LOST: The Looking glass, the sub, and the moon pool

sub2.jpgThe fourth season of LOST finally begins tonight on ABC. Hoo-rah!

Deep-sea fans weathered all sorts of abuses last season after John Locke blew up the Others’ submarine “Galaga”, and Mikhail used a hand grenade to flood the Looking Glass. The Looking Glass is an underwater jamming station equipped with a “moon pool” staffed by two tough chicks willing to throw down for the facts.

We figured the best we can do here at DSN to enhance your entertainment tonight is to give you a few facts about our favorite plot drivers- submarines and moon pools.

The “Galaga” looks like a shallow water transport vessel. It’s pretty roomy inside, so its unlikely to withstand the pressures of the deep-sea. Most submarines don’t go very deep, actually. We talk a lot about the DSV Alvin, depth rated to 6000m, and the Johnson Sea Link submersible depth rated to 1000m because these are scientific research vessels designed to plumb the depths and retrieve samples. German U-boats were designed to barely exceed 200m, while American Seawolf class nuclear attack submarines have a reported test depth of 500m and an estimated collapse depth near 750m. This barely reaches the peak height of most seamounts around the world. Not that we can’t find an exception. The USS San Francisco collided with an “uncharted” seamount south of Guam in January of 2005.

You might remember the “moon pool” from movie The Abyss. The moon pool is a cinematographer’s dream. Underwater light bounces off the walls and makes every camera angle look good. That’s why all the action happens there. A moon pool is also a handy thing to have when you’re launching submarines, ROV’s, and scuba divers.

A moon pool in a boat provides a sheltered portal from the wind and wave energy that can buffet an ROV or submersible as its retrieved by crane. Launch and retrieval are typically the most dangerous parts of the diving process. A moon pool in a submerged facility like the Looking Glass (of LOST) or the Aquarius habitat (of real life) allow saturation divers an easy portal to enter and exit the base station. While the function of the moon pool in the Abyss was clear, the function of the moon pool in the Looking Glass remains to be seen. Perhaps tonight we’ll learn more.

Charlie dives down to the Looking Glass station. Image from the Lostpedia wiki.

2 Replies to “LOST: The Looking glass, the sub, and the moon pool”

  1. There’s a really interesting bit on the physics of the Looking Glass at lostpedia.

    Because of the moon pool (through which Charlie, Desmond and Mikhail enter the station) the air pressure in the station would have to match the water pressure at the surface of the moon pool (otherwise the moon pool water would just rise into the station). This means that above the level of the moon pool (ie: at shallower depths), the pressure inside the station would be higher than the sea pressure outside, and portholes would be resisting outward pressure from the air, rather than inward pressure from the water.

    Thus losing a porthole would actually result in station air being lost outward through the porthole, while water rose proportionately (by volume) into the station through the moon pool (see explanation of moon pool hydrostatic pressure). The writers invoked the inappropriate but powerful popular image of water rushing in through the open porthole at high pressure, based on wide exposure of submarine-like submersibles where the inside pressure is maintained much lower than surrounding sea pressure through a strong shell holding out the sea. (Submarines do not have moon pools open to the interior living areas).

    Furthermore the Looking Glass cannot be flooded higher than the top of the broken porthole. The air pocket trapped above this level has nowhere to go and will prevent any more water entering. The ceiling is four to six feet above the porthole in the control room, and much more than this, perhaps twelve feet, in the submarine port, and this is how much breathable air will be left after flooding. If only Charlie had not closed the control room door and had joined Desmond in the submarine port, they would both have been quite safe, able to stand with heads above the water in the half-flooded chamber with plenty of air above.

    I doubt The Looking Glass is going to be revisited in S4… I imagine the moon pool was for docking the submarine.

  2. Fascinating. Thanks, Abbie. That’s a great interpretation.

    I watched the explosion scene more closely now. Mikhail looked like he was forced backward by the explosion. Water seemed to poured in rather than gush under pressure. Perhaps a small expulsion of air was enough to equalize the pressure? Tough call.

    Regardless, after tonight, it looks like it might be a while before we see an episode as exciting as the LG. Bring back the writers guild! Help save Hollywood!

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