Overview
- Researchers published two previously undocumented flaws in the Apollo Guidance Computer, with both teams concluding the issues did not threaten Apollo 11 in real use.
- One defect in the Inertial Measurement Unit’s gyro control path left a shared lock named LGYRO uncleared after a “cage” abort path, which two missing instructions triggered and which would silently block future gyro torques.
- The second issue in the P63 powered‑descent setup created a roughly 40 millisecond window where a DSKY keypress interrupt delayed an update, and simulation showed a brief 0.3–0.8 degree attitude error as a result.
- The JUXT team distilled the IMU routines into a behavioral specification with its Allium tooling and flagged the missing release, while the DEV authors used Ghidra static analysis, the Virtual AGC simulator, and outside peer review to validate the timing effect.
- JUXT reports the IMU mode‑switching code carrying the LGYRO behavior was reused in both Command Module (COMANCHE) and Lunar Module (LUMINARY) software, which helps explain how the omission survived earlier reviews and why specification‑led audits still pay off.