VI
Mark học AISTS-51-L · 28 January 1986 · Kennedy Space Center, Florida
Sources: Rogers Commission report (1986), chapters 4–6; flight counts from Dalal, Fowlkes and Hoadley (1989), table 1.
An organisation full of good engineers, aware of the weak point for 9 years, with engineers objecting the very night before: why did it still press the launch button? The answer lies not in one person, but in how a whole organisation slowly got used to risk.
Every time stamp below comes from chapter 3 of the Rogers Commission report.
Source: Rogers Commission report, chapter 5 (the teleconference, pad ice), chapter 6 (1977 test, the memo, flight 51-C) and chapter 7.
13 things often said about Challenger, checked against the primary record. Click each row to see why.
The consensus finding of the Rogers Commission (chapter 4), backed by images of smoke at 0.678 s and flame at 58.8 s at exactly that spot.
The 1977 test, the 1978–1979 memos calling the design "unacceptable", and damaged O-rings on 7 of the 23 flights whose boosters were recovered (Rogers, chapter 6).
Recorded in chapter 5, along with Boisjoly's testimony: "we should not fly outside of our data base, which was 53 degrees".
A plan of 24 flights a year, parts taken from other orbiters, squeezed training time (Rogers, chapter 8). Vaughan calls it the "culture of production".
They were heard for hours, and NASA's side said it would not launch over Thiokol's objection. What happened is that Thiokol's own leadership reversed after the private caucus, and the burden of proof was flipped. Engineer Bob Ebeling later said, "I could have done more".
Edward Tufte (1997) says yes. A 2002 rebuttal co-authored by Boisjoly himself says the engineers did not have the temperature data despite asking for it, that Tufte's temperature axis mixes O-ring temperature with air temperature, and that the core issue was the burden of proof, not the graphics. The dispute is unresolved.
The major broadcast networks had cut away before launch; CNN carried it live, and NASA sent a satellite feed to schools for the "Teacher in Space" program. Many pupils really did watch live, but most Americans saw replays. No original survey was found for the percentages often quoted.
There was no explosion in the sense of a detonation or shock wave. The external tank failed, the vehicle was torn apart by aerodynamic forces, and the propellants burned in a fireball. "Broke apart" is more accurate.
Dr Kerwin's report (July 1986): 3 of the 4 recovered emergency air packs had been activated by hand, so at least some of the crew were alive and acting after the breakup. But they "possibly, but not certainly" lost consciousness in the seconds that followed. Whether the cabin lost pressure could not be established.
The televised demonstration of dropping the O-ring into ice water was his. But the initial hint came from General Donald Kutyna, and after Sally Ride died (2012), Kutyna said it was she who had given him the NASA documents on O-rings stiffening in the cold. (Secondary source: Kutyna's account.)
The crew cabin separated nearly intact, with accelerations at breakup of about 12–20 G, which are "survivable". The cabin fell for about 2 minutes 45 seconds before hitting the sea. The cause of death "cannot be positively determined" (Kerwin).
The Commission investigated this rumor. Those involved stated there was no plan for a live hookup, and the launch decision was made by NASA officials "without any outside intervention or pressure" (Rogers, chapter 8).
A long-running online myth. Space journalist James Oberg, who compiled the myths about Challenger, calls the putty change "unrelated to the disaster".
Scores are Mark's assessment based on the sources in Part 8, not figures from a study.
The most avoidable disaster of the US space program, because every piece of information needed was already in the meeting room the night before.
In 2003, Columbia broke apart on re-entry because a piece of foam insulation struck its wing at launch. Foam shedding, too, had happened many times and had slowly come to be seen as normal. The Columbia Accident Investigation Board wrote that "the history of engineering decisions on foam and O-ring incidents had identical trajectories", and engineers were again asked to prove the flight was "unsafe".
Vaughan worked with the Columbia investigation board. She concluded that "from Challenger NASA learned incomplete lessons": it fixed the O-ring, but not the pressures and structure that dulled the danger signals.
Applies to any "go or no-go" meeting: a product launch, pushing code to production, signing a contract.
Primary documents first. Wherever only a secondary source exists, it is flagged in the Fact check section.