The following is a recycled post, about Diesel and other flavors of punk. Comments in italics.
I like dieselpunk a lot. I want other people to like it. Having said that, the major hurdle is to make it look retro in a way that appeals to people in the Twenty-first Century. That isn't much of a hurdle to be honest. The artwork of the period and the machines have their share of fans. There's a ton of reference images and there is a slew of wild inventions and vehicles documented and photographed.ATM interplanetary travel is neither diesel nor atom punk. As this focusses on interplanetary travel I',m going with Planetpunk!.
There are a few problems though, like the Solar System. from what we know of the Solar System it's pretty darned hostile. Earth itself, our home wrold, is pretty darned hostile and can kill you in a number of ways! Consider 90% of the population is crammed into about 25% of the land area. There's a lot of deserts, tundra, and places with bears!
If you wanted dinosaurs on Venus a/o weird elder Martians in a steampunk game, you had to just go with it and say it was an alternate universe where life sustaining planets were the norm. For some reason disbelief is still suspended, even though a lot of physical laws and biological principles have to be disregarded. Dieselpunk doesn't seem to have that luxury. By the 1930's people knew a lot of steampunk ideas would not work. Fortunately, you have another option: terraforming. Yes terraforming could take centuries or millennia. Set your calendars accordingly or hand wave it gently away into decades. Don't be afraid to put the fiction in science fiction.
We knew jack about atomic power when dieselpunk started in the 30's. We know a bit more now (Heinlein's torch ship drive remains magic). You could specify a type of fusion for 'atomic power' these days and not raise any eyebrows. I prefer to go with boron to hydrogen reactions. It's a very clean energy source without many pesky neutrons.*
Fusion power and Ultra Dense Deuterium are both things. There are mechanisms that may protect us from nasty neutrons without heavy shadow shields. It turns out there is no way to manipulate a neutron. However, the charged particles made with th neutrons CAN be manipulated and due to conservation or momentum, the neutrons can be directed.
Dieselpunk doesn't have the information managing electronics we take for granted today. No smart phones with computer functions. Slide rules ... rule. This retro future never experienced, or forgot, the Information Age (how is that for irony?) Computers weigh hundreds if not thousands of kilos. Books are on microfilm or ... books. Space fighter pilots make sense! A computer that can replace a man would weigh far more than the man even with all his life support. It would probably suck, too. Just because something with the power of a Cray computer could fill a warehouse, doesn't mean they don't have them. They can use them for all manner of experiments and experimental simulations. They won't be toting these monsters on most ships though.
A Planetary Flight Control makes sense. It sends a ship the trajectory for its course, using one of those big brains. Plotting a course onboard might take days r weeks.Of course we're still talking high speed transits and high delta bees. An error means you wasted time or fuel or both. It usually isn't fatal.
Technology is far beyond ours in areas of energy generation, as I said, and materials technology. Light alloys, super explosives, giant electromagnets and engines we can barely conceive are all possible. They remind you you're in a future. It is a future dominated by square jawed, steely eyed rocket pilots (and those are just the women!)
So I'm rolling up my sleeves again to create a Planetpunk Solar System. I do plan on introducing some modern discoveries in these worlds. For example, though Europa will have a thin breathable atmosphere, and survivable arctic temperatures, it will also have an ocean under the ice.
*Plus I get to throw out thermonuclear fission and yell "Aha!" and cite Atomic Rockets when someone tries to call BS.