... Not to throw stones but:
1. Miscalculation of distance parameters allows Mars probe to crach into the surface.
2. O-ring problems with the external SRB's didn't pose a significant threat to any mission until Challenger
3. Foam strikes observed on many/all(?) of shuttle launches didn't pose a threat until Columbia.
4. Mirror imperfections in Hubble even during 1-2 years in cold storage waiting for the Shuttle to regain flight status.
That's all I can remember at this time.
Shit happens. So much so, it fills an entire book:
Springer, "
Space System Failures", by David M. Harland and Ralph Lorenz with chapters on
1. The Missiles
2. The Shuttle
3. Back to Expendables
4. Heavyweights
5. Lightweights
6. Boom and Bust
7. The Chinese Experience
8. The Current Crop
9. Failures and Redundancy
10. Propulsion System Failures
11. Attitude Control System Failures
12. Electrical Failures
13. Environmental Failures
14. Structural Failures
15. Failures on the Ground
16. Operator and Software Errors
17. Conclusions
One more example: if you don't follow the "Count the bolts before you tilt the platform, mate!" protocol, a
mishap might happen.