 11:34 AM PDT indicating a successful landing.

Golombek, M. P.↗
NASA NTRS2019

Connecting Crop Productivity, Residue Fires, and Air Quality over Northern India

Northwestern India is known as the “breadbasket” of the country producing two-thirds of food grains, with wheat and rice as the principal crops grown under the crop rotation system. Agricultural data from India indicates a 25% increase in the post-monsoon rice crop production in Punjab during 2002–2016. NASA’s A-train satellite sensors detect a consistent increase in the vegetation index (net 21%) and post-harvest agricultural fire activity (net ~60%) leading to nearly 43% increase in aerosol loading over the populous Indo-Gangetic Plain in northern India. The ground-level particulate matter (PM2.5) downwind over New Delhi shows a concurrent uptrend of net 60%. The effectiveness of a robust satellite-based relationship between vegetation index—a proxy for crop amounts, and post-harvest fires—a precursor of extreme air pollution events, has been further demonstrated in predicting the seasonal agricultural burning. An efficient crop residue management system is critically needed towards eliminating open field burning to mitigate episodic hazardous air quality over northern India.

Hiren Jethva↗
NASA NTRS2022

Reconstructed Performance of the Mars InSight Lander’s Supersonic Parachute & Comparison with the Phoenix Lander

On November 26th, 2018 the Mars InSight landersuccessfully touched down at Elysium Planitia. InSight’s Entry,Descent, and Landing sequence included an 11.8-m supersonicallydeployed Disk-Gap-Band parachute that was a largelybuild-to-print version of the parachute used to successfully landthe Phoenix lander a decade earlier. This paper describes thereconstructed performance of InSight’s supersonic parachuteat Mars, highlighting the differences and similarities with theperformance of Phoenix’s parachute. Measurements from theonboard inertial measurement unit along with pre-launch measurementsof the parachute system and spacecraft, assumptionsabout the vehicle’s aerodynamics, and models for the Martianatmosphere were used to reconstruct the spacecraft’s trajectoryand the parachute system’s performance. The reconstruction resultswere compared against pre-flight predictions. Reconstructionof the InSight trajectory leading up to parachute deploymentshowed that the vehicle trimmed in a lift-down orientationduring entry and thus experienced greater deceleration thanexpected by most pre-flight simulations. This led to parachutedeployment conditions that diverged from the nominal preflightpredictions. The parachute was mortar-deployed at aMach number of approximately 1.5, below the nominal preflightexpectation of 1.66. The approximate dynamic pressureat mortar fire was between 518 Pa and 546 Pa, which agreedwell with pre-flight expectations. The mortar system performednominally, and the system’s deployment (0.755 s) and inflation(1.1 s) times were in line with pre-flight modeling. The peakinflation load was 45 kN, well below the parachute’s 67 kNdesign limit load. Following deployment of the parachute,the vehicle’s rotational rates and the dynamics of the systemwere in excellent agreement with pre-flight expectations. Theperformance of the InSight parachute system was also foundto agree well with that of the Phoenix parachute system, asexpected given the similarities between the two systems.

Karlgaard, Chris↗
NASA NTRS2019

Progress in Atmospheric Carbon Monitoring Using NASA's GEOS Model and Data from the OCO and GOSAT Missions

NASA's Global Modeling and Assimilation Office (GMAO) produces a variety of carbon products based the synthesis of satellite remote sensing data and outputs of the Goddard Earth Observing System (GEOS). This includes bottom-up surface fluxes due to fossil fuel emissions, biomass burning, terrestrial biospheric exchange, and ocean exchangeconstrained by measurements of nighttime lights, fire radiative power, normalized difference vegetation index, and ocean color. These fluxes are the basis of top-down estimates of carbon concentrations and fluxes. In particular, the GMAO system processes retrievals of column carbon dioxide (XCO2) from GOSAT and OCO-2 to produce a high-resolution, long-term global analysis of CO2 in three dimensions every 6 hours. Here, we discuss the potential applications of such products for satellite intercomparison and evaluation against independent, non-coincident data. We also highlight the ability to provide monthly global atmospheric growth rates inferred from the assimilated CO2 concentration product. Finally, we discuss the challenges facing such products including bias correction and the estimation and analysis of model transport errors.

Weir, B.↗
NASA NTRS1980

Twelve solar-heating/cooling systems: Design and development

Two quarterly reports describe first 6 months of development on single family, multifamily, and commercial installations in Minneapolis area. Reports discuss basic requirements, and reasons for selecting specific configurations. Systems consist of liquid cooled flat plate collectors, two fluid loops, and gas-fired forced-air auxiliary heat source.

Source record↗
NASA NTRS1978

NASA technical advances in aircraft occupant safety

NASA's aviation safety technology program examines specific safety problems associated with atmospheric hazards, crash-fire survival, control of aircraft on runways, human factors, terminal area operations hazards, and accident factors simulation. While aircraft occupants are ultimately affected by any of these hazards, their well-being is immediately impacted by three specific events: unexpected turbulence encounters, fire and its effects, and crash impact. NASA research in the application of laser technology to the problem of clear air turbulence detection, the development of fire resistant materials for aircraft construction, and to the improvement of seats and restraint systems to reduce crash injuries are reviewed.

Enders, J. H.↗