Quarter Share: A Trader's Tale from the Golden Age of the Solar Clipper by Nathan Lowell

humidity and the smell, about half the people that come in here turn around and walk right back out. The humidity’s from the matrices and the smell is from the algae.”
    “Okay, that much I understand. But there is still a lot I’m confused by.”
    “How far have you gotten in the instructional material?”
    “All of it, actually, but I can’t seem to pass the practice test. Things I get right on one, I miss on the next and around and around. I can’t seem to keep the scrubbers and the filters straight.”
    “Filter the water and scrub the air down, mix water and algae to make it all brown.” She chanted it in sing-song with a smile.
    “Wow, I actually understood that,” I said with surprise as it slowly penetrated my brain.
    “First practical piece of advice we give people. Water gets filtered and air is scrubbed. Then they get mixed together. It starts with running the water through a collection of different media to filter out finer and finer impurities. Eventually, it goes into the scrubbers where it keeps the algae matrices wet. That’s probably where your brain gets confused because the scrubbers work on both air and water.”
    “Okay, that makes sense so far. So, the air doesn’t get filtered?”
    “Actually, it does, but we don’t have a separate filtering system for it. Not like the water. There’s a simple electrostatic field that the air is passed through when it first comes into the system. It snags all the dust and other particulates out of the air. Technically, that’s not a filter because a filter is a physical barrier, like when you make coffee. The weave in the paper has holes that allow the infused water to pass without permitting the grounds themselves. It’s the same idea with the water system although the chemical processing is a bit more complex.”
    I nodded. “And because the air is passed through a field, and not a physical barrier, you call it scrubbing instead of filtering?”
    “Exactly.” She nodded and smiled. “The scrubbers also grab any odd gases that make their way into the system. Those are usually byproducts from work on the ship like trace amounts of free esters, ozone, and so forth. The goal is to keep the proportions of oxygen, nitrogen, carbon dioxide, and trace gases consistent. The air coming into the system is high on carbon dioxide and low on oxygen so we feed it into the wet algae matrix where the algae absorb the carbon dioxide and produce oxygen. Have you ever noticed that the berthing areas don’t smell like a locker room?”
    I nodded.
    “The algae loves the stuff that makes that smell. It would reek if not for that.”
    “Right, thanks, that helps.”
    “Come on.” She turned and beckoned me to follow with a wave of her hand. “I’ll give ya the half-cred tour.”
    For the next stan, she showed me the inner workings that kept our air and water clean. I expected to be disgusted by some of the processing. Sewage isn’t exactly appealing, but I found myself fascinated by the way the air and water systems intertwined on the ship. There was a certain amount of unrecoverable waste, but almost ninety-eight percent of the air and water was recycled. At each port, we topped off the elements that got lost, used up, or destroyed. I even got a perverse bit of entertainment out of the notion that coffee was continually recycled through the crew’s kidneys, down to environmental, and back to the mess deck where it started the cycle anew.
    When we got to the algae matrices, the-makes-it-all-brown part of the doggerel became apparent. According to The Handbook , the algae were a blue-green variety but when they were wet, exposed to light, and healthy, it wasn’t green at all, but a kind of reddish-brown. The matrix itself, was actually a synthetic film that held each little alga suspended to maximize its surface exposure. My preconceived notions about tanks of blue-green pond scum were blown away.
    I laughed out loud and she turned a quizzical eye in my