Thursday, January 28, 2016

Challenger - 30 years on

Hard to believe today is the 30th anniversary of the loss of the Space Shuttle Challenger. Thanks to the slow march of history, we all know the orbiter, OV-099, on its tenth mission and the 25th flight of the program - was torn apart by aerodynamic stresses after a leak in the o-ring joining sections of the right-hand solid rocket booster (SRB) burned through the side of the rocket and, eventually, into the side of the adjacent external tank. The tank failed 73 seconds after launch, and the ensuing accident destroyed the vehicle and killed the seven astronauts aboard, including teacher-in-space Christa McAuliffe.

Challenger's 10th mission, STS-51L, ended in a puff of smoke high in the crystalline-blue sky, followed by a sickening plunge into the Atlantic Ocean while a shocked nation tried to make sense of it all.

But on the day of, we knew nothing about the mechanical reason for an accident that seemed beyond the realm of believability. All we knew at the time was the horrifying reality that the most sophisticated flying machine ever built had self-destructed in front of a global audience, that a technology sold to the government and the public as something that would make spaceflight routine was anything but.

Since I view pretty much everything through the lens of technology, I see January 28, 1986 as the day our unmitigated belief in the perfection of tech was irrevocably shattered, as the investigation into the Challenger disaster uncovered a creaky organizational culture that chose to ignore growing concerns from engineers.

The long-story-short version is burn-through of the o-rings was a known issue. Engineers from Morton Thiokol, the company that designed and built the SRBs, wrote about the risks in a 1970 report as the Space Transportation System was being designed, and multiple flights - including STS-2, the program's second mission - exhibited worrisome erosion of the o-ring joint due to burn-through. NASA blindly green-lit launch after launch, figuring every successful flight validated the safety of the design. The reality was they were playing with fire, and it was only a matter of time before their luck ran out.

Morton Thiokol engineers protested NASA's decision to launch on that bitterly cold January morning. The temperatures were well below the rated design of the o-rings, and NASA, faced with growing pressure to adhere to an absolutely unrealistic flight rate, ignored their warnings. The super-cold o-ring failed to seat properly at launch, and the telltale sign of black smoke that puffed out from the booster milliseconds after ignition foreshadowed the disaster to come.

While the return-to-flight program resulted in a complete redesign of the troublesome o-rings and a top-to-bottom rethink of NASA's organizational culture, the space agency never fully purged the rot from its ranks. Challenger's lessons were not heeded, and Columbia's crew paid the same ultimate price on February 1, 2003 when their orbiter, OV-101, flying the STS-107 mission, came apart on re-entry high over Texas. The cause, then as now, a faulty organizational culture that systematically minimized the risks of foam shedding from the shuttle's external tank, and diverted engineers' concerns for mission after mission until, tragically, it was too late.

Five-and-a-half years after the last flight of the shuttle, NASA is building a new platform for deep space missions. The monster Space Launch System (SLS) rocket, topped by the Orion capsule, will take humans further into space than they've ever gone before. At the same time, SpaceX and Boeing are developing human-rated space vehicles - Crew Dragon and the CST-100 Starliner, respectively - that are scheduled for their initial test flights within the next couple of years.

One hopes the lessons of history don't fall on deaf ears, and the pressure to fly doesn't compromise safety to the point that careers are ended and lives are destroyed. To repeat the errors of the past would sully the memory of those who gave their lives in the pursuit of exploration and the advancement of human potential.

Sometimes, rocket science isn't as much about the rockets as it is the people who design, build and fly them.

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