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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 163 records · Page 9
All sourcesNASA NTRSDOE OSTI
NASA NTRS1997

Structural Design and Analysis of a Light-Weight Laminated Composite Heat Sink for Spaceflight PWBs

In order to reduce the overall weight in spaceborne electronic systems, a conventional metallic heat sink typically used for double-sided printed wiring boards was suggested to be replaced by light-weight and high-strength laminated composite materials. Through technology validation assurance (TVA) approach, it has been successfully demonstrated that using laminated composite heat sink can not only reduce the weight of the heat sink by nearly 50%, but also significantly lower the internal thermally-induced stresses that are largely responsible for potential delamination under cyclic temperature variations. With composite heat sink, both thermal and dynamic performance of the double-sided printed wiring board (PWB) exceeds that of its counterpart with metallic heat sink. Also included in this work is the original contribution to the understanding of creep behavior of the worst-case leadless chip carrier (LCC) surface mount solder joint. This was identified as the interconnection most susceptible to thermal fatigue damage in the PWB assembly.

Fan, Mark S.↗
NASA NTRS1997

Preliminary reliability evaluation of flip chip on flex interconnect technology

The study was carried out to evaluate the flip-chip-on-flex (FCOF) interconnection process in order to determine its feasibility for space flight applications. The key objectives were to: develop and apply simple and cost effective process steps needed to manufacture FCOFs and build test samples; perform a preliminary technology validation, and determine any initial environmental or application risks. The FCOF was shown to be simpler and more economical than other chip interconnection schemes.

Shaw, Jack J.↗
NASA NTRS1998

Developmental Cryogenic Active Telescope Testbed, a Wavefront Sensing and Control Testbed for the Next Generation Space Telescope

As part of the technology validation strategy of the next generation space telescope (NGST), a system testbed is being developed at GSFC, in partnership with JPL and Marshall Space Flight Center (MSFC), which will include all of the component functions envisioned in an NGST active optical system. The system will include an actively controlled, segmented primary mirror, actively controlled secondary, deformable, and fast steering mirrors, wavefront sensing optics, wavefront control algorithms, a telescope simulator module, and an interferometric wavefront sensor for use in comparing final obtained wavefronts from different tests. The developmental. cryogenic active telescope testbed (DCATT) will be implemented in three phases. Phase 1 will focus on operating the testbed at ambient temperature. During Phase 2, a cryocapable segmented telescope will be developed and cooled to cryogenic temperature to investigate the impact on the ability to correct the wavefront and stabilize the image. In Phase 3, it is planned to incorporate industry developed flight-like components, such as figure controlled mirror segments, cryogenic, low hold power actuators, or different wavefront sensing and control hardware or software. A very important element of the program is the development and subsequent validation of the integrated multidisciplinary models. The Phase 1 testbed objectives, plans, configuration, and design will be discussed.

Leboeuf, Claudia M.↗
NASA NTRS1999

Assurance of COTS Boards for Space Flight

Space Flight hardware and software designers are increasingly turning to Commercial-Off-the-Shelf (COTS) products in hopes of meeting the demands imposed on them by projects with short development cycle times. The Technology Validation Assurance (TVA) team at NASA GSFC has embarked on applying a method for inserting COTS hardware into the Spartan 251 spacecraft. This method includes Procurement, Characterization, Ruggedization/Remediation and Verification Testing process steps which are intended to increase the user's confidence in the hardware's ability to function in the intended application for the required duration. As this method is refined with use, it has the potential for becoming a benchmark for industry-wide use of COTS in high reliability systems.

Plante Jeannette↗
NASA NTRS1998

Assurance of COTS Boards for Space Flight

Space Flight hardware and software designers are increasingly turning to Commercial-Off-the-Shelf (COTS) products in hopes of meeting the demands imposed on them by projects with short development cycle times. The Technology Validation Assurance (TVA) team at NASA GSFC has embarked on applying a method for inserting COTS hardware into the Spartan 251 spacecraft. This method includes Procurement, Characterization, Ruggedization/Remediation and Verification Testing process steps which are intended to increase the uses confidence in the hardware's ability to function in the intended application for the required duration. As this method is refined with use, it has the potential for becoming a benchmark for industry-wide use of COTS in high reliability systems.

Plante, Jeannette↗
NASA NTRS1999

1999 Marsokhod Field Experiment: A Simulation of a Mars Rover Science Mission

A field experiment to simulate a rover mission to Mars was performed in February 1999. This experiment, the latest in a series of rover field experiments, was designed to demonstrate and validate technologies and investigation strategies for high-science, high-technology performance, and cost-effective planetary rover operations.

Stoker, C.↗
NASA NTRS1999

Next Generation Remote Agent Planner

In May 1999, as part of a unique technology validation experiment onboard the Deep Space One spacecraft, the Remote Agent became the first complete autonomous spacecraft control architecture to run as flight software onboard an active spacecraft. As one of the three components of the architecture, the Remote Agent Planner had the task of laying out the course of action to be taken, which included activities such as turning, thrusting, data gathering, and communicating. Building on the successful approach developed for the Remote Agent Planner, the Next Generation Remote Agent Planner is a completely redesigned and reimplemented version of the planner. The new system provides all the key capabilities of the original planner, while adding functionality, improving performance and providing a modular and extendible implementation. The goal of this ongoing project is to develop a system that provides both a basis for future applications and a framework for further research in the area of autonomous planning for spacecraft. In this article, we present an introductory overview of the Next Generation Remote Agent Planner. We present a new and simplified definition of the planning problem, describe the basics of the planning process, lay out the new system design and examine the functionality of the core reasoning module.

Jonsson, Ari K.↗
NASA NTRS1999

1999 Marsokhod Field Experiment: A Simulation of a Mars Rover Science Mission

A field experiment to simulate a rover mission to Mars was performed in February 1999. This experiment, the latest in a series of rover field experiments, was designed to demonstrate and validate technologies and investigation strategies for high-science, high-technology performance, and cost-effective planetary rover operations. Objectives: The experiment objectives were to: (1) train scientists in a mission configuration relevant to Surveyor program rover missions at a terrestrial analog field site simulating the criteria of high-priority candidate landing-sites on Mars; (2) develop optimal exploration strategies; (3) evaluate the effectiveness of imaging and spectroscopy in addressing science objectives; (4) assess the value and limitation of descent imaging in supporting rover operations; and (5) evaluate the ability of a science team to correctly interpret the geology of the field site using rover observations. A field site in the California Mojave Desert was chosen for its relevance to the criteria for landing site selection for the Mars Surveyor program. These criteria are: (1) evidence of past water activity; (2) presence of a mechanism to concentrate life; (3) presence of thermal energy sources; (4) evidence of rapid burial; and (5) excavation mechanisms that could expose traces of life.

Stoker, C.↗
NASA NTRS2000

Mars Greenhouse Experiment Module: An Experiment to Grow Flowers on Mars

NASA has entered a new phase of in-depth exploration of the planets where robotic exploration of the Solar System is focusing on in-situ missions that pave the way for human exploration. Creating a human presence on Mars will require specialized knowledge and experience concerning the Martian environment and validated technologies that will provide life-supporting consumables. An understanding of the response of terrestrial organisms to the Martian environment with respect to potential deleterious effects on crew health and changes to biological processes will be paramount. In response to these challenges an innovative selfcontained flight experiment is proposed, which is designed to assess the biocompatibility of the Martian environment by germinating seeds and following their growth through to flowering. The experiment, dubbed Mars Greenhouse Experiment Module (Mars GEM), will be accomplished in a sealed pressurized growth chamber or 'Mars Greenhouse'. Seeds will be grown in Martian soil and the Mars Greenhouse will provide ultraviolet-radiation protected, thermal-controlled environment for plant growth that actively controls the CO2 (required nutrient) and O2 (generated by the plants) levels in the chamber. The simple, but visually dramatic, demonstration of the potential to grow a plant in a man-made environment on the surface of Mars should establish a strong connection between current robotic missions and future human habitation on Mars.

MacCallum, T. K.↗
NASA NTRS1982

Agricultural Aircraft Aid

Farmers are increasingly turning to aerial applications of pesticides, fertilizers and other materials. Sometimes uneven distribution of the chemicals is caused by worn nozzles, improper alignment of spray nozzles or system leaks. If this happens, job must be redone with added expense to both the pilot and customer. Traditional pattern analysis techniques take days or weeks. Utilizing NASA's wind tunnel and computer validation technology, Dr. Roth, Oklahoma State University (OSU), developed a system for providing answers within minutes. Called the Rapid Distribution Pattern Evaluation System, the OSU system consists of a 100-foot measurement frame tied in to computerized analysis and readout equipment. System is mobile, delivered by trailer to airfields in agricultural areas where OSU conducts educational "fly-ins." A fly-in typically draws 50 to 100 aerial applicators, researchers, chemical suppliers and regulatory officials. An applicator can have his spray pattern checked. A computerized readout, available in five to 12 minutes, provides information for correcting shortcomings in the distribution pattern.

Source record↗
NASA NTRS2003

Experimental Evaluation of Verification and Validation Tools on Martian Rover Software

We report on a study to determine the maturity of different verification and validation technologies (V&V) on a representative example of NASA flight software. The study consisted of a controlled experiment where three technologies (static analysis, runtime analysis and model checking) were compared to traditional testing with respect to their ability to find seeded errors in a prototype Mars Rover. What makes this study unique is that it is the first (to the best of our knowledge) to do a controlled experiment to compare formal methods based tools to testing on a realistic industrial-size example where the emphasis was on collecting as much data on the performance of the tools and the participants as possible. The paper includes a description of the Rover code that was analyzed, the tools used as well as a detailed description of the experimental setup and the results. Due to the complexity of setting up the experiment, our results can not be generalized, but we believe it can still serve as a valuable point of reference for future studies of this kind. It did confirm the belief we had that advanced tools can outperform testing when trying to locate concurrency errors. Furthermore the results of the experiment inspired a novel framework for testing the next generation of the Rover.

Brat, Guillaume↗
NASA NTRS1999

Flight Control Laws for NASA's Hyper-X Research Vehicle

The goal of the Hyper-X program is to demonstrate and validate technology for design and performance predictions of hypersonic aircraft with an airframe-integrated supersonic-combustion ramjet propulsion system. Accomplishing this goal requires flight demonstration of a hydrogen-fueled scramjet powered hypersonic aircraft. A key enabling technology for this flight demonstration is flight controls. Closed-loop flight control is required to enable a successful stage separation, to achieve and maintain the design condition during the engine test, and to provide a controlled descent. Before the contract award, NASA developed preliminary flight control laws for the Hyper-X to evaluate the feasibility of the proposed scramjet test sequence and descent trajectory. After the contract award, a Boeing/NASA partnership worked to develop the current control laws. This paper presents a description of the Hyper-X Research Vehicle control law architectures with performance and robustness analyses. Assessments of simulated flight trajectories and stability margin analyses demonstrate that these control laws meet the flight test requirements.

Davidson, J.↗
NASA NTRS1996

INTEX Ka-Band Experiment Ground Terminal

The INTEX (interference experiment) Ka-Band Experiment Ground Terminal was developed by NASA Lewis Research Center's Advanced Space Communications Laboratory to enable space communications experiments that use the Advanced Communications Technology Satellite (ACTS). INTEX is used for a wide range of ACTS technology validation and investigation experiments as well as application demonstrations. It also supports experiments for other organizations within and outside of NASA.

Source record↗
NASA NTRS1999

High Reliability Engine Control Demonstrated for Aircraft Engines

For a dual redundant-control system, which is typical for short-haul aircraft, if a failure is detected in a control sensor, the engine control is transferred to a safety mode and an advisory is issued for immediate maintenance action to replace the failed sensor. The safety mode typically results in severely degraded engine performance. The goal of the High Reliability Engine Control (HREC) program was to demonstrate that the neural-network-based sensor validation technology can safely operate an engine by using the nominal closed-loop control during and after sensor failures. With this technology, engine performance could be maintained, and the sensor could be replaced as a conveniently scheduled maintenance action.

Guo, Ten-Huei↗
NASA NTRS2000

Feasibility Activities Completed for the Direct Data Distribution (D(sup )3) Experiment

The Direct Data Distribution (D(sup 3)) project being designed at the NASA Glenn Research Center at Lewis Field will demonstrate a high-performance communications system that transmits information at up to 1.2 gigabits per second (Gbps) from an advanced technology payload carried by the space shuttles in low Earth orbit to small (0.9-m) autonomously tracking terminals on the Earth. The flight communications package features a solid-state, phased-array antenna operating in the commercial K-band frequency that electronically steers two independently controlled downlink beams toward low-cost tracking ground terminals. The array enables agile, vibration-free beam steering at reduced size and weight with increased reliability over traditional mechanically steered reflectors. The flight experiment will also demonstrate efficient digital modulation technology that allows transmission of substantially increased amounts of latency-tolerant data (up to 72 Gb of data per minute of contact time) with very high quality (10(exp -11) bit error rate). D(sup 3) enables transmission from low-Earth-orbit science spacecraft, the shuttles, or the International Space Station directly to NASA field centers and principle investigator sites, or directly into the commercial terrestrial telecommunications network for remote distribution and archive. The ground terminal features a cryocooled receiver for ultralow noise and a reduced antenna aperture as well as open-loop tracking for unattended operations. The D(sup 3) technology validation and service demonstration will help to facilitate NASA's transition from using Government-owned communications assets to using commercially provided services.

Wald, Lawrence W.↗
NASA NTRS2006

NASA UTILIZATION OF THE INTERNATIONAL SPACE STATION AND THE VISION FOR SPACE EXPLORATION

Under U.S. President Bush s Vision for Space Exploration (January 14, 2004), NASA has refocused its utilization plans for the International Space Station (ISS). This use will now focus on: (1) the development of countermeasures that will protect crews from the hazards of the space environment, (2) testing and validating technologies that will meet information and systems needs for future exploration missions.

Robinson, Julie A.↗