Engineering Papers⌕ Search

SEARCH · Engineering Papers

Results for “prototyping and performance testing”

Search indexed NASA NTRS and DOE OSTI research on propulsion, heat transfer, battery materials and energy systems. Follow report and document links to the original sources.

Quote a phrase for an exact phrase match. Source license links do not imply unrestricted reuse.

At least 235 records · Page 13
All sourcesNASA NTRSDOE OSTI
NASA NTRS2011

Designing the STS-134 Re-Rendezvous: A Preparation for Future Crewed Rendezvous Missions

In preparation to provide the capability for the Orion spacecraft, also known as the Multi-Purpose Crew Vehicle (MPCV), to rendezvous with the International Space Station (ISS) and future spacecraft, a new suite of relative navigation sensors are in development and were tested on one of the final Space Shuttle missions to ISS. The National Aeronautics and Space Administration (NASA) commissioned a flight test of prototypes of the Orion relative navigation sensors on STS-134, in order to test their performance in the space environment during the nominal rendezvous and docking, as well as a re-rendezvous dedicated to testing the prototype sensors following the undocking of the Space Shuttle orbiter at the end of the mission. Unlike the rendezvous and docking at the beginning of the mission, the re-rendezvous profile replicates the newly designed Orion coelliptic approach trajectory, something never before attempted with the shuttle orbiter. Therefore, there were a number of new parameters that needed to be conceived of, designed, and tested for this rerendezvous to make the flight test successful. Additionally, all of this work had to be integrated with the normal operations of the ISS and shuttle and had to conform to the constraints of the mission and vehicles. The result of this work is a separation and rerendezvous trajectory design that would not only prove the design of the relative navigation sensors for the Orion vehicle, but also would serve as a proof of concept for the Orion rendezvous trajectory itself. This document presents the analysis and decision making process involved in attaining the final STS-134 re-rendezvous design.

Stuit, Timothy D.↗
NASA NTRS2012

Benchmarking Evaluation Results for Prototype Extravehicular Activity Gloves

The Space Suit Assembly (SSA) Development Team at NASA Johnson Space Center has invested heavily in the advancement of rear-entry planetary exploration suit design but largely deferred development of extravehicular activity (EVA) glove designs, and accepted the risk of using the current flight gloves, Phase VI, for unique mission scenarios outside the Space Shuttle and International Space Station (ISS) Program realm of experience. However, as design reference missions mature, the risks of using heritage hardware have highlighted the need for developing robust new glove technologies. To address the technology gap, the NASA Game-Changing Technology group provided start-up funding for the High Performance EVA Glove (HPEG) Project in the spring of 2012. The overarching goal of the HPEG Project is to develop a robust glove design that increases human performance during EVA and creates pathway for future implementation of emergent technologies, with specific aims of increasing pressurized mobility to 60% of barehanded capability, increasing the durability by 100%, and decreasing the potential of gloves to cause injury during use. The HPEG Project focused initial efforts on identifying potential new technologies and benchmarking the performance of current state of the art gloves to identify trends in design and fit leading to establish standards and metrics against which emerging technologies can be assessed at both the component and assembly levels. The first of the benchmarking tests evaluated the quantitative mobility performance and subjective fit of four prototype gloves developed by Flagsuit LLC, Final Frontier Designs, LLC Dover, and David Clark Company as compared to the Phase VI. All of the companies were asked to design and fabricate gloves to the same set of NASA provided hand measurements (which corresponded to a single size of Phase Vi glove) and focus their efforts on improving mobility in the metacarpal phalangeal and carpometacarpal joints. Four test subjects representing the design ]to hand anthropometry completed range of motion, grip/pinch strength, dexterity, and fit evaluations for each glove design in both the unpressurized and pressurized conditions. This paper provides a comparison of the test results along with a detailed description of hardware and test methodologies used.

Aitchison, Lindsay↗
NASA NTRS2013

Investigation of Sideband Index Response to Prototype Gear Tooth Damage

The objective of this analysis was to evaluate the ability of gear condition indicators (CI) to detect contact fatigue damage on spiral bevel gear teeth. Tests were performed in the NASA Glenn Spiral Bevel Gear Fatigue Rig on eight prototype gear sets (pinion/gear). Damage was initiated and progressed on the gear and pinion teeth. Vibration data was measured during damage progression at varying torque values while varying damage modes to the gear teeth were observed and documented with inspection photos. Sideband indexes (SI) and root mean square (RMS) CIs were calculated from the time synchronous averaged vibration data. Results found that both CIs respond differently to varying torque levels, damage levels and damage modes

health monitoring↗
NASA NTRS2017

Computational Modeling of Space Physiology for Informing Spaceflight Countermeasure Design and Predictions of Efficacy

MOTIVATION: Spaceflight countermeasures mitigate the harmful effects of the space environment on astronaut health and performance. Exercise has historically been used as a countermeasure to physical deconditioning, and additional countermeasures including lower body negative pressure, blood flow occlusion and artificial gravity are being researched as countermeasures to spaceflight-induced fluid shifts. The NASA Digital Astronaut Project uses computational models of physiological systems to inform countermeasure design and to predict countermeasure efficacy.OVERVIEW: Computational modeling supports the development of the exercise devices that will be flown on NASAs new exploration crew vehicles. Biomechanical modeling is used to inform design requirements to ensure that exercises can be properly performed within the volume allocated for exercise and to determine whether the limited mass, volume and power requirements of the devices will affect biomechanical outcomes. Models of muscle atrophy and bone remodeling can predict device efficacy for protecting musculoskeletal health during long-duration missions. A lumped-parameter whole-body model of the fluids within the body, which includes the blood within the cardiovascular system, the cerebral spinal fluid, interstitial fluid and lymphatic system fluid, estimates compartmental changes in pressure and volume due to gravitational changes. These models simulate fluid shift countermeasure effects and predict the associated changes in tissue strain in areas of physiological interest to aid in predicting countermeasure effectiveness. SIGNIFICANCE: Development and testing of spaceflight countermeasure prototypes are resource-intensive efforts. Computational modeling can supplement this process by performing simulations that reduce the amount of necessary experimental testing. Outcomes of the simulations are often important for the definition of design requirements and the identification of factors essential in ensuring countermeasure efficacy.

biomedical data↗
NASA NTRS1989

Development of an adsorption compressor for use in cryogenic refrigeration

A new compressor with no moving parts has been developed which is able to supply a source of high-pressure gas to a Joule-Thompson based cryogenic refrigerator. The compressor relies on a newly implemented combination of high-surface-area Saran carbon (sorbent) and krypton gas (working fluid). In addition, an integral gas-gap heat switch is used to provide improved overall efficiency. A prototype compressor has been designed, built, and tested as a part of the Jet Propulsion Laboratory effort in sorption refrigeration. Performance data from the prototype unit described here demonstrate successful compressor performance and good agreement with theoretical predictions.

Schember, Helen R.↗
NASA NTRS1972

Design and fabrication of prototype system for early warning of impending bearing failure

Ball bearing performance tests run on several identical ball bearings under a variety of load, speed, temperature, and lubrication conditions are reported. Bearing temperature, torque, vibration, noise, strain, cage speed, etc., were monitored to establish those measurements most suitable as indicators of ball bearing health. Tape records were made under steady-state conditions of a variety of speeds and loads. Sample sections were selected for narrowband spectral analysis with a real time analyzer. An artificial flow was created across the inner race surface of one bearing using an acid etch technique to produce the scratch. Tape records obtained before and after established a characteristic frequency response that identifies the presence of the flow. The signals found most useful as indicators of performance degradation were ultrasonic outputs.

Broderick, J. J.↗
NASA NTRS1974

Absolute pressure transducers for space shuttle and orbiter propulsion and control systems

A preliminary design was completed, reviewing of such subjects as: the trade studies for media isolation and one sensor vs. two sensors for two bridges; compensation resistors; unit design; hydrogen embrittlement; sealing techniques and test station design. A design substantiation phase was finished, consisting of testing of a prototype unit and fabrication technique studies. A cryogenic test station was implemented and prototype sensor cells were fabricated, sensors assembled, and cryogenic tests performed.

Bolta, J. J.↗
NASA NTRS1975

Fluid infusion system

Development of a fluid infusion system was undertaken in response to a need for an intravenous infusion device operable under conditions of zero-g. The initial design approach, pursued in the construction of the first breadboard instrument, was to regulate the pressure of the motive gas to produce a similar regulated pressure in the infusion liquid. This scheme was not workable because of the varying bag contact area, and a major design iteration was made. A floating sensor plate in the center of the bag pressure plate was made to operate a pressure regulator built into the bellows assembly, effectively making liquid pressure the directly controlled variable. Other design changes were made as experience was gained with the breadboard. Extensive performance tests were conducted on both the breadboard and the prototype device; accurately regulated flows from 6 m1/min to 100 m1/min were achieved. All system functions were shown to operate satisfactorily.

Hammond, J. C.↗
NASA NTRS1977

Electric prototype power processor for a 30cm ion thruster

An electrical prototype power processor unit was designed, fabricated and tested with a 30 cm mercury ion engine for primary space propulsion. The power processor unit used the thyristor series resonant inverter as the basic power stage for the high power beam and discharge supplies. A transistorized series resonant inverter processed the remaining power for the low power outputs. The power processor included a digital interface unit to process all input commands and internal telemetry signals so that electric propulsion systems could be operated with a central computer system. The electrical prototype unit included design improvement in the power components such as thyristors, transistors, filters and resonant capacitors, and power transformers and inductors in order to reduce component weight, to minimize losses, and to control the component temperature rise. A design analysis for the electrical prototype is also presented on the component weight, losses, part count and reliability estimate. The electrical prototype was tested in a thermal vacuum environment. Integration tests were performed with a 30 cm ion engine and demonstrated operational compatibility. Electromagnetic interference data was also recorded on the design to provide information for spacecraft integration.

Biess, J. J.↗
NASA NTRS1984

Air intakes for a probative missile of rocket ramjet

The methods employed to test air intakes for a supersonic guided ramjet powered missile being tested by ONERA are described. Both flight tests and wind tunnel tests were performed on instrumented rockets to verify the designs. Consideration as given to the number of intakes, with the goal of delivering the maximum pressure to the engine. The S2, S4, and S5 wind tunnels were operated at Mach nos. 1.5-3 for the tests, which were compartmentalized into fuselage-intake interaction, optimization of the intake shapes, and the intake performance. Tests were performed on the length and form of the ogive, the presence of grooves, the height of traps in the boundary layer, the types and number of intakes and the lengths and forms of diffusers. Attention was also given to the effects of sideslip, effects of the longitudinal and circumferential positions of the intakes were also examined. Near optimum performance was realized during Mach 2.2 test flights of the prototype rockets.

Laruelle, G.↗
NASA NTRS2005

Surface Sampling System for Low-Gravity Missions

SpaceWorks has identified several sampling missions that could benefit from the technology developed under this project. Requirements were established for the surface sampling system. SpaceWorks teamed with Virginia Tech to identify and select a baseline adhesive suitable for the surface sampling system. SpaceWorks identified Solimide foam as the baseline substrate material. SpaceWorks conducted extensive testing to characterize the performance of the substrate/adhesive combination. A prototype version of the sampler head was designed and built by SpaceWorks.

Preble, Jeffrey C.↗
NASA NTRS2010

NASA's Soil Moisture Active and Passive (SMAP) Mission

The Soil Moisture Active-Passive (SMAP) Mission is one of the first Earth observation satellites being formulated by NASA in response to the 2007 National Research Council s Decadal Survey. SMAP will make global measurements of soil moisture at the Earth's land surface and its freeze-thaw state. These measurements will allow significantly improved estimates of water, energy and carbon transfers between the land and atmosphere. Soil moisture measurements are also of great importance in assessing flooding and monitoring drought. Knowledge gained from SMAP observations can help mitigate these natural hazards, resulting in potentially great economic and social benefits. SMAP observations of soil moisture and freeze/thaw timing over the boreal latitudes will also reduce a major uncertainty in quantifying the global carbon balance and help to resolve an apparent missing carbon sink over land. The SMAP mission concept will utilize an L-band radar and radiometer sharing a rotating 6-meter mesh reflector antenna flying in a 680 km polar orbit with an 8-day exact ground track repeat aboard a 3-axis stabilized spacecraft to provide high-resolution and high-accuracy global maps of soil moisture and freeze/thaw state every two to three days. In addition, the SMAP project will use these surface observations with advanced modeling and data assimilation to provide estimates of deeper root-zone soil moisture and net ecosystem exchange of carbon. SMAP recently completed its Phase A Mission Concept Study Phase for NASA and transitioned into Phase B (Formulation and Detailed Design). A number of significant accomplishments occurred during this initial phase of mission development. The SMAP project held several open meetings to solicit community feedback on possible science algorithms, prepared preliminary draft Algorithm Theoretical Basis Documents (ATBDs) for each mission science product, and established a prototype algorithm testbed to enable testing and evaluation of the performance of candidate algorithms. SMAP conducted an Applications Workshop in September 2009 to coordinate with potential application users interested in the mission data. A draft Applications Plan describing the Project s planned outreach to potential applications users has been prepared and will be updated during Phase B. SMAP made a significant evaluation of the potential terrestrial radio frequency interference (RFI) source environment and established radiometer and radar flight hardware and ground processing mitigation approaches. SMAP finalized its science orbit and orbit injection approach to optimize launch mass and prepared launch and commissioning scenarios and timeline. A science data communications approach was developed to maximize available science data volume to improve science margins while maintaining moderately short data product latencies to support many potential applications using existing ground assets and with minimum impact to the flight system. SMAP developed rigid multi-body and flexible body dynamics and control models and system designs for the 6-meter rotating instrument reflector-boom assembly (RBA) and flight system to confirm pointing and control performance, and devised strategies to efficiently implement on-orbit balancing if needed. Industry partners were selected for the spin mechanism assembly (SMA) and RBA. Preliminary designs for the radar and radiometer were initiated, including constructing breadboards of key assemblies.

Kellogg, Kent↗
NASA NTRS2004

An Evolved Antenna for Deployment on NASA's Space Technology 5 Mission

We present an evolved X - band antenna design and flight prototype currently on schedule to be deployed on NASA's Space Technology 5(ST5) spacecraft. Current methods of designing and optimizing antennas by hand are time and labor intensive, limit complexity and require significant expertise and experience. Evolutionary design techniques can overcome these limitations by searching the design space and automatically finding effective solutions that would ordinarily not be found. The ST5 antenna was evolved to meet a challenging set of mission requirements, most notably the combination of wide beamwidth for a circularly-polarized wave and wide bandwidth.Two evolutionary algorithms were used: one used a genetic algorithm style representation that did not allow branching in the antenna arms: the second used a genetic programming style tree-structured representation that allowed branching in the antenna arms. The highest performance antennas from both algorithms were fabricated and tested and both yielded similar performance. Both were comparable in performance to a hand-designed antenna produced by a contractor for the mission, and so we consider them examples of human-competitive performance by evolutionary algorithms. One of the evolved antenna prototypes is undergoing flight qualification testing.

Lohn, Jason D.↗
NASA NTRSDate not supplied

Trace Contaminant Control Test Bed for Evaluation of TCC Prototypes with Vacuum Regenerable and Non-Regenerable Sorbents

A new Space Suit Exploration Portable Life Support System (xPLSS) is being designed, built, integrated, and tested into the Extra-Vehicular Mobility Unit (xEMU). The Trace Contaminant Control (TCC) system is a component in the oxygen ventilation loop of xPLSS that removes contaminants generated by the crewmembers’ metabolic processes. The primary trace contaminants that must be removed include ammonia (NH3), carbon monoxide (CO), formaldehyde (CH2O), and methyl mercaptan (CH3SH). The current state-of-the-art TCC sorbent is non-regenerable activated carbon. As a non-regenerable sorbent, its use negatively impacts the logistics for future missions. Thus, an ideal solution can be a vacuum-regenerable sorbent integrated with the xPLSS CO2/H2O removal system. To test new designs and sorbents, XploSafe has constructed a recirculating test bed that mimics the environment within the xPLSS by providing concentrations of the trace contaminant analytes generated at the operating temperature, humidity, pressure, and flow rates of the xPLSS. This system can perform regeneration or desorption by exposing the sorbent to a pressure swing from 4.3 psia to <1 torr over approximately 2 minutes. Using this test system, XploSafe evaluated various TCC prototypes constructed using rapid prototyping techniques and identified a process that allows vacuum regenerative TCC designs to be quickly examined for flow, pressure drop, and performance. By using toluene as a segregate for volatile organics, this test system was evaluated using both vacuum regenerable and non-regenerable sorbents to demonstrate the operational effectiveness of these sorbents in maintaining the concentrations of the trace contaminant analytes below the 7-day Spacecraft Maximum Allowable Concentrations.

Nicholas Materer↗
NASA NTRS2000

Production Strategies for Production-Quality Parts for Aerospace Applications

A combination of rapid prototyping processes (3D Systems' stereolithography and Sanders Prototyping's ModelMaker) are combined with gelcasting to produce high quality silicon nitride components that were performance tested under simulated use conditions. Two types of aerospace components were produced, a low-force rocket thruster and a simulated airfoil section. The rocket was tested in a test stand using varying mixtures of H2 and O2, whereas the simulated airfoil was tested by subjecting it to a 0.3 Mach jet-fuel burner flame. Both parts performed successfully, demonstrating the usefulness of the rapid prototyping in efforts to effect materials substitution. In addition, the simulated airfoil was used to explore the possibility of applying thermal/environmental barrier coatings and providing for internal cooling of ceramic parts. It is concluded that this strategy for processing offers the ceramic engineer all the flexibility normally associated with investment casting of superalloys.

Cawley, J. D.↗
NASA NTRS1991

Optical figure testing of prototype mirrors for JPL's Precision Segmented Reflector (PSR) program

JPL's PSR program is developing enabling technologies for large space telescopes employing segmented optics, and in particular, lightweight, thermally stable mirrors for telescopes operating at sub-mm wavelengths. JPL's vacuum cryointerferometric optical test facility includes a computer-controlled phase shifting interferometer operating at 10.59 microns and laser metrology for measurement of piston and absolute radius of curvature. The optical metrology has been integrated with a large vacuum chamber including a liquid nitrogen shroud capable of radiatively cooling 1.5 meter aperture mirrors down to 150 K. The facility is now being used to characterize prototype mirrors in both their room-temperature 'as-replicated' condition, and under orbital temperature conditions. The performance and limitations of the optical metrology hardware and software components are noted. Representative test results on prototype one meter-class composite mirrors being developed for PSR and related ground-based programs are also presented.

Hochberg, Eric B.↗
NASA NTRSDate not supplied

NOR Flash Memory Scrubbing Application for Boot File Preservation of NASA’s Descent and Landing Computer (DLC)

Progress on NASA’s Safe and Precise Landing Integrated Capabilities Evolution (SPLICE)project continues, specifically with this development of the Descent and Landing Computer(DLC). One of the DLC’s primary contributions as a SPLICE technology is its implementationof algorithms and operation of sensors to autonomously guide a spacecraft in performing moreprecise and safer landings on celestial bodies such as the Moon and Mars. The second iterationof the DLC is known as the Engineering Test Unit (ETU) and one of its desired functionalitiesis the ability to preserve the fidelity of the system’s boot file through the use of memoryscrubbing. The ETU has two primary boards, one for housing a Multi-Processor System ona Chip (MPSoC) and the other for housing a Xilinx Kintex Ultrascale FPGA3. To emulate amemory scrubbing function implemented on the ETU’s FPGA board, the design and testingof a software application was performed on a Xilinx KCU105 FPGA evaluation board. Thememory scrubbing application had to meet certain key criteria such as (1) properly utilize withthe flash memory’s Serial Peripheral Interface (SPI) to read, write, and erase flash memoryproperly, (2) be able to detect arbitrarily large or small amounts of bit-errors, (3) be able tocorrect all detected errors, and (4) perform memory scrubbing indefinitely and autonomously.A prototype implementation was constructed and tested, demonstrating successful detectionand correction of bit errors in multiple configurations. In the form of burst errors or singularbit flips, and in amounts of errors ranging from one to fifteen (per 256 Bytes), the applicationwas successful in preserving memory fidelity.

Radiation tolerant↗