My Inner Skeptic LOVES Orbital Mechanics
May. 24th, 2012 01:03 pm![[personal profile]](https://www.dreamwidth.org/img/silk/identity/user.png){kind=small}
beccastareyesI'm discovering that hard SF where you're bouncing around the solar system means my Inner Skeptic actually pays attention to people other than me and my writing.
Probably because I've spent most of my adult life following NASA missions. Maybe because I read Heinlein in high school, and Heinlein learned orbital mechanics for his solar-system SF. There might be Martians and Venusians and a spin-locked Mercury*, but by golly, things moved like they should.
But when you're gallivanting around the Solar System you have to remember that things are all moving at different rates.
I'm still working my way through the Hugo nominees, so I'm reading Leviathan Wakes by James Corey. And it's solar system SF that markets itself as 'hard SF', which is nerd-speak for 'written by people who assume their audiences are nerds' (says the woman who is writing about fact-checking in hard SF). It's a useful genre term, even if it's half the time used in a pretentious way to dismiss things not written by engineers and that have things like biology and culture and feelings. (It's why I tend to dislike the word 'hard' describing anything but the rigidity of an object, because the same damn thing happens in science: our field is hard and yours isn't, nyaa! But I don't have a good word to describe a genre I like.)
Anyway, a station is described as 'on the opposite side of the (Main Asteroid) Belt from Ceres' and I had to think about this because... things move. There are times when Ceres and Vesta are on the same side and times when they're on the opposite side. The best I can come up with is 'close to Ceres' orbital distance, but 180° away in longitude which... means they'll stay roughly opposite for hundreds of years between closest approaches'. Which, threw me because I had to think if you can do this. (You can; we look at things like that at Saturn.)
It's still going; I start critiquing why you'd put a ice refinery on Iapetus, since it's out in the sticks of the Saturnian moon system, far from the rings which is the textual source of water. Or why you'd used the rings at all; they're pretty pure water ice, but you got to get down in Saturn's gravity well to get them. Mining the outer satellites or Centaurs would get you a 50-50 rock/ice mixture, but be a lot easier to ship out. Or heck, shovel off the crust of the moons you colonize.
Or things like 'wait, why is Jupiter coincidentally in the right place on a Saturn-Ceres run so it can be a convenient 'shit things have gone to hell and we are halfway between Jupiter and Ceres, out or in?' site. I realize you have power to spare in settings like this, so things like 'two round-trips from Saturn to Ceres a year' are doable. (The fastest we've currently traveled the Jupiter-Saturn's orbit distance is 15 months, but the probe was coasting the whole way, not burning engines... on the other hand, it didn't have to slow down when it got to 9.5 AU.) But things still move, and there will be times when you might want to ship from the outer Jovian satellites or Convenient Centaurs because you have to cross the whole fracking solar system to get from Saturn to Ceres.
I feel really weird that things like this bug me enough to make petty ranty journal posts about it. Also, yes, I have calculated things like 'what's a good timescale for going from X to Y assuming no magic physics that let me ignore that if we accelerate too hard, we kill the passengers'.
* This is a SFnal dating technique: look at what things we thought we knew at the time but turned out wrong. So Mercury's rotation makes me go 'wait, what', but a quick check to the publication date makes me go with it.
Probably because I've spent most of my adult life following NASA missions. Maybe because I read Heinlein in high school, and Heinlein learned orbital mechanics for his solar-system SF. There might be Martians and Venusians and a spin-locked Mercury*, but by golly, things moved like they should.
But when you're gallivanting around the Solar System you have to remember that things are all moving at different rates.
I'm still working my way through the Hugo nominees, so I'm reading Leviathan Wakes by James Corey. And it's solar system SF that markets itself as 'hard SF', which is nerd-speak for 'written by people who assume their audiences are nerds' (says the woman who is writing about fact-checking in hard SF). It's a useful genre term, even if it's half the time used in a pretentious way to dismiss things not written by engineers and that have things like biology and culture and feelings. (It's why I tend to dislike the word 'hard' describing anything but the rigidity of an object, because the same damn thing happens in science: our field is hard and yours isn't, nyaa! But I don't have a good word to describe a genre I like.)
Anyway, a station is described as 'on the opposite side of the (Main Asteroid) Belt from Ceres' and I had to think about this because... things move. There are times when Ceres and Vesta are on the same side and times when they're on the opposite side. The best I can come up with is 'close to Ceres' orbital distance, but 180° away in longitude which... means they'll stay roughly opposite for hundreds of years between closest approaches'. Which, threw me because I had to think if you can do this. (You can; we look at things like that at Saturn.)
It's still going; I start critiquing why you'd put a ice refinery on Iapetus, since it's out in the sticks of the Saturnian moon system, far from the rings which is the textual source of water. Or why you'd used the rings at all; they're pretty pure water ice, but you got to get down in Saturn's gravity well to get them. Mining the outer satellites or Centaurs would get you a 50-50 rock/ice mixture, but be a lot easier to ship out. Or heck, shovel off the crust of the moons you colonize.
Or things like 'wait, why is Jupiter coincidentally in the right place on a Saturn-Ceres run so it can be a convenient 'shit things have gone to hell and we are halfway between Jupiter and Ceres, out or in?' site. I realize you have power to spare in settings like this, so things like 'two round-trips from Saturn to Ceres a year' are doable. (The fastest we've currently traveled the Jupiter-Saturn's orbit distance is 15 months, but the probe was coasting the whole way, not burning engines... on the other hand, it didn't have to slow down when it got to 9.5 AU.) But things still move, and there will be times when you might want to ship from the outer Jovian satellites or Convenient Centaurs because you have to cross the whole fracking solar system to get from Saturn to Ceres.
I feel really weird that things like this bug me enough to make petty ranty journal posts about it. Also, yes, I have calculated things like 'what's a good timescale for going from X to Y assuming no magic physics that let me ignore that if we accelerate too hard, we kill the passengers'.
* This is a SFnal dating technique: look at what things we thought we knew at the time but turned out wrong. So Mercury's rotation makes me go 'wait, what', but a quick check to the publication date makes me go with it.
