CAPE CANAVERAL, Fla. -- He was just 8 when NASA lost the space shuttle Columbia and he lost his astronaut mom.Now, 10 years later, Iain Clark is a young man on the cusp of college with a master's rating in scuba diving and three parachute jumps in his new log book.His mother, Dr. Laurel Clark, loved scuba and skydiving. So did her flight surgeon husband and Iain's dad, Dr. Jonathan Clark, who since the Feb. 1, 2003 accident, has been a crusader for keeping space crews safe.Altogether, 12 children lost a parent aboard Columbia. The youngest is now 15, the oldest 32. One became a fighter pilot in Israel, just like his father, and also died tragically in a crash. The oldest son of Columbia' pilot is now a Marine captain with three young children of his own. The commander's daughter is a seminary student."It's tough losing a mom, that's for sure. I think Iain was the most affected," said Jonathan Clark, a neurologist. "My goal was to keep him alive. That was the plan. It was kind of dicey for a while. There was a lot of darkness -- for him and me."Clark's wife and six other astronauts -- Commander Rick Husband, co-pilot William McCool, Kalpana Chawla, Michael Anderson, Dr. David Brown and Israeli astronaut Ilan Ramon -- were killed in the final minutes of their 16-day scientific research mission aboard Columbia.The space shuttle, with a wing damaged during launch, ripped apart in the Texas skies while headed for a landing at Kennedy Space Center. NASA planned a public memorial service for the Columbia crew at Kennedy this morning.Clark, now 59 and long gone from NASA, said he turned to alcohol in the aftermath of Columbia. If it hadn't been for his son, he doubts he would have gotten through it."He's the greatest kid ever," Clark said in a phone interview from Houston with The Associated Press. "He cares about people. He's kind of starting to get his confidence, but he's not at all cocky."Iain is set to graduate this spring from a boarding school in Arizona; he wants to study marine biology at a university in Florida."His life is like about as idyllic as you could imagine, considering all ... he's been through," said Jonathan Clark, who is still protective of his son's privacy. He would not disclose where Iain attends school, but he did provide a few snapshots.Mother and son were extremely close.After the accident, Iain told his father: "I want to invent a time machine." If he could go back in time, the child reasoned, he could warn his mother about the fate awaiting her."He asked me why she didn't bail out, that kind of stuff, because he knew she had been a parachutist," Clark recalled.Father and son were among the astronauts' families waiting at the Kennedy runway for Columbia that early Saturday morning. Once it was clear there had been trouble, the families were hustled to crew quarters, where they got the grim news.Rona Ramon's sharpest memory about that fateful Feb. 1 is how "the joy and the longing" to see her husband return from space turned so quickly into anguish. "I just looked up at the sky and said, 'God, bring him back to me.'"Her husband, already a heroic military pilot, became Israel's first spaceman on the flight.Clark hastily came up with a plan: Disappear with his son as soon as they got back home to Houston. Grab the dog, the car and as much money as possible. Then, "drop off the grid."But that didn't happen. A few years went by before father and son finally made their escape.Clark bought a house in Arizona, keeping a small apartment in Houston as he went from working for NASA at Johnson Space Center, to a teaching job at Baylor College of Medicine and an adviser's position at the National Space Biomedical Research Institute.Clark won't divulge his exact whereabouts, even now.He remains bitter over the "really bad people" who came after him in Houston for money and favors, spurred by NASA's $27 million settlement in 2007 with the Columbia families."There was a lot of grief. There was a lot of sorrow. There was a lot of destructive behavior. There were a lot of people taking advantage of you," he said.But he holds no grudges against NASA, neither the agency as a whole nor the managers who, during the flight, dismissed concerns from low-level employees about the severity of damage to Columbia's left wing. It was gouged by a piece of insulating foam that peeled off the fuel tank at liftoff.Clark learned of the foam strike during the mission, while working a shift in Mission Control. Like so many others, he wishes he'd done something.But no one knew during the flight how badly Columbia was damaged. And no effort was made to find out while there still was time to consider what would have been a risky rescue attempt by another shuttle.Surviving the actual breakup, during re-entry, was deemed impossible by all involved. At 210,000 feet going Mach 15, it was "much, much worse than anything we had ever planned for," former NASA shuttle manager and flight director Wayne Hale wrote in his blog last month.For four years after the Columbia accident, Clark assisted a NASA team that looked into how the astronauts died and how they might have survived.The tragic end to NASA's 113th shuttle flight prompted President George W. Bush to take action. He announced in 2004 that the three shuttles left would stop flying in 2010 once they finished delivering pieces of the International Space Station. The shuttles resumed flying with new safety measures in place and eked out an extra year, ending on No. 135 in 2011.The only way out of the Columbia darkness, for Clark, has been to move forward. "It doesn't mean I don't miss Laurel or have remorse about what happened," he said. "But you cannot be living in this kind of grief-stricken mode. ... Laurel would kick my ass if that happened to me."