alt Hacker News> The sealant and O-rings did not succeed in keeping the hot gasses inside (evidence: Challenger). They were not adequate
No. The whole assembly --joint, sealant and O-rings, -- failed.
"They were not adequate" - yet, after the redesign, they kept those same O-rings and declared that boosters are safe to fly, in manifest contradiction to your assertion. So your reasoning is clearly flawed.
>"They were not adequate" - yet, after the redesign, they kept those same O-rings
presumably "redesign" means some stuff changed. why is it not possible that the O-rings were inadequate for the old design, but adequate for the new design?