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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 55 records · Page 3
All sourcesNASA NTRSDOE OSTI
NASA NTRS2012

Reducing Printed Circuit Board Emissions with Low-Noise Design Practices

This paper presents the results of an experiment designed to determine the effectiveness of adopting several low-noise printed circuit board (PCB) design practices. Two boards were designed and fabricated, each consisting of identical mixed signal circuitry. Several important differences were introduced between the board layouts: one board was constructed using recommended low-noise practices and the other constructed without such attention. The emissions from the two boards were then measured and compared, demonstrating an improvement in radiated emissions of up to 22 dB.

Bradley, Arthur T.↗
NASA NTRS2022

On-board Absolute Localization Based on Orbital Imagery for a Future Mars Science Helicopter

Future Mars Rotorcraft require advanced navigationcapabilities to enable all terrain access over long distance flightsthat are executed fully autonomously. A critical component toenable precision navigation during long traverses is the abilityto perform on-board absolute localization to eliminate drift inposition estimates of the on-board odometry algorithm. Inthis paper, we present an approach for on-board map-basedlocalization to provide global reference position based on orbitalor aerial image maps. Our approach builds on a vision-basedlocalization method to localize against a map derived fromHiRISE image products – an ortho-projected image (orthoimage) and a corresponding digital elevation map. The mapis pre-computed using a feature-based approach. Features arestored with their 3D world coordinates, and a descriptor to codethe local image intensity information in the vicinity of the featurelocation. An on-board matching algorithm uses this informationto match visual features in a query image acquired during flight,guided by a pose prior from the on-board range-visual-inertialstate estimator (Range-VIO). Valid matches are then used bya perspective-n-point (PnP) algorithm to estimate the absolutepose of the vehicle in a global frame. We demonstrate andevaluate our approach on simulated data, and data from UASflights.

Balaram, J. Bob↗
NASA NTRS1967

Investigation of Solder Cracking Problems on Printed Circuit Boards

A Solder Committee designated to investigate a solder cracking phenomena occurring on the SATURN electrical/electronic hardware found the cause to be induced stress in the soldered connections rather than faulty soldering techniques. The design of the printed circuit (PC) board assemblies did not allow for thermal expansion of the boards that occurred during normal operation. The difference between the thermal expansion properties of the boards and component lead materials caused stress and cracking in the soldered connections. The failure mechanism and various PC boards component mounting configurations are examined in this report. Effective rework techniques using flanged tubelets, copper tubelets, and soft copper wiring are detailed. Future design considerations to provide adequate strain relief in mounting configurations are included to ensure successful solder terminations.

CIRCUIT BOARD↗
DOE OSTI2023

Designing interagency responses to wicked problems: A viable system model board game

Government agencies struggle to address wicked problems because they are open-ended, highly interdependent issues that cross agency, stakeholder, jurisdictional, and geopolitical boundaries. While both quantitative modelling and qualitative problem structuring methodologies have been used to support interagency decision making in the past, co-designing an effective interagency organization to collaboratively tackle wicked problems is more challenging. Few approaches have been developed to enable such efforts. This paper explains how the viable system model (VSM) was implemented through a board game, which was employed to co-design an interagency meta-organization that would be capable of more effectively collaborating to jointly address a wicked problem: international organized drug crime and its interface with local gangs in Chicago, USA. The board game was developed to make the VSM easier for the participants to learn, given that the cybernetic language and engineering-influenced diagrams in the original literature can be off-putting to leaders and managers. The board game was used as the final stage of a multi-method, systemic approach, which involved boundary critique and problem structuring as well as deployment of the VSM. The research findings indicate that the VSM board game, used as part of a larger mixed-methods systemic intervention, contributes to building trust in the value of systems thinking amongst the participants, and sets up a rich context for collaboration on multi-agency co-design. The game therefore offers significant promise as part of the co-design of interagency responses to wicked problems because it creates an embodied process for stakeholders to learn about the VSM. It also reduces the work involved in this learning. Thus, the game enables an effective appropriation of the VSM language and criteria.

Business & Economics↗
DOE OSTI2021

Cooling and Timing Tests of the ATLAS Fast TracKer VME Boards

The Fast TracKer (FTK) is an ATLAS trigger upgrade built for full-event, low-latency, high-rate tracking. The FTK core, made of 9U VME boards, performs the most demanding computational task. The associative memory board (AMB) serial link processor and the auxiliary card (AUX), plugged on the front and back sides of the same VME slot, constitute the processing unit (PU), which finds tracks using hits from eight layers of the inner detector. The PU works in pipeline with the second stage board (SSB), which finds 12-layer tracks by adding extra hits to the identified tracks. In the designed configuration, 16 PUs and four SSBs are installed in a VME crate. The high power consumption of the AMB, AUX, and SSB (respectively, of about 250, 70, and 160 W per board) required the development of a custom cooling system. Even though the expected power consumption for each VME crate of the FTK system is high compared with a common VME setup, the 8 FTK core crates will use ≈60 kW, which is just a fraction of the power and the space needed for a CPU farm performing the same task. We report on the integration of 32 PUs and eight SSBs inside the FTK system, on the infrastructures needed to run and cool them, and on the tests performed to verify the system processing rate and the temperature stability at a safe value.

72 PHYSICS OF ELEMENTARY PARTICLES AND FIELDS↗
NASA NTRS1971

Development of a highly reliable composite board for printed circuitry for use in space environment

Materials, processes and fabrication techniques have been investigated for the development of a high-temperature circuit-board laminate. High quality, void-free copper-clad laminates have been made using 7628/HS-1 style fiberglas reinforcements with filled polyimide matrices. The fabricating characteristics of P13N resin appear suitable for use as a filled matrix in this circuit board development. High-fired, ball-milled alumina appears to be necessary to obtain the desired effects in the circuit board system. Nickel-clad copper foil bonding surfaces appear to be another requirement for retention of good bond strengths after art work and plating sequences. The fabrication cycle for this circuit board system is very dependent on the heating profile. Very rapid heating with quick loading is recommended. A stack approach to lamination was successfully used.

Bradbury, E. J.↗
NASA NTRS1972

Noise generated by impingement of a jet upon a large flat board

Data were obtained on the noise generated by an air jet impinging on a large flat board. The board was large enough so that the flow leaving the edges of the board generated no significant noise. The impingement angle, nozzle shape and size, jet velocity, and the distance from the nozzle to the board were varied in the experiment. Far-field noise data are presented. The nozzle-alone noise contribution to the total noise was generally small and was subtracted from the total, leaving the impingement-only noise. The impingement-only noise was adequately correlated by eighth power of the peak impingement velocity and first power of the impingement area. The spectral data were correlated by a Strouhal number based on the peak impingement velocity and a characteristic impingement diameter.

Olsen, W. A.↗
NASA NTRS1978

Bench-top soldering aid for PC boards

Multiple-board rack allows technician to insert components into several boards, flip them all in single motion, and then systematically solder leads on reverse side. Two adjustable crossbars allow boards of any size up to 10 by 24 inches. Operator can rotate racks and adjust angle of boards from standing or sitting position.

Manton, N. R.↗
NASA NTRS1986

Coating Circuit Boards With Silicone

Techniques appropriate to boards containing CMOS circuits detailed. Document presents procedure for applying thin conformal coating to such electronic assemblies as printed-circuit boards and wire-wrapped boards. Coating is from 1 to 7 mils (25 to 178 micrometers) thick and composed of room-temperature-vulcanizing (RTV) silicone. Specifies materials, equipment, spraying method, and quality requirements. Takes into account special needs of circuits made with complementary metal-oxide/semiconductor (CMOS) devices on circuit boards. Special attention given to preventing damage by electrostatic discharge, to which CMOS circuits especially sensitive.

Gaudiano, S.↗
NASA NTRS1988

Two-dimensional graphics tools for a transputer based display board

A package of 2-D graphics routines has been developed in an effort to standardize and simplify the user interface for a transputer based graphics display board. The routines available take advantage of the graphic board's capabilities while also presenting an intuitive approach for generating drawings. The routines allow a user to perform graphics rendering in a 2-D real-coordinate space without regard to the actual screen coordinates. Multiple windows, which can be placed arbitrarily on the screen as well as the ability to use double-buffering techniques for smooth animations are also supported. The routines are designed to be run on a transputer other than the graphics display board. The window and screen parameters are maintained locally. The conversion to device coordinates is also performed locally. The only data sent to the display board are control and device coordinate display commands. The routines available include: rotation translation, and scaling commands; absolute and relative point and line commands; circle, rectangle and polygon commands; and window and viewpoint definition commands.

Ellis, Graham K.↗
NASA NTRS1988

Acceleration levels on board the Space Station and a tethered elevator for micro and variable-gravity applications

This paper investigates the dynamics and acceleration levels of a new tethered system for micro and variable-gravity applications. The system consists of two platforms tethered on opposite sides to the Space Station. A fourth platform, the elevator, is placed in between the Space Station and the upper platform. Variable-g levels on board the elevator are obtained by moving this facility along the upper tether, while micro-g experiments are carried out on board the Space Station. By controlling the length of the lower tether the position of the system CM can be maintained on board the Space Station despite variations of the station's distribution of mass. The paper illustrates the mathematical model, the environmental perturbations and the control techniques which have been adopted for the simulation and control of the system dynamics. Two sets of results from two different simulation runs are shown. The first set shows the system dynamics and the acceleration spectra on board the Space Station and the elevator during station-keeping. The second set of results demonstrates the capability of the elevator to attain a preselected g-level.

Lorenzini, E. C.↗
NASA NTRS1990

Moving Large Wiring-Harness Boards

Carrier for wiring-harness fabrication boards enables lone operator to move board easily and safely. Holds harness while operator fabricating, while being stored, and being transported to equipment frame for mounting. When positioned for assembly of wiring harness, board and carrier give operator easy and convenient access to wires and cables, when positioned for transfer of wiring harness to or from storage area, carrier holds board securely while moved by one person.

Shepherd, Samuel D.↗
NASA NTRS1991

On-board congestion control for satellite packet switching networks

It is desirable to incorporate packet switching capability on-board for future communication satellites. Because of the statistical nature of packet communication, incoming traffic fluctuates and may cause congestion. Thus, it is necessary to incorporate a congestion control mechanism as part of the on-board processing to smooth and regulate the bursty traffic. Although there are extensive studies on congestion control for both baseband and broadband terrestrial networks, these schemes are not feasible for space based switching networks because of the unique characteristics of satellite link. Here, we propose a new congestion control method for on-board satellite packet switching. This scheme takes into consideration the long propagation delay in satellite link and takes advantage of the the satellite's broadcasting capability. It divides the control between the ground terminals and satellite, but distributes the primary responsibility to ground terminals and only requires minimal hardware resource on-board satellite.

Chu, Pong P.↗
NASA NTRS1994

Technology advancements for on-board propulsion systems

On-board propulsion systems are required for all classes of space missions and usually represent a predominant fraction of the mass delivered to space by launch systems. Significant mission cost and performance benefits may, therefore, be gained via use of advanced on-board propulsion and strong international programs are in place to develop new technologies. The NASA Office of Space Access and Technology (OSAT) sponsors a program to identify, develop, and transfer on-board electric and low thrust chemical propulsion systems with potential for major impacts on the performance and competitiveness of U.S. space systems. The paper will briefly describe the overall content of the on-board propulsion program and then highlight some critical technologies with potentials for long term impacts.

Byers, David↗
NASA NTRS1994

Activities of the Space Studies Board

Since its founding as the Space Science Board in 1958, the Space Studies Board has provided independent external scientific and technical advice on the nation's civil space program. This 1991 Annual Report of the SSB and its committees represents the first of its kind. The report contains a summary of the board's meetings, complete texts of letter reports, executive summaries of full reports issued during the year, and congressional testimony. It is intended to serve as a ready reference to board activities and advisory reports in 1991.

Source record↗
NASA NTRS1994

The SAX Italian scientific satellite. The on-board implemented automation as a support to the ground control capability

This paper presents the capabilities implemented in the SAX system for an efficient operations management during its in-flight mission. SAX is an Italian scientific satellite for x-ray astronomy whose major mission objectives impose quite tight constraints on the implementation of both the space and ground segment. The most relevant mission characteristics require an operative lifetime of two years, performing scientific observations both in contact and in noncontact periods, with a low equatorial orbit supported by one ground station, so that only a few minutes of communications are available each orbit. This operational scenario determines the need to have a satellite capable of performing the scheduled mission automatically and reacting autonomously to contingency situations. The implementation approach of the on-board operations management, through which the necessary automation and autonomy are achieved, follows a hierarchical structure. This has been achieved adopting a distributed avionic architecture. Nine different on-board computers, in fact, constitute the on-board data management system. Each of them performs the local control and monitors its own functions while the system level control is performed at a higher level by the data handling applications software. The SAX on-board architecture provides the ground operators with different options of intervention by three classes of telecommands. The management of the scientific operations will be scheduled by the operation control center via dedicated operating plans. The SAX satellite flight mode is presently being integrated at Alenia Spazio premises in Turin for a launch scheduled for the end of 1995. Once in orbit, the SAX satellite will be subject to intensive check-out activities in order to verify the required mission performances. An overview of the envisaged procedure and of the necessary on-ground activities is therefore depicted as well.

Martelli, Andrea↗
NASA NTRS1994

XMM instrument on-board software maintenance concept

While the pre-launch responsibility for the production, validation and maintenance of instrument on-board software traditionally lies with the experimenter, the post-launch maintenance has been the subject of ad hoc arrangements with the responsibility shared to different extent between the experimenter, ESTEC and ESOC. This paper summarizes the overall design and development of the instruments on-board software for the XMM satellite, and describes the concept adopted for the maintenance of such software post-launch. The paper will also outline the on-board software maintenance and validation facilities and the expected advantages to be gained by the proposed strategy. Conclusions with respect to adequacy of this approach will be presented as well as recommendations for future instrument on-board software developments.

Peccia, N.↗