But Clark 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, Clark 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 earlier this 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.
For Clark, it was about "trying to find something good out of something bad. I kind of threw my heart and soul" into crew survival issues and, most recently, the faster-than-the-speed-of sound, stratospheric jump by Felix Baumgartner. Clark was the medical director for the Red Bull-sponsored feat last fall in New Mexico.
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."
The shuttle commander's widow, Evelyn Husband Thompson, finally feels free to start giving back, now that her youngest, Matthew, is 17. She wanted to focus first on her two children and then on her marriage five years ago to Bill Thompson, a widower she met through church. Bill provided the crucial male role model that Matthew so desperately needed following the accident, she said.
Now, his mother said, "he enjoys his private life."
"It was tough. Overnight, my children were thrust into this international stage," Thompson said. Having the last name "Husband" drew grief-stricken stares for the longest time in Houston, home to Johnson Space Center. "With the mercy of time, people really don't recognize it as much as they once did," she said.
Her new passions, each purposefully low-profile: her neighborhood YMCA where Husband once coached children, a ministry for widows at her church, and a Christian organization that helps fatherless boys.
"These three areas right now just fit me to a T, and I know that they would really please Rick," Thompson said in a phone interview Tuesday.
"We just still miss Rick so much," she said. "The sweet part of it is that we have made it 10 years, that God has been faithful in our lives, and we have been able to find joy in the midst of a lot of sorrow."
Daughter Laura, 22, is working on a master's degree in theology. Matthew is a high school sophomore. The entire family, as well as close friends, will gather at Kennedy for Friday's memorial service, which also will honor the seven astronauts who perished during the Jan. 28, 1986, liftoff of Challenger and the three killed on the launch pad in the Jan. 27, 1967, Apollo 1 fire.
Thompson is a featured speaker. Anderson's widow, Sandra, also plans to attend.
The two women, who attended the same church with their late husbands, remain close. The rest of the Columbia families have drifted apart, Thompson noted, but they all have a common goal.