Steampunk, Space and Aliens

[Kale]

You might want to check out "Tales of the Solar Patrol". It's pulpier than I think you want, but it does have a fairly good workup of the Jovian moons that might be useful to you.

[David Johnston2]

Originally Posted by scc

OK every so often a very weird steampunk/space campaign idea demands some attention from my head.

So the setting is the moons of a Jovian planet, three of which are habitable. Humanity evolved on one and has just enough tech to colonize the other two, which are taking the thematic place of Africa.

Currently I'm thinking that including aliens might be interesting, but as of yet I have very few firms ideas about them, they should be:

• Genre appropriate, that is conform to what people from that era thought aliens would be like, or what is likely to appear in modern fiction based upon those ideas
• Not be stupid, the campaign is going to be hard science, so no ideas based upon scientific concepts that have since been disputed
• A good stand in for Africans, so era views on Africans should apply to them
• And potential player characters

They would need a good grasp on chemistry and metallurgy to make rocket fuel and vacuum sealed compartments with enough oxygen. Here's a thought. Maybe they are seriously rocket oriented. They never came up with the concept of a "firing chamber". Their "rifles" and "cannon" are actually railguns that shoot little missiles with stabilising fins. So they never thought of the internal combustion engine. Good metallurgy means that their boilers can be very high pressure. They haven't figured out much about electricity so they use really sophisticated Babbage computers. The moons could be comparatively low gravity to make achieving lift off easier. Which means muscle powered flight becomes more practical.

[dcarson]

To replace radio use heliographs. One of the Space 1889 adventures is about a sabotage attempt on the almost completed orbital heliograph that will allow communications with mars faster then sending a ship. A image of it is at http://mateengreenway.com/steampunk/Harbinger.jpg.

[tshiggins]

Originally Posted by dcarson

To replace radio use heliographs. One of the Space 1889 adventures is about a sabotage attempt on the almost completed orbital heliograph that will allow communications with mars faster then sending a ship. A image of it is at http://mateengreenway.com/steampunk/Harbinger.jpg.

Okay. That's a seriously cool site. I like how he came up with all sorts of ways to use liftwood. :)

[dcarson]

One way to keep the science a bit harder is to have the moons be lower then one g. Given the exponential nature of fuel needed a 10% savings in delta v can matter quite a bit.

[Johnny1A.2]

Originally Posted by Flyndaran

And you're going to need some hand waving having one habitable moon, let alone three.

A habitable moon isn't a huge stretch. There are issues, but there are issues with habitable worlds generally, and yet Earth exists.

Gas giants sometimes end up close to their stars, you just need to assume that the gas giant in question landed up in the goldilocks zone when the pushing and shoving was done. In a galaxy of stars, that's probably happened many times.

You need bigger bodies than the Galilean satellites, with a higher percentage of rock and metal and less ice. The former you can get by assuming the protostellar cloud was richer in heavy elements than Sol's (probably younger than Sol too). The ice you can assume boiled off during a period during the early formation when the gas giant was really close to the primary.

A bigger problem is tide-lock. You might be able to have a human-habitable (broadly defined) world tide-locked to a gas giant, but it's iffy. So you need to assume the moons orbit further out from their gas giant than the Galilean moons do with Jupiter.

The biggest issue is having three human-habitable moons of one gas giant. That's not probable, to put it mildly, unless there is some natural process producing such that we don't know about. But that might be harnessable as a story-hook. Maybe the moons are the product of terraforming work in the deep past (by human standards), and the terraforming aliens (or whoever) left some powerful plot devices lying around.

(That might even explain part of the schizo-tech aspects of the setting.)