Interface between artifical grav and real/no grav?

[Woas]

I thought there was a topic about this a couple months back but heck if I can find it via Search.

It's a given that Traveller has some sort of 'soft' sci-fi artificial gravity technology. Especially when it comes to spacecraft (belly landers) and spaceports.
Assuming that these artificial gravity makers have a relatively tight 'field' of operation (they only generate pseudo gravity within the area of the plating and don't 'bleed' out around it), what issues might arise if someone who is operating in a zero or micro G environment suddenly entered a 1G area?

For example say a character is doing some EVA on an asteroid with what we'll just say amounts zero G for the sake of an example. The character is weightless and doing some work. When finished they walk back to their ship and climb up the ramp to the airlock and as they step through the door they suddenly are hit instantaneously with 1G of 'force' pulling on them.

I guess a real world example is how do astronauts feel/handle the approach back from space (which has no artificial gravity obviously so is just one long zero G period) down to Earth and the effects of one Earth G on them? Certainly they don't just pass some 'magical' gravity barrier like a potential Traveller character might, but I've the anecdotes of returned space shuttle crew having many difficulties upon return.

And if some one does remember a post (I'm thinking it was up and active back around the turn of the new year but I really am not sure) about this sort of thing and can link it please do.

Thanks,
Woas

 

[Rikki Tikki Traveller]

I would say that it is POSSIBLE to injure someone that way, but normal protocol will limit that.

I would argue that the airlock has a feature that slowly varies the gravity as the air pressure varies. So, at vacuum, it is zero-g and at normal ship atmosphere it is normal ship gravity. That way you don't get the gravity shear.

I would also put protections in the internal G fields that normally limit how fast you can change the internal gravity field. It might allow you to reduce it a lot more quickly than you can increase it, but it should not allow you to instantaneously change it. Smashing someone to the ceiling and then the floor sounds like fun, but I don't think the designers would normally let you do that. Of course, any safety protocol could be overriden by a determined hacker.

Imagine standing with 1/2 of your body in a 1g field and the other half in a zero-g field. That can't be good for your internal organs and bloodflow. It COULD be a nasty way to injury or even kill someone.

 

[kristof65]

I handle it almost exactly how RTT said.

The big thing is how the airlock G-plates handle it is a setting that has to be set, based on the known Gs on the other side. In deep space, you're going to want it to go from 0G to 1G (or whatever the ship standard is), but if you're in port on an airless moon that's 0.25G, you're going to want it to transition between 1G and 0.25G, not 0G.

Likewise, if you're on a heavy G world.

 

[Dave Chase]

Ping pong or dribbling boarders is an old 'trick' talked about for some time with Gravity control

You could take the gravity and turn it off, reverse it, or even increase it in sections. This is one of the reasons that C&C or engineering are prime targets during boardings.

I even had one group of players pay extra for the entire hull to be gravity deck modified. They went hunting pirates. Would play along with various things and if/when the pirates boarded or attempted to board they would find them selves stuck to the hull at 3 G or bounced up and down the corridors.

Until they ran across some pirates with power combat and battle suits.

IT was a hell of a fight then.

Dave Chase

 

[GypsyComet]

I would say that it is POSSIBLE to injure someone that way, but normal protocol will limit that.

I would argue that the airlock has a feature that slowly varies the gravity as the air pressure varies. So, at vacuum, it is zero-g and at normal ship atmosphere it is normal ship gravity. That way you don't get the gravity shear.

I would also put protections in the internal G fields that normally limit how fast you can change the internal gravity field. It might allow you to reduce it a lot more quickly than you can increase it, but it should not allow you to instantaneously change it. Smashing someone to the ceiling and then the floor sounds like fun, but I don't think the designers would normally let you do that. Of course, any safety protocol could be overriden by a determined hacker.

Imagine standing with 1/2 of your body in a 1g field and the other half in a zero-g field. That can't be good for your internal organs and bloodflow. It COULD be a nasty way to injury or even kill someone.

On the first point, I agree with the this and the other posts. If your species had just discovered A/G last year, this might be a problem. When that discovery was 5000 years ago and at least one of the cultures involved is proverbial for technological caution, safeguards will not only exist, but be second nature.

On the health effects of sitting in a transition zone, I suspect the health effects will be more subtle, and will depend on which parts of the body are where and in what orientation. If you head were "upside down" in a gravity field while the rest of you was in zero-G, that's probably a quick recipe for unconsciousness and brain damage, since the human circulatory system does use gravity to some extent. If your head is either in zero-G or oriented properly in the gravity field you'll probably have no problem. A limb sticking into gravity or out of gravity may exhibit from circulatory oddities after some time, but its not going to be immediate. This likely isn't going to be worse that having a limb "fall asleep" unless it persists or, as with the head scenario, the gravity on the limb is strong and away from the rest of the body, causing pooling.

 

[Shiloh]

For example say a character is doing some EVA on an asteroid with what we'll just say amounts zero G for the sake of an example. The character is weightless and doing some work. When finished they walk back to their ship and climb up the ramp to the airlock and as they step through the door they suddenly are hit instantaneously with 1G of 'force' pulling on them.

Handling G-field transition/shear is part of spacer training. Anyone with considerable shiptime or any 0-G or Vacc or Battledress experience will be able to handle *known* interfaces between tolerable Gs with a greater or lesser degree of grace, but little or no danger. Sudden, severe and unexpected G-shear probably needs a Dex roll to avoid mishap, with 0-G/Vacc/Battledress/[terms of space service] as a modifier.

I guess a real world example is how do astronauts feel/handle the approach back from space (which has no artificial gravity obviously so is just one long zero G period) down to Earth and the effects of one Earth G on them? Certainly they don't just pass some 'magical' gravity barrier like a potential Traveller character might, but I've the anecdotes of returned space shuttle crew having many difficulties upon return.

Not really comparable. Current astronauts cross the g-boundary in minutes while strapped into acceleration couches, and make the final transition with a greater (dry-land thumpdown) or lesser (Shuttle runway landing) bump. The problems they experience are due to the extended periods they have spent in microgravity. A normal spacewalk for asteroid mining purposes won't have any short term consequences upon retunr to "normal" G.

 

[Woas]

Ahh, I suppose my first post didn't harp on it (maybe I picked the wrong examples) but yeah, I figured that airlock procedure probably included slow gravity readjustment as part of the procedure.

I was more thinking of a sudden event. I guess a better example of the situation I am thinking of is if say a character was in a ships closed cargo bay that had the arto-grav off working and then walked through an open door to the fresher that still had arto-grav up.

 

[Rikki Tikki Traveller]

Woas, those are the kinds of examples that I think would be considered as part of the design.

Either the fresher would also be in Zero-G if the Cargo Compartment was, or there would be a separate gravity control for the fresher.

Doors (especially iris valves) probably have safeguards that will not allow them to open if the G-force on the other side is too different from what is on your side. Since many staterooms have individual gravity control, likely EVERY door on a starship has this safety feature.

So, to enter the Fresher from the zero-g Cargo Bay, you will have to lower the Fresher grav field (or raise the cargo bay g-field) so that they match, then the door will open. Once inside the fresher (with the door closed) you can adjust the grav field for a comfortable level while you do your business. To leave the Fresher, you would have to match the Grav Field of the cargo compartment to get the door to open.

That might actually make a fun little mini-episode while in Jump Space:

Passengers sharing a stateroom are having some adult fun in Zero-G, when the G-controller for their room shorts out and cannot be changed. Now they are stuck in the room (can't even get into the fresher, because it has a different Grav field. The PCs (as the ship's crew) have to either lower the gravity in the entire corridor, or somehow override the safeties to the door. Either way, much embarrassment for the occupants.

Thinking about this, starship doors, even the simplest of them just got a bit more complicated...

 

[Baroun Tardis]

I thought there was a topic about this a couple months back but heck if I can find it via Search.

(snip)

I guess a real world example is how do astronauts feel/handle the approach back from space (which has no artificial gravity obviously so is just one long zero G period) down to Earth and the effects of one Earth G on them? Certainly they don't just pass some 'magical' gravity barrier like a potential Traveller character might, but I've the anecdotes of returned space shuttle crew having many difficulties upon return.

(snip)

Thanks,
Woas

In all probability, you've experienced this in real life...
Gone on a roller coaster? Sundry other amusement park rides?
That moment of free-fall during the ride, then gravity resumes?

Only becomes an issue with the astronauts when they've been in Zero-G a few days and gotten used to it.

I talked to an astronaut at KSC once who'd been on the ISS for a while. He joked about having gotten used to being able to just put things in the air nearby and they'd be there... and that moment the first morning back when he let go of his coffee cup, expecting it to stay there (floating near his head) while he used both hands to mess with the newspaper....

 

[Woas]

Actually no. Well sort of. Once. I guess I have a phobia of... falling? Not just like off a bike and ooof, scrape my knee. That moment I got when I was younger on the Log Flume just as it tipped over for the big drop at the end... that little bit of weightlessness as you float for a second. Ugh... makes me sick thinking about it right now

 

[Gaidheal]

Weightlessness and (relatively) high apparent g are the kind of things that make my eyes light up and my wallet lighter, hehe! I guess we're wired very differently :¬)

At any rate, unless it's extreme and unexpected, it wouldn't be a big deal anyway and I am pretty sure there are standard, taken for granted, protocols and gadgets built into anything which has to deal with a gravity differential on board a ship - it's the kind of thing you sort out before you can go 'mass market'.

 

[Woas]

Yeah I figured that safety protocols would be in place. Maybe I'm still not asking this right. Forget the real life astronaut and taking a leak while in the cargo bay examples...

What I'm asking is pretend there are no protocols. Pretend there is a ship that was left derelict and booby trapped or something. Or don't I dunno. Your 'floating' down a hall way that has no gravity. Down the hall the doorway to the bridge is open and you can see right in there. You decide to check it out so kick off and sail down the hall. As you pass through the threshold of the doorway into the bridge you are hit with 1G of arto-grav. Apparently the bridge was still under arto-grav. What would happen to you? Just fall to the ground and feel 'normal' again? Get some sort of motion sickness/reverse vertigo?

 

[Gaidheal]

Well, you get accelerated at the appropriate rate to local 'floor', unexpectedly.

What happens to you is down to the referee but the simple answer is "roll for falling damage", basically.

 

[Oaty_bars]

I would say that it is POSSIBLE to injure someone that way, but normal protocol will limit that.

I would argue that the airlock has a feature that slowly varies the gravity as the air pressure varies. So, at vacuum, it is zero-g and at normal ship atmosphere it is normal ship gravity. That way you don't get the gravity shear.

I would also put protections in the internal G fields that normally limit how fast you can change the internal gravity field. It might allow you to reduce it a lot more quickly than you can increase it, but it should not allow you to instantaneously change it. Smashing someone to the ceiling and then the floor sounds like fun, but I don't think the designers would normally let you do that. Of course, any safety protocol could be overriden by a determined hacker.

Imagine standing with 1/2 of your body in a 1g field and the other half in a zero-g field. That can't be good for your internal organs and bloodflow. It COULD be a nasty way to injury or even kill someone.

Nooo, it wouldn't kill at all, it may raise your blood pressure but thats about it, well unless you only had your head in the 1G field, and that could kill if left long enough, (in the same way it could if you hung upside down, blood pooling under pressure)

I expect the gravity field would be a softer field at its edge (like a magnetic field) and slowly increased in strength as you got closer to the source of the field, the ships hull would be thick enough to encompass the lesser fields effect, so by the time you reach the floor plating it would be at its full effect,

You would suddenly feel like lead though,
If you know what its like to float in water for a few hours, then climb out you could have an idea what this could be like,

But I don't think you could push someone in to the ceiling, just negate the Gravity, (you would just float)

well thats how I see it :wink:

 

[Gaidheal]

In order to efficiently do the 'inertial damping' lark that is handwaved into the setting, you would have to be able to make the ceiling become 'local floor', actually.

 

[Oaty_bars]

In order to efficiently do the 'inertial damping' lark that is handwaved into the setting, you would have to be able to make the ceiling become 'local floor', actually.

Using the gravity as 'inertial damping'?
would it be quick enough for that?
(but I do see your point)

in Star Trek it has its own bit of kit outside of the gravity system known as....'inertial dampeners' which extends to the hull of the ship,

 

[Gaidheal]

Well, it's implied that it's the same technology (not necessarily the same kit, of course, though actually, they amount to the same thing, really).

Thing is, the idea of killing inertia is what we can call 'speculative', politely, or 'bullshit' less politely. ;¬)

In essence though, manipulating gravity fields implies manipulating inertia if you're not messing with mass and we get into really theoretical stuff here because, to all intents and purposes, inertia is mass, or "mass is a measure of an object's inertia".

F = m.a is the equation most people are familiar with; now imagine that we suddenly have a change in F because the ship has just fired off the main drive but we want to avoid any change in a (which is our effective gravity, of course). This means that either we need to somehow apply a 'reaction' that is equal and opposite to the main drive's vector but only within the ship itself or we need to mess with the nature of matter itself, within the ship, such that under this new force vector a remains what it previously was. 'Gravitics' is supposedly this latter area.

 

[StephenT]

When finished they walk back to their ship and climb up the ramp to the airlock and as they step through the door they suddenly are hit instantaneously with 1G of 'force' pulling on them.

Here I'm going to quote from the first chapter of 'On Basilisk Station' by David Weber:

Commander Harrington floated easily down the last few meters of tube, then spun in midair and caught the final scarlet-hued grab bar that marked the edge of Fearless's internal grav field. She crossed the interface like a gymnast dismounting from the rings to land lightly before him. [...] He saluted sharply, the side party came to attention, and the bosun's calls shrilled. All activity stilled around the entry port, and her hand came up in an answering salute.

"Permission to come aboard?"

If you're not as graceful as Commander Harrington, I imagine moving from zero-G to the starship would be rather more awkward.

 

[Gaidheal]

Actually, that scene handled it pretty well and is one I use to explain to new players in settings where I have enough 'hard' elements for it to be an issue.

Of course, part of an officer's training, even unofficially, is going to be " 'Ow ta get on a starship from zero-gee without looking like a bunch o' pratts! So listen up, you 'orrible lot..." Don't you think? ;¬)

 

[Oaty_bars]

Well, it's implied that it's the same technology (not necessarily the same kit, of course, though actually, they amount to the same thing, really).

Thing is, the idea of killing inertia is what we can call 'speculative', politely, or 'bullshit' less politely. ;¬)

In essence though, manipulating gravity fields implies manipulating inertia if you're not messing with mass and we get into really theoretical stuff here because, to all intents and purposes, inertia is mass, or "mass is a measure of an object's inertia".

F = m.a is the equation most people are familiar with; now imagine that we suddenly have a change in F because the ship has just fired off the main drive but we want to avoid any change in a (which is our effective gravity, of course). This means that either we need to somehow apply a 'reaction' that is equal and opposite to the main drive's vector but only within the ship itself or we need to mess with the nature of matter itself, within the ship, such that under this new force vector a remains what it previously was. 'Gravitics' is supposedly this latter area.

But a form of inertial damping would be less problematic than trying to shoe horn a gravity system to do the same job,

How would such a gravity system be fitted/used within a ship?
and on top of that you really would run in to trouble with shearing if it was out of sync in even the slightest way, (which could chew up the crew or even tear the ship apart from the inside out,)

I think a general field of inertial damping makes more sense,
(And I maybe wrong but I think inertial damping was mentioned in T4)