That day in January 1986, I was in a restaurant somewhere near the Arboretum in Austin, chatting over coffee with colleagues Paul and Mike. I clearly remember looking at Paul when we heard the news: a sort of blank, disbelieving expression settled on his face. We rushed back to the office, where it seemed like everyone in the huge plant was crammed into a tiny room near the entrance. Silent, watching television. What else was there to do? Watching those pure white trails -- strangely beautiful for all the tragedy we knew they held within -- paint and scar that glorious blue sky. Over and over again the channels played the images, to the point that I find they are scarred in my mind too. Even 17 years on.

And 17 years on, white streaks across blue once more. You watch in silence, every millimetre of you aware that seven fellow human beings are buried somewhere in those streaks, as seven others were in 1986, and disintegrating with the streaks. And all over again, it is a strangely beautiful sight.

Does horror make you more aware of the beauty, even magnify it?

Walking to my office here in Bombay this week, I stopped at Flora Fountain, at a memorial to Kalpana Chawla. There were flowers, that now-famous photograph of her wearing her astronaut suit and a smile, and a book that I stood in line to sign. And while I waited, while I wrote my six words, I reflected: people die in accidents -- or not-so-accidents -- every day. All around us. Forty gone in a bus accident in West Bengal; man leans out of a Bombay suburban train and hits a passing pole; six dead as a wheel explodes on a speeding Sumo and it turns turtle on the highway. Everyday stories.

Is the disintegration of a spacecraft 40 miles above Texas any different?

Yet you know as I do: something about this tragedy was utterly compelling. To the extent that it stops us in our tracks; that there are people whose hope in India, in humanity, is renewed purely because of the waves of emotion we all felt for the seven on the shuttle. Why?

To answer that, I think back to the first shuttle mission after the 1986 Challenger disaster. It happened some three years later, after a detailed investigation of which Richard Feynman was a famous part. As millions must have, I followed the lead up to that mission with an awestruck fascination, an overflowing admiration for the nearly incomprehensible courage on display. Think of what it must have taken for that crew to go through their training, strap themselves in, do their pre-flight checks, lift off -- all while knowing that the last team to do these routine shuttle things had been blown to bits. What degree of faith did they have that NASA had found and corrected the tiny problem that killed those who went before? What kind of faith did they have in their teammates and colleagues?

Even though the questions probably grew less fraught with each mission that passed safely, every subsequent shuttle crew must have grappled with them, as everyone who rockets into space in the future will grapple with them. That is the courage we admired in Chawla and her colleagues.

No doubt there are ways in which we all go through such grappling in our own lives. A bus tragedy happens in West Bengal, but we have to, and do, go on using buses every day. Is that courage?

But of course, there is a difference. On the shuttle, they fly into the absolute unknown, into surroundings nearly malevolent in their inhumanity. That human beings can stare into overwhelming danger, fully conscious of its primeval threat, that they stare it down, do what they set out to do, live and return to us most of the time: that too is the courage we admired in that shuttle crew. There's something about danger on that scale.

Through his life, the writer Jon Krakauer found he was deliberately seeking out dangerous, difficult challenges. Often, they terrified him. In his brooding book Into the Wild, he writes of setting out alone in 1977 to climb an Alaskan peak called the Devil's Thumb. At one point, he realised that 'the frost feathers holding me up were maybe five inches thick and had the structural integrity of stale corn bread. Below was thirty-seven hundred feet of air.'

At second-hand in a dog-eared book, those words steal my breath away. On those feathers that day, Krakauer himself began hyperventilating from fear, fighting the 'sour taste of panic.'

Krakauer's passion for climbing suffuses his writing, but it's much more than just passion. Searching, unsparing, he analyses the meaning of such ordeals. He delves into the intensely personal appeal, the import, of walking the edge of danger. Reflecting on the Devil's Thumb ascent, he says:

'I was stirred by the dark mystery of mortality. I couldn't resist stealing up to the edge of doom and peering over the brink. The hint of what was concealed in those shadows terrified me, but I caught sight of something in the glimpse, some forbidden and elemental riddle.'

Why is a world so moved by the deaths of the shuttle seven? Why are we so aware of the beauty in those wispy, yet infinitely tragic, vapour trails?

To me, the answer lies somewhere in that dark mystery, that riddle, that Krakauer caught sight of. For they stand for the only god I'm willing to acknowledge, the only god that means anything to me: the human spirit. In Husband and Ramon, Clark and Brown, Chawla, Anderson and McCool, that spirit lived. And lives.

Columbia Space Shuttle Mishap