Gravity and atmospheres in stsrships

[Hame]

The Expanse dealt with G-forces and Space Combat/Travel in a cool, hard science manner that isn’t a problem in Traveller thanks to Grav Plates. And hence the designs of all the deck plans, with occupants at right angles to the vector of acceleration.

So, presumably the internal starship environment can be manipulated for crew performance. Analogous to high-altitude athletic training. Presumably during routine travel one could increase gravity and decrease the partial pressure of oxygen to promote physiological adaptation in humans or other sophonts. Similarly reducing gravity and increasing the partial pressure of oxygen could then provide an edge in emergencies. More oxygen will be more of a fire risk and no one wants another Apollo 1. And there will be limits to how far the body can be pushed before the negatives outweigh the gains. However, with enough travel time for adaptation it’s also a help with acclimatisation en route to a planet with different conditions to earth standard.

Now if everyone is doing it maybe there’s no need to over complicate the game mechanics for starship combat etc. On the other hand if you know you’re travelling to Unpleasant World and are going to have negative modifiers when you get there, maybe it’s a fair technique to reduce the modifier?

I haven’t played any Traveller since about 1991 and was only ever on planets that were Earth-like, so if I’m retreading old ground known to the community I’m happy to be updated.

 

[Condottiere]

Not so much as to whether it can be done, more whether it's actually installed, and to what degree.

You can install spinning hulls and hamster cages, in lieu of gravitational tiling.

Commercially, if there was a cheaper version that's preset, I'd use that.

 

[whartung]

On the other hand if you know you’re travelling to Unpleasant World and are going to have negative modifiers when you get there, maybe it’s a fair technique to reduce the modifier?

Sort of a "it depends".

I think that if you were going to a world with thin/thick atmosphere, you can likely readily acclimate via the life support system in the week or so while in jump.

However, if you're going from a 1G to 2G world, I don't think that could be well adapted in a weeks time. Even with exercise, I think one week isn't necessarily enough to adapt.

On a high G world, though, you could perhaps use a powered exo-skeleton to help you work better while in the higher G, and use the 7 days to acclimate yourself to the use of the exo-skeleton augmentation in the new high G environment.

 

[Condottiere]

Drugs, I believe, is the usual solution.

Or, like me, spending a lot of time in climate controlled rooms and buildings, when in the tropics.

 

[spank]

The Expanse dealt with G-forces and Space Combat/Travel in a cool, hard science manner that isn’t a problem in Traveller thanks to Grav Plates. And hence the designs of all the deck plans, with occupants at right angles to the vector of acceleration.

So, presumably the internal starship environment can be manipulated for crew performance. Analogous to high-altitude athletic training. Presumably during routine travel one could increase gravity and decrease the partial pressure of oxygen to promote physiological adaptation in humans or other sophonts. Similarly reducing gravity and increasing the partial pressure of oxygen could then provide an edge in emergencies. More oxygen will be more of a fire risk and no one wants another Apollo 1. And there will be limits to how far the body can be pushed before the negatives outweigh the gains. However, with enough travel time for adaptation it’s also a help with acclimatisation en route to a planet with different conditions to earth standard.

Now if everyone is doing it maybe there’s no need to over complicate the game mechanics for starship combat etc. On the other hand if you know you’re travelling to Unpleasant World and are going to have negative modifiers when you get there, maybe it’s a fair technique to reduce the modifier?

I haven’t played any Traveller since about 1991 and was only ever on planets that were Earth-like, so if I’m retreading old ground known to the community I’m happy to be updated.

I'd think altering the gravity and atmosphere would be of great aid when dealing with boarding, hijacking and mutinies. Crews or boarders who are zero-G trained and have breathers/ low pressure gear would have a substantial advantage. Holing the hull would be a very easy way for boarders to tip the odds, if this is the plan they would arrive with vac suits.

 

[Grav_Moped]

1. Thw cliche' game of grav-plate ping-pong.
2 Brace yourself,, then connect any surviving Jump Capacitors to what's left of the M-Drive and hope the boarders get squished.
You've got one shot. Roll; add Engineering skill.

 

[spank]

I would have loved to see a boarding action in the Expanse. Defenders strapped in, most boarder in vac suits, trying not to get turned into salsa. A couple in power armor for dramatic tension.

2 Brace yourself,, then connect any surviving Jump Capacitors to what's left of the M-Drive and hope the boarders get squished.
You've got one shot. Roll; add Engineering skill.

 

[Rupert]

I assume that ships generally run at standard atmosphere temperature, pressure, and composition, and do use standard gravity unless the crew specifically set it differently (as they might if they all come from a small world with a thin atmosphere). This is actually higher G and thicker air than the average world in Traveller, but it's between the extremes of habitable worlds, and for humans removes the need for drugs and/or special therapy to keep bone density and muscle mass up.

However, some ships might run a more 'adaptive' scheme, where they shift the ship's internal air and gravity to match that of their destination world to aid acclimatisation, possibly slowly over the course of a trip, especially with gravity - there's probably less point with air when many people will just use a mask with adjusted pressure (or at least supplemental oxygen or oxygen reduction).

 

[Spinward Flow]

I'm just going to leave this here ...

Think about all the "life support" issues that smokers would have to deal with in sealed habitats in space.
And then you have terrorists who want to get attention by destroying stuff ...



And then there's this ...

 

[spank]

I'm just going to leave this here ...

Think about all the "life support" issues that smokers would have to deal with in sealed habitats in space.
And then you have terrorists who want to get attention by destroying stuff ...



And then there's this ...

For smokers it would depend, It could be anywhere from a full smoking ship to designated smoking areas to fully no smoking.

A couple if stories, one of the airplanes I was on once came from Air China, the cockpit had a thick nicotine glaze. They ended up striping the whole cockpit, replacing the carpet, cleaning the trim and control panels with orange solvent. It got rid of about 90% of the odor, or about 75% when operating, because of the nicotine in the vents.

Another airplane from Royal Air Morocco had a curtained off smoking area. There was a "smoking" switch the flight attendants would flip to activate a vent fan and open an overboard vent .

 

[Grav_Moped]

Time was, one could find aircraft cabin pressure leaks by looking for streaks of smoking residue on the outside.

 

[Hame]

It’d take more than one jump.

On earth sports teams will try to get 7-14 days to adapt to differing conditions (latitude, altitude). For extended deployments the military will factor 2-4 weeks. This is for rapid air travel. Sea/land travel usually gives more chance to adapt en route, so shorter times when you get there. Moving from sea level to Everest Base Camp altitude (change in oxygen partial pressure and no significant change in gravity) and the typical advice is do it over 2-3 weeks to allow physiological adaptation (changes to blood composition and cardiac, pulmonary, vascular and renal changes) to prevent altitude sickness, HAPE and HACE. With more rapid changes eg a chopper flight to base camp, you’ll notice the difference but be OK as long as you don’t stay too long. Medication and oxygen helps. Rapid changes in pressure (e.g aircrew, divers) put you at risk of pulmonary injury, the bends, and depending on what you are breathing; nitrogen narcosis and oxygen toxicity. From aerospace medicine the fitter and more trained you are the longer you can tolerate increased G. Your fighter pilot cousin could function at 2G for days. But your grandma’s frailer’s cardiovascular system can succumb to increased G pretty quickly. Minutes to a couple of hours at 2G. Prolonged high G exposure would cause damage to the cardiovascular system regardless.

I was thinking keeping your marines and crew at something like 1.1 or 1.2G and a reduced partial pressure of oxygen then going to hyper-oxygenation and 0.8 or 0.9G in emergencies could give an advantage. And the marines would be ready to hit the beach on an Earth-like world with that physical conditioning.

When we were teenagers we grabbed guns and cutlasses to fight off the boarders. Never thought to give them hard vacuum, or zero-G, or nitrogen and carbon dioxide but no oxygen… and never thought of how moving heavy loads in the cargo bay could be easier if you could reduce the G and still account for the mass and inertia…

 

[Condottiere]

Gravitated light dispersed hull costs eighteen and three quarters kilostarbux per fourteen cubic metres, and you can construct a building complex based on that formula, dirtside, for interstellar transients.

Since most of the operating costs tend to be life support, on a planet with oxygen, you can, I suppose, just pump in the air, purify it, and possibly, pressurize it, for substantially less.

 

[Grav_Moped]

Since most of the operating costs tend to be life support, on a planet with oxygen, you can, I suppose, just pump in the air, purify it, and possibly, pressurize it, for substantially less.

If you're electrolytically cracking water for hydrogen fuel, you ought to be able to grab some of the waste oxygen from the process too.

 

[Condottiere]

You don't need a lot for the power plant, compared to the energy budget for a starship.

Wonder if carbon capture would apply.

 

[Grav_Moped]

You don't need a lot for the power plant, compared to the energy budget for a starship.

Wonder if carbon capture would apply.

The chemistry is simple:
2 H20 molecules get split into 4 H atoms and 2 O atoms,, which then promptly re-combine into 2 H2 molecules and one of O2.

Since (by definition) you can chill/compress H2 into a liquid for storage, it should be easy enough to do that with the O2 (which would otherwise just be discarded) as well. The only question is whether you'd bring along the chemistry set to make oxygen candles (wikipedia) with it instead of storing it as a liquid or even conpressed gas.

The ship would need something to strip CO2 out of the cabin air, but that's separate from this

 

[spank]

More exactly you are probably going to be doing some kind of Sabatier or Bosch process. Sabatier is simpler and more maintenances free, but it's simplest from only get you back about 1/2 of your H₂ (as H₂O), The other half is lost as CH₄.

The addition of things like Plasma Pyrolysis can break down the Methane into Carbon+ Hydrogen, Ethylene + Hydrogen or Ethane + Hydrogen.

Which gives better results, but still not closed loop. Some Hydrogen still leaves as hydrocarbons.

Bosch on the other hand give near 100% Carbon removal and returns all the H2 as water. The down side being the that the Carbon is collected on a catalyst which must be removed and either cleaned or discarded.



As far as Oxygen Candles, they are shelf stable, and some chemicals, such as Lithium perchlorate provide greater oxygen density than liquid oxygen. But the flow rate isn't adjust able, and the waste heat needs to be dealt with.
Here is an interesting report from 1971 evaluating different portable oxygen generation systems.

https://ntrs.nasa.gov/api/citations/19720019462/downloads/19720019462.pdf

 

[Black Vulmea]

I would have loved to see a boarding action in the Expanse.

There are several: the Donnager battle, Thoth Station, Klaes Ashford's attempt to capture Marco Innaros all come to mind.

Presumably during routine travel one could increase gravity and decrease the partial pressure of oxygen to promote physiological adaptation in humans or other sophonts.

That's SOP IMTU: ships spend the week in jump adjusting the gravity and atmosphere from the origin to the destination.

There's an illness - AAS, acute aclimation sickness - that's well-known to starship medics, and a drug - Acclimate, a far future flavor of acetazolamide - that helps, if it's started early enough, to treat it. Imperial Marines go through a drug and conditioning program called the Buriina Protocols developed to allow them to be in fighting shape on a week's notice for most destinations compatible with human and similar sophont physiology. Compression masks are sometimes worn to help sensitive travellers adapt, often in conjunction with the aforementioned Acclimate.

In the real world, ideally you gain no more than 500 m per day based on the elevation where you sleep for the night, which is about 5 kPa on Earth, between 2500-6000 m, and about half that at higher elevations.

Similarly reducing gravity and increasing the partial pressure of oxygen could then provide an edge in emergencies.

Belters often keep their boats and ships pressurized between 46-56 kPa - thin atmosphere.

 

[ady]

Gravity is one of those things that is often missed out in some Scifi. Yes, I did like how the Expanse included it - High G maneuvers, coralis effect of spinning habitats on pouring liquids or throwing things, etc. Babylon 5 touched on it occasionally, like when Sheridan's tube train was bombed, so he just leapt out and instead of falling to the surface, just floated in the middle of the spinning station.

In Traveller, G plates do make life more comfortable. Inertial compensators can reduce injury from violent maneuvers and even crashes (I assume all grav vehicles have them). I also assume that most liners will slowly adjust the gravity, air pressure and lighting on the ship to match the destination world (within comfortable limits), so it's less of a shock for the passengers when they step off the ship.

For low tech worlds, arrivals will just have to adapt to the higher/lower Gs, with maybe the richer travellers constantly wearing grav belts at low power to ofset the difference (not just used for flying). For some industrialised higher tech worlds though, grav plates (similar to the ones in starships) might be standard inside most buildings and on walkways, sort of the way we use heaters in cold climates or air conditioning in hot, to make the conditions more comfortable. Grav plates could also be used to cover a starport landing field, to assist those feeble Free and Subsidised Traders (1G thrust) trying to take off from high G planets, or to pin defaulted/seized ships to the tarmac.

On non spinning zero G environments (Belter colonies, etc) or even on high tech worlds, 'up' and 'down' might become arbitrary, with roads and walkways running up and down the sides of buildings, or grav plates on the walls and ceiling to increase the 'floor' space use. For people not used to up and down like us 'Well Dwellers' are, their colony enteriors might look like an escher maze (though this would be a nightmare for the Ref to map) There is the potential of problems if it fails, but hopefully they will have more redundancy and advanced AI overwatching it all. If not, it can make for a good cliff hanger moment, the players trying to get down from a km high 'vertical road during a powercut?

 

[Krikkitone]

I’m pretty sure most merchant/passenger ships would have an adaptive scheme, where ship grav+pressure slowly changed to that of the destination starport rather than the destination world. (the world atmosphere maybe D, but what pressure are the major mountain cities actually at?)

That also helps for when you take on passengers. I do imagine going from a 0.5 g to 1.5 g world would involve some drugs to help the adaptation (especially those who grew up on that 0.5 g world)

Now there maybe special medical differences, some people might be kept in low G the whole time (but that would probably be because they will be kept at low g at the destination as well, security/military forces might stay in/slightly higher g to help with workouts…although adapting to how fast things will fall at your new location might be better.