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At least 1,477 records · Page 82
All sourcesNASA NTRSDOE OSTI
NASA NTRS2009

Earth Science Missions Engineering Challenges

This presentation gives a general overlook of the engineering efforts that are necessary to meet science mission requirement especially for Earth Science missions. It provides brief overlook of NASA's current missions and future Earth Science missions and the engineering challenges to meet some of the specific science objectives. It also provides, if time permits, a brief summary of two significant weather and climate phenomena in the Southern Hemisphere: El Nino and La Nina, as well as the Ozone depletion over Antarctica that will be of interest to IEEE intercom 2009 conference audience.

Marius, Julio L.↗
NASA NTRS2009

NASA Composite Materials Development: Lessons Learned and Future Challenges

Composite materials have emerged as the materials of choice for increasing the performance and reducing the weight and cost of military, general aviation, and transport aircraft and space launch vehicles. Major advancements have been made in the ability to design, fabricate, and analyze large complex aerospace structures. The recent efforts by Boeing and Airbus to incorporate composite into primary load carrying structures of large commercial transports and to certify the airworthiness of these structures is evidence of the significant advancements made in understanding and use of these materials in real world aircraft. NASA has been engaged in research on composites since the late 1960 s and has worked to address many development issues with these materials in an effort to ensure safety, improve performance, and improve affordability of air travel for the public good. This research has ranged from synthesis of advanced resin chemistries to development of mathematical analyses tools to reliably predict the response of built-up structures under combined load conditions. The lessons learned from this research are highlighted with specific examples to illustrate the problems encountered and solutions to these problems. Examples include specific technologies related to environmental effects, processing science, fabrication technologies, nondestructive inspection, damage tolerance, micromechanics, structural mechanics, and residual life prediction. The current state of the technology is reviewed and key issues requiring additional research identified. Also, grand challenges to be solved for expanded use of composites in aero structures are identified.

Tenney, Darrel R.↗
NASA NTRS2009

Computing Challenges in Coded Mask Imaging

This slide presaentation reviews the complications and challenges in developing computer systems for Coded Mask Imaging telescopes. The coded mask technique is used when there is no other way to create the telescope, (i.e., when there are wide fields of view, high energies for focusing or low energies for the Compton/Tracker Techniques and very good angular resolution.) The coded mask telescope is described, and the mask is reviewed. The coded Masks for the INTErnational Gamma-Ray Astrophysics Laboratory (INTEGRAL) instruments are shown, and a chart showing the types of position sensitive detectors used for the coded mask telescopes is also reviewed. Slides describe the mechanism of recovering an image from the masked pattern. The correlation with the mask pattern is described. The Matrix approach is reviewed, and other approaches to image reconstruction are described. Included in the presentation is a review of the Energetic X-ray Imaging Survey Telescope (EXIST) / High Energy Telescope (HET), with information about the mission, the operation of the telescope, comparison of the EXIST/HET with the SWIFT/BAT and details of the design of the EXIST/HET.

Skinner, Gerald↗
NASA NTRS2008

Space Computing Systems Validation Challenges

To examine the challenges of spaceborne computing systems and the past, present and future approaches to verification and validation in hardware and software systems.

Commercial Orbital Transportation Services (COTS)↗
NASA NTRS2010

IT Challenges for Space Medicine or How do We Protect Medical Information and Still Get Useful Work Done?

Space Medicine provides healthcare services of various types for astronauts throughout their lifetime starting from the time they are selected as astronauts. IT challenges include: protection of private medical information, access from locations both inside and outside NASA, nearly 24x7 access, access during disasters, international partner access, data archiving, off-region backup, secure communication of medical data to people outside the NASA system (e.g. expert consultants), efficient movement of medical record information between locations, search and retrieval of relevant information, and providing all of these services/capabilities within a limited budget. In Space Medicine, we have provided for these in various ways: limit the amount of private medical information stored locally, utilize encryption mechanisms that the international partners can also use, utilize 2-factor authentication, virtualize servers, employ concept-based search, and use of standardized terminologies (SNOMED) and messaging (HL7).

Johnson-Throop, Kathy A.↗
NASA NTRS2010

The Challenge of Mars EDL (Entry, Descent, and Landing)

This slide presentation reviews the some of the challenges of Martian atmospheric entry, descent and landing (EDL) on the surface of Mars. It reviews some of the technological difficulties, and some solutions that are being developed for future unmanned missions with larger payloads than previous landers, and ultimately human spacecraft landing.

Sostaric, Ronald↗
NASA NTRS2010

Dynamics of the Earth's Inner Magnetosphere and its Connection to the Ionosphere: Current Understanding and Challenges

The Earth's inner magnetosphere, a vast volume in space spanning from 1.5 Re (Earth radii) to 10 Re, is a host to a variety of plasma populations (with energy from 1 eV to few MeV) and physical processes where most of which involve plasma and field coupling. As a gigantic particle accelerator, the inner magnetosphere includes three overlapping regions: the plasmasphere, the ring current, and the Van Allen radiation belt. The complex structures and dynamics of these regions are externally driven by solar activities and internally modulated by intricate interactions and coupling. As a major constituent of Space Weather, the inner magnetosphere is both scientifically intriguing and practically important to our society. In this presentation, I will discuss our recent results from the Comprehensive Ring Current Model, in the context of our current understanding of the inner magnetosphere in general and challenges ahead in making further progresses.

Zheng, Yihua↗
NASA NTRS2010

Mars Science Laboratory Sample Acquisition, Sample Processing and Handling: Subsystem Design and Test Challenges

The Sample Acquisition/Sample Processing and Handling subsystem for the Mars Science Laboratory is a highly-mechanized, Rover-based sampling system that acquires powdered rock and regolith samples from the Martian surface, sorts the samples into fine particles through sieving, and delivers small portions of the powder into two science instruments inside the Rover. SA/SPaH utilizes 17 actuated degrees-of-freedom to perform the functions needed to produce 5 sample pathways in support of the scientific investigation on Mars. Both hardware redundancy and functional redundancy are employed in configuring this sampling system so some functionality is retained even with the loss of a degree-of-freedom. Intentional dynamic environments are created to move sample while vibration isolators attenuate this environment at the sensitive instruments located near the dynamic sources. In addition to the typical flight hardware qualification test program, two additional types of testing are essential for this kind of sampling system: characterization of the intentionally-created dynamic environment and testing of the sample acquisition and processing hardware functions using Mars analog materials in a low pressure environment. The overall subsystem design and configuration are discussed along with some of the challenges, tradeoffs, and lessons learned in the areas of fault tolerance, intentional dynamic environments, and special testing

Jandura, Louise↗
NASA NTRS2009

The Diagnostic Challenge Competition: Probabilistic Techniques for Fault Diagnosis in Electrical Power Systems

Reliable systems health management is an important research area of NASA. A health management system that can accurately and quickly diagnose faults in various on-board systems of a vehicle will play a key role in the success of current and future NASA missions. We introduce in this paper the ProDiagnose algorithm, a diagnostic algorithm that uses a probabilistic approach, accomplished with Bayesian Network models compiled to Arithmetic Circuits, to diagnose these systems. We describe the ProDiagnose algorithm, how it works, and the probabilistic models involved. We show by experimentation on two Electrical Power Systems based on the ADAPT testbed, used in the Diagnostic Challenge Competition (DX 09), that ProDiagnose can produce results with over 96% accuracy and less than 1 second mean diagnostic time.

Ricks, Brian W.↗
NASA NTRS2010

Engineering Innovations for Exploration Challenges

This slide presentation reviews some of the engineering innovations requirements for the challenges of space exploration which NASA has and will be involved in. It reviews some significant successes in space transportation, exploration and science accomplished during 2009, and it reviews some of the places that are available for exploration in the near term and the specific missions that NASA has assigned to Marshall. It also reviews the project lifecycle management model, that is designed to reduce undefined, but known, risks. It also demonstrates the sustainable long-term program of block upgrades that contribute to long-term success of programs.

Dumbacher, Daniel L.↗
NASA NTRS2010

Remaining Technical Challenges and Future Plans for Oil-Free Turbomachinery

The application of Oil-Free technologies (foil gas bearings, solid lubricants and advanced analysis and predictive modeling tools) to advanced turbomachinery has been underway for several decades. During that time, full commercialization has occurred in aircraft air cycle machines, turbocompressors and cryocoolers and ever-larger microturbines. Emerging products in the automotive sector (turbochargers and superchargers) indicate that high volume serial production of foil bearings is imminent. Demonstration of foil bearings in APU s and select locations in propulsion gas turbines illustrates that such technology also has a place in these future systems. Foil bearing designs, predictive tools and advanced solid lubricants have been reported that can satisfy anticipated requirements but a major question remains regarding the scalability of foil bearings to ever larger sizes to support heavier rotors. In this paper, the technological history, primary physics, engineering practicalities and existing experimental and experiential database for scaling foil bearings are reviewed and the major remaining technical challenges are identified.

DellaCorte, Christopher↗
NASA NTRS2010

ECLSS and Thermal Systems Integration Challenges Across the Constellation Architecture

As the Constellation Program completes its initial capability Preliminary Design Review milestone for the Initial Capability phase, systems engineering of the Environmental Control and Life Support (ECLS) and Thermal Systems for the various architecture elements has progressed from the requirements to design phase. As designs have matured for the Ares, Orion, Ground Systems, and Extravehicular (EVA) System, a number of integration challenges have arisen requiring analyses and trades, resulting in changes to the design and/or requirements. This paper will address some of the key integration issues and results, including the Orion-to-Ares shared compartment venting and purging, Orion-to-EVA suit loop integration issues with the suit system, Orion-to-ISS and Orion-to-Altair intermodule ventilation, and Orion and Ground Systems impacts from post-landing environments.

Carrasquillo, Robyn↗
NASA NTRS2010

Evolving from Planning and Scheduling to Real-Time Operations Support: Design Challenges

Versions of Scheduling and Planning Interface for Exploration (SPIFe) have supported a variety of mission operations across NASA. This software tool has evolved and matured over several years, assisting planners who develop intricate schedules. While initially conceived for surface Mars missions, SPIFe has been deployed in other domains, where people rather than robotic explorers, execute plans. As a result, a diverse set of end-users has compelled growth in a new direction: supporting real-time operations. This paper describes the new needs and challenges that accompany this development. Among the key features that have been built for SPIFe are current time indicators integrated into the interface and timeline, as well as other plan attributes that enable execution of scheduled activities. Field tests include mission support for the Lunar CRater Observation and Sensing Satellite (LCROSS), NASA Extreme Environment Mission Operations (NEEMO) and Desert Research and Technology Studies (DRATS) campaigns.

Marquez, Jessica J.↗
NASA NTRS2010

Microbial Challenge Testing of Single Liquid Cathode Feed Water Electrolysis Cells for the International Space Station (ISS) Oxygen Generator Assembly (OGA)

The International Space Station (ISS) Oxygen Generator Assembly (OGA) operational performance may be adversely impacted by microbiological growth and biofilm formation over the electrolysis cell membranes. Biofilms could hinder the transport of water from the bulk fluid stream to the membranes and increase the cell resistance resulting in higher cell voltages and a shorter cell life. A microbial challenge test was performed on duplicate single liquid cathode feed electrolyzer cells to evaluate operational performance with increasing levels of a mixture of five bacteria isolated from ISS and Space Shuttle potable water systems. Baseline performance of the single water electrolysis cells was determined for approximately one month with deionized water. Monthly performance was also determined following each inoculation of the feed tank with 100, 1000, 10,000 and 100,000 cells/ml of the mixed suspension of test bacteria. Water samples from the feed tank and recirculating water loops for each cell were periodically analyzed for enumeration and speciation of bacteria and total organic carbon. While initially a concern, this test program has demonstrated that the performance of the electrolysis cell is not adversely impacted by feed water containing the five species of bacteria tested at a concentration measured as high as 1,000,000 colony forming units (CFU)/ml. This paper presents the methodologies used in the conduct of this test program along with the performance test results at each level of bacteria concentration.

Diderich, Greg S.↗
NASA NTRS2004

Challenger and Columbia Lessons Learned

The Space Shuttle Challenger and Columbia accidents resulted in tragic loss of life and national assets, and investigations into both accidents produced important lessons to prevent future accidents

Hoffman, William C., III↗
NASA NTRS2011

Design, Development and Test Challenges: Separation Mechanisms for the Orion Pad Abort-1 Flight Test

On May 6, 2010, NASA launched the first successful integrated flight test, Pad Abort-1, of the Orion Project from the White Sands Missile Range in Las Cruces, New Mexico. This test demonstrated the ability to perform an emergency pad abort of a full-scale 4.8 m diameter, 8200 kg crew capsule. During development of the critical separation mechanisms for this flight test, various challenges were overcome related to environments definition, installation complications, separation joint retraction speed, thruster ordnance development issues, load path validation and significant design loads increases. The Launch Abort System retention and release (LAS R&R) mechanism consisted of 6 discrete structural connections between the LAS and the crew module (CM) simulator, each of which had a preloaded tension tie, Superbolt torque-nut and frangible nut. During the flight test, the frangible nuts were pyrotechnically split, permitting the CM to separate from the LAS. The LAS separation event was the driving case in the shock environment for many co-located hardware items. During development testing, it was necessary to measure the source shock during the separation event so the predicted shock environment could be validated and used for certification testing of multiple hardware items. The Lockheed Martin test team measured the source separation shock due to the LAS R&R function, which dramatically decreased the predicted environment by 90% at 100 Hz. During development testing a hydraulic tensioner was used to preload the joint; however, the joint relaxation with the tensioner proved unsatisfactory so the design was modified to include a Superbolt torque-nut. The observed preload creep during lab testing was 4% after 30 days, with 2.5% occurring in the first 24 hours. The conversion of strain energy (preload) to kinetic energy (retraction) was measured to be 50-75%. Design features and careful monitoring of multiple strain gauges on each tension tie allowed a pure tensile load to be applied after stacking at the launch pad. Following installation, preload in each joint was monitored for 24 hours. Due to unforeseen complications and the influence of temperature on the portable data acquisition system, the team encountered difficulty in tracking the joint relaxation. In some cases, bond-line failure of the strain gauges occurred.

Dinsel, Alison↗