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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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NASA NTRS2003

International Space Station Internal Thermal Control System Lab Module Simulator Build-Up and Validation

As part of the Sustaining Engineering program for the International Space Station (ISS), a ground simulator of the Internal Thermal Control System (ITCS) in the Lab Module was designed and built at the Marshall Space Flight Center (MSFC). To support prediction and troubleshooting, this facility is operationally and functionally similar to the flight system and flight-like components were used when available. Flight software algorithms, implemented using the LabVIEW(Registered Trademark) programming language, were used for monitoring performance and controlling operation. Validation testing of the low temperature loop was completed prior to activation of the Lab module in 2001. Assembly of the moderate temperature loop was completed in 2002 and validated in 2003. The facility has been used to address flight issues with the ITCS, successfully demonstrating the ability to add silver biocide and to adjust the pH of the coolant. Upon validation of the entire facility, it will be capable not only of checking procedures, but also of evaluating payload timelining, operational modifications, physical modifications, and other aspects affecting the thermal control system.

Paul Wieland↗
NASA NTRS2000

Multidisciplinary High-Fidelity Analysis and Optimization of Aerospace Vehicles: Preliminary Results - Part 2

An objective of the High Performance Computing and Communication Program at the NASA Langley Research Center is to demonstrate multidisciplinary shape and sizing optimization of a complete aerospace vehicle configuration by using high-fidelity finite-element structural analysis and computational fluid dynamics aerodynamic analysis in a distributed, heterogeneous computing environment that includes high performance parallel computing. A software system has been designed and implemented to integrate a set of existing discipline analysis codes, some of them computationally intensive, into a distributed computational environment for the design of a high-speed civil transport configuration. The paper describes both the preliminary results from implementing and validating the multidisciplinary analysis and the results from an aerodynamic optimization. The discipline codes are integrated by using the Java programming language and a Common Object Request Broker Architecture compliant software product. A companion paper describes the formulation of the multidisciplinary analysis and optimization system.

Walsh, J. L.↗
NASA NTRS2000

FACET: Future ATM Concepts Evaluation Tool

FACET (Future ATM Concepts Evaluation Tool) is an Air Traffic Management research tool being developed at the NASA Ames Research Center. This paper describes the design, architecture and functionalities of FACET. The purpose of FACET is to provide E simulation environment for exploration, development and evaluation of advanced ATM concepts. Examples of these concepts include new ATM paradigms such as Distributed Air-Ground Traffic Management, airspace redesign and new Decision Support Tools (DSTs) for controllers working within the operational procedures of the existing air traffic control system. FACET is currently capable of modeling system-wide en route airspace operations over the contiguous United States. Airspace models (e.g., Center/sector boundaries, airways, locations of navigation aids and airports) are available from databases. A core capability of FACET is the modeling of aircraft trajectories. Using round-earth kinematic equations, aircraft can be flown along flight plan routes or great circle routes as they climb, cruise and descend according to their individual aircraft-type performance models. Performance parameters (e.g., climb/descent rates and speeds, cruise speeds) are obtained from data table lookups. Heading, airspeed and altitude-rate dynamics are also modeled. Additional functionalities will be added as necessary for specific applications. FACET software is written in Java and C programming languages. It is platform-independent, and can be run on a variety of computers. FACET has been designed with a modular software architecture to enable rapid integration of research prototype implementations of new ATM concepts. There are several advanced ATM concepts that are currently being implemented in FACET airborne separation assurance, dynamic density predictions, airspace redesign (re-sectorization), benefits of a controller DST for direct-routing, and the integration of commercial space transportation system operations into the U.S. National Airspace System (NAS).

Bilmoria, Karl D.↗
NASA NTRS2005

What Sensing Tells Us: Towards a Formal Theory of Testing for Dynamical Systems

Just as actions can have indirect effects on the state of the world, so too can sensing actions have indirect effects on an agent's state of knowledge. In this paper, we investigate "what sensing actions tell us", i.e., what an agent comes to know indirectly from the outcome of a sensing action, given knowledge of its actions and state constraints that hold in the world. To this end, we propose a formalization of the notion of testing within a dialect of the situation calculus that includes knowledge and sensing actions. Realizing this formalization requires addressing the ramification problem for sensing actions. We formalize simple tests as sensing actions. Complex tests are expressed in the logic programming language Golog. We examine what it means to perform a test, and how the outcome of a test affects an agent's state of knowledge. Finally, we propose automated reasoning techniques for test generation and complex-test verification, under certain restrictions. The work presented in this paper is relevant to a number of application domains including diagnostic problem solving, natural language understanding, plan recognition, and active vision.

McIlraith, Sheila↗
NASA NTRS2004

Development of Message Passing Routines for High Performance Parallel Computations

Computational Fluid Dynamics (CFD) calculations require a great deal of computing power for completing the detailed computations involved. In an effort shorten the time it takes to complete such calculations they are implemented on a parallel computer. In the case of a parallel computer some sort of message passing structure must be used to communicate between the computers because, unlike a single machine, each computer in a parallel computing cluster does not have access to all the data or run all the parts of the total program. Thus, message passing is used to divide up the data and send instructions to each machine. The nature of my work this summer involves programming the "message passing" aspect of the parallel computer. I am working on modifying an existing program, which was written with OpenMP, and does not use a multi-machine parallel computing structure, to work with Message Passing Interface (MPI) routines. The actual code is being written in the FORTRAN 90 programming language. My goal is to write a parameterized message passing structure that could be used for a variety of individual applications and implement it on Silicon Graphics Incorporated s (SGI) IRIX operating system. With this new parameterized structure engineers would be able to speed up computations for a wide variety of purposes without having to use larger and more expensive computing equipment from another division or another NASA center.

Summers, Edward K.↗
NASA NTRS2006

User Guide for Compressible Flow Toolbox Version 2.1 for Use With MATLAB(Registered Trademark); Version 7

This report provides a user guide for the Compressible Flow Toolbox, a collection of algorithms that solve almost 300 linear and nonlinear classical compressible flow relations. The algorithms, implemented in the popular MATLAB programming language, are useful for analysis of one-dimensional steady flow with constant entropy, friction, heat transfer, or shock discontinuities. The solutions do not include any gas dissociative effects. The toolbox also contains functions for comparing and validating the equation-solving algorithms against solutions previously published in the open literature. The classical equations solved by the Compressible Flow Toolbox are: isentropic-flow equations, Fanno flow equations (pertaining to flow of an ideal gas in a pipe with friction), Rayleigh flow equations (pertaining to frictionless flow of an ideal gas, with heat transfer, in a pipe of constant cross section.), normal-shock equations, oblique-shock equations, and Prandtl-Meyer expansion equations. At the time this report was published, the Compressible Flow Toolbox was available without cost from the NASA Software Repository.

Melcher, Kevin J.↗
NASA NTRS2003

Real-time Java for flight applications: an update

The RTSJ is a specification for supporting real-time execution in the Java programming language. The specification has been shaped by several guiding principles, particularly: predictable execution as the first priority in all tradeoffs, no syntactic extensions to Java, and backward compatibility.

RTSJ Java↗
NASA NTRS2006

Progress Toward a Format Standard for Flight Dynamics Models

In the beginning, there was FORTRAN, and it was... not so good. But it was universal, and all flight simulator equations of motion were coded with it. Then came ACSL, C, Ada, C++, C#, Java, FORTRAN-90, Matlab/Simulink, and a number of other programming languages. Since the halcyon punch card days of 1968, models of aircraft flight dynamics have proliferated in training devices, desktop engineering and development computers, and control design textbooks. With the rise of industry teaming and increased reliance on simulation for procurement decisions, aircraft and missile simulation models are created, updated, and exchanged with increasing frequency. However, there is no real lingua franca to facilitate the exchange of models from one simulation user to another. The current state-of-the-art is such that several staff-months if not staff-years are required to 'rehost' each release of a flight dynamics model from one simulation environment to another one. If a standard data package or exchange format were to be universally adopted, the cost and time of sharing and updating aerodynamics, control laws, mass and inertia, and other flight dynamic components of the equations of motion of an aircraft or spacecraft simulation could be drastically reduced. A 2002 paper estimated over $ 6 million in savings could be realized for one military aircraft type alone. This paper describes the efforts of the American Institute of Aeronautics and Astronautics (AIAA) to develop a standard flight dynamic model exchange standard based on XML and HDF-5 data formats.

Jackson, E. Bruce↗
NASA NTRS2007

In-Trail Procedure (ITP) Algorithm Design

The primary objective of this document is to provide a detailed description of the In-Trail Procedure (ITP) algorithm, which is part of the Airborne Traffic Situational Awareness In-Trail Procedure (ATSA-ITP) application. To this end, the document presents a high level description of the ITP Algorithm and a prototype implementation of this algorithm in the programming language C.

Munoz, Cesar A.↗
NASA NTRS2004

New Software for Ensemble Creation in the Spitzer-Space-Telescope Operations Database

Some of the computer pipelines used to process digital astronomical images from NASA's Spitzer Space Telescope require multiple input images, in order to generate high-level science and calibration products. The images are grouped into ensembles according to well documented ensemble-creation rules by making explicit associations in the operations Informix database at the Spitzer Science Center (SSC). The advantage of this approach is that a simple database query can retrieve the required ensemble of pipeline input images. New and improved software for ensemble creation has been developed. The new software is much faster than the existing software because it uses pre-compiled database stored-procedures written in Informix SPL (SQL programming language). The new software is also more flexible because the ensemble creation rules are now stored in and read from newly defined database tables. This table-driven approach was implemented so that ensemble rules can be inserted, updated, or deleted without modifying software.

Spitzer Science Center (SSC)↗
NASA NTRS2007

[Interview Questions]

The Goddard Mission Services Evolution Center, or GMSEC, was started in 2001 to create a new standard approach for managing GSFC missions. Standardized approaches in the past involved selecting and then integrating the most appropriate set of functional tools. Assumptions were made that "one size fits all" and that tool changes would not be necessary for many years. GMSEC took a very different approach and has proven to be very successful. The core of the GMSEC architecture consists of a publish/subscribe message bus, standardized message formats, and an Applications Programming Interface (API). The API supports multiple operating systems, programming languages and messaging middleware products. We use a GMSEC-developed free middleware for low-cost development. A high capacity, robust middleware is used for operations and a messaging system with a very small memory footprint is used for on-board flight software. Software components can use the standard message formats or develop adapters to convert from their native formats to the GMSEC formats. We do not want vendors to modify their core products. Over 50 software components are now available for use with the GMSEC architecture. Most available commercial telemetry and command systems, including the GMV hifly Satellite Control System, have been adapted to run in the GMSEC labs.

Smith, Dan↗
NASA NTRS2005

Reusable and Extensible High Level Data Distributions

This paper presents a reusable design of a data distribution framework for data parallel high performance applications. We are implementing the design in the context of the Chapel high productivity programming language. Distributions in Chapel are a means to express locality in systems composed of large numbers of processor and memory components connected by a network. Since distributions have a great effect on,the performance of applications, it is important that the distribution strategy can be chosen by a user. At the same time, high productivity concerns require that the user is shielded from error-prone, tedious details such as communication and synchronization. We propose an approach to distributions that enables the user to refine a language-provided distribution type and adjust it to optimize the performance of the application. Additionally, we conceal from the user low-level communication and synchronization details to increase productivity. To emphasize the generality of our distribution machinery, we present its abstract design in the form of a design pattern, which is independent of a concrete implementation. To illustrate the applicability of our distribution framework design, we outline the implementation of data distributions in terms of the Chapel language.

patterns↗
NASA NTRS2008

On Certain New Methodology for Reducing Sensor and Readout Electronics Circuitry Noise in Digital Domain

NASA Hubble Space Telescope (HST) and upcoming cosmology science missions carry instruments with multiple focal planes populated with many large sensor detector arrays. These sensors are passively cooled to low temperatures for low-level light (L3) and near-infrared (NIR) signal detection, and the sensor readout electronics circuitry must perform at extremely low noise levels to enable new required science measurements. Because we are at the technological edge of enhanced performance for sensors and readout electronics circuitry, as determined by thermal noise level at given temperature in analog domain, we must find new ways of further compensating for the noise in the signal digital domain. To facilitate this new approach, state-of-the-art sensors are augmented at their array hardware boundaries by non-illuminated reference pixels, which can be used to reduce noise attributed to sensors. There are a few proposed methodologies of processing in the digital domain the information carried by reference pixels, as employed by the Hubble Space Telescope and the James Webb Space Telescope Projects. These methods involve using spatial and temporal statistical parameters derived from boundary reference pixel information to enhance the active (non-reference) pixel signals. To make a step beyond this heritage methodology, we apply the NASA-developed technology known as the Hilbert- Huang Transform Data Processing System (HHT-DPS) for reference pixel information processing and its utilization in reconfigurable hardware on-board a spaceflight instrument or post-processing on the ground. The methodology examines signal processing for a 2-D domain, in which high-variance components of the thermal noise are carried by both active and reference pixels, similar to that in processing of low-voltage differential signals and subtraction of a single analog reference pixel from all active pixels on the sensor. Heritage methods using the aforementioned statistical parameters in the digital domain (such as statistical averaging of the reference pixels themselves) zeroes out the high-variance components, and the counterpart components in the active pixels remain uncorrected. This paper describes how the new methodology was demonstrated through analysis of fast-varying noise components using the Hilbert-Huang Transform Data Processing System tool (HHT-DPS) developed at NASA and the high-level programming language MATLAB (Trademark of MathWorks Inc.), as well as alternative methods for correcting for the high-variance noise component, using an HgCdTe sensor data. The NASA Hubble Space Telescope data post-processing, as well as future deep-space cosmology projects on-board instrument data processing from all the sensor channels, would benefit from this effort.

Kizhner, Semion↗
NASA NTRS2008

Virtual Satellite

Virtual Satellite (VirtualSat) is a computer program that creates an environment that facilitates the development, verification, and validation of flight software for a single spacecraft or for multiple spacecraft flying in formation. In this environment, enhanced functionality and autonomy of navigation, guidance, and control systems of a spacecraft are provided by a virtual satellite that is, a computational model that simulates the dynamic behavior of the spacecraft. Within this environment, it is possible to execute any associated software, the development of which could benefit from knowledge of, and possible interaction (typically, exchange of data) with, the virtual satellite. Examples of associated software include programs for simulating spacecraft power and thermal- management systems. This environment is independent of the flight hardware that will eventually host the flight software, making it possible to develop the software simultaneously with, or even before, the hardware is delivered. Optionally, by use of interfaces included in VirtualSat, hardware can be used instead of simulated. The flight software, coded in the C or C++ programming language, is compilable and loadable into VirtualSat without any special modifications. Thus, VirtualSat can serve as a relatively inexpensive software test-bed for development test, integration, and post-launch maintenance of spacecraft flight software.

Hammrs, Stephan R.↗
NASA NTRS2008

Simulating Avionics Upgrades to the Space Shuttles

Cockpit Avionics Prototyping Environment (CAPE) is a computer program that simulates the functions of proposed upgraded avionics for a space shuttle. In CAPE, pre-existing space-shuttle-simulation programs are merged with a commercial-off-the-shelf (COTS) display-development program, yielding a package of software that enables high-fi46 NASA Tech Briefs, September 2008 delity simulation while making it possible to rapidly change avionic displays and the underlying model algorithms. The pre-existing simulation programs are Shuttle Engineering Simulation, Shuttle Engineering Simulation II, Interactive Control and Docking Simulation, and Shuttle Mission Simulator playback. The COTS program Virtual Application Prototyping System (VAPS) not only enables the development of displays but also makes it possible to move data about, capture and process events, and connect to a simulation. VAPS also enables the user to write code in the C or C++ programming language and compile that code into the end-product simulation software. As many as ten different avionic-upgrade ideas can be incorporated in a single compilation and, thus, tested in a single simulation run. CAPE can be run in conjunction with any or all of four simulations, each representing a different phase of a space-shuttle flight.

Deger, Daniel↗
NASA NTRS2009

Geospatial Authentication

A software package that has been designed to allow authentication for determining if the rover(s) is/are within a set of boundaries or a specific area to access critical geospatial information by using GPS signal structures as a means to authenticate mobile devices into a network wirelessly and in real-time has been developed. The advantage lies in that the system only allows those with designated geospatial boundaries or areas into the server. The Geospatial Authentication software has two parts Server and Client. The server software is a virtual private network (VPN) developed in Linux operating system using Perl programming language. The server can be a stand-alone VPN server or can be combined with other applications and services. The client software is a GUI Windows CE software, or Mobile Graphical Software, that allows users to authenticate into a network. The purpose of the client software is to pass the needed satellite information to the server for authentication.

Lyle, Stacey D.↗
NASA NTRS2007

Cross-Compiler for Modeling Space-Flight Systems

Ripples is a computer program that makes it possible to specify arbitrarily complex space-flight systems in an easy-to-learn, high-level programming language and to have the specification automatically translated into LibSim, which is a text-based computing language in which such simulations are implemented. LibSim is a very powerful simulation language, but learning it takes considerable time, and it requires that models of systems and their components be described at a very low level of abstraction. To construct a model in LibSim, it is necessary to go through a time-consuming process that includes modeling each subsystem, including defining its fault-injection states, input and output conditions, and the topology of its connections to other subsystems. Ripples makes it possible to describe the same models at a much higher level of abstraction, thereby enabling the user to build models faster and with fewer errors. Ripples can be executed in a variety of computers and operating systems, and can be supplied in either source code or binary form. It must be run in conjunction with a Lisp compiler.

James, Mark↗