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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
All sourcesNASA NTRSDOE OSTI
NASA NTRS1991

Arcjet thruster research and technology, phase 2

The principle objective of Phase 2 was to produce an engineering model N2H4 arcjet system which met typical performance, lifetime, environmental, and interface specifications required to support a 10-year N-S stationkeeping mission for a communications spacecraft. The system includes an N2H4 arcjet thruster, power conditioning unit (PCU), and the interconnecting power cable assembly. This objective was met with the successful conclusion of an extensive system test series.

Yano, Steve E.↗
NASA NTRS1999

A Discussion of Zero Spring Rate Mechanisms Used for the Active Isolation Mount Experiment

In the summer of 1995 the Structural Dynamics Branch at NASA Langley Research Center set out to conceive a small, lightweight, low frequency isolation mount that could be used for spaceflight experiments. The Engineering Design Branch undertook the task of developing the isolation mount. This report describes the engineering process that led to three phases of a study entitled "Active Isolation Mounts" (AIM). A zero spring rate mechanism was used to achieve low fundamental frequencies for a payloads in the 1 to 10 pound range. It worked by balancing both a positive and a negative stiffness so that the net result was a small positive stiffness. The study demonstrated devices that could reduce the initial corner frequency by a factor of six for brief periods and a factor of two for extended periods. The designs were relatively simple and minimized weight, volume, and power. They could be scaled down and they were made of spaceflight compatible materials. All designs offered the ability to continuously vary the fundamental frequency. Yet, the goal of reducing the frequency by an order of magnitude was not achieved because the systems were too unstable at low frequencies. There was a trade between performance and stability.

Teter, John E., Jr.↗
NASA NTRS1999

Intelligent Command and Control Systems for Satellite Ground Operations

This grant, Intelligent Command and Control Systems for Satellite Ground Operations, funded by NASA Goddard Space Flight Center, has spanned almost a decade. During this time, it has supported a broad range of research addressing the changing needs of NASA operations. It is important to note that many of NASA's evolving needs, for example, use of automation to drastically reduce (e.g., 70%) operations costs, are similar requirements in both government and private sectors. Initially the research addressed the appropriate use of emerging and inexpensive computational technologies, such as X Windows, graphics, and color, together with COTS (commercial-off-the-shelf) hardware and software such as standard Unix workstations to re-engineer satellite operations centers. The first phase of research supported by this grant explored the development of principled design methodologies to make effective use of emerging and inexpensive technologies. The ultimate performance measures for new designs were whether or not they increased system effectiveness while decreasing costs. GT-MOCA (The Georgia Tech Mission Operations Cooperative Associate) and GT-VITA (Georgia Tech Visual and Inspectable Tutor and Assistant), whose latter stages were supported by this research, explored model-based design of collaborative operations teams and the design of intelligent tutoring systems, respectively. Implemented in proof-of-concept form for satellite operations, empirical evaluations of both, using satellite operators for the former and personnel involved in satellite control operations for the latter, demonstrated unequivocally the feasibility and effectiveness of the proposed modeling and design strategy underlying both research efforts. The proof-of-concept implementation of GT-MOCA showed that the methodology could specify software requirements that enabled a human-computer operations team to perform without any significant performance differences from the standard two-person satellite operations team. GT-VITA, using the same underlying methodology, the operator function model (OFM), and its computational implementation, OFMspert, successfully taught satellite control knowledge required by flight operations team members. The tutor structured knowledge in three ways: declarative knowledge (e.g., What is this? What does it do?), procedural knowledge, and operational skill. Operational skill is essential in real-time operations. It combines the two former knowledge types, assisting a student to use them effectively in a dynamic, multi-tasking, real-time operations environment. A high-fidelity simulator of the operator interface to the ground control system, including an almost full replication of both the human-computer interface and human interaction with the dynamic system, was used in the GT-MOCA and GT-VITA evaluations. The GT-VITA empirical evaluation, conducted with a range of'novices' that included GSFC operations management, GSFC operations software developers, and new flight operations team members, demonstrated that GT-VITA effectively taught a wide range of knowledge in a succinct and engaging manner.

Mitchell, Christine M.↗
NASA NTRS2000

Understanding the Manager of the Project Front-End

Historical data and new findings from interviews with managers of major National Aeronautics and Space Administration (NASA) projects confirm literature reports about the criticality of the front-end phase of project development, where systems engineering plays such a key role. Recent research into the management of ten contemporary NASA projects, combined with personal experience of the author in NASA, provide some insight into the relevance and importance of the project manager in this initial part of the project life cycle. The research findings provide evidence of similar approaches taken by the NASA project manager.

Mulenburg, Gerald M.↗
NASA NTRS2004

Reducing the Time and Cost of Testing Engines

Producing a new aircraft engine currently costs approximately $1 billion, with 3 years of development time for a commercial engine and 10 years for a military engine. The high development time and cost make it extremely difficult to transition advanced technologies for cleaner, quieter, and more efficient new engines. To reduce this time and cost, NASA created a vision for the future where designers would use high-fidelity computer simulations early in the design process in order to resolve critical design issues before building the expensive engine hardware. To accomplish this vision, NASA's Glenn Research Center initiated a collaborative effort with the aerospace industry and academia to develop its Numerical Propulsion System Simulation (NPSS), an advanced engineering environment for the analysis and design of aerospace propulsion systems and components. Partners estimate that using NPSS has the potential to dramatically reduce the time, effort, and expense necessary to design and test jet engines by generating sophisticated computer simulations of an aerospace object or system. These simulations will permit an engineer to test various design options without having to conduct costly and time-consuming real-life tests. By accelerating and streamlining the engine system design analysis and test phases, NPSS facilitates bringing the final product to market faster. NASA's NPSS Version (V)1.X effort was a task within the Agency s Computational Aerospace Sciences project of the High Performance Computing and Communication program, which had a mission to accelerate the availability of high-performance computing hardware and software to the U.S. aerospace community for its use in design processes. The technology brings value back to NASA by improving methods of analyzing and testing space transportation components.

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NASA NTRS2005

Reliability Improvements in Liquid Rocket Engine Instrumentation

Instrumentation hardware is often the weak link in advanced liquid fueled propulsion systems. The development of the Space Shuttle Main Engine (SSME) was no exception. By sheer necessity, a reusable, high energy, low weight engine system often relegates the instrumentation hardware to the backseat in the critical hardware development process. This produces less than optimum hardware constraints; including size, location, mounting, redundancy, and signal conditioning. This can negatively affect the development effort and ultimately the system reliability. The challenge was clear, however, the outcome was less certain. Unfortunately, the SSME hardware development culminated in series of measurement failures, most significant of which was the premature engine shutdown during the launch of STS-51F on July 29, 1985. The Return to Flight activities following the Challenger disaster redoubled our efforts to eliminate, once and for all, sensor malfunctions as the determining factor in overall engine reliability. This paper describes each phase of this effort in detail and includes discussion of the tasks related to improving measurement reliability.

Hill, A.↗
NASA NTRS2006

Advanced Health Management System for the Space Shuttle Main Engine

Pratt & Whitney Rocketdyne, Inc., in cooperation with NASA-Marshall Space Flight Center (MSFC), has developed a new Advanced Health Management System (AHMS) controller for the Space Shuttle Main Engine (SSME) that will increase the probability of successfully placing the shuttle into the intended orbit and increase the safety of the Space Transportation System (STS) launches. The AHMS is an upgrade o the current Block II engine controller whose primary component is an improved vibration monitoring system called the Real-Time Vibration Monitoring System (RTVMS) that can effectively and reliably monitor the state of the high pressure turbomachinery and provide engine protection through a new synchronous vibration redline which enables engine shutdown if the vibration exceeds predetermined thresholds. The introduction of this system required improvements and modification to the Block II controller such as redesigning the Digital Computer Unit (DCU) memory and the Flight Accelerometer Safety Cut-Off System (FASCOS) circuitry, eliminating the existing memory retention batteries, installation of the Digital Signal Processor (DSP) technology, and installation of a High Speed Serial Interface (HSSI) with accompanying outside world connectors. Test stand hot-fire testing along with lab testing have verified successful implementation and is expected to reduce the probability of catastrophic engine failures during the shuttle ascent phase and improve safely by about 23% according to the Quantitative Risk Assessment System (QRAS), leading to a safer and more reliable SSME.

Davidson, Matt↗
NASA NTRS2004

Mars Exploration Rover: Launch, Cruise, Entry, Descent, and Landing

The Mars Exploration Rover Project was an ambitious effort to land two highly capable rovers on Mars and concurrently explore the Martian surface for three months each. Launched in June and July of 2003, cruise operations were conducted through January 4, 2004 with the first landing, followed by the second landing on January 25. The prime mission for the second rover ended on April 27, 2004. This paper will provide an overview of the launch, cruise, and landing phases of the mission, including the engineering and science objectives and challenges involved in the selection and targeting of the landing sites, as well as the excitement and challenges of atmospheric entry, descent and landing execution.

Entry, Descent, Landing, (EDL)↗
NASA NTRS1951

Factors Affecting the Starting Characteristics of Gas-Turbine Engines

This report summarizes the effects of fuel volatility and engine design variables on the problem of starting gas-turbine engines at sea-level and altitude conditions. The starting operation for engines with tubular combustors is considered as three steps; namely, (1) ignition of a fuel-air mixture in the combustor, (2) propagation of flame through cross-fire tubes to all combustors, and (3) acceleration of the engine from windmilling or starting speed to the operating speed range. Pertinent data from laboratory researches, single-combustor studies, and full-scale engine investigations are presented on each phase of the starting problem.

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NASA NTRS2009

Citric Acid Passivation of Stainless Steel

Passivation is a process for cleaning and providing corrosion protection for stainless steel. Currently, on Kennedy Space Center (KSC), only parts passivated with nitric acid are acceptable for use. KSC disposes of approximately 125gal of concentrated nitric acid per year, and receives many parts from vendors who must also dispose of used nitric acid. Unfortunately, nitric acid presents health and environmental hazards. As a result, several recent industry studies have examined citric acid as an alternative. Implementing a citric acid-based passivation procedure would improve the health and environmental safety aspects of passivation process. However although there is a lack of published studies that conclusively prove citric acid is a technically sound passivation agent. In 2007, NASA's KSC Materials Advisory Working Group requested the evaluation of citric acid in place of nitric acid for passivation of parts at KSC. United Space Alliance Materials & Processes engineers have developed a three-phase test plan to evaluate citric acid as an alternative to nitric acid on three stainless steels commonly used at KSC: UNS S30400, S41000, and S17400. Phases 1 and 2 will produce an optimized citric acid treatment based on results from atmospheric exposure at NASA's Beach Corrosion Facility. Phase 3 will compare the optimized solution(s) with nitric acid treatments. If the results indicate that citric acid passivates as well or better than nitric acid, NASA intends to approve this method for parts used at the Kennedy Space Center.

Yasensky, David↗
NASA NTRS2011

Reliability and Maintainability Engineering - A Major Driver for Safety and Affordability

The United States National Aeronautics and Space Administration (NASA) is in the midst of an effort to design and build a safe and affordable heavy lift vehicle to go to the moon and beyond. To achieve that, NASA is seeking more innovative and efficient approaches to reduce cost while maintaining an acceptable level of safety and mission success. One area that has the potential to contribute significantly to achieving NASA safety and affordability goals is Reliability and Maintainability (R&M) engineering. Inadequate reliability or failure of critical safety items may directly jeopardize the safety of the user(s) and result in a loss of life. Inadequate reliability of equipment may directly jeopardize mission success. Systems designed to be more reliable (fewer failures) and maintainable (fewer resources needed) can lower the total life cycle cost. The Department of Defense (DOD) and industry experience has shown that optimized and adequate levels of R&M are critical for achieving a high level of safety and mission success, and low sustainment cost. Also, lessons learned from the Space Shuttle program clearly demonstrated the importance of R&M engineering in designing and operating safe and affordable launch systems. The Challenger and Columbia accidents are examples of the severe impact of design unreliability and process induced failures on system safety and mission success. These accidents demonstrated the criticality of reliability engineering in understanding component failure mechanisms and integrated system failures across the system elements interfaces. Experience from the shuttle program also shows that insufficient Reliability, Maintainability, and Supportability (RMS) engineering analyses upfront in the design phase can significantly increase the sustainment cost and, thereby, the total life cycle cost. Emphasis on RMS during the design phase is critical for identifying the design features and characteristics needed for time efficient processing, improved operational availability, and optimized maintenance and logistic support infrastructure. This paper discusses the role of R&M in a program acquisition phase and the potential impact of R&M on safety, mission success, operational availability, and affordability. This includes discussion of the R&M elements that need to be addressed and the R&M analyses that need to be performed in order to support a safe and affordable system design. The paper also provides some lessons learned from the Space Shuttle program on the impact of R&M on safety and affordability.

Safie, Fayssal M.↗
NASA NTRS2012

Testing of the NASA Hypersonics Project Combined Cycle Engine Large Scale Inlet Mode Transition Experiment (CCE LlMX)

Status on an effort to develop Turbine Based Combined Cycle (TBCC) propulsion is described. This propulsion technology can enable reliable and reusable space launch systems. TBCC propulsion offers improved performance and safety over rocket propulsion. The potential to realize aircraft-like operations and reduced maintenance are additional benefits. Among most the critical TBCC enabling technologies are: 1) mode transition from turbine to scramjet propulsion, 2) high Mach turbine engines and 3) TBCC integration. To address these TBCC challenges, the effort is centered on a propulsion mode transition experiment and includes analytical research. The test program, the Combined-Cycle Engine Large Scale Inlet Mode Transition Experiment (CCE LIMX), was conceived to integrate TBCC propulsion with proposed hypersonic vehicles. The goals address: (1) dual inlet operability and performance, (2) mode-transition sequences enabling a switch between turbine and scramjet flow paths, and (3) turbine engine transients during transition. Four test phases are planned from which a database can be used to both validate design and analysis codes and characterize operability and integration issues for TBCC propulsion. In this paper we discuss the research objectives, features of the CCE hardware and test plans, and status of the parametric inlet characterization testing which began in 2011. This effort is sponsored by the NASA Fundamental Aeronautics Hypersonics project

Saunders, J. D.↗
NASA NTRS2011

Thermal Management Tools for Propulsion System Trade Studies and Analysis

Energy-related subsystems in modern aircraft are more tightly coupled with less design margin. These subsystems include thermal management subsystems, vehicle electric power generation and distribution, aircraft engines, and flight control. Tighter coupling, lower design margins, and higher system complexity all make preliminary trade studies difficult. A suite of thermal management analysis tools has been developed to facilitate trade studies during preliminary design of air-vehicle propulsion systems. Simulink blocksets (from MathWorks) for developing quasi-steady-state and transient system models of aircraft thermal management systems and related energy systems have been developed. These blocksets extend the Simulink modeling environment in the thermal sciences and aircraft systems disciplines. The blocksets include blocks for modeling aircraft system heat loads, heat exchangers, pumps, reservoirs, fuel tanks, and other components at varying levels of model fidelity. The blocksets have been applied in a first-principles, physics-based modeling and simulation architecture for rapid prototyping of aircraft thermal management and related systems. They have been applied in representative modern aircraft thermal management system studies. The modeling and simulation architecture has also been used to conduct trade studies in a vehicle level model that incorporates coupling effects among the aircraft mission, engine cycle, fuel, and multi-phase heat-transfer materials.

McCarthy, Kevin↗
NASA NTRS2012

Model-Based Systems Engineering Pilot Program at NASA Langley

NASA Langley Research Center conducted a pilot program to evaluate the benefits of using a Model-Based Systems Engineering (MBSE) approach during the early phase of the Materials International Space Station Experiment-X (MISSE-X) project. The goal of the pilot was to leverage MBSE tools and methods, including the Systems Modeling Language (SysML), to understand the net gain of utilizing this approach on a moderate size flight project. The System Requirements Review (SRR) success criteria were used to guide the work products desired from the pilot. This paper discusses the pilot project implementation, provides SysML model examples, identifies lessons learned, and describes plans for further use on MBSE on MISSE-X.

Vipavetz, Kevin G.↗
NASA NTRS2015

Low-Mass, Low-Power Hall Thruster System

NASA is developing an electric propulsion system capable of producing 20 mN thrust with input power up to 1,000 W and specific impulse ranging from 1,600 to 3,500 seconds. The key technical challenge is the target mass of 1 kg for the thruster and 2 kg for the power processing unit (PPU). In Phase I, Busek Company, Inc., developed an overall subsystem design for the thruster/cathode, PPU, and xenon feed system. This project demonstrated the feasibility of a low-mass power processing architecture that replaces four of the DC-DC converters of a typical PPU with a single multifunctional converter and a low-mass Hall thruster design employing permanent magnets. In Phase II, the team developed an engineering prototype model of its low-mass BHT-600 Hall thruster system, with the primary focus on the low-mass PPU and thruster. The goal was to develop an electric propulsion thruster with the appropriate specific impulse and propellant throughput to enable radioisotope electric propulsion (REP). This is important because REP offers the benefits of nuclear electric propulsion without the need for an excessively large spacecraft and power system.

Pote, Bruce↗
NASA NTRS2018

Development and Qualification of the Primary Structure of the Orion European Service Module

This paper presents an overview of the development and qualification test campaign for the primary structure of the European Service Module of ORION, the NASA spacecraft which will serve the future human exploration missions to the Moon, Mars and beyond. Under an agreement between NASA and ESA, the ORION will be powered by a European Service Module (ESM), providing also water and oxygen for astronauts' life sustainability. The development and qualification of the European Service Module (ESM) is under ESA responsibility with Airbus Defense and Space as the prime contractor. Thales Alenia Space Italia is responsible for design development, manufacturing, assembly and qualification of the Structure subsystem. The European Service Module, installed onto the launch adapter, shall support the crew module with its adapter and a launch abort system. It shall sustain: - A combination of global and local launch loads during lift off and ascent phases, - On orbit loads induced by engine firing for orbital transfers and attitude control. The ESM structure is based on a core made of Composite Fiber Reinforced Polymer (CFRP) sandwich panels complemented by aluminum alloy platforms, longerons and secondary structures. A development campaign has been implemented in order to define and validate composite parts' strength allowable values for design: coupon tests at material level, test at component level up to breadboards tests performed on main structural components (composite to metallic joints, and at panels' discontinuities). An incremental approach as defined in [1] has been followed. A qualification static test campaign at primary structure assembly level has been implemented in order to validate the design against static stiffness and ultimate strength as well as to correlate the structural Finite Element Model (FEM) used for sizing and confirm the margins of safety. The tests have been performed successfully by Thales Alenia Space Italia (TAS-I) on two flight representative structural models (STA1, STA2), in Turin facilities (Italy) between August 2015 and March 2017, with engineering support of technical representatives from Airbus, ESA, NASA and LMCO. The main development and qualification test activities and associated results are presented and discussed in the paper

Structural Testing↗
NASA NTRS2021

Segregation Evolution and Diffusion of Titanium in Directed Energy Deposited NASA HR-1

Titanium segregation in single-pass directed energy deposited (DED) NASA HR-1 is very difficult to control because grain size varies considerably and many large grains (>100 μm) are present. Therefore, homogenization kinetic analysis was performed to see how the homogenization process should be adjusted to mitigate titanium segregation. A basic model for titanium diffusion in NASA HR-1 was developed to project titanium segregation as a function of homogenization temperature, time, and grain size. The homogenization kinetic analysis provides a valuable reference on how the homogenization treatment should be adjusted to reduce titanium segregation to a very low level for DED NASA HR-1.

liquid rocket engine↗