Space Shuttle Columbia STS-1 launch delay
The first-ever Space Shuttle launch was scrubbed 20 minutes before liftoff and delayed two days, becoming a famous early case study in software engineering.
The damage was public. The root cause was preventable.
The first-ever Space Shuttle launch was scrubbed 20 minutes before liftoff and delayed two days, becoming a famous early case study in software engineering.
What the software actually got wrong
A rare timing skew, introduced by a software change made a year earlier, caused Columbia's backup flight computer to power up at just the wrong moment to fail to synchronize with the four primary flight computers, a 1-in-67 chance timing bug that had gone undetected through extensive testing.
A rare timing skew, introduced by a software change...
A rare timing skew, introduced by a software change made a year earlier, caused Columbia's backup flight computer to power up at just the wrong moment to fail to synchronize with the four primary flight computers, a 1-in-67 chance timing bug that had gone undetected through extensive testing.
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.
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.
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