EVENT
Challenger Disaster
The January 28, 1986 destruction of the Space Shuttle Challenger — the canonical twentieth-century demonstration that engineering judgment, however calibrated by experience, is useless without institutional willingness to weigh it against the absence of quantitative proof.
On the morning of January 28, 1986, the temperature at Kennedy Space Center was thirty-six degrees Fahrenheit — fifteen degrees below the lowest temperature at which the Space Shuttle had previously launched. The night before, engineers at
Morton Thiokol had argued in a teleconference with NASA managers that the launch should be postponed. Their concern was specific: the O-rings that sealed the joints
between segments of the solid rocket boosters lost resilience at low temperatures. The data showed erosion at temperatures above thirty-six degrees. The data did not extend to thirty-six degrees. Roger Boisjoly, the engineer who had been studying the O-ring problem for months, could feel — in the engineering sense — that thirty-six degrees was wrong. NASA managers asked for quantitative proof. The engineers could not provide it, because the phenomenon had not been tested at the relevant temperature. The absence of quantitative proof was interpreted as the absence of risk. The launch proceeded. Seventy-three seconds after liftoff, the