"It just kind of hit me out of nowhere. You've got no leg, nothing you ever do the rest of your life will ever be a normal process," he says. "But it's not something I dwell on. I do not doubt that I can do whatever I want to do. I am grossly overconfident in myself."
At the airport, Pettigrew is greeted by his wife, Ann, and, to his surprise, a contingent of soldiers and wives from Fort Carson. "The one thing I was afraid of was how he was going to cope psychologically with what had happened," says Ann.
To ease the transition, Ann sold their two-story townhouse and bought a new place with everything on one floor. But is this what Ann signed up for when she married David?
"I looked a long time to find my husband. I have 35 ex-boyfriends, I've looked under every rock, in every crevice, down every bar," says Ann. "It didn't matter if he had one leg, both legs, no legs. Dave was the right person for me."
"There was never, 'Hey, goodbye, I realize you lost your leg, and now you lost your wife. Later,'" adds Pettigrew. "That would have been very hard. I don't know how I would have dealt with that. And I'm glad I didn't have to."
But to Robert Acosta, now back with his parents, it all seems unreal.
"I was in the desert one day and in the hospital the next day, and now I'm here. Everything's going so fast," says Acosta, putting down his crutches and sitting down. "God, I feel like an old man."
"It's hard to accept, 'cause you know he left good," says Acosta's father, Robert Sr. "You'd think he'd come back the same way you let him go."
He received a hero's welcome from the city of Santa Ana, Calif., but things have changed. "I just feel different, like something's wrong, almost," says Acosta. "Sometimes I'm really rude. Sometimes people stare and I say, 'Yeah, it's a hand gone, what are you staring at?' I really don't know how to deal with it sometimes."
Acosta says he replays the tragic incident every day: "People don't see it, like, what their family has to go through. On TV, you see two soldiers wounded. It doesn't say, 'One guy's lost both legs, one won't make it through the night, and the other guy is missing his eyesight.'"
"Nobody wants to know what wounded means. The people who are willing to deal with the fact that this is what we pay for what we do, they'll find out, and the people who don't want to know will ignore it anyway," adds Pettigrew. "War has very personal costs. And if you're not directly affected by them, you don't know."
Despite what this war cost him, Acosta is seriously thinking about staying in the Army, even if it means limited duty. "I wish I was still there. I miss my buddies a lot," he says.
For Pettigrew, however, the Army was never more than a detour: "I just wanted to do my time and finish it up, kind of like a jail sentence, I guess," he says.
He and Ann had planned to start a family, and he thinks someday he'd like to teach high school. But for now, he's focused on regaining his independence. "Right now, there's a lot of things that I just cannot do, and it's hard for me to accept that," he says. "So the things that I can do, I like to do."
He's also learned to drive again, in a new black pick-up, specially modified with help from the V.A. hospital. "It's a big step for me, that whole independence thing that I wanted. This is part of it," he says.
But there's another piece of equipment even more key to his independence: a C-Leg, the latest $100,000 computer-controlled artificial leg. It continuously makes minute-adjustments for balance and speed.
"I want the leg. I really want the leg and I want to use it," says Pettigrew. "Because if I can walk on legs without crutches, then I've got my arms and my hands and all the rest of my body to do stuff again."
Today, he's being fitted for a special molded form that attaches to the leg. "It takes a tremendous amount of energy to learn how to walk with it," he says. "If I can get around great with it, fine. If I can't, I'll sort it out. I'll work from there."
Acosta, meanwhile, is about to shed his crutches. His foot is slowly healing, but he's not exactly taken to his new arm yet. "One of them I broke when I was crushing cans," he says, laughing. "And the other one I think I was mad and I threw it against the wall or something."
He says he feels more comfortable without the prosthesis. But after a month's leave, he's returning to Walter Reed for more physical therapy.
After nearly four months at Walter Reed, Alan Lewis says he's more than ready to move on: "This is not going to stop me from doing what I want to do."
Back in Milwaukee, his mother, Audrey, is preparing her apartment and herself, to take care of her injured son. But Lewis says he doesn't want to be treated like someone who needs a wheelchair: "It's all become second nature now, walking regular, just don't think about it any more. First, it was like concentrating on the right foot, concentrating on the left foot. Now, it's just walking."
"We'll take it one step at a time, one day at a time," says Audrey. "I don't know what's going to happen when he comes home. I can only pray that everything works out."
At the V.A. Medical Center in Denver, David Pettigrew is taking one step closer to walking again with his new computerized leg.
The first steps are a bit awkward, but with an hour's practice, he's on his way. "It's a strange way to learn how to walk," he says. "I wish I could remember what it was like when I did it the first time."
He's confident that he'll no longer need his crutches by Christmas. "I believe that God still has stuff for me to do. What that stuff is I don't know and I don't question," he says. "But that there is still something there for me, yeah, I believe that. I believe that entirely."
"I have no regrets at all. I'd do it all over again if I could," says Acosta, who has come to terms with his artificial arm, and now uses it like a pro. But he says he's decided not to stay in the Army: "I just can't do the things like I used to."
As the guest of honor at a recruiting event, he's donned his dress blues for perhaps the last time. But he doesn't consider himself a hero. "Why am I a hero? What did I do that any other soldier would have done," says Acosta. "I know if my buddy was put in my position, he would have grabbed that grenade also. Or any soldier would have grabbed that grenade."
"I don't think of myself as a hero," adds Pettigrew. "The guys who are over there, who are still doing it, are more heroes than me."