Software

Method for Authorizing Critical Effector Commands in a Space-Based Integrated Modular Avionics System

Lyndon B. Johnson Space Center, Houston, Texas An Integrated Modular Avionics (IMA) architecture provides a common platform for software partitions with shared processing and input/output (I/O) resources. A key feature of the IMA architecture is I/O partitioning. An IMA system will prevent one software partition from changing an I/O resource that is owned by another software partition. This prevents one software partition from controlling the outputs of another due to hardware fault or software error. The IMA system must have protection mechanisms in place to enforce the I/O partitioning.

Posted in: Electronics & Computers, Software, Briefs

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Fully Configurable Interrupt Controller

The controller is used in a method for authorizing critical effector commands in a space-based integrated modular avionics system. Lyndon B. Johnson Space Center, Houston, Texas An interrupt is a signal in an interrupt controller (IC) that pulses to indicate an event or error. The IC is responsible for processing multiple internal interrupts and making these interrupts available to a host computer via a data bus or external output pins. Since there exist numerous interrupts, a method must be developed for routing the interrupts to the external output pins.

Posted in: Electronics & Computers, Software, Briefs

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Using a Multicast File Transfer Protocol to Update the Firmware of Multiple Embedded Devices Simultaneously

This method minimizes the amount of time and network bandwidth required to update the firmware in all smart sensor devices. John F. Kennedy Space Center, Florida Smart sensors for measuring temperature and pressure have been developed as part of the Advanced Ground Systems Maintenance (AGSM) project. The sensors have flash memory for storing firmware, calibration data, and configuration information. In anticipation of the sensors being installed at multiple locations (possibly numbering in the hundreds) around the Kennedy Space Center, a method was devised to update the firmware of many sensors quickly and easily.

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Model of Radiation Effects on Electronics (MREE)

Marshall Space Flight Center, Alabama An updated software model has been developed for predicting the single-event effect (SEE) rates in circuit designs as they are being designed. This tool will be used for estimating the frequency of the various SEEs, such as logic upsets and circuit latch-up. It may also be used to estimate the total radiation dose effects to microelectronic devices operated in the natural space radiation environment or in ionizing radiation test environments.

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Development of an Analytical Parameterized Linear Lateral Dynamic Model for an Aerobot Airship

The method relies on the use of aircraft stability derivative methods with the basic geometric and aerodynamic properties of the airship. NASA’s Jet Propulsion Laboratory, Pasadena, California Saturn’s moon Titan is of high interest for in situ study due to its many intriguing features. This moon has a dense atmosphere; rough, icy terrain; and low surface winds that make it the ideal place to send a controlled aerial robotic platform, such as a conceptual Aerobot Airship. An important feature of a self-propelled, lighter-than-air aerial vehicle is that it must be autonomously controlled to navigate and avoid obstacles because of a 2.6-hour communication delay between the Earth and Titan. Developing a dynamic model that can be tuned will enable robust and reliable control of the Aerobot Airship.

Posted in: Mechanical Components, Software, Briefs

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Algorithm Enhancements to Powered Descent Guidance Software

The solutions guarantee minimum fuel usage, satisfaction of position constraints, and adherence to thrust magnitudes that are within physical minimum and maximum limits. NASA’s Jet Propulsion Laboratory, Pasadena, California The Powered Descent Guidance (PDG) software provides a computationally efficient guidance algorithm for powered descent that ensures satisfaction of the governing dynamics, along with adherence to physical control and state constraints, such as avoid the surface, limit thrust magnitude and pointing, and divert based on available fuel. The software can generate guidance profiles for precision landing (or pinpoint landing when feasible) and also incorporate smart diverts to avoid the backshell landing corridor.

Posted in: Mechanical Components, Software, Briefs

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Using Describing Functions for Aeroservoelastic Models with Free-Play

The effect of free-play in a system can be accurately estimated without the need for simulation. Neil A. Armstrong Flight Research Center, Edwards, California Aerodynamic control surfaces, with excessive free-play, can cause limit cycle oscillations (LCO), a sustained vibration of constant amplitude. The LCO is caused by a combination of aeroservoelastic effects and free-play. If the amplitude is sufficiently large, it can impact handling qualities, ride quality, and can cause structural fatigue, ultimately leading to structural failure. Free-play is typically distributed throughout the actuator and control surface, with contributions from actuator mounting bearings as well as the surface hinge.

Posted in: Mechanical Components, Software, Briefs

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