The USS Pasadena is a nuclear-powered submarine currently docked at the largest naval base in the country for maintenance.

Channel 5 News was given a rare look inside the submarine.

The spaces on the sub are crowded, and the men and women on them spend months underwater. 

“You don't realize how much you miss sunshine until you don't have it,” a crew member said.

Food is a morale booster for those who haven't seen the sun. The submarine carries enough food for three to four months.

Meals are also prepped for the ship's mascot, a tortoise named frumpy who replaced a snapping turtle brought aboard by a previous generation of sailors after it got too big to keep onboard.

Space for sleeping is limited too. Sailors sleep in shifts for as many hours they can get.

The USS Pasadena is gradually winding down to become a training sub for sailors in the Navy.

For now, it's still operational and ready to deploy.

Watch the video above for the full story.