Music.
When most people think of the ships in NASA's fleet,
they think of the space shuttles that pierce the sky as they carry astronauts toward space.
But NASA has two seagoing ships -- the Liberty Star and the Freedom Star -- that also stand ready on shuttle launch day.
Their mission: heading to sea to retrieve the solid rocket boosters that power the shuttle's ascent.
"Freedom Star and her sister ship, Liberty Star, leave the Cape Canaveral Air Force Station about 24 hours in advance of the launch.
We usually arrive at the site about three hours prior to lift off.
At liftoff, we're about eight miles to 10 miles from where we expect the boosters to splash down.
The boosters usually separate about two minutes after liftoff. About four minutes later, they are splashing down in the ocean."
Each ship retrieves one booster, a potentially dangerous operation.
It requires that the ships' crew and divers closely follow safety procedures as they work with the booster components.
They also must stay constantly aware of the ever-changing conditions around them.
After they first recover the main parachutes and the cone-shaped cover -- called the frustum -- the dive operations begin.
"We'll deploy our dive team with six to eight divers, and we'll launch two boats. We'll then deploy our diver-operated plug."
At a depth of 100 feet, the dive team inserts a plug and an air hose to remove water from the booster.
After an inspection by a second team,
the process begins and the booster rises from the water until it rests horizontally on the surface of the ocean.
"It takes us about 40 minutes before that booster rises up out of the water and falls over on its side into what we call the 'log mode."
In this position, the boosters can be towed back to shore behind the two ships.
"It takes us about 20-plus hours to get back to the entrance of Port Canaveral.
We'll disconnect our tow wire and maneuver the ship around so that the booster is alongside the ship."
This positioning allows the two ships, with the boosters along side, to navigate the Banana River.
They return to the hangar, where the boosters are dismantled so they can be refurbished and used again for future shuttle launches.