Shuttle SRM Field-Joint Data · 1981 – 1986

The Road to Challenger

The Challenger workbook plots every Space Shuttle flight from STS-1 to STS-51-L by its solid-rocket-motor joint temperature against the number of O-ring erosion incidents observed afterwards. The mission patches are the data points. Where the original author highlighted source passages from the Rogers Commission report and House Report 99-1016, those clippings appear directly in the timeline below.

24
Flights inspected
53°F
Coldest before
Challenger (STS 51-C)
31°F
Predicted joint temp
STS-51-L · 28 Jan 1986
7
Crew members lost

Erosion incidents vs. joint temperature

Each patch lands at the joint temperature recorded for its launch (x-axis) and the count of O-ring erosion incidents found in the post-flight inspection (y-axis). The 31°F mark is where Challenger’s field joints sat the morning of January 28, 1986.

Inspected, no erosion
Erosion observed
Below 32°F (freezing)
Challenger (STS 51-L)

Erosion incidents vs. joint temperature

Each patch lands at the joint temperature recorded for its launch (x-axis) and the count of O-ring erosion incidents found in the post-flight inspection (y-axis). The 31°F mark is where Challenger’s field joints sat the morning of January 28, 1986.

Inspected, no erosion
Erosion observed
Below 32°F (freezing)
Challenger (STS 51-L)

The road to Challenger

From the 1973 contract decision through the engineers’ final warnings, a slow-scrolling record of design choices, observed anomalies, and the launches that should have been a warning.

1973 →