NASA Office of Logic Design

NASA Office of Logic Design

A scientific study of the problems of digital engineering for space flight systems,
with a view to their practical solution.

References - General Aerospace

Usage of this WWW Site

Title and Reference Abstract

A Zero-Gyro Safemode Controller for HST

F. Landis Markley1 and John D. Nelson2
1NASA Goddard Space Flight Center
2Lockheed Missles & Space Company, Inc. 1992 AIAA Guidance, Navigation and Control Conference
August 10-12, 1992, Hilton Head Island, SC A Collection of Technical Papers, Part 3, pp. 1445-1459 AIAA-92-4613-CP

The purpose of this paper is to document the Zero-Gyro Sunpoint mode for Hubble Space Telescope, a safemode designed to ensure a power positivestate without the use of rate gyros. This paper presents an overview of the Zero-Gyro Sunpoint algorithm, followed by details of the algorithm, control system design, and simulation results. A new, related safemode test, the System Momentum Test, is also discussed.

Are There Too Many MBAs in Aerospace?

Douglas E. Chappelle
IEEE AESS Systems Magazine
May 2000, pp. 3-5


As many hive intuitively sensed, if not outright admitted to themselves, American corporate society has turned their focus to the bottom line. Everywhere you turn it seems another unprofitable aerospace division is being sold to the highest bidder or liquidated. The effective system engineer needs to be aware of the choices. Do you use Cost-As-an-Independent-Variable (CAIV) to meet the bottom line today so you can live to fight another day? Do you stand on your principles so that, when tomorrow comes, you will be prepared'? Can you do both? What happens when you guess wrong? This op-ed paper explores the question of management for the bottom line versus management for technical excellence.

GPS Guidance System Increases Projectile Accuracy

Jim Grace
IEEE AESS Systems Magazine
June 2000, pp. 15-17


Recent events in Kosovo and the Persian Gulf War have increased public awareness to a politically charged state to reduce collateral damage. Global humanitarian concerns are becoming less tolerant of allied and innocent civilian casualties. Meanwhile, Congressional pressures to lower the cost of weapons, especially expendable rounds, have forced the military to becorne more efficient and cost-effective.

Status of CHIPS: A NASA University Explorer Astronomy Mission

Will Marchant1 and Dr. Ellen Riddle Taylor2
1Space Sciences Laboratory - UC Berkeley
2DesignNet Engineering Group

14th Annual/USU Conference on Small Satellites


In the age of "Faster, Better, Cheaper", NASA's Goddard Space Flight Center has been looking for a way to implement university based world class science missions for significantly less money. The University Explorer (UNEX) program is the result. UNEX missions are designed for rapid turnaround with fixed budgets in the $10 million US dollar range. The CHIPS project was selected in 1998. The CHIPS mission has passed the Concept Study and will be having the Confirmation Review in August 2000. Many lessons have already been learned from the CHIPS UNEX project. This paper will discuss the early issues surrounding the use of commercial satellite constellations as the bus and the politics of small satellites using foreign launchers. The difficulties of finding a spacecraft in the UNEX price range will be highlighted. The advantages of utilizing Internet technologies from the earliest phases of the project through to communications with the spacecraft on orbit will be discussed. The current state of the program will be summarized and the project's plans for the future will be charted.

[Note: This used the PowerPC 750 and a TCP/IP stack]

Computers Take Flight; A History of NASA's Pioneering Fly-By-Wire Project

James E. Tomayko

One hundred years after the Wright brothers, first powered flight, airplane designers are unshackled from the constraints that they lived with for the first seven decades of flight because of the emergence of digital fly-by-wire (DFBW) technology.

New designers seek incredible maneuverability, survivability, efficiency, or special performance through
configurations which rely on a DFBW system for stability and controllability. DFBW systems have contributed to major advances in human space flight, advanced fighters and bombers, and safe, modern civil transportation.

The story of digital fly-by-wire is a story of people, of successes, and of overcoming enormous obstacles and problems. The fundamental concept is relatively simple, but the realization of the concept in hardware and software safe enough for human use confronted the NASA-industry team with enormous challenges. But the team was victorious, and Dr. Tomayko tells the story extremely well.

The F-8 DFBW program, and the technology it spawned, was an outgrowth of the Apollo program and of the genius of the Charles Stark Draper Laboratory staff. The DFBW program was the high point of my own career, and it was one of the most difficult undertakings of the NASA Dryden Flight Research Center. It was not easy to do the first time in the F-8 and it will not be easy to do in the next new airplane. I hope the history of this program is helpful to the designers of the DFBW systems that will enable new and wonderful aerospace vehicles of the future.

Kenneth J. Szalai, F-8 DFBW Principal Investigator
Former Director, NASA Dryden Flight Research Center, 5 October 1999
Basics of Space Flight This is a training module designed primarily to help JPL operations people identify the range of concepts
associated with deep space missions and grasp the relationships these concepts exhibit for space flight. It also enjoys growing popularity among high school and college students, as well as faculty and people
everywhere who are interested in interplanetary space flight.

The Basics of Space Flight attempts to offer a broad scope, but limited depth, as a background for further investigation; many other resources are available, of course, for delving into each of the topics related here. Indeed, any one of these topics can involve a lifelong career of specialization. This module's purpose is met if the participant learns the scope of concepts that apply to interplanetary space exploration and the relationships between them.

Reliability of Future European Launchers with Abort Capability

Pilar Gonzalez

AIAA Journal of Spacecraft and Rockets
Vol. 37, No. 6, November-December 2000
pp. ??

Since 1994, the aim of the Future European Space Transportation Investigation Program has been identifying technically feasible and financially affordable reusable or semireusable launcher concepts, with the chief objective of increasing availability and significantly decreasing cost.  An overview is given on how consideration of abort modes in reusable and semireusable launchers would fairly increase launcher reliability and lifetime and reduce recurring costs.  Results are analyzed of the preliminary reliability assessment of eight different concepts, performed during Slice C of the program.  This study has proved that probabilistic reliability analyses are also a good decision tool in the early phases of a program where conceptual design will be fixed.   It can be used as a comparative argument for concept selection, giving a quantitative idea of the reliability of different conceptual design options, and as a tool to select subsystem design options considered reliable from the beginning.

Avionics Architecture for the U.S. Segment of the International Space Station Alpha

J. Smith1, M. McDonald2, S. Suchting3, and J. Schikner1
1McDonnel Douglas Aerospace
2NASA - Johnson Space Center
3Boeing Defense and Space Group

A Collection of Technical Papers
AIAA Computing in Aerospace 10
March 28-30, 1995/San Antonio, TX
pp. 163-172

The International Space Station Alpha (ISSA) is a joint project between the United States, European Space Agency, Japan, Canada and Russia to develop and fly a space station in the later part of the 1990s.  Each of these partners will contribute one or more pressurized modules or other elements to this new space station.  The United States will be the largest hardware contributor to this project, and this paper will describe the avionics architecture for the U.S. provided pressurized modules and truss segments.   The avionics contained within these U.S. modules and segments will perform many of the core engineering and payload support functions for the ISSA.  These functions include: the command and data handling, communications and tracking, guidance navigation and control (in partnership with the Russian elements), and electrical power generation and distribution.  This paper will describe the architecture of the avionics systems that will perform these core engineering avionics functions, as well as provide a discussion on the avionics necessary for the proper functioning of the core engineering avionics supported functions such as thermal control, life support, and mechanisms.

Control of Robotic Systems on the Space Station

M. Stieber1, D. Hunter1, C. Trudel1, and R. Ravindran2
1Canadian Space Agency
2MD Robotics

Space Technology, Vol. 20, No. 2, pp. 71-76, 2000

Robotic systems will play a critical role in the on-orbit assembly, external maintennce and operations of the International Space Station.  This paper provides an overview of the robotic systems of the Mobile Servicing System (MSS), focussing on the MSS control system concepts and architecture.

Current Results of the Electronic Part Sterilization Program at the Jet Propulsion Laboratory

J. Visser, JPL

1967 Annual Symposium on Reliability
January 10-12, 1967
Washington, D.C.
pp. 312-322

This report documents some of the preliminary results of the electronic parts sterilization program at the Jet Propulsion Laboratory (JPL).  The program is geared to reflect current NASA sterilization policy.  The primary objective of the electronic part sterilization programs is to establish an approved list of sterilizable electronic parts.  The major effect of the current JPL program is concerned with heat sterilization studies on representative part types from each major part category, specifically in relationship to the reliability of the devices.

Magellan Mission Planning and Orbital Operations

J. Carter and A. Tavormina
Jet Propulsion Laboratory
California Institute of Technology

Proceedings of the ESA Symposium on Spacecraft Flight Dynamics
Darmstadt, Germany
September 30 - October 4, 1991
ESA SP-326, December, 1991
pp. 457-464

The goal of NASA's Magellan mission is to understand the geological and geophysical processes that have shaped the planet Venus.  Through synthetic aperture radar, radiometric, altimetric, and gravity measurements, the scientific community hopes to improve its knowledge of the planet's topography and internal mass distribution.   This paper provides an overview of the Magellan mission; describes the spacecraft sequence software design, development, and test; addresses the nominal operational flow of stored sequence design and generation; briefly describes the ground processing of engineering telemetry and imaging data; and then summarizes the Magellan operational experience with non-routine behavior of the spacecraft during the cruise and mapping portions of the prime mission.
Russian Space Program References  

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