Pacific Vortex: National Space Headquarters and more

pg 117

It was difficult for him to believe that he was in a submarine beneath the sea instead of a highly complex command center at the National Space Headquarters.

The USA does not have a National Space Headquarters. (China does, interestingly enough.)

"He went aft to check for flooded compartments and to make sure the Hyperion Missiles are still snug in their cradles."
There is also no such thing as Hyperion Missiles. Cussler is naming the missiles after a Greek titan.

Hyperion ("The High-One") was one of the twelve Titans of Ancient Greece, the sons and daughters of Gaia (the physical incarnation of Earth) and Ouranos (literally meaning 'the Sky'), which were later supplanted by the Olympians. He was the brother of Kronos. He was also the lord of light, and the Titan of the east.

He was referred to in early mythological writings as Helios Hyperion ('Sun High-one'.

In Homer's Odyssey, Hesiod's Theogony and the Homeric Hymn to Demeter, the Sun is once in each work called Hyperionides, 'son of Hyperion', and Hesiod certainly imagines Hyperion as a separate being in other writings. In later Ancient Greek literature, Hyperion is always distinguished from Helios; the former was ascribed the characteristics of the 'God of Watchfulness and Wisdom', while the latter became the physical incarnation of the Sun. Hyperion plays virtually no role in Greek culture and little role in mythology, save in lists of the twelve Titans. Later Greeks intellectualized their myths:

Of Hyperion we are told that he was the first to understand, by diligent attention and observation, the movement of both the sun and the moon and the other stars, and the seasons as well, in that they are caused by these bodies, and to make these facts known to others; and that for this reason he was called the father of these bodies, since he had begotten, so to speak, the speculation about them and their nature.
—Diodorus Siculus (5.67.1)

Missiles in their cradles:
Torpedoes swim out horizontally from weapon tubes in the bow (front) of the submarine having been forced out of the tubes by pressurised air or water. They are loaded into the tubes from within the submarine. Some are guided from the submarine by an attached wire, whilst others use built-in guidance systems to ‘home’ onto their targets.

Moved by an instinct as old as man, Pitt gently reached down and closed March's eyes.

When a person dies, all of their muscles relax. If the eyes are open at the moment of death, they will usually stay that way. Also, if someone had their eyes closed at the moment of death, they will tend to open a short time later due to the relaxation of the muscles that open and close the eyes. This isn't always the case, but for the majority of people, the eyes will be open. Morticians do not sew the eyes shut. The old fashioned way was to take some cotton and place it under the eyelids. This kept them shut and gave them shape, as the eyes tend to sink back into the sockets after death. The current method of keeping the eyes closed is to use what are called eye caps. They have little grippers on one side, and are smooth on the other. The grippers keep the lids closed.