The space shuttle accident
Further evidence that a piece of insulation did it
SCIENTISTS like experiments. It is no surprise, then, to find that the investigation into the loss of the shuttle Columbia is following eerily similar lines to the investigation into the explosion of Challenger in 1986.
In that year, the cause of the accident was fixed in the public's mind after a dramatic public experiment by Richard Feynman, a Nobel prize-winning physicist. He dropped a piece of the shuttle called an “O-ring” into a cup of iced water to show how it failed at low temperatures. This time round, investigators have fired a piece of foam at a wing panel in order to simulate the action of a falling piece of foam that was seen to strike Columbia shortly after the shuttle took off.
This is the second such experiment. The first merely knocked loose a seal. This time, though, the drama of the event suggests another watershed moment in NASA history. “Oh my God!” one spectator is reported to have cried as the foam punched a hole about 40cm across into the panel.
Scott Hubbard, a member of the board investigating the accident, said the experiment showed that the foam was the most probable cause of the breach that led to the loss of Columbia. Gaps created in the protective shielding of the shuttle by the collision probably led superheated gases to breach the craft's left wing, causing it to disintegrate.
The board has already recommended that shuttle crew should be able to repair damaged wing tiles during a mission. But a hole of the size produced by the most recent experiment would be hard to mend. The board is now wrapping up its research and a final report is expected by the end of the month.