Well, I was going to post the second part of The Shipping Trade today, except that writing it didn’t happen because of day job, and so forth. Then, I thought I might post a sketch of the ship involved, just to give y’all an idea of what you’ll be looking at, but then that would require me to go out and hire a scanner. That, and I made said sketch, and then looked at it, and then concluded that I couldn’t possibly inflict such a terrible picture on my readers…
So permit me, please, instead to sketch a verbal picture for you of the
CMS Greed and Mass-Energy
To start with, Greed and Mass-Energy is atypically large for a free trader; in those leagues, which principally deal in small, high-value-to-mass/volume cargoes, lugging around 40,000 tons displacement of cargo is huge. (It’s still not in the major freight line league, though; those guys can use freighters that are million ton-displacement behemoths.) Thus, the shipcorp that owns her (it’s essentially a syndicate of officers, crew, and former crew, with executive power vested in the captain-owner) is pretty prosperous to be able to cover her running costs. Dealing in brokered cargo actually isn’t her main business – she specializes in contracts like the RCS-assembly charter from Kerbol to Kythera she just left, but an empty hold is a hole that drinks money, so you take the cargo when you can get it.
Also, obviously, at a size like that, she’s not streamlined, or built to land planetside (gravity wells being acutely expensive); and is even rather more massy than anything that most stations like to have dock directly to them. Her cargo’s generally ferried to station, or upwell and downwell, by local lighters at each end of the trip. Rather, she’s built very much in the classic mode; a long, relatively thin, open-frame truss structure. Attached to that, going from fore to aft, we find these different sections of the ship:
Right at the bow, sitting on the end of the main truss, is the command capsule, an ellipsoid slightly stretched along the ship’s main axis, relatively tiny compared to the rest of the ship, and containing, for starters, the bridge and associated avionics systems. (The bridge is actually buried in the center of the capsule, for its protection; it’s displaced off to the front end of the ship, however, because the command capsule is also where the primary sensors are housed to keep them out of the way of cargo, fuel, and drive radiation, and this positioning cuts down on sensor lag. It’s still pretty safe; it’s not like anyone’s going to be shooting at them.) The first of the other two notable features it houses is docks and locks, right for’ard on the axis where it’s easiest to match thrust and spin, which usually houses a couple of cutters used for taking the crew ashore and for occasional maintenance, and a skimmer for in-field refueling. (The fuel itself doesn’t pass through here – the skimmer docks aft to offload what it scoops. No fuel for’ard of the support plate, that’s the general rule.) The second, aft by the truss, is the robot hotel for all the little space-rated utility spiders you may see now and them crawling about the structure doing maintenance, thus saving the engineering department any need to get suited up and go outside for routine work, although they still may need to do so from time to time.
Just aft of that, accommodations and secondary systems are housed in a toroidal gravity wheel. This is actually a very unusual design feature in an Imperial ship-class; just about everyone and especially the spacer-clades are genetically adapted to microgravity, and the spacer-clades prefer it, as a rule; but the Cheneos-class architects originally designed her class for near-frontier work, and included this for occasional passenger service. Greed and Mass-Energy only rarely carries passengers, so they keep it geared all the way down, producing only a tenth of a standard gravity, which doesn’t offend the spacer-clades all that much. There’s a second, smaller wheel rotating inside it to null out the gyroscopic effects; it’s used to house some other equipment that likes a little gravity, but for the most part, this one’s just a countermass.
(The wheel does, however, provide enough gravity to let the CELSS Manager run a pretty decent microbrewery in the spare volume, and perhaps more importantly, provides a place where you can drink it off-shift without suffering from a nasty case of the zero-g bloat. [Remember, folks, bubbles don’t rise in microgravity!] And apart from crew morale, having decent beer makes for good PR when traders meet.)
These areas, incidentally, are one of the few places on board where the really high-tech ontotechnological stuff makes an appearance, in the form of inertial damping. The people who built her liked microgravity, and weren’t all that keen on losing that while under thrust, especially since she was built to fly brachistochrones or near-brachistochrones (bulk tankers and ore freighters, etc., are usually built to fly economic minimum-delta/Hohmann transfers; no-one else wants to wait that long for their cargo) and so would be spending most of her time under thrust. The job of the inertial dampers is to apply the thrust of the drives evenly across the entire area’s structure and everything in it, thus ensuring that no-one actually feels any acceleration, and the lovely microgravity environment is preserved. (It also avoids having to come up with some wretchedly complicated gimbal arrangement for the already wretchedly complicated seals-and-bearings for the gravity wheel, no longer having to do which is something that made architects particularly grateful for this innovation.)
Behind this, the cargo. ‘Way back along the truss there is a very large, solid plate, the support plate. The cargo containers are simply stacked “atop” – by which we mean for’ard – of it, in six big blocks arranged around the axis with sixfold symmetry (this arrangement being a reasonable compromise between use-of-volume and convenient straight lines), and are designed to lock to the plate, the truss, and each other to form a solid interlocked structure. There’s no hold or other walls around the cargo; the containers are themselves spacetight when they need to be, and so lighters can just drop them into place and pick them up freely while in port.
The breakbulk cargo, on the other hand, is messy. It has to be podded up individually when not spacetight, and then individually lashed down and made secure atop the cargo container stacks. This annoys the cargomaster, which is why breakbulk is unpopular these days despite the fact that breakbulk shippers usually pay a premium in exchange for you having to do this (the “lash comp”). Actually, what really annoys the cargomaster is that she can punch a button and have the ship automatically query the v-tags on the container cargo for its mass stats, and so forth, whereas for breakbulk she’s got to recall her Academy training, dig out the spreadsheets, and work out the corrections to the center-of-mass-and-moment-of-inertia chart by hand. Well, still by computer, but you know what I mean.
Aft of the support plate, still in sixfold symmetry, you have the bunkerage – fuel tanks, stacked three deep in multiple rows, all filled with slush deuterium, running right to the stern, where they surround the cylindrical shroud of the mostly-unpressurized engineering hull (you can take a crawlway right back along the truss to the small, pressurized maneuvering room back this far, should you need to examine the drives close-up in flight, but the actual machinery space isn’t), which contains the interlinked systems of the main power reactors and the fusion torches themselves, strapped to the aftmost extent of the main truss.
And there are lots of fuel tanks. Even though said fusion torches are miracles of a mature nuclear technology, capable of achieving near-theoretical efficiencies and outputs and delta-v per unit fuel that routinely makes naval architects from less advanced civilizations throw down their slide rules in despair and weep into their terrible coffee-equivalents, the one unchangeable rule of space travel is that your mass ratio is always much, much less favorable than you might want it to be.
Good thing deuterium’s so cheap, isn’t it?
(Edited to add: And I must have been half-asleep this morning, because I forgot…)
…and most prominently of all from a distance – dominating the entire view of the ship from a distance, by area as well as by temperature – sweeping out from among the fuel tanks (although comfortably retracted to sit alongside them, leaving approximately a sixth of their radiative area useful, while idling in dock – the vast panels and pipework of the heat radiators. Because the other one unchangeable rule of space travel is that you always have waste heat, too damn much waste heat, and you’ve got to get rid of it somehow. Especially once you fire up those fusion torches. (The radiators, however, unlike the rest of the ship, have only fourfold symmetry – so that they can be perpendicular to each other when unfolded, because there’s very little point in radiating heat right back at your own radiators.)