Titan IV-B/Centaur Milstar satellite loss
An $800 million Milstar military communications satellite was placed into a useless low orbit and declared a total loss.
The damage was public. The root cause was preventable.
An $800 million Milstar military communications satellite was placed into a useless low orbit and declared a total loss.
What the software actually got wrong
A software engineer manually re-typed a lost guidance data file and mistyped a roll-rate filter constant (0.1992476 instead of 1.992476), zeroing out roll-axis data in the Centaur upper stage's flight software and causing it to tumble; the transcription error was not caught by the software development and quality-assurance process.
A software engineer manually re-typed a lost guidance data...
A software engineer manually re-typed a lost guidance data file and mistyped a roll-rate filter constant (0.1992476 instead of 1.992476), zeroing out roll-axis data in the Centaur upper stage's flight software and causing it to tumble
Requs AI Edge Case flags this exact pattern at the requirements and architecture stage — before a single line of code implementing it exists — so the assumption behind it gets challenged while it is still cheap to fix.
The transcription error was not caught by the software...
the transcription error was not caught by the software development and quality-assurance process
Requs AI Software FMEA traces this failure mode back to the system-level hazard it feeds, tagging it against the Common Defect Enumeration so it surfaces in review instead of in the field.
Beyond code coverage and "shall" testing
Root causes like this one rarely show up in code coverage or requirements-compliance testing, because nobody wrote a requirement anticipating the specific edge case that broke. Requs AI Edge Case and Requs AI Software FMEA are built to surface exactly this class of overlooked failure mode — before the software is written.
Surfaces this before code exists
Identifies edge cases like this one at requirements and architecture time, using the Common Defect Enumeration to catalog failure patterns seen across hundreds of real-world software failures — including this one.
Connects the failure mode to the hazard
Traces this class of root cause directly to the system-level hazard it can produce, so a defect pattern like this one gets flagged during design review instead of after it ships.
Find the overlooked root causes before they ship.
Schedule a demonstration, or explore how Requs AI Edge Case and Software FMEA use the Common Defect Enumeration.