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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 973 records · Page 54

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NASA NTRS1993

Knowledge engineering for temporal dependency networks as operations procedures

This paper presents a case study of the knowledge engineering process employed to support the Link Monitor and Control Operator Assistant (LMCOA). The LMCOA is a prototype system which automates the configuration, calibration, test, and operation (referred to as precalibration) of the communications, data processing, metric data, antenna, and other equipment used to support space-ground communications with deep space spacecraft in NASA's Deep Space Network (DSN). The primary knowledge base in the LMCOA is the Temporal Dependency Network (TDN), a directed graph which provides a procedural representation of the precalibration operation. The TDN incorporates precedence, temporal, and state constraints and uses several supporting knowledge bases and data bases. The paper provides a brief background on the DSN, and describes the evolution of the TDN and supporting knowledge bases, the process used for knowledge engineering, and an analysis of the successes and problems of the knowledge engineering effort.

Fayyad, Kristina E.↗

NASA NTRS2000

Biotechnology Facility: An ISS Microgravity Research Facility

The International Space Station (ISS) will support several facilities dedicated to scientific research. One such facility, the Biotechnology Facility (BTF), is sponsored by the Microgravity Sciences and Applications Division (MSAD) and developed at NASA's Johnson Space Center. The BTF is scheduled for delivery to the ISS via Space Shuttle in April 2005. The purpose of the BTF is to provide: (1) the support structure and integration capabilities for the individual modules in which biotechnology experiments will be performed, (2) the capability for human-tended, repetitive, long-duration biotechnology experiments, and (3) opportunities to perform repetitive experiments in a short period by allowing continuous access to microgravity. The MSAD has identified cell culture and tissue engineering, protein crystal growth, and fundamentals of biotechnology as areas that contain promising opportunities for significant advancements through low-gravity experiments. The focus of this coordinated ground- and space-based research program is the use of the low-gravity environment of space to conduct fundamental investigations leading to major advances in the understanding of basic and applied biotechnology. Results from planned investigations can be used in applications ranging from rational drug design and testing, cancer diagnosis and treatments and tissue engineering leading to replacement tissues.

Gonda, Steve R.↗

NASA NTRS1975

HELIOS dual swept frequency radiometer

The HELIOS dual swept frequency radiometer, used in conjunction with a dipole antenna, was designed to measure electromagnetic radiation in space. An engineering prototype was fabricated and tested on the HELIOS spacecraft. Two prototypes and two flight units were fabricated and three of the four units were integrated into the HELIOS spacecraft. Two sets of ground support equipment were provided for checkout of the radiometer.

White, J. R.↗

NASA NTRS1977

Effect of inlet disturbances on fan inlet noise during a static test

Measurements of fan rotor inlet noise taken during static test situations are at variance with aircraft engine flight data. In particular, static tests generally yield a significantly higher tone at blade passage frequency than that measured during flight. To explain this discrepancy, the extent of the influence of inlet ground vortices and large-scale inlet turbulence on the forward-radiated fan noise measured at a static test facility was investigated. While such inlet disturbances were generated intentionally in an anechoic test chamber, far-field acoustic measurements and inlet flow-field hot-film mappings of a fan rotor were obtained. Experimental results indicate that the acoustic effect of such disturbances appears to be less severe for supersonic than for subsonic tip speeds. Further, a reverse flow that occurs on the exterior cowl in static test facilities appears to be an additional prime candidate for creating inlet disturbances and causing variance between flight and static acoustic data.

Bekofske, K. L.↗

NASA NTRS1977

Fan inlet disturbances and their effect on static acoustic data

There is evidence that measurements of fan-rotor inlet noise taken during static test situations are at variance with aircraft engine flight data. In particular, static tests generally yield a significantly higher tone at blade passing frequency than that measured during flight. An experimental program was carried out to investigate this discrepancy. Inlet ground vortices and large-scale inlet turbulence were generated intentionally in an anechoic test chamber. Far-field acoustic measurements and inlet flow field hot film mappings of a fan rotor were then carried out to study the influence of such inlet disturbances at a static test facility. Experimental results indicate that the acoustic effect of such disturbances appears to be less severe for supersonic than for subsonic tip speeds. Further, a reverse flow that occurs on the exterior cowl in static test facilities appears to be an additional prime candidate for creating inlet disturbances and causing variance between flight and static acoustic data.

Bekofske, K. L.↗

NASA NTRS1988

Hardware development for the surface tension driven convection experiment aboard the USML-1 spacelab mission

The Surface Tension Driven Convection Experiment is a Space Transportation System flight experiment to study both transient and steady thermocapillary fluid flows aboard the USML-1 Spacelab mission planned for March 1992. Hardware is under development to establish the experimental conditions and perform the specified measurements, for both ground based research and the flight experiment in a Spacelab single rack. Major development areas include an infrared thermal imaging system for surface temperature measurement, a CO2 laser and control system for surface heating, and for flow visualization, a He-Ne laser and optical system in conjunction with an intensified video camera. For ground based work the components of each system were purchased or designed, and tested individually. The three systems will be interfaced with the balance of the experimental hardware and will constitute a working engineering model. A description of the three systems and examples of the component performance is given along with the plans for the development of flight hardware.

Pline, A. D.↗

NASA NTRS1989

Interior noise control ground test studies for advanced turboprop aircraft applications

The measurement and analysis procedures are documented, and the results of interior noise control ground tests conducted on a DC-9 aircraft test section are summarized. The objectives of these tests were to study the fuselage response characteristics of treated and untreated aircraft with aft-mount advanced turboprop engines and to analyze the effectiveness of selected noise control treatments in reducing passenger cabin noise on these aircraft. The results of fuselage structural mode surveys, cabin cavity surveys and sound intensity surveys are presented. The performance of various structural and cabin sidewall treatments is assessed, based on measurements of the resulting interior noise levels under simulated advanced turboprop excitation.

Simpson, Myles A.↗

NASA NTRS1989

Hardware development for the Surface Tension Driven Convection Experiment aboard the USML-1 Spacelab mission

Pline, A. D.↗

NASA NTRS1992

Comparison ofdvanced turboprop interior noise control ground and flight test data

Interior noise ground tests conducted on a DC-9 aircraft test section are described. The objectives were to study ground test and analysis techniques for evaluating the effectiveness of interior noise control treatments for advanced turboprop aircraft, and to study the sensitivity of the ground test results to changes in various test conditions. Noise and vibration measurements were conducted under simulated advanced turboprop excitation, for two interior noise control treatment configurations. These ground measurement results were compared with results of earlier UHB (Ultra High Bypass) Demonstrator flight sts with comparable interior treatment configurations. The Demonstrator is an MD-80 test aircraft with the left JT8D engine replaced with a prototype UHB advanced turboprop engine.

Simpson, Myles A.↗

NASA NTRS2005

Comparison of the Effects of using Tygon Tubing in Rocket Propulsion Ground Test Pressure Transducer Measurements

This paper documents acoustics environments data collected during liquid oxygen- ethanol hot-fire rocket testing at NASA Marshall Space Flight Center in November- December 2003. The test program was conducted during development testing of the RS-88 development engine thrust chamber assembly in support of the Orbital Space Plane Crew Escape System Propulsion Program Pad Abort Demonstrator. In addition to induced environments analysis support, coincident data collected using other sensors and methods has allowed benchmarking of specific acoustics test measurement methodologies during propulsion tests. Qualitative effects on data characteristics caused by using tygon sense lines of various lengths in pressure transducer measurements is discussed here.

Farr, Rebecca A.↗

NASA NTRS2012

Flight Simulator Evaluation of Enhanced Propulsion Control Modes for Emergency Operation

This paper describes piloted evaluation of enhanced propulsion control modes for emergency operation of aircraft. Fast Response and Overthrust modes were implemented to assess their ability to help avoid or mitigate potentially catastrophic situations, both on the ground and in flight. Tests were conducted to determine the reduction in takeoff distance achievable using the Overthrust mode. Also, improvements in Dutch roll damping, enabled by using yaw rate feedback to the engines to replace the function of a stuck rudder, were investigated. Finally, pilot workload and ability to handle the impaired aircraft on approach and landing were studied. The results showed that improvement in all aspects is possible with these enhanced propulsion control modes, but the way in which they are initiated and incorporated is important for pilot comfort and perceived benefit.

Litt, Jonathan, S↗

NASA NTRS1941

Progress Report on Cowlings for Air-Cooled Engines Investigated in the NACA 19-Foot Pressure Wind Tunnel

At the present time there is considerable demand for improvement in the aerodynamic characteristics of cowlings for radial air-cooled aircraft engines. During the past year, numerous cowling arrangements have been investigated in various departments of the NACA laboratory. Although a few full-scale investigation have been carried out, most of the studies have been preliminary in nature and have been confined to the investigation of model arrangement in wind tunnels. Because of the existing national emergency it appears advisable to release immediately to the aircraft industry the information available on the more promising of the arrangements that have been studied. An investigation having as its aim the improvement in performance and flying qualities of single-engine air-cooled military pursuit airplanes is being conducted in the NACA 10-foot pressure wind tunnel. As a part of that investigation, studies have been made of the relative merits of a conventional NACA open-nose cowling arrangement and of a less conventional but better streamline NACA high-speed cowling arrangement in which the cooling air enters the cowling through an opening ahead of the propeller, passes internally through an element of the cowling which rotates with the propeller, and thence past the engine cylinders to the exit at the rear of the engine. These investigations indicate that at airplane speeds of around 400 miles per hour there is not a great deal to be gained in high-speed performance through the application of the latter cowling arrangement, but at speeds in excess of about 450 miles per hour a very appreciable gain is indicated. Present indications are that improved engine cooling can be obtained throughout the speed range as well as ground cooling through the use of the high-speed cowling. This paper summarizes the results obtained from wind-tunnel tests of models of the two cowling arrangements.

McHugh, James G.↗

NASA NTRS2021

Lunar Asset Messaging and On Orbit Navigation

NASA has titled its 2020 thrust for the Moon, Artemis. The increased focus on the Moon as a destination for future human and robotic expeditions necessitates general purpose navigational and communications infrastructure reducing their complexity to help establish a sustained presence. A framework through which Lunar missions can relay communications and localize their positions shifts the burden from the individual mission and enables resource allocation tailored to mission-specific goals. During the summer of 2020, student interns under the Innovation to Flight (i2F) program at the National Aeronautics and Space Administration’s (NASA) Jet Propulsion Laboratory (JPL) in collaboration with the University of Colorado Boulder designed, built, and tested a prototype framework capable of providing surface assets with communication and positioning services. The team utilized the existing i2F CubeSat bus in addition to developing several CubeSat engineering development units (EDUs), a ground vehicle, and a ground station to simulate a scenario in which a lunar surface mission is supported by these services. A primary goal of the summer was to develop a method for localizing the ground vehicle through trilateration. Distances are inferred from the round-trip time of flight (ToF) of radio signals between an asset and several elements. Signals were sent and received using LimeSDR software defined radios on-board both the ground vehicle and the EDUs; ToF and trilateration were calculated on a Qualcomm Snapdragon development board located within the LA MOON payload data system. The ModalAI chipset on the Qualcomm was instrumental in executing visual based position estimation. Communications was facilitated through a bent-pipe approach addressing the NASA requirement to provide solutions for in communication denied locations. The ground vehicle relayed information to other surface assets in addition to its ground station through the supporting constellation. This project demonstrates the feasibility of a lunar CubeSat constellation for the support of surface assets and explores packaging and operations of the components critical to trilateration and bent-pipe communication into a standard CubeSat form factor. When implemented, this framework will open a door for new surface missions designed with lower power requirements and increased operational access.

Huang, Calvin↗

NASA NTRS2023

An MBSE Approach for Developing an Autonomous Rover Platform

The proliferation of increasingly autonomous systems calls for new ways to address how safety is assured. As these systems become more advanced and complex, it becomes more important to model and prototype autonomous functions at the systems level and the functions that assure they are operating safely and as expected. To that effect, researchers at the National Aeronautics and Space Administration (NASA) 's Robust Software Engineering (RSE) group are working on prototyping a Research Autonomous Vehicle, commonly referred to as R-RAV. The R-RAV is an autonomous rover platform designed to act as a case study for assured autonomy research. Moreover, an overarching goal is for the R-RAV to serve as a training ground for other mission projects. In this paper, we will detail how we have used a Model-Based Systems Engineering (MBSE) approach to model a prototype of the R-RAV and test and verify its different functionalities.

MBSE↗

DOE OSTI2024

Demonstrating autonomous controls on hardware test beds is a necessity for successful missions to Mars and beyond

NASA and the Department of Defense are planning for a mission to Mars in the 2030s–2040s using nuclear thermal propulsion (NTP). NTP uses a nuclear reactor to heat flowing hydrogen and create thrust. A serious concern for crewed and uncrewed missions to Mars is the loss of reactor control. The reactor startup and initial rocket impulse are initiated in cislunar or near-earth orbital regions; therefore, radio communications between ground control and the NTP engine should occur in real time. However, radio communications can take more than 20 min, depending on planet positions, to reach Mars orbiters from ground control. To address this delay, local autonomous controls are implemented onboard the NTP engine to ensure acceptable operation. However, autonomous controls have not been demonstrated or implemented in research or power reactor contexts because of safety and reliability concerns. To enable autonomous controls development, demonstration, and validation, Oak Ridge National Laboratory has created a nonnuclear hardware-in-the-loop test bed. Sensors throughout the test bed relay system status and hardware response to the user control algorithm, including measurements of temperature, flow, pressure of a loop, control drum position, and drum speed. This paper discusses the development of this facility and user accessibility.

33 ADVANCED PROPULSION SYSTEMS↗

NASA NTRS2002

Extending Ion Engine Technology to NEXT and Beyond

Extending ion engine technology beyond the current state-of-the art primary interplanetary electric propulsion system, the 2.3-kW NASA Solar Electric Propulsion Technology and Applications Readiness (NSTAR) system, will require thrusters with improved propellant throughput and total impulse capability. Many of the design choices that culminated in the NSTAR thrusters must be revisited, and their application to next generation ion engine technology must be evaluated. The concept of derating, which was successfully employed in NSTAR, has been applied to the 40 cm NASA Evolutionary Xenon Thruster (NEXT) currently under development at NASA Glenn Research Center (GRC). At 5-kW, NEXT operates with the same average beam current density as NSTAR, and at 10-kW, the peak beam current density is only ten percent greater than NSTAR. The result is that similar Ion optics technology is expected to yield comparable lifetime. Thick-accelerator- grid ion optics are also being tested to realize additional lifetime benefits. A 40-A discharge cathode is being developed for NEXT based on scaling the NSTAR design. Nevertheless, the experiences of the NSTAR ground tests and the thruster on the Deep Space One spacecraft indicate that the discharge cathode wear must be studied experimentally and theoretically to ensure that it meets the lifetime requirements. Although NEXT is in its infancy, investigations have already begun to examine possible modifications to engine design for even higher-power and higher-specific impulse engines. Ion optics using alternate materials such as titanium, graphite, or carbon-carbon composite are currently being investigated due to their low sputter yields at high voltage. To avoid the difficulties encountered using electrodes at high-currents, the use of a microwave-based ion thruster is under investigation for potential high-power ion thruster systems requiring long lifetimes. Additionally, alternative propellants are being considered for applications requiring high-specific impulse (>> 5000 s) and extremely long-life (>> 15,000 hr). Testing requirements make condensable propellants attractive for high-power engines. Although the NSTAR ion engine demonstrated the flight maturity of ion thruster technology, many challenges remain for the development of thrusters with improved propellant throughput and power handling capabilities.

Domonkos, Matthew T.↗

DOE OSTI2020

Operational Modes of a 2.0 MWth Chloride Molten-Salt Pilot-Scale System

The limit of traditional solar-salt thermal stability is around 600 °C with ambient air as the cover gas. Nitrate molten salt concentrating solar power (CSP) systems are currently deployed globally and are considered to be state-of the art heat transfer fluids (HTFs) for present day high-temperature operation. However, decomposition challenges occur with these salts for operation beyond 600 C. Although slightly higher limits may be possible with solar salt, to fully realize SunShot efficiency goals of $15/kWhth HTFs and an LCOE of 6¢/kWh, molten-salt technologies working at higher temperatures (e.g., 650 °C to 750 °C) will require an alternative salt chemistry composition, such as chlorides. In this investigation a 2.0MWth Pilot-scale CSP plant design is developed to assess thermodynamic performance potential for operation up to 720 C. Here, an Engineering Equation Solver (EES) model is developed with respect to 14 state-points from the base of a solar tower at the Sandia National Laboratories, National Solar Thermal Test Facility (NSTTF), to solar receiver mounted 120 ft. above the ground. The system design considers a ternary chloride ternary chloride (20%NaCl/40%MgCl/40%KCl by mol%) salt as the HTF, with 6 hrs. of storage and a 1 MWth primary salt to sCO2 heat exchanger. Preliminary system modelling results indicate a minimum non-dimensional Cv of 60 required for both cold and hot-side throttle recirculation valves for the operational pump operating between speeds of 1800 and 2400 RPM. Further receiver comparison study results suggest that the ternary salt requires an average 15.2% higher receiver flux with a slightly lower calculated receiver efficiency when compared to a binary carnelite salt to achieve a 2.0 MWth desired input power design.

associated liquids↗

NASA NTRS2013

Internship at NASA Kennedy Space Center's Cryogenic Test laboratory

NASA's Kennedy Space Center (KSC) is known for hosting all of the United States manned rocket launches as well as many unmanned launches at low inclinations. Even though the Space Shuttle recently retired, they are continuing to support unmanned launches and modifying manned launch facilities. Before a rocket can be launched, it has to go through months of preparation, called processing. Pieces of a rocket and its payload may come in from anywhere in the nation or even the world. The facilities all around the center help integrate the rocket and prepare it for launch. As NASA prepares for the Space Launch System, a rocket designed to take astronauts beyond Low Earth Orbit throughout the solar system, technology development is crucial for enhancing launch capabilities at the KSC. The Cryogenics Test Laboratory at Kennedy Space Center greatly contributes to cryogenic research and technology development. The engineers and technicians that work there come up with new ways to efficiently store and transfer liquid cryogens. NASA has a great need for this research and technology development as it deals with cryogenic liquid hydrogen and liquid oxygen for rocket fuel, as well as long term space flight applications. Additionally, in this new era of space exploration, the Cryogenics Test Laboratory works with the commercial sector. One technology development project is the Liquid Hydrogen (LH2) Ground Operations Demonstration Unit (GODU). LH2 GODU intends to demonstrate increased efficiency in storing and transferring liquid hydrogen during processing, loading, launch and spaceflight of a spacecraft. During the Shuttle Program, only 55% of hydrogen purchased was used by the Space Shuttle Main Engines. GODU's goal is to demonstrate that this percentage can be increased to 75%. Figure 2 shows the GODU layout when I concluded my internship. The site will include a 33,000 gallon hydrogen tank (shown in cyan) with a heat exchanger inside the hydrogen tank attached to a refrigerator capable of removing 850 Watts at 20 Kelvin (shown in green). The refrigerator and most of its supporting equipment will be kept in a standard shipping container (shown in pink). Currently, GODU is in the fabrication process and some of the large components have already been purchased.

Holland, Katherine↗