Even in his not-so-dark moments, Jon Clark wishes they had all died in that plane crash in West Texas.

Then they'd all be together now — he, his wife Laurel and their son, Iain. And the six other Columbia astronauts would still be alive.

"I've lamented about that, wishing that we had all just died because then it would have changed the course of history. They wouldn't have launched," Clark said in a telephone interview from Houston on a dreary January day that marked the anniversary of the space shuttle's doomed liftoff.

Laurel Clark (search— his wife, best friend, NASA colleague and the mother of 9-year-old Iain — was aboard Columbia when it fell from the Texas sky in pieces last Feb. 1.

Just six weeks earlier, in December, all three Clarks had plummeted from the sky over the same state in their single-engine Beech Bonanza (search). They were flying from their home in Houston to Albuquerque, N.M., to spend Christmas with Laurel's family.

The plane hit strong turbulence over West Texas and, for the first time ever, Laurel got air sick. Jon Clark was trying to land when the plane got caught in a downdraft. In a flash, the stall warning went off and the craft was sucked down, careered off the runway and smashed into an embankment.

The plane was damaged beyond repair. But the Clarks walked away.

Three weeks later, Iain was afraid to get on a turboprop to fly to Cape Canaveral (searchfor his mother's launch. The propellers frightened him.

The plane crash also may have exacerbated his dismay about his mother's first shuttle flight. Iain cried at the launch and badgered her for leaving every time they talked during the private family radio hookups during the mission, his father recalls.

Clark wonders whether his son had a premonition.

He says his wife traveled often and had even been sent to Russia, so it wasn't just the separation between mother and son that bothered the child. "There was something different about this. It is spooky," he says.

In the long days and weeks and months since that gut-wrenching February morning, Clark has agonized over the crew's final seconds a thousand times, trying to figure out what his wife and the other astronauts may have been doing and how long they may have lived.

He wants NASA to talk openly about all the circumstances surrounding their deaths, in order to learn and benefit future space crews. The cabin remnants, stored at Kennedy Space Center along with the rest of the wreckage, have been off-limits to all but a handful of cleared personnel. Details are sparse.

"You've got to be out in the open about it," says Clark, a NASA flight surgeon and neurologist. "You've got to say, 'How did this thing come apart? How did the crew die?' "

He's also insistent — even obsessed — that the space agency's lingering safety culture woes be addressed.

Accident investigators came down hard on a NASA bureaucracy that ignored the chronic problem of breaking fuel-tank foam insulation and then allowed engineers' worries to be buried while Columbia was aloft.

Clark nags NASA's boss, Sean O'Keefe, every chance he gets.

"He's very deferential," Clark says. "I also realize that actions speak louder than words and I don't want to hear about it. I want to see it."

The 50-year-old Clark remains at NASA only because he feels he can better initiate change from within. Of all the Columbia astronauts' immediate family members, he is the only one who works for the space agency and often speaks on behalf of the others at public events.

His psychiatry training comes in handy dealing with his son, but it's not enough.

"I am not a child grief person," he says. "That's why instead of soccer games, we go to the psychologists in the afternoons.

"He's gone through that denial-bargaining phase where he's trying to invent a time machine to go back and warn her, or clone her."

Laurel Clark's death at age 41 has brought father and son closer together and provided some precious intimate moments. "But then we also have to contend with no mom, no wife, nobody to goof off and have fun with, camping or hiking or all of the things that we loved to do together," he says quietly.

Every so often, Iain asks his father, "Why didn't they listen to that engineer?"

He's talking about the engineer at Johnson Space Center in Houston who feared Columbia might be gravely wounded but did not express anything to the right people at the top and who kept silent at the mission management meeting where the topic was put to rest.

The question breaks the father's heart.

"Well, you know, honey," he gently tells Iain, "it's like at school when you don't listen to the teacher and she really knows that this is the thing you need to do to not get hurt, but you don't listen. That's kind of like what NASA is doing. They're the child that doesn't listen to somebody who might know better."