Richard Feynman handwritten document regarding the Space Shuttle Challenger disaster. Feynman wrote this document during his investigation into the crash, listing the dates of 1960-1983, with data regarding NASA's growing optimism of the success rate of the Space Shuttle program, a rate not grounded in reality.

During the years 1960-1973, Feynman writes ''Igniter seal failures''; it was in 1973 that NASA contracted Morton-Thiokol to design its solid rocket boosters, even though the company scored last for safety, but first for cost. Listing the year 1976, Feynman writes in part, ''Probability 1/100'' which was the space shuttle failure rate provided by NASA engineers during the investigation, much lower than the rate of 1/100,000 provided by NASA management. He continues, ''Pitch in 1979 failure rate 1/59 as good or better than shuttle.'' He continues, ''We are flying a manned system and if we thought numbers were so bad wouldn't fly.'' He also writes, ''Factor of safety 1.65'', and much more regarding the seals.

For the date of 1978, Feynman writes, ''Nuclear in space is safe?...Wiggins report is first reliability study or failure study''. Released by the J.H. Wiggins Co., the Wiggins report came to the conclusion that the failure rate of the solid rocket boosters was excessively high - too high for a manned mission - but after consultation with NASA, revised the failure rate down, due to what they believed would be a steep learning curve. The failure rate estimate was subsequently decreased to 1/1,000, a figure believed by many to be too optimistic.

Feynman then lists 1983, two years after the launch of the space shuttle program, and three years before Challenger. He writes, ''Nuclear again Teledyne (Basically a review of Wiggins report)''. The Teledyne Corporation was contracted by the Air Force to review the Wiggins Report, and advised that Wiggins ''seriously underrate the Shuttle risk...and should not be relied upon''. They concluded that the failure rate for a single solid rocket booster was 1/70; since the shuttle had two boosters, the failure rate would subsequently be 1/35. With much more content on this page, measuring 8.5'' x 11'', in near fine condition. From the Richard Feynman estate.