Challenger - 20 years on

January 28, 1986. 11:39 a.m. ET.

I still remember what it felt like. In an instant, my idealistic beliefs in the infallibility of technology evaporated as I sat in stunned, disbelieving silence, watching the shattered pieces of humanity's most vaunted technological icon splash ingloriously into the ocean.

It's cliche to call the seven astronauts who died in the explosion of the space shuttle Challenger heroes. But in so many ways, they were. As were the seven who perished aboard Columbia 17 years later, and the three lost in the Apollo 1 launchpad fire in 1967. They risked - and ultimately lost - it all so that we would continue to push the bounds of exploration.

They were doing what humans have done forever; constantly challenging the limits of movement imposed on us by our current technology. From the earliest wheels to ancient ships to the latest aircraft, no new transportation system into a new environment has been developed, exploited and made routine without risk, or loss.

When I think of Apollo, Challenger and Columbia, I think of the countless aviators who perished in primitive contraptions so that we could cross the planet in a day with little more than some bothersome jet lag and a kinked neck from the lousy little pillows they hand out on trans-oceanic flights.

The extreme has become mundane. But only because explorers among us were willing to go there first. And possibly not return.

I shudder to think where we'd be without their kind. Likely nowhere.

I remember their names as clearly today as I did long before they first lifted off on that tragic day: Francis "Dick" Scobee, Michael Smith, Judith Resnik, Ellison Onizuka, Ronald McNair, Gregory Jarvis and Christa McAuliffe. I think of Commander Scobee and Pilot Smith, who by ancient tradition were ultimately responsible for the ship and its crew, who never got to bring their crewmates home - not because of anything they did, but because of the flawed organizational underpinnings of NASA, the organization they trusted with their lives.

Ms. McAuliffe, the first teacher in space, never did get to teach her lesson from orbit, and it was her loss that most poignantly galvanized the nation's sense of loss. Yet in the years since, we've started to learn how to turn unspeakable loss into hope for the future. We've lost another orbiter, endured the same painful analysis of the organizational and human factors that drove both losses, and emerged from the other side with the same drive to improve, advance and look forward.

Folding up our tents and going home was never an option. Nor should it ever be.

I never saw Ms. McAuliffe's lesson plans for that flight, but I suspect they very likely incorporated those very themes. May the exploration she and her crewmates so selflessly pursued never be hindered by those among us whose fear of risk would have us not try at all.

Onward.

Your turn: Thoughts?