SEARCH · Engineering Papers

Results for “building engineers”

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.

SourceResearch connectionFrom yearThrough year

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

At least 973 records · Page 54

All sources NASA NTRS DOE OSTI

NASA NTRS1993

Developing interpretable models with optimized set reduction for identifying high risk software components

Applying equal testing and verification effort to all parts of a software system is not very efficient, especially when resources are limited and scheduling is tight. Therefore, one needs to be able to differentiate low/high fault frequency components so that testing/verification effort can be concentrated where needed. Such a strategy is expected to detect more faults and thus improve the resulting reliability of the overall system. This paper presents the Optimized Set Reduction approach for constructing such models, intended to fulfill specific software engineering needs. Our approach to classification is to measure the software system and build multivariate stochastic models for predicting high risk system components. We present experimental results obtained by classifying Ada components into two classes: is or is not likely to generate faults during system and acceptance test. Also, we evaluate the accuracy of the model and the insights it provides into the error making process.

Briand, Lionel C.↗

NASA NTRS2000

Development of a Two Dimensional Synthetic Aperture Radiometer at L-Band

A radiometer that uses aperture synthesis in two dimensions is being built as part of research under NASA's Instrument Incubator Program. The instrument development team consists of engineers at the Goddard Space Flight Center, the University of Massachusetts and Quadrant Engineering. This will be an aircraft instrument operating at L-band which builds on the heritage of ESTAR. The choice of L-band was made because the problem of achieving adequate resolution in space is most critical at this wavelength and because a polarimetric, conical scanning airborne radiometer for future experiments to validate soil moisture and ocean salinity retrieval algorithms is not currently available. The instrument will be designed to fly on the NASA P-3 aircraft in a nadir pointing mode, although other options are possible. The antenna will consist of an array of modules arranged in a rectangular grid. Each module will be comprised of a printed circuit dual-polarized patch and integrated receiver. The distribution of modules within the rectangular array will be adjustable so that several different imaging configurations (e.g. "+","Y", "T") can be employed. The integrated receiver will provide amplification and conversion to IF. The IF signal will be routed to a processor where the required correlations performed. The I and Q channels will be created digitally and the correlations will be done digitally in this processor. The digitization will be done with sufficient bits to study the effects of quantization on radiometer performance. A computer/controller will store the data for conversion to an image and will also perform temperature control and other data interfacing and housekeeping tasks. The instrument is currently in the bread boarding phase of development. A design of the critical components has been completed and hardware is being assembled to test the individual elements. It is expected that a complete 2-channel correlator will be tested by the summer of 2000 and that the complete instrument will be ready for flight tests the following summer (2001).

LeVine, D. M.↗

NASA NTRS2000

Development of a Two Dimensional Synthetic Aperture Radiometer at L-Band

A radiometer that uses aperture synthesis in two dimensions is being built as part of research under NASA's Instrument Incubator Program. The instrument development team consists of engineers at the Goddard Space Flight Center, the University of Massachusetts and Quadrant Engineering. This will be an aircraft instrument operating at L-band which builds on the heritage of Electronically Steered Thinned Array Radiometer (ESTAR). This instrument is a next step in the development of aperture synthesis (STAR technology) to meet the goal of a future mission to monitor soil moisture globally from space. The instrument will be designed to fly on the NASA P-3 aircraft in a nadir pointing mode, although other options are possible. The antenna will consist of an array of modules in a rectangular grid. Each module will be comprised of a printed circuit dual-polarized patch and integrated receiver. The distribution of modules within the rectangular array will be adjustable so that several different imaging configurations (e.g. '+', 'Y', 'T') can be employed. The integrated receiver will provide amplification and conversion to infrared (IF). The IF signal will be routed to a processor where the required correlations performed. The I and Q channels will be created digitally and the correlations will be done digitally in this processor. The digitization will be done with sufficient bits to study the effects of quantization on radiometer performance. A computer/controller will store the data for conversion to an image and will also perform temperature control and other data interfacing and housekeeping tasks. The design of critical components has been completed and hardware is being assembled to test the individual elements. It is expected that a complete two-channel correlator will be tested by the end of 2000 and that the complete instrument will be ready for flight tests the following summer (2001).

LeVine, D. M.↗

NASA NTRS1990

Pressure Analysis

FluiDyne Engineering Corporation, Minneapolis, MN is one of the world's leading companies in design and construction of wind tunnels. In its designing work, FluiDyne uses a computer program called GTRAN. With GTRAN, engineers create a design and test its performance on the computer before actually building a model; should the design fail to meet criteria, the system or any component part can be redesigned and retested on the computer, saving a great deal of time and money.

Source record↗

NASA NTRS2002

NASA Microgravity Science Competition for High-school-aged Student Teams

NASA participates in a wide variety of educational activities including competitive events. There are competitive events sponsored by NASA and student teams which are mentored by NASA centers. This participation by NASA in public forums serves to bring the excitement of aerospace science to students and educators. A new competition for highschool-aged student teams involving projects in microgravity has completed two pilot years and will have national eligibility for teams during the 2002-2003 school year. A team participating in the Dropping In a Microgravity Environment will research the field of microgravity, develop a hypothesis, and prepare a proposal for an experiment to be conducted in a microgravity drop tower facility. A team of NASA scientists and engineers will select the top proposals and those teams will then design and build their experiment apparatus. When the experiment apparatus are completed, team representatives will visit NASA Glenn in Cleveland, Ohio for operation of their facility and participate in workshops and center tours. Presented in this paper will be a description of DIME, an overview of the planning and execution of such a program, results from the first two pilot years, and a status of the first national competition.

DeLombard, Richard↗

NASA NTRS2004

From Bridges and Rockets, Lessons for Software Systems

Although differences exist between building software systems and building physical structures such as bridges and rockets, enough similarities exist that software engineers can learn lessons from failures in traditional engineering disciplines. This paper draws lessons from two well-known failures the collapse of the Tacoma Narrows Bridge in 1940 and the destruction of the space shuttle Challenger in 1986 and applies these lessons to software system development. The following specific applications are made: (1) the verification and validation of a software system should not be based on a single method, or a single style of methods; (2) the tendency to embrace the latest fad should be overcome; and (3) the introduction of software control into safety-critical systems should be done cautiously.

Holloway, C. Michael↗

NASA NTRS2002

Key ingredients needed when building large data processing systems for scientists

Why is building a large science software system so painful? Weren't teams of software engineers supposed to make life easier for scientists? Does it sometimes feel as if it would be easier to write the million lines of code in Fortran 77 yourself? The cause of this dissatisfaction is that many of the needs of the science customer remain hidden in discussions with software engineers until after a system has already been built. In fact, many of the hidden needs of the science customer conflict with stated needs and are therefore very difficult to meet unless they are addressed from the outset in a system's architectural requirements. What's missing is the consideration of a small set of key software properties in initial agreements about the requirements, the design and the cost of the system.

Earth Observing System EOS↗

NASA NTRS2008

NASA's Ares I and Ares V Launch Vehicles--Effective Space Operations Through Efficient Ground Operations

The United States (U.S.) is charting a renewed course for lunar exploration, with the fielding of a new human-rated space transportation system to replace the venerable Space Shuttle, which will be retired after it completes its missions of building the International Space Station (ISS) and servicing the Hubble Space Telescope. Powering the future of space-based scientific exploration will be the Ares I Crew Launch Vehicle, which will transport the Orion Crew Exploration Vehicle to orbit where it will rendezvous with the Altair Lunar Lander, which will be delivered by the Ares V Cargo Launch Vehicle (fig. 1). This configuration will empower rekindled investigation of Earth's natural satellite in the not too distant future. This new exploration infrastructure, developed by the National Aeronautics and Space Administration (NASA), will allow astronauts to leave low-Earth orbit (LEO) for extended lunar missions and preparation for the first long-distance journeys to Mars. All space-based operations - to LEO and beyond - are controlled from Earth. NASA's philosophy is to deliver safe, reliable, and cost-effective architecture solutions to sustain this multi-billion-dollar program across several decades. Leveraging SO years of lessons learned, NASA is partnering with private industry and academia, while building on proven hardware experience. This paper outlines a few ways that the Engineering Directorate at NASA's Marshall Space Flight Center is working with the Constellation Program and its project offices to streamline ground operations concepts by designing for operability, which reduces lifecycle costs and promotes sustainable space exploration.

Singer, Christopher E.↗

NASA NTRS2005

Reusable Hybrid Propellant Modules for Outer-Space Transport

A report summarizes the concept of reusable hybrid propellant modules (HPMs), which would be used in outer space for long-term cryogenic storage of liquefied spacecraft-propellant gases, including for example, oxygen and hydrogen for combustion-based chemical rocket engines and xenon for electric thrusters. The HPM concept would provide the fundamental building block for an efficient, reusable in-space transportation system for both crewed and uncrewed missions. Each HPM would be equipped to implement an advanced zero-boil-off method of managing cryogenic fluids, and would include a fluid-transfer interface comprising standardized fittings that would be compatible with fittings on all supply facilities and on spacecraft to be supplied. The HPM, combined with a chemical or electric orbital transfer spacecraft, would provide an integrated propulsion system. HPMs would supply chemical propellant for time-critical transfers such as crewed missions, and utilize the more efficient electric-propulsion transfer vehicles to transport filled HPMs to the destinations and to return empty HPMs back to near-Earth orbits or other intermediate locations for replenishment and reuse. The HPM prepositioned using electric propulsion would provide the chemical propellant for the crew s return trip in a much more efficient manner than a chemical-only approach. The propellants to fill the HPMs would be delivered from the Earth or other initial supply locations to the intermediate locations by use of automated, compatible spacecraft designed specifically for that purpose. Additionally, multiple HPMs could be aggregated and positioned in orbits and on planets, moons, and asteroids to supply fluids to orbiting and interplanetary spacecraft.

Mazanek, Daniel D.↗

NASA NTRS2011

ISS Solar Array Alpha Rotary Joint (SARJ) Bearing Failure and Recovery: Technical and Project Management Lessons Learned

The photovoltaic solar panels on the International Space Station (ISS) track the Sun through continuous rotating motion enabled by large bearings on the main truss called solar array alpha rotary joints (SARJs). In late 2007, shortly after installation, the starboard SARJ had become hard to turn and had to be shut down after exceeding drive current safety limits. The port SARJ, of the same design, had been working well for over 2 years. An exhaustive failure investigation ensued that included multiple extravehicular activities to collect information and samples for engineering forensics, detailed structural and thermal analyses, and a careful review of the build records. The ultimate root cause was determined to be kinematic design vulnerability coupled with inadequate lubrication, and manufacturing flaws; this was corroborated through ground tests, metallurgical studies, and modeling. A highly successful recovery plan was developed and implemented that included replacing worn and damaged components in orbit and applying space-compatible grease to improve lubrication. Beyond the technical aspects, however, lie several key programmatic lessons learned. These lessons, such as running ground tests to intentional failure to experimentally verify failure modes, are reviewed and discussed so they can be applied to future projects to avoid such problems.

DellaCorte, Christopher↗

NASA NTRS2013

Composite Crew Module (CCM) Permeability Characterization

In January 2007, the NASA Administrator chartered the NASA Engineering and Safety Center (NESC) to form an Agency team to design and build a composite crew module in 18 months in order to gain hands-on experience in anticipation that future exploration systems may be made of composite materials. One of the conclusions from this Composite Crew Module Primary Structure assessment was that there was a lack of understanding regarding the ability for composite pressure shells to contain consumable gases, which posed a technical risk relative to the use of a metallic design. After the completion of the Composite Crew Module test program, the test article was used in a new program to assess the overall leakage/permeability and identify specific features associated with high leak rates. This document contains the outcome of the leakage assessment.

Kirsch, Michael T.↗

NASA NTRS2013

Science Opportunity Analyzer (SOA) Version 8

SOA allows scientists to plan spacecraft observations. It facilitates the identification of geometrically interesting times in a spacecraft s orbit that a user can use to plan observations or instrument-driven spacecraft maneuvers. These observations can then be visualized multiple ways in both two- and three-dimensional views. When observations have been optimized within a spacecraft's flight rules, the resulting plans can be output for use by other JPL uplink tools. Now in its eighth major version, SOA improves on these capabilities in a modern and integrated fashion. SOA consists of five major functions: Opportunity Search, Visualization, Observation Design, Constraint Checking, and Data Output. Opportunity Search is a GUI-driven interface to existing search engines that can be used to identify times when a spacecraft is in a specific geometrical relationship with other bodies in the solar system. This function can be used for advanced mission planning as well as for making last-minute adjustments to mission sequences in response to trajectory modifications. Visualization is a key aspect of SOA. The user can view observation opportunities in either a 3D representation or as a 2D map projection. Observation Design allows the user to orient the spacecraft and visualize the projection of the instrument field of view for that orientation using the same views as Opportunity Search. Constraint Checking is provided to validate various geometrical and physical aspects of an observation design. The user has the ability to easily create custom rules or to use official project-generated flight rules. This capability may also allow scientists to easily assess the cost to science if flight rule changes occur. Data Output allows the user to compute ancillary data related to an observation or to a given position of the spacecraft along its trajectory. The data can be saved as a tab-delimited text file or viewed as a graph. SOA combines science planning functionality unique to both JPL and the sponsoring spacecraft. SOA is able to ingest JPL SPICE Kernels that are used to drive the tool and its computations. A Percy search engine is then included that identifies interesting time periods for the user to build observations. When observations are then built, flight-like orientation algorithms replicate spacecraft dynamics to closely simulate the flight spacecraft s dynamics. SOA v8 represents large steps forward from SOA v7 in terms of quality, reliability, maintainability, efficiency, and user experience. A tailored agile development environment has been built around SOA that provides automated unit testing, continuous build and integration, a consolidated Web-based code and documentation storage environment, modern Java enhancements, and a focus on usability

Witoff, Robert J.↗

NASA NTRS2015

Inheriting Curiosity: Leveraging MBSE to Build Mars2020

The success of the Jet Propulsion Laboratory's (JPL) Martian mission Mars Science Laboratory (MSL) prompted NASA to challenge JPL to build a second rover, Mars2020. Mars2020 has chosen to infuse Model Based Systems Engineering (MBSE) in pursuit of aiding the design of the Flight System. This paper will derive the motivation for MBSE infusion and will explain the current state of the Mars2020 Flight System Model. Successes in MBSE adoption will be discussed, as will limitations to the methodology.

Mars↗

NASA NTRSDate not supplied

VIPER: Mission Design & Development

The NASA Artemis Program plans to return humans to the Moon to stay. Extended human stays on the Moon will require substantial resources to sustain human presence over the long-term, requiring continuous supplies delivered from the Earth. However, if some of the resources were indigenously available, substantial logistical complexity and costs could be saved by “living off the land”, wherever possible. The LCROSS, LRO and other missions have confirmed the presence of resources such as volatiles in polar regions, so the next step is to understand the scientific nature and physical distribution of those candidate resources. Those local volatiles could be processed into propellants and human life-supporting needs, reducing risk of maintaining a permanent human presence on the Moon. The Volatiles Investigating Polar Exploration Resource (VIPER) is a surface mobility scientific platform, designed to spend ~100 days mapping and surveying four different Ice Stability Regions to understand the scientific nature and distribution of water and other volatiles. VIPER will also provide scientific mineralogical context of the lunar regolith, such as the presence of silicon and light metals in lunar regolith, providing a composite picture of resource availability and sustainment. This paper will discuss the latest development progress by the VIPER team, following our initial introduction to this mission at IAC2021. The VIPER team has passed both its NASA Preliminary Design Review (PDR) and Critical Design Reviews (CDR), and is now looking to performing significant testing of engineering units representing the design, prior to the team turning its attention to building the flight hardware. VIPER is managed within NASA’s Science Mission Directorate (SMD), utilizing the Commercial Lunar Payload Services (CLPS) delivery model with partner, Astrobotic, Inc.

Daniel Andrews↗

NASA NTRS2024

Establishing Standards for Lunar In Situ Resource Utilization Structural Materials

Lunar structures will be exposed to one of the most extreme environments that have ever been considered for human settlements. In situ, regolith-based materials are being proposed for construction on the moon, offering the benefit of reducing the cost of transporting large amounts of materials or prefabricated elements, and relying on the ability to transport mainly the equipment needed to construct landing pads, shelters, blast shields, habitats, roadways, etc. However, the properties of materials that are made, all or in part, from indigenous lunar resources are likely to change based on the make-up of the material, the location where it was taken from, the production processes, and time. No standards or building codes exist for the design and construction of infrastructure on the moon. Engineers will need dependable information about these materials before any design can be completed. Hard-won lessons from centuries of using similar resources on Earth need to be leveraged to develop the best procedures that will be critical for testing such materials for structural applications. Here we discuss the technical challenges of establishing such standards. Using the timely example of a landing pad on the moon, we identify the gaps in both knowledge and testing capabilities that exist today.

Shirley J. Dyke↗

DOE OSTI2023

The Hydrofluorocarbon Phasedown and Commercial Space Conditioning: A Guide to the Transition

You may be aware of the hydrofluorocarbon (HFC) phasedown, but the details and its impact on your operations may still be unclear. Or perhaps this is the first you're hearing about the phasedown. In either case, this guide provides information to aid conversations with facility managers and engineers and provides an explanation of how the phasedown affects equipment in commercial buildings. It also includes actions you and your organization can take now to properly plan and prepare.

ENERGY CONSERVATION, CONSUMPTION, AND UTILIZATION↗

DOE OSTI2023

La Reduccion Gradual de Refrigerantes de Hidrofluorocarburos y el Acondicionamiento de Espacios Comerciales: Guia para la Transicion

ENERGY CONSERVATION, CONSUMPTION, AND UTILIZATION↗

DOE OSTI2026

Engineering an aldoxime dehydratase with high activity and isomer tolerance for biosynthesis of an O -protected primary cyanohydrin

O-protected primary cyanohydrins (glycolonitriles) are important building blocks for many difunctionalized compounds and precursors to known bioactive molecules. Their synthesis, however, utilizes toxic cyanide, which raises significant safety concerns for industrial synthesis. Here, in this study, we present a cyanide-free enzymatic synthesis of an o-benzyl protected primary cyanohydrin from an (E)- or (Z)-α-oxygen protected aldoxime using an engineered aldoxime dehydratase enzyme from Bacillus sp. OxB-1 (OxdB). In contrast to many evolved enzymes that tend to “specialize” as their activity increases, we used directed evolution to engineer OxdB for efficient dehydration of both isomers in a mixture of (E)- or (Z)-α-oxygen aldoximes with high activity and substrate loading to achieve near quantitative yield. Using this enzyme, we further demonstrate a cyanide-free chemoenzymatic pathway to an o-protected primary cyanohydrin starting from a readily available aldehyde, where the aldehyde is first condensed with hydroxylamine, followed by dehydration using our evolved enzyme. This pathway was readily scaled up to 1 g scale with high substrate loading, demonstrating its utility in industrial synthesis of these important building block functional groups.

Aldoxime dehydratase↗