How Does Flying at 1G work?

[Rhodium]

I'm not sure I understand the concept. I know the Argo is designed to simulate gravity while stationary by spinning the habitation pods, but I believe Kiva explained that while in flight, these pods are folded back as the Gs are simulated by way of moving the ship forwards through space.

This made sense to me at first... until I remembered that any Gs you create through forward motion are going to be based on Acceleration, not Velocity. So does that meanwhile the ship is moving it is constantly accelerating at a consistent rate?

Wouldn't this mean the ship would go exponentially faster the further it goes, meaning you get increasing returns on travel distance so it takes 2 days to get 100,000 miles and 3 days to get 200,000 miles? And furthermore wouldn't you eventually hit the universal speed limit meaning you can't go any faster, thus causing gravity to give way? What about when you slow the ship down, wouldn't you have to flip the pods upside down and slow the ship down for as long as you've been accelerating it?

 

[Jacobkosh]

The ship is constantly accelerating, yes. This is really common in a lot of sci-fi and there's tons of math out there about it.

The idea is you accelerate at 1G, flip over in the middle of your journey, and then spend the second half of the trip decelerating. Constant 1g "gravity" for the passengers the entire time except during the time it takes to execute the flip.

Astronomical distances are huge. Getting from Earth to Jupiter would take days. Getting to Alpha Centauri would still be a journey of years. You will not come anywhere close to light speed; as relativistic effects take hold, the energy required to keep accelerating increases on a steep curve.

 

[Rhodium]

Astronomical distances are huge. Getting from Earth to Jupiter would take days. Getting to Alpha Centauri would still be a journey of years. You will not come anywhere close to light speed; as relativistic effects take hold, the energy required to keep accelerating increases on a steep curve.

Sure sure, but I'd think it wouldn't take too long before the ship can't accelerate fast enough to maintain gravity due to these relativistic forces. The fact that moving the ship at 1.2 Gs is an upgrade, implying the ship can't accelerate that fast normally makes me think that doubly so.

The idea is you accelerate at 1G, flip over in the middle of your journey, and then spend the second half of the trip decelerating. Constant 1g "gravity" for the passengers the entire time except during the time it takes to execute the flip.

I wonder if the Argo's pods can flip or if the whole ship is going to flip...

 

[Jacobkosh]

I wonder if the Argo's pods can flip or if the whole ship is going to flip...

The whole ship would have to flip. The thrust is coming out of the butt, so it needs to face the direction of travel to slow the ship down.

Sure sure, but I'd think it wouldn't take too long before the ship can't accelerate fast enough to maintain gravity due to these relativistic forces. The fact that moving the ship at 1.2 Gs is an upgrade, implying the ship can't accelerate that fast normally makes me think that doubly so.

It would take nearly a year of constant acceleration to approach c (the speed of light). Battletech ships are typically traveling for only a couple of weeks at a time, the amount of time required to get from the outer system to the inhabited inner worlds.

The advantage of going 1.2g is that you get places faster in exchange for being uncomfortable and more prone to injuries and accidents.

 

[44th MAC|Bonsai]

in exchange for being uncomfortable and more prone to injuries and accidents.

But also more efficient workout and training, getting more muscle strength and possibly bone density in the long run

 

[Adam Steiner]

accelerating and decelerating at 1g would take thousands of years to get anywhere, that can't be right.

 

[ronhatch]

accelerating and decelerating at 1g would take thousands of years to get anywhere, that can't be right.

That's what the Jump Ships are for... you're just navigating within each system.

 

[Adam Steiner]

That's what the Jump Ships are for... you're just navigating within each system.

OK but Jump Ships have some sort of inertial dampening system surely? Or do they travel without acceleration somehow?

 

[Spartakus]

Dropships travel from a planet to a jumpship waiting at a jumppoint. That travel usually takes a couple days and gets you to about 1% of lightspeed. Not enough to get noticable relativistic effects.
At the jumppoint it docks with a jumpship which has a FTL drive for instant travel up to 30 lightyears.
Jumppoints are technically every point in space far enough from a gravity well. For our sun thats a little further the Jupiters orbit. For practical reasons jumpshis choose a point at that distance above or below the ecliptic. These are the standard jumppoints refered to as zenit and nadir.
Lagrange points work as jumppoints too and are much closer to their planet drastically reducibg travel time. These so-called pirate points however are small and in constant movement which makes jumping to them difficult and dangerous. So comercial jumpships will always use either zenit or nadir.

 

[Jacobkosh]

In Battletech, you take a DropShip off a planet, fly at 1G for several days/a week to the system's jump point (usually located somewhere in the outer edge of the system), and dock with a JumpShip. The JumpShip "jumps" - teleports, basically - to another system's jumppoint many light-years away. That's where the FTL element comes in. Then, assuming you've jumped into your destination system, the DropShip undocks from the JumpShip and spends a few more days accelerating at 1G toward the planet or moon or whatever where the mission is.

JumpShips are limited in how far and how often they can jump. They can go a few light years on a jump and it takes a week or two to recharge the batteries to jump again. So if you're going somewhere several jumps away, your travel time grows and grows and grows, unless you happen to be able to move from the JumpShip you were on (which has just jumped and needs to recharge) to a second JumpShip that is charged up and ready to go.

The long and the short of it is that you spend a lot of time in Battletech waiting around, which helps justify the setting's feudal-government conceit, but you get to spend a decent amount of it flying around at 1g so your pilots don't have brittle bones.

 

[Adam Steiner]

In Battletech, you take a DropShip off a planet, fly at 1G for several days/a week to the system's jump point (usually located somewhere in the outer edge of the system), and dock with a JumpShip. The JumpShip "jumps" - teleports, basically - to another system's jumppoint many light-years away. That's where the FTL element comes in. Then, assuming you've jumped into your destination system, the DropShip undocks from the JumpShip and spends a few more days accelerating at 1G toward the planet or moon or whatever where the mission is.

JumpShips are limited in how far and how often they can jump. They can go a few light years on a jump and it takes a week or two to recharge the batteries to jump again. So if you're going somewhere several jumps away, your travel time grows and grows and grows, unless you happen to be able to move from the JumpShip you were on (which has just jumped and needs to recharge) to a second JumpShip that is charged up and ready to go.

The long and the short of it is that you spend a lot of time in Battletech waiting around, which helps justify the setting's feudal-government conceit, but you get to spend a decent amount of it flying around at 1g so your pilots don't have brittle bones.

So you're saying the Jump Ships travel from point to point instantly? There's no acceleration like with the Warp Drive of Star Trek or the Hyperdrive of Star Wars.

 

[Jacobkosh]

So you're saying the Jump Ships travel from point to point instantly? There's no acceleration like with the Warp Drive of Star Trek or the Hyperdrive of Star Wars.

Correct. It's like boom, flash of light, we're in the new place. In the novels I think they describe the experience as disorienting and mildly nauseating, although I might be confusing those with the eight zillion other sci-fi novels that describe similar kinds of travel.

 

[Spartakus]

So you're saying the Jump Ships travel from point to point instantly? There's no acceleration like with the Warp Drive of Star Trek or the Hyperdrive of Star Wars.

Exactly. More like Battlestar Galactica.

 

[Adam Steiner]

Interesting. You'd probably want to frame your FTL transition scenes from the interior rather than the less interesting flash-pop of the exterior. Perhaps try to replicate the first person perspective.

ETA: I'm just trying to visualize how the universe would play out on screen. I don't think that would work for a game. Showing it from the ship's perspective is definitely the way to go with this title.

 

[Adam Steiner]

In the novels I think they describe the experience as disorienting and mildly nauseating, although I might be confusing those with the eight zillion other sci-fi novels that describe similar kinds of travel.

I haven't read much sci-fi outside of the classics, and Trek&Wars when I was a kid. So this is somewhat unusual to me. There isn't even a wormhole?

 

[Jacobkosh]

I haven't read much sci-fi outside of the classics, and Trek&Wars when I was a kid. So this is somewhat unusual to me. There isn't even a wormhole?

Nope. Although for what it's worth, since wormholes are incredibly theoretical and have mostly arbitrary properties for the purposes of writing science fiction, there are lots of sci-fi novels where the FTL works a lot like in Battletech but the ships are supposedly traveling through wormholes.

'm not sure to what extent the Battletech fiction ever goes into the nuts and bolts of the Kearney-Fuchida Drive; it's entirely possible they just take it as a setting element and leave it alone, although it's also entirely possible that some nerd somewhere has written a dissertation on sarna.net about it.

Anyway, yeah, this idea - hyperspace "jumps" - goes back at the very least to Asimov's Foundation novels in the 40s if not earlier, and is one of the very common imaginary FTL conceits. If you're a sci-fi writer, or creating a sci-fi setting for a game, it's important to carefully choose the arbitrary properties of your FTL to support the kinds of stories you want to tell.

So in Star Trek, they have warp drive, where you travel faster than light but cover the intervening distance. That makes it easier to tell stories about exploration - because you can just point your ship somewhere and turn on the engine and see where you go - and have a vibe reminiscent of 19th-century sailing ships, which is of course part of the vibe that Trek is going for.

But if FTL is instantaneous and gets people from A to B instantly, then you don't need to waste a lot of time thinking or writing about what happens during FTL travel. That makes it popular for military science fiction like Battletech, where what the writers want to focus on is the stuff that happens in "real space" - cool tactics and semi-realistic physics - rather than exploring the entirely made-up properties of a made-up mode of travel.

 

[Calantyr]

Correct. It's like boom, flash of light, we're in the new place. In the novels I think they describe the experience as disorienting and mildly nauseating, although I might be confusing those with the eight zillion other sci-fi novels that describe similar kinds of travel.

The effect is described as mildly nauseating to most people, like mild motion sickness. However a rare few people are completely debilitated by it and they're useless until they recover.
It's even worse for AI's. If an AI is switched on while it jumps, once it reaches the destination it goes completely insane and starts attacking everything. This is one of the reasons why AI research never actually progressed very far in the Battletech universe.
The Word of Blake made a few advances, but that's far outside the timeframe.

 

[Jacobkosh]

The effect is described as mildly nauseating to most people, like mild motion sickness. However a rare few people are completely debilitated by it and they're useless until they recover.
It's even worse for AI's. If an AI is switched on while it jumps, once it reaches the destination it goes completely insane and starts attacking everything. This is one of the reasons why AI research never actually progressed very far in the Battletech universe.
The Word of Blake made a few advances, but that's far outside the timeframe.

Oh wow, that's really interesting. I didn't know Battletech had ever even engaged with the question of AI.

I wonder if some of our pilots could be affected by debilitating jump sickness, like maybe it's a hidden tag some of them could have. That'd be an interesting wrinkle!

 

[Adam Steiner]

Nope. Although for what it's worth, since wormholes are incredibly theoretical and have mostly arbitrary properties for the purposes of writing science fiction, there are lots of sci-fi novels where the FTL works a lot like in Battletech but the ships are supposedly traveling through wormholes.

'm not sure to what extent the Battletech fiction ever goes into the nuts and bolts of the Kearney-Fuchida Drive; it's entirely possible they just take it as a setting element and leave it alone, although it's also entirely possible that some nerd somewhere has written a dissertation on sarna.net about it.

Anyway, yeah, this idea - hyperspace "jumps" - goes back at the very least to Asimov's Foundation novels in the 40s if not earlier, and is one of the very common imaginary FTL conceits. If you're a sci-fi writer, or creating a sci-fi setting for a game, it's important to carefully choose the arbitrary properties of your FTL to support the kinds of stories you want to tell.

So in Star Trek, they have warp drive, where you travel faster than light but cover the intervening distance. That makes it easier to tell stories about exploration - because you can just point your ship somewhere and turn on the engine and see where you go - and have a vibe reminiscent of 19th-century sailing ships, which is of course part of the vibe that Trek is going for.

But if FTL is instantaneous and gets people from A to B instantly, then you don't need to waste a lot of time thinking or writing about what happens during FTL travel. That makes it popular for military science fiction like Battletech, where what the writers want to focus on is the stuff that happens in "real space" - cool tactics and semi-realistic physics - rather than exploring the entirely made-up properties of a made-up mode of travel.

Good points. I agree with them all.

 

[Pointyearedgit]

Sure sure, but I'd think it wouldn't take too long before the ship can't accelerate fast enough to maintain gravity due to these relativistic forces. The fact that moving the ship at 1.2 Gs is an upgrade, implying the ship can't accelerate that fast normally makes me think that doubly so.



I wonder if the Argo's pods can flip or if the whole ship is going to flip...

Just to add, the way to think about relativity here is that as far as you are concerned, you are accelerating (and decelerating) at 1G the whole time. However, someone watching you will see you eventually start approaching (but never reaching) the speed of light (in a vacuum). You, however, never think the acceleration changes.

Basically, how you measure distances and time changes, but you really wouldn’t notice a difference accelerating at 1G when you are at 0.9c or at rest relative to your reference. Depending on the technology, it might make sense to accelerate like this. If we modify human physiology, have different engines, somehow sleep through the trip, it will change what the optimal acceleration would be.

You would need to flip (most) spacecraft as otherwise a second engine (or reflector) would be needed and mass will be at a premium.

TL;DR. 1G acceleration for ‘gravity’ still works even if you get to relativistic speeds. Other practical issues (like fuel) could of course pop up.