Behind-the-scenes look at the USS Abraham Lincoln overhaul

One of the most recognized ships in the U.S. Navy is ready for service again after a massive overhaul. The USS Abraham Lincoln just finished a four-year, $4 billion makeover in Virginia.

The 90,000 ton USS Abraham Lincoln is one of the largest warships in the world. When the U.S. prepared to take on Saddam Hussein in 1991, the newly-built USS Lincoln patrolled the Persian Gulf, reports CBS News correspondent Jan Crawford.

During the 2003 invasion of Iraq, the ship launched over 100 missions a day and served as the site of one of President George W. Bush's most famous announcements.

When a devastating tsunami killed hundreds of thousands in Southeast Asia, the Lincoln rushed to the region to provide relief. Now, nearly three decades after it first departed Newport News, Virginia, the Lincoln is heading out again for another 25 years at sea – better than ever after a four-year upgrade and overhaul at the Huntington Ingalls shipyard.

Huntington Ingalls CEO Mike Petters gave us a tour of the carrier just before it was turned back over to the Navy. During the overhaul every component aboard the Lincoln underwent extensive renovation – a responsibility Petters said he and his employees take seriously. "It's a privilege" to work on the aircraft carrier, he said.

"The nation entrusts us with creating these complex platforms that are going to take, really, the most valuable resource we have, which is our young sailors, and take 'em into harm's way," Petters said.

Often deployed for months at a time, more than 5,000 people can live aboard the Lincoln when it is fully staffed.

"It is a city with its own airport," Petters said. "It's got all the things that you need to accommodate 5,000 people in a city – between food, sleeping arrangements, entertainment, training. … Every single thing that has to happen to support the mission of the ship. And then you're going to go and drive this city around out there at sea, in an environment that's actually pretty harsh. At some point, the quality of our work is going to get tested."

"It won't fail," he added.

The man who steered this massive construction project was U.S. Navy Capt. Ron Ravelo.

"Before it came here to Newport News, you looked at maps?" Crawford asked.

"Right, absolutely," Ravelo said.

"And one of the things you've done the last four years is now this will all be navigated with electronics," Crawford said.

"Right," Ravelo said.

Ravelo said it's important to remind the crew what they're working towards.

"Conceivably one of their sons or daughters will be a member of the last crew of this ship, you know, 25 years from now. That's how much capability, that's how much life we're putting back into this," Ravelo said. "It's another generation of sailors. Maybe even two."

To help recruit and train qualified shipbuilders, Huntington Ingalls relies on its apprentice school, with an admissions process as competitive as the Ivy League. Students get paid to take classes while getting hands-on experience and working full time towards a college degree.

Ed Spruill has been a pipefitter at Newport News for 39 years and his son now also works in the shipyard. Spruill helped build the Lincoln and plans to retire once the overhaul is complete.

"There's just something about this stage, when you're ready to go to sea, that when you go down that river and you know all those hours were put in, and now you're going out on sea trials. It's just a pride in what you do," Spruill said.

Ramirez Crumbley, 33, an electrical foreman, also feels the pride.

"I mean, I didn't get it at first. When I first got here, I mean, I just thought it was a job. And then to actually complete a carrier and to actually see it go out to sea, I mean, is just outstanding. And it just makes you feel special, as a person, that, hey, I was a part of that project," Crumbley said.

His colleagues Famatta Cole and Kristoph Lucas both served aboard aircraft carriers in the Navy.

"It kind of makes you work a little bit harder, especially after knowing what it's like to live on that ship," Cole said.

All four shipbuilders said working on equipment that helps keep the country safe carries with it a heightened sense of responsibility, and building ships with a 50-year lifespan can quickly become personal.

"My son is 7 years old and he tells me every day how he wants to be in the military, be in the Navy, or something like that," Lucas said. "I was 17 when I got in the military. And if he follows in my shoes, he's gonna want to do the same thing. And if he's on a ship, I want it to be right."

With the next generation of carriers already under construction, Huntington Ingalls promises to be busy for decades to come. To make sure he has shipbuilders ready for the work, Petters donates his base salary to provide pre-school scholarships for the children of his employees, hoping some of them may follow their parents into the shipyard.