The space shuttle Challenger

On 28 January 1986, the launch of the space shuttle Challenger ended in disaster, as seconds after take-off the shuttle exploded, killing all seven astronauts on board. William Graham, the head of NASA (National Aeronautics and Space Administration), who was a former student of Feynman, asked him to join a commission to investigate the accident. Reluctantly Feynman accepted, and then

Courtesy of NASA.

went about the task in his usual fashion. The commission, which was chaired by William Rogers, the former Secretary of State, held numerous official meetings (both public and private) and formal discussions, with lots of bureaucracy. Feynman went off on his own, talked to technicians and engineers, and learned details about the construction of the rocket from workers on the shop floor. He found that there was a lack of communication between technicians and management, and that their worries never seemed to reach the ears of those at the top. One particular worry was that the seals around airtight joints in the rocket engines might leak under violent vibration.

At a public meeting, shown on national television, Feynman removed an O-ring from a model of the rocket engine and dipped it into a glass of iced water. He showed that rubber used in the insulating rings had no resilience when squeezed at the temperature of iced water. The temperature on the morning of the launch had been two degrees below zero, whereas the coldest previous launch had taken place at +12°C. At the critical moment, the seals had failed and allowed rocket fuel to leak and go on fire. The partial cause of the accident had been demonstrated with a clamp

and pliers which Feynman had bought at a hardware store on his way to the television studio!

When the commission published its final report, Feynman added an appendix in which he gave reasons for his personal view that the deterioration in cooperation between scientists and engineers on the one hand and management on the other contributed to the failures which caused the Challenger disaster.

Despite serious illness during the last years of his life, Feynman never lost his spirit of adventure. An unusual ambition, at the back of his mind despite his many other activities, was to visit Tannu Tuva. Since childhood he remembered seeing triangular and diamond-shaped postage stamps from Tuva, a small Soviet republic situated north-west of Mongolia and surrounded by mountains. A peculiar reason attracted his attention — the capital, Kyzyl, was the only five-letter word he had come across that was made up only of consonants! Laboriously, using a combination of Tuvan-Russian and Russian-English dictionaries, he and a friend, Ralph Leighton, composed a letter asking for permission to make a cultural visit to that country.

The climate of Soviet-American relations was not sufficiently amenable for such a visit at that time, and no permission was forthcoming over a period of some ten years. His students at Caltech queued in hundreds to donate blood during his final major operation, but Feynman died on

15 February 1988, a few days before a formal invitation arrived from Moscow, addressed to 'Feynman and his party', to visit Tannu Tuva.

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