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At least 1,495 records · Page 83

Update: Advancement of Contact Dynamics Modeling for Human Spaceflight Simulation Applications

Pong is a new software tool developed at the NASA Johnson Space Center that advances interference-based geometric contact dynamics based on 3D graphics models. The Pong software consists of three parts: a set of scripts to extract geometric data from 3D graphics models, a contact dynamics engine that provides collision detection and force calculations based on the extracted geometric data, and a set of scripts for visualizing the dynamics response with the 3D graphics models. The contact dynamics engine can be linked with an external multibody dynamics engine to provide an integrated multibody contact dynamics simulation. This paper provides a detailed overview of Pong including the overall approach and modeling capabilities, which encompasses force generation from contact primitives and friction to computational performance. Two specific Pong-based examples of International Space Station applications are discussed, and the related verification and validation using this new tool are also addressed.

Contact dynamics↗

Evolving the Reuse Process at the Flight Dynamics Division (FDD) Goddard Space Flight Center

This paper presents the interim results from the Software Engineering Laboratory's (SEL) Reuse Study. The team conducting this study has, over the past few months, been studying the Generalized Support Software (GSS) domain asset library and architecture, and the various processes associated with it. In particular, we have characterized the process used to configure GSS-based attitude ground support systems (AGSS) to support satellite missions at NASA's Goddard Space Flight Center. To do this, we built detailed models of the tasks involved, the people who perform these tasks, and the interdependencies and information flows among these people. These models were based on information gleaned from numerous interviews with people involved in this process at various levels. We also analyzed effort data in order to determine the cost savings in moving from actual development of AGSSs to support each mission (which was necessary before GSS was available) to configuring AGSS software from the domain asset library. While characterizing the GSS process, we became aware of several interesting factors which affect the successful continued use of GSS. Many of these issues fall under the subject of evolving technologies, which were not available at the inception of GSS, but are now. Some of these technologies could be incorporated into the GSS process, thus making the whole asset library more usable. Other technologies are being considered as an alternative to the GSS process altogether. In this paper, we outline some of issues we will be considering in our continued study of GSS and the impact of evolving technologies.

Condon, S.↗

A dynamic integrated test for the Space Shuttle

The dynamic integrated test (DIT) has been designed to perform a final checkout of the assembled Space Shuttle vehicle at Kennedy Space Center. The fact that the vehicle is not in a laboratory environment for the test represents a significant constraint in that the use of test equipment is extremely limited, and environment models cannot be used. In essence, the DIT causes the vehicle to believe that it is flying, so that hardware and software systems are exercised much as they would be for a real flight. This technique provides a tool for verifying such items as data bus activity patterns, critical timing sequences, software and hardware moding as a function of flight parameters, absence of EMI problems and other systems interactions which cannot be tested fully in the laboratory.

Brody, S.↗

An Overview of the Guided Parafoil System Derived from X-38 Experience

The NASA Johnson Space Center built a 4200 sq ft parafoil for the U.S. Army Natick Soldier Center to demonstrate autonomous flight using a guided parafoil system to deliver 10,000 lbs of useable payload. The parafoil's design was based upon that developed during the X-38 program. The drop test payload consisted of a standard 20-foot Type V airdrop platform, a standard 12-foot weight tub, a 60 ft drogue parachute, a 4200 ft2 parafoil, an instrumentation system, and a Guidance, Navigation, and Control (GN&C) system. Instrumentation installed on the load was used to gather data to validate simulation models and preflight loads predictions and to perform post flight trajectory and performance reconstructions. The GN&C system, developed during NASA's X-38 program, consisted of a flight computer, modems for uplink commands and downlink data, a compass, laser altimeter, and two winches. The winches were used to steer the parafoil and to perform the dynamic flare maneuver for a soft landing. The laser was used to initiate the flare. The GN&C software was originally provided to NASA by the European Space Agency. NASA incorporated further software refinements based upon the X-38 flight test results. Three full-scale drop tests were conducted, with the third being performed during the Precision Airdrop Technology Conference and Demonstration (PATCAD) Conference at the U.S. Army Yuma Proving Ground (YPG) in November of 2003. For the PATCAD demonstration, the parafoil and GN&C software and hardware performed well, concluding with a good flare and the smallest miss distance ever experienced in NASA's parafoil drop test program. This paper describes the 4200 sq ft parafoil system, simulation results, and the results of the drop tests.

Stein, Jenny M.↗

Mission design for flight safety.

Manned space flight safety through mission trajectory design, considering hardware, software and operational constraints

MANNED SPACE FLIGHT↗

Characterizing and Modeling the Cost of Rework in a Library of Reusable Software Components

In this paper we characterize and model the cost of rework in a Component Factory (CF) organization. A CF is responsible for developing and packaging reusable software components. Data was collected on corrective maintenance activities for the Generalized Support Software reuse asset library located at the Flight Dynamics Division of NASA's GSFC. We then constructed a predictive model of the cost of rework using the C4.5 system for generating a logical classification model. The predictor variables for the model are measures of internal software product attributes. The model demonstrates good prediction accuracy, and can be used by managers to allocate resources for corrective maintenance activities. Furthermore, we used the model to generate proscriptive coding guidelines to improve programming, practices so that the cost of rework can be reduced in the future. The general approach we have used is applicable to other environments.

Basili, Victor R.↗

Power, Avionics and Software - Phase 1.0:

This report describes Power, Avionics and Software (PAS) 1.0 subsystem integration testing and test results that occurred in August and September of 2013. This report covers the capabilities of each PAS assembly to meet integration test objectives for non-safety critical, non-flight, non-human-rated hardware and software development. This test report is the outcome of the first integration of the PAS subsystem and is meant to provide data for subsequent designs, development and testing of the future PAS subsystems. The two main objectives were to assess the ability of the PAS assemblies to exchange messages and to perform audio testing of both inbound and outbound channels. This report describes each test performed, defines the test, the data, and provides conclusions and recommendations.

Communiocations↗

Software Approach for the Regenerative Fuel Cell Project

The Regenerative Fuel Cell (RFC) project is developing a system that combines a fuel cell subsystem for energy production with an electrolysis subsystem for energy storage. The system is primarily being developed at the Glenn Research Center with support from Johnson Space Center under the Space Technology Mission Directorate / Game Changing Development Program. Currently, the intent is to operate the RFC system in an equivalent environment to a lunar equator location for a period of several lunar day/night cycles with minimal operator input. Demonstrating an automated RFC system in this environment is a step towards showing the extensibility to a flight system. This paper describes the RFC software team’s approach for development of the monitoring and control software that allows for the automated operation of the RFC system. We describe the rationale for the choice of Core Flight System architecture, as well as the plan for software/hardware integration.

Mathew J Mccaskey↗

NASA Technology Demonstrations Missions Program Overview

The National Aeronautics and Space Administration (NASA) Fiscal Year 2010 (FY10) budget introduced a new strategic plan that placed renewed emphasis on advanced missions beyond Earth orbit. This supports NASA s 2011 strategic goal to create innovative new space technologies for our exploration, science, and economic future. As a result of this focus on undertaking many and more complex missions, NASA placed its attention on a greater investment in technology development, and this shift resulted in the establishment of the Technology Demonstrations Missions (TDM) Program. The TDM Program, within the newly formed NASA Office of the Chief Technologist, supports NASA s grand challenges by providing a steady cadence of advanced space technology demonstrations (Figure 1), allowing the infusion of flexible path capabilities for future exploration. The TDM Program's goal is to mature crosscutting capabilities to flight readiness in support of multiple future space missions, including flight test projects where demonstration is needed before the capability can transition to direct mission The TDM Program has several unique criteria that set it apart from other NASA program offices. For instance, the TDM Office matures a small number of technologies that are of benefit to multiple customers to flight technology readiness level (TRL) 6 through relevant environment testing on a 3-year development schedule. These technologies must be crosscutting, which is defined as technology with potential to benefit multiple mission directorates, other government agencies, or the aerospace industry, and they must capture significant public interest and awareness. These projects will rely heavily on industry partner collaboration, and funding is capped for all elements of the flight test demonstration including planning, hardware development, software development, launch costs, ground operations, and post-test assessments. In order to inspire collaboration across government and industry, more than 70% of the TDM funds will be competitively awarded as a result of yearly calls for proposed flight demonstrators and selected based on possible payoff to NASA, technology maturity, customer interest, cost, and technical risk reduction. This paper will give an overview of the TDM Program s mission and organization, as well as its current status in delivering advanced space technologies that will enable more flexible and robust future missions. It also will provide several examples of missions that fit within these parameters and expected outcomes.

Turner, Susan↗

ACTE Wing Loads Analysis

The Adaptive Compliant Trailing Edge (ACTE) project modified a Gulfstream III (GIII) aircraft with a new flexible flap that creates a seamless transition between the flap and the wing. As with any new modification, it is crucial to ensure that the aircraft will not become overstressed in flight. To test this, Star CCM a computational fluid dynamics (CFD) software program was used to calculate aerodynamic data for the aircraft at given flight conditions.

CFD↗

COSMIC DAWN: Distributed Analysis of Wireless at Nextscale

Distributed Analysis of Wireless at Nextscale (DAWN) is a novel simulation framework for large-scale design-space exploration (DSE) of unmodified software-defined radio (SDR) applications interacting in a scalable, high-fidelity, virtual physics environment. The software-defined nature of the coupled software-physics simulation leverages hardware emulation to permit in-depth examination and modification of not only the electromagnetic environment, including each signal in flight, but also the precise state of system software and components. DAWN supports modular, customizable physics environments allowing realistic propagation effects so that computationally efficient empirical models, reduced order/surrogate models, or large-scale, high-fidelity, site-specific simulations can be used as a propagation medium based on scenario requirements. This paper introduces DAWN’s design and initial implementation, detailing key architectural components, including the Physics Realization Engine (PhyRE), Runtime Infrastructure for Simulation Environments (RISE), and the design space exploration (DSE) suite. It concludes with demonstrations using unmodified 4G/LTE software available from srsRAN on computing resources ranging from a small cluster to ORNL’s Frontier Exascale system.

Wise, Mike [ORNL] (ORCID:0000000266120641)↗

Space Shuttle - The new baseline

Recent design alterations and refinements in the Space Shuttle program are considered with particular attention to the present baseline Shuttle configurations, performance characteristics, mission profiles, and flight and ground operations. Hardware and software development and testing, propulsion systems, entry trajectory events, and payload capability are covered. The refined Space Shuttle system design is characterized as one reflecting firm technical and economic considerations. Systems development is well under way, with all major contractors progressing on schedule.

Malkin, M. S.↗

Combinations of 148 navigation stars and the star tracker

The angular separation of all star combinations for 148 nav star on the onboard software for space transportation system-3 flight and following missions is presented as well as the separation of each pair that satisfies the viewing constraints of using both star trackers simultaneously. Tables show (1) shuttle star catalog 1980 star position in M 1950 coordinates; (2) two star combination of 148 nav stars; and (3) summary of two star-combinations of the star tracker 5 deg filter. These 148 stars present 10,875 combinations. For the star tracker filters of plus or minus 5 deg, there are 875 combinations. Formalhaut (nav star 26) has the best number of combinations, which is 33.

Duncan, R.↗

The Build System - Integration and management of large software avionic systems

The Build System comprises the software tools and procedures creating the flight memory load for the Space Shuttle Backup Flight System. The system has six functions: (1) configuration management, which insures that the memory load contains the proper modules, all clearly marked; (2) source translation, which translates the source code into a relocatable machine code; (3) module integration, which combines and assigns memory locations to all the object modules produced in source translation; (4) static code analysis, which verifies the integration process; (5) deliverables generation, which yields release documentation and deliverable items; and (6) release maintenance, which controls all system patches subsequent to release. Further developments will include more automation in the producing of patches from source-code updates and system requirements for tracking.

Mayer, J. T. B.↗

Software-Engineering Data-Base System

Software Engineering Laboratory Data Base Maintenance System (SEL/DBAM) collects and maintains data base for evaluating software-development methodologies. SEL/DBAM provides interactive facilities for management of data collected by Software Engineering Laboratory at Goddard Space Flight Center.

Card, D. N.↗

Development and Evaluation of a Performance Modeling Flight Test Approach Based on Quasi Steady-State Maneuvers

The development, implementation and flight test evaluation of a performance modeling technique which required a limited amount of quasisteady state flight test data to predict the overall one g performance characteristics of an aircraft. The concept definition phase of the program include development of: (1) the relationship for defining aerodynamic characteristics from quasi steady state maneuvers; (2) a simplified in flight thrust and airflow prediction technique; (3) a flight test maneuvering sequence which efficiently provided definition of baseline aerodynamic and engine characteristics including power effects on lift and drag; and (4) the algorithms necessary for cruise and flight trajectory predictions. Implementation of the concept include design of the overall flight test data flow, definition of instrumentation system and ground test requirements, development and verification of all applicable software and consolidation of the overall requirements in a flight test plan.

Yechout, T. R.↗

NASA's approach to flight confidence

NASA's confidence in the flight readiness of aerospace hardware and software is achieved by a thorough integration of safety activities into every program facet, from concept through the mission. This involves technical and administrative personnel, organizations that specify requirements, design, manufacturing, test and the operators. Reviews by inhouse and external specialists form an integral part of the assurance process. Examples of safety issues and their resolution for some power and propulsion functions are given (lithium cells, autoignition/fretting in high pressure oxygen environments, ignition sources from auxiliary power unit, and low thrust rocket engines). Finally, some comments on NASA's integrated safety activities and the Aerospace Safety Advisory Panel's role in the NASA review and assessment process all of which provides added confidence in achieving a high level of mission safety and success.

Roth, G. L.↗

Data collection and evaluation for experimental computer science research

The Software Engineering Laboratory was monitoring software development at NASA Goddard Space Flight Center since 1976. The data collection activities of the Laboratory and some of the difficulties of obtaining reliable data are described. In addition, the application of this data collection process to a current prototyping experiment is reviewed.

Zelkowitz, Marvin V.↗