The story people read in Feynman's autobiography was that General Donald Kutyna came by and made some very knowledgeable suggestions about areas worthy of inves

The story people read in Feynman's autobiography was that General Donald Kutyna came by and made some very knowledgeable suggestions about areas worthy of investigation. Kutyna revealed after her death that Sally Ride clued him in, and he in turn passed the knowledge on to Feynman. Kutyna: On STS-51C, which flew a year before, it was 53 degrees [at launch, then the coldest temperature recorded during a shuttle launch] and they completely burned through the first O-ring and charred the second one. One day [early in the investigation] Sally Ride and I were walking together. She was on my right side and was looking straight ahead. She opened up her notebook and with her left hand, still looking straight ahead, gave me a piece of paper. Didn't say a single word. I look at the piece of paper. It's a NASA document. It's got two columns on it. The first column is temperature, the second column is resiliency of O-rings as a function of temperature. It shows that they get stiff when it gets cold. Sally and I were really good buddies. She figured she could trust me to give me that piece of paper and not implicate her or the people at NASA who gave it to her, because they could all get fired. Kutyna: I wondered how I could introduce this information Sally had given me. So I had Feynman at my house for dinner. I have a 1973 Opel GT, a really cute car. We went out to the garage, and I'm bragging about the car, but he could care less about cars. I had taken the carburetor out. And Feynman said, "What's this?" And I said, "Oh, just a carburetor. I'm cleaning it." Then I said, "Professor, these carburetors have O-rings in them. And when it gets cold, they leak. Do you suppose that has anything to do with our situation?" He did not say a word. We finished the night, and the next Tuesday, at the first public meeting, is when he did his O-ring demonstration. We were sitting in three rows, and there was a section of the shuttle joint, about an inch across, that showed the tang and clevis [the two parts of the joint meant to be sealed by the O-ring]. We passed this section around from person to person. It hit our row and I gave it to Feynman, expecting him to pass it on. But he put it down. He pulled out pliers and a screwdriver and pulled out the section of O-ring from this joint. He put a C-clamp on it and put it in his glass of ice water. So now I know what he's going to do. It sat there for a while, and now the discussion had moved on from technical stuff into financial things. I saw Feynman's arm going out to press the button on his microphone. I grabbed his arm and said, "Not now." Pretty soon his arm started going out again, and I said, "Not now!" We got to a point where it was starting to get technical again, and I said, "Now." He pushed the button and started the demonstration. He took the C-clamp off and showed the thing does not bounce back when it's cold. And he said the now-famous words, "I believe that has some significance for our problem." https://www.popularmechanics.com/space/a18616/an-oral-history-of-the-space-shuttle-challenger-disaster/ https://www.popularmechanics.com/space/a18616/an-oral-histor...