But What Does It Feel Like?

I remember once, Tycho was saying something, I think in connection with Kirby's Epic Yarn, about the depiction of fabric in that being weird, because fabric's so familiar, while videogames routinely give us alien superconductors, and we have no idea what those should look like. I don't entirely agree—Reach has flawless renditions of various metals, and snow and sand and junipers, and Elites' plastic-looking armor and the Covenant's ablative heat-shield barriers; ODST and Halo 3 more than know their way around brushed concrete (New Mombasa looks a hell of a lot like the University of Arizona campus) and the high-density black plastic that gun casings are made of—but certes, one might do a better job with the portrayal and description of SF stuff.

It's fairly easy to do with fictional substances; my felinoids' swords look like vaguely pearlescent white plastic, and their guns look like they're carved from chrysoberyl. One ought, though, to extrapolate as much as possible from scientific theory, e.g.:

• Spacefolds, since they create an event horizon, cause a portion of a starfield to black out for a moment.
• Similarly, metric-patching engines make a sphere of blackness around a ship.
• People in airlocks are likely to have their ears pop, if the pressure between the two ships isn't equal.
  
• F-class and K-class stars probably look a lot like the sun in their planets' skies, except slightly bluer or redder, respectively; this might have weird effects on colonists' circadian rhythms.

But what about real equipment? Through dangers untold and hardships unnumbered, I've found the following bits of factual information:

• Aerogel feels like packing foam.
• A mechanical counterpressure spacesuit is like wearing a wetsuit.
• Spaceships' dust shields, as distinct from ablative reentry shields, are usually black, with a dull, powdery sheen. Why? They're graphite.
• It doesn't matter what color you make spaceships, since their exhaust and quite possibly their radiators are going to be glowing at least a dim red anyway.
• Spherical tanks are best for resisting pressure (their volume's also the easiest to calculate). You need one m³ of tankage for every 71 kg of liquid hydrogen fuel.
• Caseless rounds look like itsy-bitsy shotgun shells sculpted out of clay.

Remember, the purpose of writing is to convey the thing in your head to the reader's head. The more vivid you make it, the better you've done your job.