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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 379 records · Page 21
All sourcesNASA NTRSDOE OSTI
NASA NTRS2009

Towards a Framework for Generating Tests to Satisfy Complex Code Coverage in Java Pathfinder

We present work on a prototype tool based on the JavaPathfinder (JPF) model checker for automatically generating tests satisfying the MC/DC code coverage criterion. Using the Eclipse IDE, developers and testers can quickly instrument Java source code with JPF annotations covering all MC/DC coverage obligations, and JPF can then be used to automatically generate tests that satisfy these obligations. The prototype extension to JPF enables various tasks useful in automatic test generation to be performed, such as test suite reduction and execution of generated tests.

Staats, Matt↗
NASA NTRS2015

Rocket Propulsion 21 Steering Committee Meeting (RP21) NASA In-Space Propulsion Update

In-house Support of NEXT-C Contract Status Thruster NEXT Long Duration Test post-test destructive evaluation in progress Findings will be used to verify service life models identify potential design improvements Cathode heater fabrication initiated for cyclic life testing Thruster operating algorithm definition verification initiated to provide operating procedures for mission users High voltage propellant isolator life test voluntarily terminated after successfully operating 51,200 h Power processor unit (PPU) Replaced all problematic stacked multilayer ceramic dual inline pin capacitors within PPU Test bed Rebuilt installed discharge power supply primary power board Completed full functional performance characterization Final test report in progress Transferred PPU Testbed to contractor to support prototype design effort.

Electric Propulsion↗
NASA NTRS2022

Maturation of Dynamic Power Convertors for RPS Robotic Space Exploration

NASA is developing dynamic power conversion technologies for future robotic space science and exploration missions powered by Radioisotope Power Systems (RPS). The Dynamic Radioisotope Power Systems (DRPS) Project is working to mature numerous dynamic power convertors and controllers for potential infusion into future flight generators. Maturation of power conversion technologies is being managed by the RPS Program and executed by the DRPS Project and Thermal Energy Conversion Branch located at NASA’s Glenn Research Center (GRC). Convertor maturation includes multiple convertor technology development contracts to deliver new prototypes and continued testing of relevant legacy convertors, commissioned during past projects. The convertor technology development contracts include two Stirling contractor teams and one Brayton team. All contracts have now completed prototype fabrication and testing planned during Phase 2. Government assessment of the new prototypes includes verification of performance in relevant environments and validation of the design with a focus on robustness.

Scott Wilson↗
NASA NTRSDate not supplied

Maturation of Dynamic Power Convertors for RPS Robotic Space Exploration

NASA is developing dynamic power conversion technologies for future robotic space science and exploration missions powered by Radioisotope Power Systems (RPS). The Dynamic Radioisotope Power Systems (DRPS) Project is working to mature numerous dynamic power convertors and controllers for potential infusion into future flight generators. Maturation of power conversion technologies is being managed by the RPS Program and executed by the DRPS Project and Thermal Energy Conversion Branch located at NASA’s Glenn Research Center (GRC). Convertor maturation includes multiple convertor technology development contracts to deliver new prototypes and continued testing of relevant legacy convertors, commissioned during past projects. The convertor technology development contracts include two Stirling contractor teams and one Brayton team. All contracts have now completed prototype fabrication and testing planned during Phase 2. Government assessment of the new prototypes includes verification of performance in relevant environments and validation of the design with a focus on robustness.

Scott Wilson↗
NASA NTRS2015

Simplified Abrasion Test Methodology for Candidate EVA Glove Lay-Ups

During the Apollo Program, space suit outer‐layer fabrics were badly abraded after performing just a few extravehicular activities (EVAs). For example, the Apollo 12 commander reported abrasive wear on the boots that penetrated the outer‐layer fabric into the thermal protection layers after less than 8 hrs of surface operations. Current plans for the exploration planetary space suits require the space suits to support hundreds of hours of EVA on a lunar or Martian surface, creating a challenge for space suit designers to utilize materials advances made over the last 40 years and improve on the space suit fabrics used in the Apollo Program. Over the past 25 years the NASA Johnson Space Center Crew and Thermal Systems Division has focused on tumble testing as means of simulating wear on the outer layer of the space suit fabric. Most recently, in 2009, testing was performed on 4 different candidate outer layers to gather baseline data for future use in design of planetary space suit outer layers. In support of the High Performance EVA Glove Element of the Next Generation Life Support Project, testing a new configuration was recently attempted in which require 10% of the fabric per replicate of that need in 2009. The smaller fabric samples allowed for reduced per sample cost and flexibility to test small samples from manufacturers without the overhead to have a production run completed. Data collected from this iteration was compared to that taken in 2009 to validate the new test method. In addition the method also evaluated the fabrics and fabric layups used in a prototype thermal micrometeoroid garment (TMG) developed for EVA gloves under the NASA High Performance EVA Glove Project. This paper provides a review of previous abrasion studies on space suit fabrics, details methodologies used for abrasion testing in this particular study, results of the validation study, and results of the TMG testing.

Rabel, Emily↗
NASA NTRS2015

In-Flight Suppression of an Unstable F/A-18 Structural Mode Using the Space Launch System Adaptive Augmenting Control System

NASA's Space Launch System (SLS) Flight Control System (FCS) includes an Adaptive Augmenting Control (AAC) component which employs a multiplicative gain update law to enhance the performance and robustness of the baseline control system for extreme off-nominal scenarios. The SLS FCS algorithm including AAC has been flight tested utilizing a specially outfitted F/A-18 fighter jet in which the pitch axis control of the aircraft was performed by a Non-linear Dynamic Inversion (NDI) controller, SLS reference models, and the SLS flight software prototype. This paper describes test cases from the research flight campaign in which the fundamental F/A-18 airframe structural mode was identified using post-flight frequency-domain reconstruction, amplified to result in closed loop instability, and suppressed in-flight by the SLS adaptive control system.

VanZwieten, Tannen S.↗
NASA NTRS2015

In-Flight Suppression of a Destabilized F/A-18 Structural Mode Using the Space Launch System Adaptive Augmenting Control System

NASA's Space Launch System (SLS) Flight Control System (FCS) includes an Adaptive Augmenting Control (AAC) component which employs a multiplicative gain update law to enhance the performance and robustness of the baseline control system for extreme off nominal scenarios. The SLS FCS algorithm including AAC has been flight tested utilizing a specially outfitted F/A-18 fighter jet in which the pitch axis control of the aircraft was performed by a Non-linear Dynamic Inversion (NDI) controller, SLS reference models, and the SLS flight software prototype. This paper describes test cases from the research flight campaign in which the fundamental F/A-18 airframe structural mode was identified using frequency-domain reconstruction of flight data, amplified to result in closed loop instability, and suppressed in-flight by the SLS adaptive control system.

Wall, John H.↗
NASA NTRS1980

Heat storage capability of a rolling cylinder using Glauber's salt

The rolling cylinder phase change heat storage concept was developed to the point where a prototype design is completed and a cost analysis is prepared. A series of experimental and analytical tasks are defined to establish the thermal, mechanical, and materials behavior of rolling cylinder devices. These tasks include: analyses of internal and external heat transfer; performance and lifetime testing of the phase change materials; corrosion evaluation; development of a mathematical model; and design of a prototype and associated test equipment.

Herrick, C. S.↗
NASA NTRS2012

GeoLab 2011: New Instruments and Operations Tested at Desert RATS

GeoLab is a geological laboratory and testbed designed for supporting geoscience activities during NASA's analog demonstrations. Scientists at NASA's Johnson Space Center built GeoLab as part of a technology project to aid the development of science operational concepts for future planetary surface missions [1, 2, 3]. It is integrated into NASA's Habitat Demonstration Unit, a first generation exploration habitat test article. As a prototype workstation, GeoLab provides a high fidelity working space for analog mission crewmembers to perform in-situ characterization of geologic samples and communicate their findings with supporting scientists. GeoLab analog operations can provide valuable data for assessing the operational and scientific considerations of surface-based geologic analyses such as preliminary examination of samples collected by astronaut crews [4, 5]. Our analog tests also feed into sample handling and advanced curation operational concepts and procedures that will, ultimately, help ensure that the most critical samples are collected during future exploration on a planetary surface, and aid decisions about sample prioritization, sample handling and return. Data from GeoLab operations also supports science planning during a mission by providing additional detailed geologic information to supporting scientists, helping them make informed decisions about strategies for subsequent sample collection opportunities.

Evans, Cindy A.↗
NASA NTRS1979

A review of Curtiss-Wright rotary engine developments with respect to general aviation potential

Aviation related rotary (Wankel-type) engine tests, possible growth directions and relevant developments at Curtiss-Wright have been reviewed. Automotive rotary engines including stratified charge are described and flight test results of rotary aircraft engines are presented. The current 300 HP engine prototype shows basic durability and competitive performance potential. Recent parallel developments have separately confirmed the geometric advantages of the rotary engine for direct injected unthrottled stratified charge. Specific fuel consumption equal to or better than pre- or swirl-chamber diesels, low emission and multi-fuel capability have been shown by rig tests of similar rotary engine.

Jones, C.↗
NASA NTRS2011

Design and Test of Advanced Thermal Simulators for an Alkali Metal-Cooled Reactor Simulator

The Early Flight Fission Test Facility (EFF-TF) at NASA Marshall Space Flight Center (MSFC) has as one of its primary missions the development and testing of fission reactor simulators for space applications. A key component in these simulated reactors is the thermal simulator, designed to closely mimic the form and function of a nuclear fuel pin using electric heating. Continuing effort has been made to design simple, robust, inexpensive thermal simulators that closely match the steady-state and transient performance of a nuclear fuel pin. A series of these simulators have been designed, developed, fabricated and tested individually and in a number of simulated reactor systems at the EFF-TF. The purpose of the thermal simulators developed under the Fission Surface Power (FSP) task is to ensure that non-nuclear testing can be performed at sufficiently high fidelity to allow a cost-effective qualification and acceptance strategy to be used. Prototype thermal simulator design is founded on the baseline Fission Surface Power reactor design. Recent efforts have been focused on the design, fabrication and test of a prototype thermal simulator appropriate for use in the Technology Demonstration Unit (TDU). While designing the thermal simulators described in this paper, effort were made to improve the axial power profile matching of the thermal simulators. Simultaneously, a search was conducted for graphite materials with higher resistivities than had been employed in the past. The combination of these two efforts resulted in the creation of thermal simulators with power capacities of 2300-3300 W per unit. Six of these elements were installed in a simulated core and tested in the alkali metal-cooled Fission Surface Power Primary Test Circuit (FSP-PTC) at a variety of liquid metal flow rates and temperatures. This paper documents the design of the thermal simulators, test program, and test results.

Garber, Anne E.↗
NASA NTRS1980

Characterization of prototype secondary lithium battery

The performance characteristics of ambient temperature secondary lithium batteries were determined through continuous cycle tests with periodic current and voltage measurements. Cycle life of the lithium anode was found to be an important problem area as was the formation of dentrite breakage and subsequent shorting. Energy density was increased by using more efficient cathode structures.

Somoano, R.↗
NASA NTRS2007

A One-Piece Lunar Regolith Bag Garage Prototype

Shelter structures on the moon, even in early phases of exploration, should incorporate lunar materials as much as possible. This Technical Memorandum details the design and construction of a prototype for a one-piece regolith bag unpressurized garage concept and a materials testing program to investigate six candidate fabrics to learn how they might perform in the lunar environment. The conceptualization was that a lightweight fabric form be launched from Earth and landed on the lunar surface to be robotically filled with raw lunar regolith. Regolith bag fabric candidates included: Vectran(TM), Nextel(TM), Gore PTFE Fabric(TM), Zylon(TM), Twaron(TM), and Nomex(TM). Tensile (including post radiation exposure), fold, abrasion, and hypervelocity impact testing were performed under ambient conditions, and also performed under cold and elevated temperatures. In some cases, Johnson Space Center lunar simulant (JSC-1) was used in conjunction with testing. A series of preliminary structures was constructed during final prototype design based on the principles of the classic masonry arch. The prototype was constructed of Kevlar(TM) and filled with vermiculite. The structure is free-standing, but has not yet been load tested. Future plans would be to construct higher fidelity prototypes and to conduct appropriate tests of the structure.

Smithers, G. A.↗
NASA NTRS2013

Unmanned Aircraft Systems (UAS) Integration in the National Airspace System (NAS) Project

NASA's UAS Integration in the NAS project, has partnered with Rockwell Collins to develop a concept Control and Non-Payload Communication system prototype radio, operating on recently allocated UAS frequency spectrum bands. The prototype radio will be used to validate initial proposed performance requirements for UAS control communications. This presentation will give an overview of the current status of the design, development, and flight test planning for this prototype radio.

Griner, James H.↗
NASA NTRS2014

EVA Suit R and D for Performance Optimization

Designing a planetary suit is very complex and often requires difficult trade‐offs between performance, cost, mass, and system complexity. To verify that new suit designs meet requirements, full prototypes must be built and tested with human subjects. However, numerous design iterations will occur before the hardware meets those requirements. Traditional draw‐prototype‐test paradigms for R&D are prohibitively expensive with today's shrinking Government budgets. Personnel at NASA are developing modern simulation techniques which focus on human‐centric designs by creating virtual prototype simulations and fully adjustable physical prototypes of suit hardware. During the R&D design phase, these easily modifiable representations of an EVA suit's hard components will allow designers to think creatively and exhaust design possibilities before they build and test working prototypes with human subjects. It allows scientists to comprehensively benchmark current suit capabilities and limitations for existing suit sizes and sizes that do not exist. This is extremely advantageous and enables comprehensive design down‐selections to be made early in the design process, enables the use of human performance as design criteria, and enables designs to target specific populations

Cowley, Matthew S.↗
NASA NTRS2001

A Low Cost, Self Acting, Liquid Hydrogen Boil-Off Recovery System

The purpose of this research was to develop a prototype liquid hydrogen boll-off recovery system. Perform analyses to finalize recovery system cycle, design detail components, fabricate hardware, and conduct sub-component, component, and system level tests leading to the delivery of a prototype system. The design point and off-design analyses identified cycle improvements to increase the robustness of the system by adding a by-pass heat exchanger. Based on the design, analysis, and testing conducted, the recovery system will liquefy 31% of the gaseous boil off from a liquid hydrogen storage tank. All components, including a high speed, miniature turbocompressor, were designed and manufacturing drawings were created. All hardware was fabricated and tests were conducted in air, helium, and hydrogen. Testing validated the design, except for the turbocompressor. A rotor-to-stator clearance issue was discovered as a result of a concentricity tolerance stack-up.

Pelfrey, Joy W.↗