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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 991 records · Page 55
All sourcesNASA NTRSDOE OSTI
NASA NTRS1989

O-ring sealing verification for the space shuttle redesign solid rocket motor

As a part of the redesign of the Space Shuttle Solid Rocket Motor, the field and nozzle-to-case joints were redesigned to minimize the dynamic flexure caused by internal motor pressurization during ignition. The O-ring seals and glands for the joints were designed to accommodate both structural deflections and to promote pressure assistance. A test program was conducted to determine if a fluorocarbon elastomeric O-ring could meet this criteria in the redesigned gland. Resiliency tests were used to investigate the O-ring response to gap motion while static seal tests were used to verify design criteria of pressure assistance for sealing. All tests were conducted in face seal fixtures mounted in servo-hydraulic test machines. The resiliency of the O-ring was found to be extremely sensitive to the effects of temperature. The External Tank/Solid Rocket Booster attach strut loads had a negligible affect on the ability of the O-ring to track the simulated SRB field joint deflection. In the static pressure-assisted seal tests, as long as physical contact was maintained between the O-ring and the gland sealing surface, pressure assistance induced instantaneous sealing.

Lach, Cynthia L.↗
NASA NTRS1991

Rotary-To-Axial Motion Converter For Valve

Nearly frictionless mechanism converts rotary motion into axial motion. Designed for use in electronically variable pressure-regulator valve. Changes rotary motion imparted by motor into translation that opens and closes valve poppet. Cables spaced equidistantly around edge of fixed disk support movable disk. As movable disk rotated, cables twist, lifting it. When rotated in opposite direction, cables untwist, lowering it. Spider disk helps to prevent cables from tangling. Requires no lubrication and insensitive to contamination in fluid flowing through valve.

Reinicke, Robert H.↗
NASA NTRS1989

First incremental buy for Increment 2 of the Space Transportation System (STS)

Thiokol manufactured and delivered 9 flight motors to KSC on schedule. All test flights were successful. All spent SRMs were recovered. Design, development, manufacture, and delivery of required transportation, handling, and checkout equipment to MSFC and to KSC were completed on schedule. All items of data required by DPD 400 were prepared and delivered as directed. In the system requirements and analysis area, the point of departure from Buy 1 to the operational phase was developed in significant detail with a complete set of transition documentation available. The documentation prepared during the Buy 1 program was maintained and updated where required. The following flight support activities should be continued through other production programs: as-built materials usage tracking on all flight hardware; mass properties reporting for all flight hardware until sample size is large enough to verify that the weight limit requirements were met; ballistic predictions and postflight performance assessments for all production flights; and recovered SRM hardware inspection and anomaly identification. In the safety, reliability, and quality assurance area, activities accomplished were assurance oriented in nature and specifically formulated to prevent problems and hardware failures. The flight program to date has adequately demonstrated the success of this assurance approach. The attention focused on details of design, analysis, manufacture, and inspection to assure the production of high-quality hardware has resulted in the absence of flight failures. The few anomalies which did occur were evaluated, design or manufacturing changes incorporated, and corrective actions taken to preclude recurrence.

Source record↗
NASA NTRS1991

Status of NASA's Stirling Space Power Converter Program

An overview is presented of the NASA-Lewis Free-Piston Stirling Space Power Convertor Technology Program. The goal is to develop the technology base needed to meet the long duration, high capacity power requirements for future NASA space initiatives. Efforts are focused upon increasing system power output and system thermal and electric energy conversion efficiency at least fivefold over current SP-100 technology, and on achieving systems that are compatible with space nuclear reactors. Stirling experience in space and progress toward 1050 and 1300 K Stirling Space Power Converters is discussed. Fabrication is nearly completed for the 1050 K Component Test Power Converters (CTPC); results of motoring tests of cold end (525 K), are presented. The success of these and future designs is dependent upon supporting research and technology efforts including heat pipes, bearings, superalloy joining technologies, high efficiency alternators, life and reliability testing and predictive methodologies. An update is provided of progress in some of these technologies leading off with a discussion of free-piston Stirling experience in space.

Dudenhoefer, James E.↗
NASA NTRS1992

Study of optical techniques for the Ames unitary wind tunnels. Part 1: Schlieren

Alignment procedures and conceptual designs for the rapid alignment of the Ames Unitary Wind Tunnel schlieren systems were devised. The schlieren systems can be aligned by translating the light source, the mirrors, and the knife edge equal distances. One design for rapid alignment consists of a manual pin locking scheme. The other is a motorized electronic position scheme. A study of two optical concepts which can be used with the schlieren system was made. These are the 'point diffraction interferometers' and the 'focus schlieren'. Effects of vibrations were studied.

Lee, George↗
NASA NTRS1995

Environmentally compatible solid rocket propellants

Hercules' clean propellant development research is exploring three major types of clean propellant: (1) chloride-free formulations (no chlorine containing ingredients), being developed on the Clean Propellant Development and Demonstration (CPDD) contract sponsored by Phillips Laboratory, Edwards Air Force Base, CA; (2) low HCl scavenged formulations (HCl-scavenger added to propellant oxidized with ammonium perchlorate (AP)); and (3) low HCl formulations oxidized with a combination of AN and AP (with or without an HCl scavenger) to provide a significant reduction (relative to current solid rocket boosters) in exhaust HCl. These propellants provide performance approaching that of current systems, with less than 2 percent HCl in the exhaust, a significant reduction (greater than or equal to 70 percent) in exhaust HCl levels. Excellent processing, safety, and mechanical properties were achieved using only readily available, low cost ingredients. Two formulations, a sodium nitrate (NaNO3) scavenged HTPB and a chloride-free hydroxy terminated polyether (HTPE) propellant, were characterized for ballistic, mechanical, and rheological properties. In addition, the hazards properties were demonstrated to provide two families of class 1.3, 'zero-card' propellants. Further characterization is planned which includes demonstration of ballistic tailorability in subscale (one to 70 pound) motors over the range of burn rates required for retrofit into current Hercules space booster designs (Titan 4 SRMU and Delta 2 GEM).

Jacox, James L.↗
NASA NTRS2001

Goals, History and Current Programs of Workshop

Mr. Robert Fusaro, coordinator for the Glenn Research Center Space Mechanisms program, presented the goals of the workshop, history of previous workshops and gave an overview of current space mechanisms work performed by Glenn Research Center. Highlights of his presentation are shown. Following the presentation, Mr. Fusaro demonstrated the new NASA Space Mechanisms Handbook and Reference Guide CD ROM, which was featured as a highlight of the workshop. The handbook is an authoritative guide for design and testing of space mechanisms and related components. Over 600 pages of guidelines written by 25 experts in the field provide in-depth information on how to design space mechanisms and components, including: deployables, release devices, latches, rotating and pointing mechanisms, dampers, motors, gears, fasteners, valves, etc. The handbook provides details on appropriate environmental and tribological testing methods and practices required to evaluate new mechanisms and components. Distribution of the Handbook and Reference Guide is limited by ITAR (International Traffic in Arms Regulations). It is available only to US companies and citizens. A request form for the CD ROM can be found on the Space Mechanisms Project website at http://www.grc.nasa.gov/WWW/spacemech/.

Source record↗
NASA NTRS2001

Helicopter Rotor Antenna

This effort was directed toward demonstration of the efficacy of a concept for mitigation of the rotor blade modulation problem in helicopter communications. An antenna is envisioned with radiating elements mounted on the rotor and rotating with it. The rf signals are coupled to the radio stationary with respect to the airframe via a coupler of unique design. The coupler has an rf cavity within which a mode is established and the field distribution of this mode is sampled by probes rotating with the radiating elements. In this manner the radiated pattern is "despun" with respect to the rotor. Theoretical analysis has indicated that this arrangement will be less susceptible to rotor blade modulation that would be a conventional fixed mounted antenna. A small coupler operating at S-band was designed, fabricated, and mounted on a mockup representative of a helicopter body. A small electric motor was installed to rotate the rotor portion of the coupler along with a set of radiating elements during testing. This test article was be evaluated using the JPL Mesa Antenna Measurement Facility to establish its ability to mitigate rotor blade modulation. It was found that indeed such a coupler will result in a despun pattern and that such a pattern can be effective in mitigation of rotor blade modulation.

Pogorzelski, Ronald J.↗
NASA NTRS2009

Advanced Embedded Active Assemblies for Extreme Space Applications

This work describes the development and evaluation of advanced technologies for the integration of electronic die within membrane polymers. Specifically, investigators thinned silicon die, electrically connecting them with circuits on flexible liquid crystal polymer (LCP), using gold thermo-compression flip chip bonding, and embedding them within the material. Daisy chain LCP assemblies were thermal cycled from -135 to +85degC (Mars surface conditions for motor control electronics). The LCP assembly method was further utilized to embed an operational amplifier designed for operation within the Mars surface ambient. The embedded op-amp assembly was evaluated with respect to the influence of temperature on the operational characteristics of the device. Applications for this technology range from multifunctional, large area, flexible membrane structures to small-scale, flexible circuits that can be fit into tight spaces for flex to fit applications.

lead bonding↗
NASA NTRS2010

Systems Engineering and Reusable Avionics

One concept for future space flights is to construct building blocks for a wide variety of avionics systems. Once a unit has served its original purpose, it can be removed from the original vehicle and reused in a similar or dissimilar function, depending on the function blocks the unit contains. For example: Once a lunar lander has reached the moon's surface, an engine controller for the Lunar Decent Module would be removed and used for a lunar rover motor control unit or for a Environmental Control Unit for a Lunar Habitat. This senior design project included the investigation of a wide range of functions of space vehicles and possible uses. Specifically, this includes: (1) Determining and specifying the basic functioning blocks of space vehicles. (2) Building and demonstrating a concept model. (3) Showing high reliability is maintained. The specific implementation of this senior design project included a large project team made up of Systems, Electrical, Computer, and Mechanical Engineers/Technologists. The efforts were made up of several sub-groups that each worked on a part of the entire project. The large size and complexity made this project one of the more difficult to manage and advise. Typical projects only have 3-4 students, but this project had 10 students from five different disciplines. This paper describes the difference of this large project compared to typical projects, and the challenges encountered. It also describes how the systems engineering approach was successfully implemented so that the students were able to meet nearly all of the project requirements.

Conrad, James M.↗
NASA NTRSDate not supplied

Space Suit Portable Life Support System Oxygen Regulator History, Development, & Testing Results

An oxygen regulator has been in development for the space suit Exploration Extravehicular Mobility Unit (xEMU) Portable Life Support System (PLSS). The regulator provides the necessary oxygen pressure for the crew member during pre-breathe, extra-vehicular activity (EVA), post EVA airlock operations, and decompression sickness treatment. The last time a spacesuit oxygen regulator was designed was for the Space Shuttle Program EMU. The regulator & EMU were then used on the International Space Station (ISS) with no significant changes to the regulator throughout its life. This xEMU PLSS spacesuit oxygen regulator implements many elements of the previous EMU Secondary Oxygen Pack (SOP) design while integrating numerous new improvements and changes. There are changes both to the high-level regulator architecture approach in the suit itself, in addition to modernizations with electrical motor control & sensing. For architecture, there are two oxygen regulators for each space suit, a primary and secondary that are nearly identical to each other and have the same maximum design pressure of 3750 Pounds per Square Inch Absolute (PSIA). The primary regulator provides nominal pressure during EVA, while the secondary provides a backup pressure only in case of primary regulator failure or if an emergency purge of the suit oxygen is required. The design was based originally off of the secondary oxygen regulator on the EMU which utilizes a two-stage regulator to improve safety and controllability. The xEMU PLSS Oxygen Regulator development started with a modification to add a linear actuator to the design to control the downstream pressure electronically instead of a manual control with a wire linkage system used with the EMU. The design was iterated to include a Monel body for oxygen fire safety, and sensors for pressure verification at each stage. Then the regulator design was packaged to fit into the xEMU PLSS envelope. Development included extensive testing which brought to light some issues with the design which were addressed at each stage of development. This paper will review the design history, development, testing results, and lessons learned designing the xEMU PLSS Oxygen Regulator.

Ryan Ogilvie↗
NASA NTRSDate not supplied

Experimental Characterization of an Electric Ducted Fan for the SUSAN 25% Scale Research Vehicle

An electric ducted fan (EDF) was tested in the NASA Langley 12-Foot Low-Speed Tunnel for the SUbsonic Single Aft eNgine (SUSAN) Electrofan 25% scale research vehicle, which incorporates distributed electric fans along the wings and serves as a scaled electrified transport aircraft testbed. The commercial-off-the-shelf EDF was selected as a propulsor that can meet the 25% scale vehicle geometry constraints, along with the performance requirements throughout the flight profile. The test included a series of one-factor-at-a-time (OFAT) and design of experiments (DOE) approaches that were implemented across a range of fan speed, voltage, freestream dynamic pressure, and incidence angle settings to characterize the performance of the EDF. Several test matrix designs and modeling approaches were considered. System identification methods were used to develop a static motor model, a dynamic motor model, an EDF thrust model, and a power consumption model. The model predictive capabilities were then evaluated with validation data not used in the modeling process. The results provide a comprehensive set of models developed to characterize the fan, and offer general insight into EDF modeling approaches.

electric ducted fan↗
NASA NTRS1990

Electromechanical actuation for thrust vector control applications

The advanced launch system (ALS), is a launch vehicle that is designed to be cost-effective, highly reliable, and operationally efficient with a goal of reducing the cost per pound to orbit. An electromechanical actuation (EMA) system is being developed as an attractive alternative to the hydraulic systems. The controller will integrate 20 kHz resonant link power management and distribution (PMAD) technology and pulse population modulation (PPM) techniques to implement field-oriented vector control (FOVC) of a new advanced induction motor. The driver and the FOVC will be microprocessor controlled. For increased system reliability, a built-in test (BITE) capability will be included. This involves introducing testability into the design of a system such that testing is calibrated and exercised during the design, manufacturing, maintenance, and prelaunch activities. An actuator will be integrated with the motor controller for performance testing of the EMA thrust vector control (TVC) system. The EMA system and work proposed for the future are discussed.

Roth, Mary Ellen↗
NASA NTRS2005

Nanoactuators Based on Electrostatic Forces on Dielectrics

Nanoactuators of a proposed type would exploit the forces exerted by electric fields on dielectric materials. As used here, "nanoactuators" includes motors, manipulators, and other active mechanisms that have dimensions of the order of nanometers and/or are designed to manipulate objects that have dimensions of the order of nanometers. The underlying physical principle can be described most simply in terms of the example of a square parallel-plate capacitor in which a square dielectric plate is inserted part way into the gap between the electrode plates (see Figure Typically, the force is small from our macroscopic human perspective. The above equation shows that the force depends on the ratio between the capacitor dimensions but does not depend on the size. In other words, the force remains the same if the capacitor and the dielectric slab are shrunk to nanometer dimensions. At the same time, the masses of all components are proportional to third power of their linear dimensions. Therefore the force-to-mass ratio (and, consequently, the acceleration that can be imparted to the dielectric slab) is much larger at the nanoscale than at the macroscopic scale. The proposed actuators would exploit this effect. The upper part of Figure 2 depicts a simple linear actuator based on a parallel- plate capacitor similar to Figure 1. In this case, the upper electrode plate would be split into two parts (A and B) and the dielectric slab would be slightly longer than plate A or B. The actuator would be operated in a cycle. During the first half cycle, plate B would be grounded to the lower plate and plate A would be charged to a potential, V, with respect to the lower plate, causing the dielectric slab to be pulled under plate A. During the second half cycle, plate A would be grounded and plate B would be charged to potential V, causing the dielectric slab to be pulled under plate B. The back-and-forth motion caused by alternation of the voltages on plates A and B could be used to drive a nanopump, for example. A rotary motor, shown in the middle part of Figure 2, could include a dielectric rotor sandwiched between a top and a bottom plate containing multiple electrodes arranged symmetrically in a circle. Voltages would be applied sequentially to electrode pairs 1 and 1a, then 2 and 2a, then 3 and 3a in order to attract the dielectric rotor to sequential positions between the electrode pairs.

Wang, Yu↗
NASA NTRS2017

Personal Rotorcraft Design and Performance with Electric Hybridization

Recent and projected improvements for more or all-electric aviation propulsion systems can enable greater personal mobility, while also reducing environmental impact (noise and emissions). However, all-electric energy storage capability is significantly less than present, hydrocarbon-fueled systems. A system study was performed exploring design and performance assuming hybrid propulsion ranging from traditional hydrocarbon-fueled cycles (gasoline Otto and diesel) to all-electric systems using electric motors generators, with batteries for energy storage and load leveling. Study vehicles were a conventional, single-main rotor (SMR) helicopter and an advanced vertical takeoff and landing (VTOL) aircraft. Vehicle capability was limited to two or three people (including pilot or crew); the design range for the VTOL aircraft was set to 150 miles (about one hour total flight). Search and rescue (SAR), loiter, and cruise-dominated missions were chosen to illustrate each vehicle and degree of hybrid propulsion strengths and weaknesses. The traditional, SMR helicopter is a hover-optimized design; electric hybridization was performed assuming a parallel hybrid approach by varying degree of hybridization. Many of the helicopter hybrid propulsion combinations have some mission capabilities that might be effective for short range or on-demand mobility missions. However, even for 30 year technology electrical components, all hybrid propulsion systems studied result in less available fuel, lower maximum range, and reduced hover and loiter duration than the baseline vehicle. Results for the VTOL aircraft were more encouraging. Series hybrid combinations reflective of near-term systems could improve range and loiter duration by 30. Advanced, higher performing series hybrid combinations could double or almost triple the VTOL aircrafts range and loiter duration. Additional details on the study assumptions and work performed are given, as well as suggestions for future study effort.

electric motors↗
NASA NTRS2021

Improved Potting of Litz Wires for High Power Density Electric Motor

Specific details including selections of process materials, tooling/fixture setups, and a step-by-step procedure for scaling-up demonstrations of the newly developed potting process, namely vacuum-assisted axial injection potting (VaAIP) have been fully developed for the stator winding of high power density electric motors for the future electrified aircrafts. Various essential pre-trial subtasks identified for the full-scale demonstrations were carried out. To date, optimization of cure condition and thermal stability of the coating epoxy and determination of optimum application conditions and thermal stability of the high temperature encapsulant wax were completed successfully and other subtasks were under way. The efforts to enhance thermal conductivity of the selected potting compound by adding conductive nano fillers such as boron nitride nanosheets (BNNS) have also been advanced. Initially, selection of the best mixing method and procedures was attempted via extensive and systematic experimental design.

Litz wire↗
NASA NTRSDate not supplied

Integrated Design Results for the MSR DAC-0.0 Mars Ascent Vehicle

The NASA Mars Sample Return (MSR) Campaign endeavors to return Martian regolith, rock, and atmospheric samples to Earth for scientific study. One of many significant challenges to overcome in the return of these samples lies in transporting them from the Martian surface to space. In order to surmount this challenge, the Campaign has conceptualized the need for a Mars Ascent Vehicle (MAV) to perform this function and deliver Martian samples to orbit. There, the samples will be ejected and captured by a separate spacecraft for return to Earth. Many concepts for a MAV have existed in the past, but it has not been until now that an integrated, detailed design solution has been developed and analyzed. Preliminary assessments of the initial architecture examined multiple methods of propulsion. The team ultimately determined that a Two Stage to Orbit (TSTO) solid propulsion vehicle would provide the most effective performance and be the most technologically ready to support this mission. Following the decision to adopt a TSTO solid propelled vehicle, the first official Design Analysis Cycle, DAC-0.0, was performed in Spring 2020 to formally advance the fidelity of the vehicle to a maturity level acceptable for NASA Key Decision Point A (KDP-A). This paper describes the resultant MAV design concept developed as part of the DAC-0.0 study by the NASA Marshall Space Flight Center (MSFC), in association with the NASA Jet Propulsion Laboratory (JPL). The TSTO vehicle features two solid rocket motors, one powering each stage. Their thrust vectors are controlled with Thrust Vector Control (TVC) systems consisting of independent electromechanical actuators acting on gimballed nozzles. The vehicle is designed to deliver up to 0.47kg of Martian samples to a Mars circular orbit of 343km at 27° inclination. Due to the unique environmental conditions that this vehicle is required to operate in, the subsystem design teams were compelled to develop creative and unorthodox designs to ensure a successful mission. The detailed design and analysis of these subsystems are discussed in this paper and include topics on the MAV Guidance, Navigation, and Control (GNC); structures and mechanisms; integrated vehicle thermal; avionics and flight software; a hydrazine-based Reaction Control System (RCS); aerosciences; and vehicle assembly, integration, and test (AI&T) considerations, among others. Following the conclusion of the MAV DAC-0.0, additional alternative architecture concepts were also studied to further reduce the mass of the overall system. The results of these studies will also be examined in this paper.

Darius Yaghoubi↗
NASA NTRSDate not supplied

Integrated Design Results for the MSR DAC-0.0 Mars Ascent Vehicle

The NASA Mars Sample Return (MSR) Campaign endeavors to return Martian regolith, rock, and atmospheric samples to Earth for scientific study. One of many significant challenges to overcome in the return of thesesamples lies in transporting them from the Martian surface to space. In order to surmount this challenge, the Campaign has conceptualized the need for a Mars Ascent Vehicle (MAV) to perform this function and deliver Martian samples to orbit. There, the samples will be ejected and captured by a separate spacecraft for return to Earth. Many concepts for a MAV have existed in the past, but it has not been until now that an integrated, detailed design solution has been developed and analyzed. Preliminary assessments of the initial architecture examined multiple methods of propulsion. The team ultimately determined that a Two Stage to Orbit (TSTO) solid propulsion vehicle would provide the most effective performance and be the most technologically ready to support this mission. Following the decision to adopt a TSTO solid propelled vehicle, the first official Design Analysis Cycle, DAC-0.0, was performed in Spring 2020 to formally advance the fidelity of the vehicle to a maturity level acceptable for NASA Key Decision Point A (KDP-A). This paper describes the resultant MAV design concept developed as part of the DAC-0.0 study by the NASA Marshall Space Flight Center (MSFC), in association with the NASA Jet Propulsion Laboratory (JPL). The TSTO vehicle features two solid rocket motors, one powering each stage. Their thrust vectors are controlled with Thrust Vector Control (TVC) systems consisting of independent electromechanical actuators acting on gimballed nozzles. The vehicle is designed to deliver up to 0.47kg of Martian samples to a Mars circular orbit of 343km at 27° inclination. Due to the unique environmental conditions that this vehicle is required to operate in, the subsystem design teams were compelled to develop creative and unorthodox designs to ensure a successful mission. The detailed design and analysis of these subsystems are discussed in this paper and include topics on the MAV Guidance, Navigation, and Control (GNC); structures and mechanisms; integrated vehicle thermal; avionics and flight software; a hydrazine-based Reaction Control System (RCS); aerosciences; and vehicle assembly, integration, and test (AI&T) considerations, among others. Following the conclusion of the MAV DAC-0.0, additional alternative architecture concepts were also studied to further reduce the mass of the overall system.

Mars↗