Space Ship Habitat

2018-12-18

I’ve written about this before and I’ll say it again: fore-and-aft spaceship design is silly. By which I mean the common assumption that a space-going vessel is laid out like a sea-going boat: horizontal decks, a bridge in “front”, engines in “back”, and some kind of gravity operating at right angles to the direction of motion.

The Space Shuttle looked like that because it was a shuttle between Earth’s gravity well and orbit. TV and movie space opera get a pass because they’re shooting on Earth. A few movies tried to get it right: 2001 strove mightily to simulate near-future space travel with 1960s practical effects, and The Black Hole despite its other problems started with its cast on wires floating around their tiny ship.

But in games, particularly maps, there’s no real excuse. Very few maps on Drive Thru RPG portray the more likely scenario: the crew habitat uses acceleration to simulate gravity, so it’s laid out like a tower or office building where “up” is the direction of motion. Also, since windows are unnecessary and perhaps a hazard, the “bridge” can be anywhere. Accelerating through interplanetary space means dust and small debris will bombard the top floors. If the engines are “under” or aft of the habitat the bottom floors might not be so safe either. Therefore, the middle floors are the safest part of the ship.

If I were building the habitat of the ship, here’s how I’d lay out the floors:

  1. (aft, bottom-most): A perhaps unpressurized empty space for fuel, shock absorbers, airlocks, and/or access to the engines aft of the ship.

  2. Cargo and storage, also not necessarily pressurized.

  3. Pressurized and radiation-proof storage for provisions, hydroponics, life support, and anything else the crew would need access to on a regular basis.

  4. One or more laboratories, machine shops, or other work places that might need proximity to ship stores, airlocks, and/or side-mounted engines if they exist.

  5. Crew quarters, living areas, recreation areas, etc.

  6. Radiation-shielded computer and sensor equipment, and possibly stations for monitoring it.1

  7. Dead space for fuel, sensor arrays, impact shielding, and/or radiation shielding.

The “bridge”, i.e. the place where pilots steer the ship, could be anywhere in the middle levels. Section 4 would put it with the other work areas of the ship. Section 6 includes the sensor equipment and information processing needed to steer the ship. One can even put it in section #5 so crew can get to it quickly in an emergency. Maybe the primary bridge is in Section 4 and a backup in Section 6 (“engineering”), as in Star Trek and other space operas. Or maybe one splits the functions of steering/astrogating, monitoring internal systems, communications, and battle among several stations as submarines currently do. Just because Star Trek and Babylon 5 put everyone in the same room for dramatic purposes doesn’t mean that’s necessarily the best layout. Ubiquitous and fault-tolerant communication across the ship means anyone can work anywhere, limited only by human factors and safety concerns. Consider, too, that for the most part pilots will steer using instruments – also like modern submarines – so they don’t need to sit in front of big windows1.

The ship and its crew must also adapt to changes in acceleration, both direction and magnitude. At the very least, a long-range ship accelerating at 1g must turn around to decelerate about halfway along its path, so crew would have to strap themselves in for a few minutes. Never mind the kind of space battles one sees in popular media, where the acceleration and deceleration would turn Earth humans into a sticky paste. (“Real” space battles might more closely resemble something from one of Larry Niven’s “Protector” novels: maneuver for a few days, fire a laser on closest approach, maneuver for another day, fire again, repeat until someone is disabled.) We underestimate how vast the distances between planets, and how long it would take to get there even at a steady acceleration our squishy forms could tolerate.

All this assumes something like Earth humans traveling between planets. An alien species of brachiators, or beings fully adapted to space, might prefer a space full of monkey bars and webbing with platforms and alcoves for necessary work stations. That’s assuming Charles Stross isn’t right, and the only feasable interplanetary or interstellar probe isn’t a nanotech A.I. atop a giant reactor that builds whatever and whoever it needs from materials at its destination. Which pretty much throws out everything except planet-bound roleplaying games. If the whole crew hibernates – or doesn’t exist – until the ship enters orbit, why bother with the layout at all?2


  1. In space windows are a hazard: breakage, air leaks around the frame, radiation leaks, probably others I can’t think of at the moment. ↩︎

  2. One RPG setting I came up with did that: the only non-machine creatures who could travel between stars reliably, albeit at less than the speed of light, were aliens called the Elders who seeded multiple worlds with Earth-derived life. For their own mostly non-sinister reasons they’d cart hibernating humans between orbitals over planets they’d previously seeded, or drop them on a new colony world. The Elders themselves had wholly adapted to space travel, to the point they almost never ventured into a gravity well, and only mingled with humans in awkward-looking travel machines: spidery limbs arranged in varying configurations around a marbled ellipsoidal shell, with no visible sensory apparatus and only a small grill that produced obviously synthesized speech. The only other interstellar powers were the Machines – artificial intelligences who primarily lived on airless worlds or deep space – and a few stubborn remnants of the Fifth Terran Empire who limped from star to star using their own aging fleet of generation ships. Next to a Stargate-style setting, this was the best way I could think of to avoid space opera star travel tropes. ↩︎