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.

Archives of Home Page

Interesting Op-Ed (Complexity and Human Understanding): "Drilling for Certainty" by David Brooks in the NY Times.

"But the real issue has to do with risk assessment. It has to do with the bloody crossroads where complex technical systems meet human psychology. ... These systems, which allow us to live as well as we do, are too complex for any single person to understand. Yet every day, individuals are asked to monitor the health of these networks, weigh the risks of a system failure and take appropriate measures to reduce those risks. "

The Apollo Guidance Computer: Architecture and Operation

Description: The Apollo Guidance Computer: Architecture and Operation is the first comprehensive description of the Apollo computer, beginning with its internal organization to its user interface and flight software. Particular emphasis is placed on the instruction set, Executive capabilities, the Interpreter and the detailed procedures for mission application software. Launch, landing on the Moon and entry back on Earth are explained in rich detail and show how the computer was an integral part of the spacecraft operation.

Click for a high resolution image.
Apollo 8 Recovery: A team of U.S. Navy underwater demolition swimmers prepares the Apollo 8 command module for being hoisted aboard the carrier U.S.S. Yorktown, prime recovery vessel for the initial manned lunar orbital mission. The crew members - astronauts Frank Borman, James A. Lovell, Jr., and William A. Anders - had already egressed the spacecraft and were aboard the recovery ship at the time of this photo.

LRO on launch pad with a Shuttle in the background.

Need a caption for this one.


S110E6019_high.jpg (1484622 bytes) GPN-2000-001085_hst_eva_high.jpg (6371862 bytes) "Hate When That Happens ..." GanymedeAndEuropa.jpeg (299755 bytes)
iss.jpg (219060 bytes) Shhhh!!!!!!!!!  It's a Secret. The Augmented Target Docking Adapter (ATDA) as seen from the Gemini 9 spacecraft during one of their three rendezvous in space. The ATDA and Gemini 9 spacecraft are 66.5 ft. apart. Failure of the docking adapter protective cover to fully separate on the ATDA prevented the docking of the two spacecraft. The ATDA was described by the Gemini 9 crew as an "angry alligator."  (6/3/1966) STS-113 Shuttle-ISS Docking Video This hangar was rigged with light/heat sensitive gear designed to detect fires and then flood the hangar with foam if triggered. The system is armed each night after everyone leaves. The janitor thought the airplanes looked pretty cool in the hangar and decided to take some photos one night... He doesn't work there anymore.
newyork.jpg (1245370 bytes) Astronaut Thomas D. Jones assembling a breakfast burrito during STS-80.  He later went on to assemble the Destiny laboratory to ISS-Alpha during STS-98, during several spacewalks.  Note that Tom is having decaf with his breakfast. Lift-off of Gemini-Titan 11 (GT-11) on Complex 19. The Gemini 11 mission included a rendezvous with an Agena target vehicle.  September 12, 1966. surveyor_apollo.gif (1234344 bytes)
  Suspended from an overhead crane in the Vehicle Assembly Building at NASA’s Kennedy Space Center, the orbiter Discovery is lowered toward the Solid Rocket Booster and External Tank (seen below) already stacked on the top of the Mobile Launcher Platform (MLP). After Discovery has been mated to the External Tank/Solid Rocket Booster assembly on the MLP and all umbilicals have been connected, workers will perform an electrical and mechanical verification of the mated interfaces to verify all critical vehicle connections.    

Information about Robert Goddard
About Robert Goddard

About Wilbur Wright
The Luna 20 spacecraft returned samples from the Moon.  It was launched on February 14, 1972.

About Luna 20
The Mariner 2 spacecraft was the second of a series of spacecraft used for planetary exploration in the flyby, or nonlanding, mode and the first spacecraft to successfully encounter another planet. Mariner 2 was a backup for the Mariner 1 mission which failed shortly after launch to Venus. The objective of the Mariner 2 mission was to fly by Venus and return data on the planet's atmosphere, magnetic field, charged particle environment, and mass. It also made measurements of the interplanetary medium during its cruise to Venus and after the flyby.
About Mariner 2
Skylab was launched on May 14, 1973.

About Skylab


About the LEM


Margaret Hamilton, the Lead Apollo Flight Software Designer, In a Mockup of the Apollo Command Module (MIT Photo)


About Margaret Hamilton

Enterprise Restoration and the Steven F. Udvar-Hazy Center

About Ken Iliff

Maxime A. Faget.

About Max Faget

This mission was the first to be sent to the outer solar system and the first to investigate the planet Jupiter, after which it followed an escape trajectory from the solar system. The spacecraft achieved its closest approach to Jupiter on December 3, 1973, when it reached approximately 2.8 Jovian radii (about 200,000 km).

About Pioneer 10

Montgomery Scott: July 20, 2005

Montgomery Scott: July 20, 2005 

Six A1020CQ84B FPGAs were in the Aerospace Corporation build Data Processing Unit for NASA Goddard Space Flight Center's SAMPEX spacecraft.  SAMPEX was the first of the Small Explorer missions.

About the First FPGA In Space


October 4, 1957:    Sputnik and the Dawn of the Space Age     (Sputnik Telemetry .wav file)

October, 2002: We have ET Cam!   (.ram)   (.qt)

Here's a nice set of space pictures, enjoy: (.pps)   (.ppt)   (sorry, couldn't make a good .pdf file)

Video: STS-114 does a backflip for inspection (July 2005)This grand mosaic consists of 126 images acquired in a tile-like fashion, covering one end of Saturn's rings to the other and the entire planet in between. The images were taken over the course of two hours on Oct. 6, 2004, while Cassini was approximately 6.3 million kilometers from Saturn. Three images (red, green and blue) were taken of each of 42 locations, or "footprints," across the planet. The full color footprints were put together to produce a mosaic that is 8,888 pixels across and 4,544 pixels tall. The smallest features seen here are 38 kilometers across. Many of Saturn's splendid features noted previously in single frames taken by Cassini are visible in this one detailed, all-encompassing view: subtle color variations across the rings, the thread-like F ring, ring shadows cast against the blue northern hemisphere, the planet's shadow making its way across the rings to the left, and blue-grey storms in Saturn's southern hemisphere to the right. Tiny Mimas and even smaller Janus are both faintly visible at the lower left.Gemini 7 as seen from Gemini 6A"OK, let's change the tires!" - Pistol Grip Tool in use.Discovery showing it's belly on STS-114 (July. 2005)View of the Flight Directors console in the Mission Control Center (MCC), Houston, Texas, during the Gemini 5 flight. Seated at the console are Eugene F. Kranz (foreground) and Dr. Christopher C. Kraft Jr. (background). Standing in front of the console are Dr. Charles Berry (left), an unidentified man in the center and astronaut Elliot M. See. (8/21/1965)Discovery hits bird on STS-114 (July. 2005)

Crew of the Challenger on STS-51L: Francis R. Scobee, Michael J. Smith, Judith A. Resnik, Ellison S. Onizuka, Ronald E. McNair, Gregory B. Jarvis, Sharon Christa McAuliffe

January 27, 1967: Apollo AS-204

January 28, 1986: Challenger

February 1, 2003: Columbia

Crew of the Columbia on STS-107: Rick Husband, William McCool, Michael Anderson, Kalpana Chawla, David Brown, Laurel Clark, and Ilan Ramon Apollo 1 Crew: Virgil "Gus" Ivan Grissom, Edward Higgins White, II, Roger Bruce Chafee


Rick Husband

William McCool

Michael Anderson

Kalpana Chawla

David Brown

Laurel Clark

Ilan Ramon

Crew of the Columbia on STS-107  

President Addresses Nation

Sean O'Keefe Statement

Grissom Family Condolences

Israel viewed from the Space Shuttle Columbia - Movie

We came here, you and I...

Columbia Pictorial Essay

Space Flight Awareness Site

To my colleagues and other visitors to this site:  Every January I honor the memories of Apollo AS-204 and Challenger crews.  These are sad events but we should not and will not forget them.  Today, February 1, 2003, we had a tragedy with Columbia, STS-107, and I shall honor the memory of the seven astronauts who died in the pursuit of science and space.  Richard B. Katz, Office of Logic Design, National Aeronautics and Space Administration.

OLD Reliability Tips

Notes on Units and Their Proper Usage

Personal Observations on Reliability of Shuttle by R. P. Feynman

Heat Sinks In Integrated Circuit Packages Can Cause Shorts

Powered vs. Unpowered Vibration: NASA Reliability Practice

OLD News #17: Actel SXA, RTSX-S, and RTSX-SU FPGAs in Mission- and Safety-Critical Systems

HDL design representations use coded text based techniques that are similar in appearance to those used for software representations. This similarity in appearance can mislead one to attempt to use software verification methods directly on the design representation of HDL or other equivalent hardware specification languages.


Update: ICCI Inrush Data for SX-S FPGAs


Numerous "device failures" have occurred with a significant fraction of these resulting from improper testing.  Note that testing of modern, complex, programmable devices is far from trivial and is not risk free, as shown by our failure analyses.  Below are statements from two manufacturers on this subject about trying to improve the quality of devices by field testing along with a paper from the 2002 MAPLD International Conference related to this subject.
  • Unfortunately I have to do a "repeat" on this note:

    • Never program the security fuse (Actel) unless you have a real good reason.


Design Checklists

TTL Design  Checklist
CMOS Design Checklist
Memory Design Checklist

Some of the technologies are a bit dated but the principles and tips are still good.

Naval Reactor success depends on several key elements
(from the Columbia Accident Investigation Board (CAIB) Mishap Report, p. 182):
  • Concise and timely communication of problems using redundant paths

  • Insistence on airing minority opinions

  • Formal written reports based on independent peer-reviewed recommendations from prime contractors

  • Facing facts objectively and with attention to detail

  • Ability to manage change and deal with obsolescence of classes of warships over their lifetime


  • Many modern, high-speed devices have increased susceptibility to ESD.

  • Referring to HDL text as "code" or "software" and calling writing HDL "programming" have led some people to erroneously believe that designing hardware is software.  Such assumptions, without understanding, lead directly to failure.

  • "There are two ways of constructing a software design: One way is to make it so simple that there are obviously no deficiencies and the other way is to make it so complicated that there are no obvious deficiencies." -- C.A.R. Hoare, The 1980 ACM Turing Award Lecture

"Do not believe everything you read."

I have recently become aware of several documents, authored by others, stating my positions on the usage and application of FPGA technology -- positions that I do not support.  This has been a problem over the years but the incidence rate is increasing thus this note.

Similarly, there are many rumors in the industry, presented as fact by "politicians" and as representing organizations that are simply fantasy.

You may safely believe this reliability note.  ;-)


"Drive Strength of Actel FPGAs"

"Analysis of Printed Circuit Board Artwork: Bypassing"

Call For Failures: Programmable Device Reliability

These tips are not jokes (unfortunately):

* OLD News #15
* First summary report.
* NASA Advisory released.
 I'm now working on Design Guidelines and Criteria for high-reliability digital electronics.
Feel free to browse these pages and send comments, material, and suggestions in for inclusion.

Conference Schedule


Invited Speakers

Late Papers

Panel: "Why Is Software So Hard?"

Authors and Abstracts

Displays and Exhibits

2003 MAPLD International Conference

The 6th annual Military and Aerospace Programmable Logic Device International Conference will cover programmable devices and technologies, as well as digital engineering and related fields, for mil/aero applications.

New - MAPLD Merchandise

Technical Program

Registration Now Open

Having Registration Problems?

"An Application Engineer's View"

Hosts and Sponsors

Industrial/Gov't Exhibits

New Facility and Location! Wow!!

Previous Conferences and Proceedings

About Clarence L. Kelly Johnson

About Clarence L. Kelly Johnson

Received January 23, 2005 An Award Winning www Site!!!! is "rehosted"  to this server.  Please contact me if you need help locating anything.


Home - NASA Office of Logic Design
Last Revised: December 09, 2010
Web Grunt: Richard Katz