Reliability? It was the early mantra of the Space Agency that components and systems must be not merely 99 percent reliable, but 99.999999999 percent. In other words, “out to nine nines,” as the saying went. As we have learned, such approaches to perfection reflect the earnestness of a program but are in many cases impossible to reach and unprovable.
If something can go wrong, eventually it will. An inexorable entropy beckons the very universe we live in. Whatever Einstein thought about it, something is throwing dice somewhere.
The efficient cause of the Challenger accident was easily pinned down. A faulty O-ring did not seal properly at ignition of a solid booster, allowing a propellant burn-through that eventually destroyed the central tank. Would it have happened that way in warmer weather, with the ring consequently more pliable? Maybe not. Had we seen hints of this before, in the recovered solid casings? Maybe so. Were we out to nine nines on this one? Maybe not.
The Columbia catastrophe is another case. Can foam falling away during boost phase inflict fatal damage on a shuttle wing? Or is this a false positive, leading all down a blind alley? Did some other force cause the shuttle to start shedding tile when it reached the sensible ocean of air we live at the bottom of, was there damage from an exogenous source? Remember the cartoon character who went around with a metal dome over his head, fearing meteorites? He was living life out to many 9’s, taking no chances of being victim to the first case of its kind. But he was not fearing an impossibility.
Did the onboard computer guidance overreact? Was the craft really doing what it sensed and what telemetry told the ground. If an answer lies within the ken of man, he will find it, or reduce the riddle to a few possibilities, one of which will eventually become favored.
As it happens, President Bush has been promoting fuel cell propulsion as an alternative to petroleum combustion engines these days. It was a cell tank that exploded on Apollo 13’s outward bound trip to the moon and required the subsequent lunar roundabout that brought a harrowing but safe return. It is hydrogen and oxygen from that big orange central tank that feeds the shuttle main engines as they slip the surly bonds of Florida. There is chance in all. Reducing the odds is everything.
I am reminded of a fateful interview with Robert Lusser, one of Wernher von Braun’s compatriots from Germany who was a reliability chief at Huntsville, where the rocket systems were being developed in the early days. He told this reporter in an on-camera interview in Texas in the mid-Fifties that the reliability requirements of spaceflight were so stringent “that man can never go to the moon, let alone to the Mars.” An honest judgment by a cautious man, but one charged with helping make it happen. A few years later I asked Dr. von Braun whatever happened to Dr. Lusser and he said with some surprise at the question: “He returned to Germany.”
“Press on” is another phrase out of the astronaut lexicon. In each of the eulogy speeches there is expressed that old determination, to “press on.” It is sometimes buttressed by the other arguments, the wealth of knowledge obtained by space exploration, the gimcracks we have because of it, a desire to somehow introduce a profit motive to refute those who in their grief insist on asking why.
The more honest answer is because we can. We can live the life imagined. And there is something here, in DNA, that wants to go there.
Because we can.