Those magnifcent flying machines

I stood on the banks of the Potomac River this morning to take my last glimpse at one of America's least-appreciated, most astounding technological achievements-- the Space Shuttle Orbiter Discovery, in a low-altitude flyover of the nation's capital before it came to rest, "wheel stop," at the Dulles Airport wing of the Smithsonian Air and Space Museum.

The decision to scuttle the shuttle fleet was made following the Columbia spaceflight tragedy in 2003.  Columbia, laden with precursor research experiments of the kind that would be performed on the International Space Station, was returning home to Kennedy Space Center from its long-duration space mission when a crack on the leading edge of its left wing permitted the hot plasma flows from re-encountering Earth's atmosphere to travel rapid-fire through its wing and under-belly, incinerating its internal systems and causing the orbiter to break violently apart over Texas.

The "failure mode" which destroyed Columbia and her crew of seven dedicated astronauts had caught NASA by surprise.  While a theory of her potential demise did, in fact, circulate briefly among engineers at mission control in Houston upon examining videotapes that showed icy chunks of foam from its giant external fuel tank striking the leading edge of the orbiter wing, a high-level review afterwards concluded that even if NASA had acted on the information, few practical options existed to save the crew.

Few practical options existed, too, for saving the program.  That same review drew the conclusion that flying the space shuttles beyond 2010 or thereabouts was, ultimately begging further death.  The space shuttle, the panel pointed out, had never achieved status as a truly operational system.  Because each flight was so system-specific and unique, despite repetitive success, each mission was an experimental flight, costing an average of $500 million apiece.  Moreover, the sheer complexity of the shuttle systems had aged in 30+ years unevenly and unpredictably, perhaps exceeding NASA engineers' ability to analyze and maintain them much longer.

But what a miracle it was.  Just thinking about the number of successful missions, set against the statistically stratospheric odds of disaster-- millions of inspections and opportunities for human error on every flight-- flying the space shuttle was an epic engineering and managerial feat of the highest order.  For persons who witnessed the entire shuttle program, from its inception in the 1970s until today's landing of the 747 carrier aircraft at Dulles will not see another orchestration of imagination, skill, guts and talent of this magnitude ever again.