Engineering topics
Wallace, Shawn
Publications and source records attributed to Wallace, Shawn.
Safety and Mission Assurance (SMA) Automated Task Order Management System (ATOMS) Operation Manual
This document describes operational aspects of the ATOMS system. The information provided is limited to the functionality provided by ATOMS and does not include information provided in the contractor's proprietary financial and task management system.
Flight Avionics Hardware Roadmap
As part of NASA's Avionics Steering Committee's stated goal to advance the avionics discipline ahead of program and project needs, the committee initiated a multi-Center technology roadmapping activity to create a comprehensive avionics roadmap. The roadmap is intended to strategically guide avionics technology development to effectively meet future NASA missions needs. The scope of the roadmap aligns with the twelve avionics elements defined in the ASC charter, but is subdivided into the following five areas: Foundational Technology (including devices and components), Command and Data Handling, Spaceflight Instrumentation, Communication and Tracking, and Human Interfaces.
Application of Reconfigurable Avionics for the Bantam Launch Vehicle
The modern market is placing increasing pressure on launch costs. This is particularly true for small university science payloads, where the cost of the experiment itself is relatively low, and the launch frequency is potentially very high. It is the stated goal of the Bantam Program to dramatically reduce the costs of launching this class of payloads. This is a goal that will require that the avionics not only be reduced in production costs, but also in maintenance and operation costs, because the Bantam vehicle is envisioned as a reusable launch system. However, the costs of avionics is a relatively small fraction of the overall cost of launching a payload, and a simple reduction in the avionics costs will not immediately realize the necessary gains. Instead, to reduce the total system launch costs, it is also necessary to improve avionics performance. Only by reducing weight, volume, and power, while enhancing computational capability can the avionics be used to address the system-level cost reduction requirements. The National Aeronautics and Space Administration is currently pursuing technology development tasks, in order to support the Bantam requirements. One technology task is to develop a low-cost, high-performance reconfigurable avionics core unit. In addition to providing low cost and high performance, the use of reconfigurability will be used to explore the options of accommodating multiple launch configurations, and addressing such areas as redundancy management, single-event upset immunity, and low maintenance. This paper will address how emerging developments in reconfigurable avionics can be used to meet these challenges.
Design of a Low Cost Avionics System for Launch Vehicles
Marshall Space Flight Center has long been one of the leaders in development of propulsion systems. Due to current launch vehicle costs, Marshall Space Flight Centers (MSFC) Advanced Space Transportation Program (ASTP) office has emphasized the development of low cost launch vehicles. The Bantam launch vehicle is one of the primary programs that has low cost as a requirement. One of the driving factors for a low cost launch vehicle is a low cost avionics system. This paper will summarize MSFC's Astrionics Laboratories efforts in designing a low cost avionics system. MSFC has done Phase A avionics system design and has been working with various contractors on a Phase B preliminary avionics design. Deriving the major requirements, trade studies and cost drivers are some of the topics to be discussed.
A Table-Driven Control Method to Meet Continuous, Near-Real-Time Observation Requirements for the Solar X-Ray Imager
The design of the Solar X-Ray Imager (SXI) for the Geostationary Operational Environmental Satellite (GOES) presents an unusual scenario for controlling the observing sequences. The SXI is an operational instrument, designed not primarily for scientific research, but for providing "operational" data used by the National Oceanic and Atmospheric Administration (NOAA) to forecast the near-term space weather. To this end, a sequence of images selected to cover the full dynamic range of the sun will be executed routinely. As the dynamics of the sun have differing temporal cadences, the frequency of various images will differ. These images must be routinely received at the forecast center in near real-time, 24-hours a day, with a minimum of interruptions. While these requirements clearly lead to a 'routine patrol' of images, the parameters for each do not form a static set. The dynamics of the sun will change with the I 1-year solar cycle. The performance of the imaging will vary with on-orbit conditions and time. And while the SXI is not intended as a research instrument, forecasting techniques may change with time, which in turn will further alter the imaging sequences. An additional complication is the highly restricted commanding window, and a very slow commanding rate. To fulfill these requirements, the SXI was designed to utilize a table-driven approach. Sequences are defined using structured loops, with nested repetitions and delays. These sequences reference combinations of imaging parameters which in turn reference tables of parameters than can be loaded by ground commands. Multiple sequences can be built and stored in preparation for execution when determined appropriate by the NOAA forecasters. The result is an approach that can be used to provide a flexible, yet autonomous SXI capable of meeting both arbitrary forecasting requirements, and operating within the commanding constraints.