SEPAC software configuration control plan and procedures, revision 1
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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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Control system software, simulation, and robotic applications
All essential existing capabilities needed to create a man-machine interaction dynamics and performance (MMIDAP) capability are reviewed. The multibody system dynamics software program Order N DISCOS will be used for machine and musculo-skeletal dynamics modeling. The program JACK will be used for estimating and animating whole body human response to given loading situations and motion constraints. The basic elements of performance (BEP) task decomposition methodologies associated with the Human Performance Institute database will be used for performance assessment. Techniques for resolving the statically indeterminant muscular load sharing problem will be used for a detailed understanding of potential musculotendon or ligamentous fatigue, pain, discomfort, and trauma. The envisioned capacity is to be used for mechanical system design, human performance assessment, extrapolation of man/machine interaction test data, biomedical engineering, and soft prototyping within a concurrent engineering (CE) system.
Frisch, Harold P.↗
Alaska SAR processor implementation of E-ERS-1
The synthetic aperture radar (SAR) data processing algorithm used by the Alaska SAR Facility (ASF) for the European Space Agency's first Remote-Sensing Satellite (E-ERS-1) SAR data are examined. Preprocessing highlights two features: signal measurement, which includes signal-to-noise ratio, replica measurement, and noise measurement; and Doppler measurement, which includes clutter lock and autofocus. The custom pipeline architecture performs the main processing with controls at the input interface, range correlator, corner-turn memory, azimuth correlator, and multi-look memory. The control software employs a flexible control scheme. The Committee on Earth Observation Satellites (CEOS) format encapsulates the ASF products. System performance for SAR image processing of E-ERS-1 data is reviewed.
Cuddy, David↗
Experimental control in software reliability certification
There is growing interest in software 'certification', i.e., confirmation that software has performed satisfactorily under a defined certification protocol. Regulatory agencies, customers, and prospective reusers all want assurance that a defined product standard has been met. In other industries, products are typically certified under protocols in which random samples of the product are drawn, tests characteristic of operational use are applied, analytical or statistical inferences are made, and products meeting a standard are 'certified' as fit for use. A warranty statement is often issued upon satisfactory completion of a certification protocol. This paper outlines specific engineering practices that must be used to preserve the validity of the statistical certification testing protocol. The assumptions associated with a statistical experiment are given, and their implications for statistical testing of software are described.
Trammell, Carmen J.↗
Attitude Control System Design for the Solar Dynamics Observatory
The Solar Dynamics Observatory mission, part of the Living With a Star program, will place a geosynchronous satellite in orbit to observe the Sun and relay data to a dedicated ground station at all times. SDO remains Sun- pointing throughout most of its mission for the instruments to take measurements of the Sun. The SDO attitude control system is a single-fault tolerant design. Its fully redundant attitude sensor complement includes 16 coarse Sun sensors, a digital Sun sensor, 3 two-axis inertial reference units, 2 star trackers, and 4 guide telescopes. Attitude actuation is performed using 4 reaction wheels and 8 thrusters, and a single main engine nominally provides velocity-change thrust. The attitude control software has five nominal control modes-3 wheel-based modes and 2 thruster-based modes. A wheel-based Safehold running in the attitude control electronics box improves the robustness of the system as a whole. All six modes are designed on the same basic proportional-integral-derivative attitude error structure, with more robust modes setting their integral gains to zero. The paper details the mode designs and their uses.
Starin, Scott R.↗
IV and V Issues in Achieving High Reliability and Safety in Critical Control System Software
Risk analysis and integrated verification and validation are two important elements in a plan for ensuring the safety of critical software systems. We describe an approach we are currently developing for integrating risk analysis, and metrics analysis, and propose a fault predictor that would integrate the results of these activities. Practical difficulties associated with our approach are also discussed, as are limitations of the proposed predictor. We conclude with a discussion of what as been learned to date, and with suggestions for future work.
validation software reliability software risk asse↗
In-Flight Loading of the Galileo Spacecraft's Attitude and Articulation Control Subsystem Software
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Galileo spacecraft Jupiter-bound dual-spin configu↗
Spaceport Command and Control System Software Development
During the course of this internship, software was developed to ensure the efficient management and allocation of an employee to an area of their expertise or experience that may otherwise have gone unnoticed. This directly affects any future missions prescribed to the SLS by allowing management to easily see where employees can be re-allocated to different mission specific projects or assist a project that may be lacking in a specific field. This software is intended to provide proof of NASA's diligence and deliberation in hiring new employees and in providing training and guidance to employees who may have fallen short of expectations. Allowing management to more easily statistically track and monitor the supply and demand of employees with specific experience will help introduce a beneficial culture where employees are given the ability to grow and hone skills which might otherwise atrophy over time. With this new system in place, NASA can prove the employees they hire and already have are exemplary and will remain exemplary to serve the nation as a whole.
Kessluk, Jonathan↗
Spaceport Command and Control System Software Development
There is an immense challenge in organizing personnel across a large agency such as NASA, or even over a subset of that, like a center's Engineering directorate. Workforce inefficiencies and challenges are bound to grow over time without oversight and management. It is also not always possible to hire new employees to fill workforce gaps, therefore available resources must be utilized more efficiently. The goal of this internship was to develop software that improves organizational efficiency by aiding managers, making employee information viewable and editable in an intuitive manner. This semester I created an application for managers that aids in optimizing allocation of employee resources for a single division with the possibility of scaling upwards. My duties this semester consisted of developing frontend and backend software to complete this task. The application provides user-friendly information displays and documentation of the workforce to allow NASA to track diligently track the status and skills of its workforce. This tool should be able to prove that current employees are being effectively utilized and if new hires are necessary to fulfill skill gaps.
SCCS↗
Command and Control System Software Development
Kennedy Space Center has been the heart of human space flight for decades. From the Apollo Program to the Space Shuttle Program, and now to the coming Space Launch System (SLS) and Orion, NASA will be a leader in deep space exploration for mankind. Before any rockets blast off, there is significant work to be done in preparation for launch. People working on all aspects of spaceflight must contribute by developing new technology that has yet to participate in a successful launch, and which can work with technology already proven in flight. These innovations, whether hardware or software, must be tried and true, and includes the projects to which interns contribute to. For this internship, the objective was to create a data recording system for the developers of a LCS section that records certain messages in the traffic of the system. Developers would then be able to use these recordings for analysis later on, either manually or by an automated test. The tool would be of convenience to a developer as it would be used if the system's main data recorder was not available for tests.
Velasquez, Ricky↗
The Effects of Propellant Slosh Dynamics on the Solar Dynamics Observatory
The Solar Dynamics Observatory (SDO) mission, which is part of the Living With a Star program, was successfully launched and deployed from its Atlas V launch vehicle on February 11, 2010. SDO is an Explorer-class mission now operating in a geosynchronous orbit (GEO). The basic mission is to observe the Sun for a very high percentage of the 5-year mission (10-year goal) with long stretches of uninterrupted observations and with constant, high-data-rate transmission to a dedicated ground station located in White Sands, New Mexico. A significant portion of SDO's launch mass was propellant, contained in two large tanks. To ensure performance with this level of propellant, a slosh analysis was performed. This paper provides an overview of the SDO slosh analysis, the on-orbit experience, and the lessons learned. SDO is a three-axis controlled, single fault tolerant spacecraft. The attitude sensor complement includes sixteen coarse Sun sensors, a digital Sun sensor, three two-axis inertial reference units, two star trackers, and four guide telescopes. Attitude actuation is performed either using four reaction wheels or eight thrusters, depending on the control mode, along with single main engine which nominally provides velocity-change thrust. The attitude control software has five nominal control modes: three wheel-based modes and two thruster-based modes. A wheel-based Safehold running in the Attitude Control Electronics (ACE) box improves the robustness of the system as a whole. All six modes are designed on the same basic proportional-integral-derivative attitude error structure, with more robust modes setting their integral gains to zero. To achieve and maintain a geosynchronous orbit for a 2974-kilogram spacecraft in a cost effective manner, the SDO team designed a high-efficiency propulsive system. This bi-propellant design includes a 100-pound-force main engine and eight 5-pound-force attitude control thrusters. The main engine provides high specific impulse for the maneuvers to attain GEO, while the smaller Attitude Control System (ACS) thrusters manage the disturbance torques of the larger main engine and provide the capability for much smaller orbit adjustment burns. SDO's large solar profile produces a large solar torque disturbance and momentum buildup. This buildup drives the frequency of momentum unloads via ACS thrusters. SDO requires 1409 kilograms (which is approximately half the launch mass) of propellant to achieve and maintain the GEO orbit while performing the momentum unloads for 10 years.
Mason, Paul↗
Pilot Evaluation of Model Based Design Tooling for Guidance, Navigation, and Control Flight Software Development
No abstract available
Jamison, Brian R.↗
Verification and Validation Challenges for Adaptive Flight Control of Complex Autonomous Systems
Autonomy of aerospace systems requires the ability for flight control systems to be able to adapt to complex uncertain dynamic environment. In spite of the five decades of research in adaptive control, the fact still remains that currently no adaptive control system has ever been deployed on any safety-critical or human-rated production systems such as passenger transport aircraft. The problem lies in the difficulty with the certification of adaptive control systems since existing certification methods cannot readily be used for nonlinear adaptive control systems. Research to address the notion of metrics for adaptive control began to appear in the recent years. These metrics, if accepted, could pave a path towards certification that would potentially lead to the adoption of adaptive control as a future control technology for safety-critical and human-rated production systems. Development of certifiable adaptive control systems represents a major challenge to overcome. Adaptive control systems with learning algorithms will never become part of the future unless it can be proven that they are highly safe and reliable. Rigorous methods for adaptive control software verification and validation must therefore be developed to ensure that adaptive control system software failures will not occur, to verify that the adaptive control system functions as required, to eliminate unintended functionality, and to demonstrate that certification requirements imposed by regulatory bodies such as the Federal Aviation Administration (FAA) can be satisfied. This presentation will discuss some of the technical issues with adaptive flight control and related V&V challenges.
Nguyen, Nhan T.↗
Node-red Software Architecture For Soec System Control
The software workflows that have been developed are open-source and therefore can be accessed and utilized by researchers and students all around the world for free of cost. The software is flexible and easily modifiable to suit the needs for testing bench-scale to system-level setups, and is not limited to just hydrogen generation facilities. The web-interface of the code allows for easy remote access and management, which is especially useful for distributed systems. This is more challenging with traditional PLCs, which often require direct connections or specialized software, making remote troubleshooting more cumbersome. Additionally, since the underlying interface is open-source, with an active community contributing to its development, regular updates, new features, and a wealth of community support and shared solutions will keep improving the overall architecture without excessive fees for upgrades.
Shigrekar, Amey [Idaho National Laboratory (INL), ↗
Software for System for Controlling a Magnetically Levitated Rotor
In a rotor assembly having a rotor supported for rotation by magnetic bearings, a processor controlled by software or firmware controls the generation of force vectors that position the rotor relative to its bearings in a 'bounce' mode in which the rotor axis is displaced from the principal axis defined between the bearings and a 'tilt' mode in which the rotor axis is tilted or inclined relative to the principal axis. Waveform driven perturbations are introduced to generate force vectors that excite the rotor in either the 'bounce' or 'tilt' modes.
Carlos R Morrison↗
Flight software development for the isothermal dendritic growth experiment
The Isothermal Dendritic Growth Experiment (IDGE) is a microgravity materials science experiment scheduled to fly in the cargo bay of the shuttle on the United States Microgravity Payload (USMP) carrier. The experiment will be operated by real-time control software which will not only monitor and control onboard experiment hardware, but will also communicate, via downlink data and uplink commands, with the Payload Operations Control Center (POCC) at NASA George C. Marshall Space Flight Center (MSFC). The software development approach being used to implement this system began with software functional requirements specification. This was accomplished using the Yourdon/DeMarco methodology as supplemented by the Ward/Mellor real-time extensions. The requirements specification in combination with software prototyping was then used to generate a detailed design consisting of structure charts, module prologues, and Program Design Language (PDL) specifications. This detailed design will next be used to code the software, followed finally by testing against the functional requirements. The result will be a modular real-time control software system with traceability through every phase of the development process.
Levinson, Laurie H.↗
Flight software development for the isothermal dendritic growth experiment
The Isothermal Dendritic Growth Experiment (IDGE) is a microgravity materials science experiment scheduled to fly in the cargo bay of the shuttle on the United States Microgravity Payload (USMP) carrier. The experiment will be operated by real-time control software which will not only monitor and control onboard experiment hardware, but will also communicate, via downlink data and unlink commands, with the Payload Operations Control Center (POCC) at NASA George C. Marshall Space Flight Center (MSFC). The software development approach being used to implement this system began with software functional requirements specification. This was accomplished using the Yourdon/DeMarco methodology as supplemented by the Ward/Mellor real-time extensions. The requirements specification in combination with software prototyping was then used to generate a detailed design consisting of structure charts, module prologues, and Program Design Language (PDL) specifications. This detailed design will next be used to code the software, followed finally by testing against the functional requirements. The result will be a modular real-time control software system with traceability through every phase of the development process.
Levinson, Laurie H.↗
Virtual Infrastructure Twins: Software Testing Platforms for Computing-Instrument Ecosystems
Science ecosystems are being built by federating computing systems and instruments located at geographically distributed sites over wide-area networks. These computing-instrument ecosystems are expected to support complex workflows that incorporate remote, automated AI-driven science experiments. Their realization, however, requires various designs to be explored and software components to be developed, in order to support the orchestration of distributed computations and experiments. It is often too expensive, infeasible, or disruptive for the entire ecosystem to be available during the typically long software development and testing periods. We propose a Virtual Infrastructure Twin (VIT) of the ecosystem that emulates its network and computing components, and incorporates its instrument software simulators. It provides a software environment nearly identical to the ecosystem to support early development and testing, and design space exploration. We present a brief overview of previous digital infrastructure twins that culminated in the VIT concept, including (i) the virtual science network environment for developing software-defined networking solutions, and (ii) the virtual federated science instrument environment for testing the federation software stack and remote instrument control software. We briefly describe VITs for Nion microscope steering and access to GPU systems.
Rao, Nageswara↗