System and Software Safety

Spring 2004

This website contains the materials for the Spring 2004 NASA class on software system safety.
The website will be populated as the class progresses so keep checking it. Links to the papers and class notes are also in the class Description.

Description, Schedule, and Readings (doc)

New Book Draft (pdf)

The Role of Software in Spacecraft Accidents (pdf)

Ariane 501 Accident Report (html)

Titan Accident Report (doc)

Intent Specifications Paper (pdf)

N-Version Programming Paper (pdf)

A Reply to the Critics of the N-version Programming Paper (pdf)

Class Notes for Feb. 3 (pdf)

Class Notes for Feb. 10 (pdf)

Class Notes for Feb. 17 (pdf)

Robert Follensbee Notes (html) Notes from a presentation at an FAA DER meeting on reliability versus safety and examples of misleading risk assessments.

STAMP Model of a Water Contamination Accident (pdf) for class 4

This is the only description I have so far of STPA (Hazard Analysis Based on STAMP) but it is embedded in a long technical report. The only relevant part for class 4 is Chapter 3 (doc). The rest is a duplicate of the other reading.

Evaluating Accident Models using Recent Aerospace Accidents: Part 1: Event-Based Models (pdf) A report I wrote on spacecraft and aircraft accidents. I recommend skipping chapters 1 and 2 (they are much better written in my new book). Chapter 3 describes the the accidents in detail using a hierarchical event-based model. (Sorry that the screen .pdf file is pixillated -- it prints fine.)

Class Notes for Feb. 24 (pdf)

Describing and Probing Complex System Behavior: A Graphical Approach (doc)

Reusable Software Architectures for Aerospace Systems (pdf)

Use of SpecTRM in Space Applications (doc)

Class Notes for March 2 - Part 1 (pdf)
Class Notes for March 2 - Part 2 (doc)
Requirements Analysis Exercise (pdf)

Class Notes for March 9 (pdf)

N-Version Programming Paper (pdf)

Class Notes for March 16 (pdf)

Class Notes for April 6 (pdf)

Draft Software Safety Standard (doc)