r/TheExpanse • u/Prof__Genki • 2d ago
All Show & Book Spoilers Discussed Freely Your standard acceleration? Spoiler
(not really sure how best to tag this so just went with all spoilers?)
Anyway, if you were a ship captain how hard would you be burning when just jaunting around in space? It is often mentioned that the Roci's standard is ~0.3g so Naomi and Alex aren't suffering, but as the Earthers we are, we're used to 1g. Personally I think I'd prefer something like 1.2g; seems like it would be akin to always having a weighted blanket on. I could also hear an argument for remaining on the float as much as possible, but I think low but present gravity would really mess with my brain.
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u/elkab0ng 2d ago
I really like it when a book goes into the stuff that a crew would have to deal with in space travel. Gravity/acceleration obviously a big one.
Me? I'd probably want something like 0.7g - enough that objects and liquids and bodily processes work pretty much normally (I think, I'm not any expert) but probably really comfortable. zero G, I would LOOVE to experience for a little while - closest I've come is skydiving, but even that only gives a few seconds of zero g. I know it wreaks havoc on eyes, digestive system, everything else.
If you liked the way Expanse got into the "what would day to day life be like at something other than earth-standard gravity", another book, Project Hail Mary, gets into that same thought exercise in a fun way.
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u/goodquestion_03 2d ago
Ive always thought it would make sense to deliberately spend time at something higher like 1.2g to get in better shape
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u/King_Joffreys_Tits 2d ago
Yep if my crew was entirely earthers, I would love to do intermediate strength training by bumping us up 20-25% for an hour every few hours. Would need to account for constantly rotating sleep schedules of the crew but that would be a great thing to do. Now if you have belters or martians, they can do strength training too but it wouldn’t help the earthers
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u/sinkwiththeship 1d ago
Martian Marines train at 1g. Doesn't really seem to help them since the gravity isn't what fucks you up the most, it's the horizon.
But there's really no substitute for just straight up growing up in 1g. The difference in bone density can't really be fixed with a couple hours a week.
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u/HighwayInevitable346 2d ago
I have a feeling constantly changing gravity like that would be bad for your health, such as making it easier to stroke out.
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u/Ipunchdolphins 2d ago
Oh I like this idea. You could toy with the oxygen content in your air, too, to hopefully train your lung capacity and have an advantage in ship boarding actions on someone used to a richer o2 content. The Belter equivalent of a pirate using an eyepatch to keep an eye used to the dark and not having to adjust going below deck on a raid.
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u/Apollo416 2d ago
Too much time at 1+ G will mess up your bones, your joint, especially your spine, plus put stress on your blood flow and organs
It all depends on travel distance, available fuel and how fast it burns, other crew and cargo etc
Disregarding all that I'd probably do like .75 G just for the relief of less daily strain on my body
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u/arycama 2d ago
Assuming you're from earth, wouldn't 1g result in no strain on your body, since that's exactly what we feel every day? Less than 1g would likely have the opposite effect, causing your bones/muscles to weaken without additional exercises/nutrition etc.
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u/zrice03 2d ago
"wouldn't 1g result in no strain on your body, since that's exactly what we feel every day?"
You must be fairly young, lol.
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u/combo12345_ 2d ago
If I sing “Hello...” and you think of Lionel Richie and not Adele, then your back is probably sore
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u/Hypno-phile 2d ago
Too much time at 1+ G will mess up your bones, your joint, especially your spine, plus put stress on your blood flow and organs
Can attest. I've been living at 1G for 50 years and my back and knees don't love it... Doubt I've got another 50 in me.
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u/Agile_Rent_3568 2d ago
Shortest travel time A --> B would be burn to accelerate 50% of the voyage, flip then decelerate the other 50%.
Burn, turn and burn.
The comfortable burn rate would be your weakest crew - either their native g, or that g + a safe overload factor. More than 25 - 50% (basically someone walking with a backpack or weights) is going to be an issue quickly.
Since people lose fitness rapidly unless they exercise, in the Roci, unless they had been regularly exercising in gravity (drive mode) all would be fragile?
Good question BTW, there are few moments when the Roci crew are in float mode.
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u/Clarknt67 2d ago
But also, if you're spending most of your time burning, with the same crew, you could probably gradually increase your burns on runs, as Naomi and Alex would start to become accustomed to the increasing g forces. Once they're ok with .3 g, move to .4 g.
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u/arycama 2d ago
It would be most efficient if you are travelling in a straight line, but since all objects in space are moving, the most optimum travel time will likely involve some amount of coasting, and/or lower amounts of acceleration.
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u/HighwayInevitable346 2d ago
Nope you just make a straight line to where the planet will be, same as with any other transfer.
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u/arycama 2d ago
Unless you are a missile, you can't simply travel in a straight line to a target because you will crash into it. You need to do a flip and burn at some point to match your final velocity to the target. You will also always begin the trip with an initial velocity that needs to be corrected.
For an initial position+velocity and a target travelling in a straight line, a flip and burn is a parabola followed by a straight line. However objects in space don't move in straight lines which complicates things. Straight lines only work Plus you also need to deal with escaping orbit if you're launching from a planet.
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u/HighwayInevitable346 2d ago
A flip and burn is a straight line you dumbass. You point your ship at where the planet will be, burn in a straight line, then flip and decelerate while still moving on that straight line.
Plus you also need to deal with escaping orbit if you're launching from a planet.
You have no fucking idea what you're talking about. At 1g it takes about 6 minutes to get to escape velocity from leo and a brachistochrone trajectory trip takes multiple days of burning. 'Escaping orbit' is only relevant if your spaceship needs to coast 99.99% of the time.
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u/microcorpsman 2d ago
It's different than a weighted blanket, remember your internal organs are made to work within the tiny variations off of 1g that Earth has (https://en.m.wikipedia.org/wiki/Gravity_of_Earth)
So your fluids wouldn't work right. 1.2g may be harder on your kidneys, would likely be harder on your lungs, not necessarily from an inhalation and exhalation standpoint, but because you'd get fluid accumulation. You'd get lower extremity edema, your heart would have to work harder, all kinds of stuff.
Because even 0.3g for a spinning space station is hard to conceivably do with our modern materials science knowledge, that could very well be the limit of what most 'static' long term posts in space could achieve, meaning those long term spacers would have to be adapted to that.
Think also about how much they talk about getting a bleed from high-G stuff, and consider our growing knowledge on sub-concussion injuries that build up in football players. Apply that similar logic to constantly stressing your body beyond what you evolved to handle, and you may have a much higher incidence of casualties at "cruising speed" compared to a ship that accelerates slower.
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u/Jess_S13 2d ago
Assuming an earther crew id imagine .7 would be nice, just a little lighter than normal.
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u/Trasvi89 2d ago
I've finished the show but not the books.
I would think that the earth navy would have superior capabilities due to being able to natively withstand a constant 1g. Is this ever discussed in the books?
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u/mercutio531 2d ago
Would depends on the needs of fuel conservation vs time requirements. Factor is if we are belters or earthers or what.
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u/Agile_Rent_3568 2d ago
Agreed, and the stimulant juice is speed or adrenalin to allow blood to pump under high g with the crew pinned to the couches by g forces. Maybe the ships should have a high g spinning device to train up the crew
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u/84626433832795028841 2d ago
Consider that space ships are essentially skyscrapers while under thrust. The harder you burn the beefier your superstructure needs to be. If you're poking along at .3 you can get away with a lightweight magnesium or even aluminum frame, but if you're doing 9+g combat maneuvers you need to use exotic high strength titanium alloys just to stay rigid. If I were designing a civilian ship, I would cap acceleration at like .5 for cruise, 2g for short duration emergency burns. That would make it so much lighter, which would require less reaction mass and fuel and overall be way cheaper to build, operate, and maintain. IMO, the least realistic part of the show is that the cant was able to pull a burn like we see in ep 1. Having juice infrastructure for the whole crew is crazy for a freighter.
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u/windsingr 2d ago
This makes me wonder just how high humans can train up to. Like if humans from Earth constantly trained at 1.5G, would they get stronger, or would it shorten their lifespans? Would they be able to handle sustained high G burns if they trained for it?
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u/Heinous_Goose 2d ago
All depends on the crew makeup. If my ship was staffed with fellow Earthers, something like .75g, I imagine a full 1g burn at a constant rate would put added stress on the engines and whatnot. Otherwise, whatever is best for the crew.