Questions regarding Grav technology

[Iron Guardian]

Don't know if this has ever come up before, but I am curious as to what the limits of grav technology are. That is, I was wondering what the minimum and maximum gravity conditions gravbelts and grav vehicles (i.e. air-raft, g-carriers, etc.) are able to function in... what minimum gravity is needed for them to work effectively...what maximum gravity the technology can handle and so forth. Also, when controlling gravity aboard a starship or non-starship, what is the maximum gravity that can be generated internally (assuming safety protocols or whatever are overridden and the crew want the gravity to exceed 1G for some reason)? Up to the individual GM or is there some precedent set out there by some game designer or physicist? :?

Also, can't wait for the Droyne Sourcebook which I hope is being planned for in the future... :wink:

 

[GamerDude]

Don't know if this has ever come up before, but I am curious as to what the limits of grav technology are. That is, I was wondering what the minimum and maximum gravity conditions gravbelts and grav vehicles (i.e. air-raft, g-carriers, etc.) are able to function in... what minimum gravity is needed for them to work effectively...what maximum gravity the technology can handle and so forth.

While I don't know the math on it all but I would think it is pretty close to planetary orbit. I'm not sure what altitude that is at LEO, Geosync or somewhere in between.

 

[Treebore]

I think for anyone to "know" they would first have to know how the technology actually works. Since no one knows that yet, impossible to say for sure.

So go with what makes sense to you.

I would guess a probably premise would be that there has to be a gravitic field to interact with. The interesting question is how strong/weak it can be and still have the technology work effectively.

 

[Rev503]

I think for anyone to "know" they would first have to know how the technology actually works. Since no one knows that yet, impossible to say for sure.

So go with what makes sense to you.

I would guess a probably premise would be that there has to be a gravitic field to interact with. The interesting question is how strong/weak it can be and still have the technology work effectively.

Yeah thats the question
In theory there isn't a place with no gravity, just places where the gradient is more or less steep.
On the other tentacle (So whens the Hiver sourcebook coming out?) I get the impression the M-Drive of shps/boats isn't wholly gravitic and is a reactionless drive which eitehr implies a minimum gravitational gradient the things work in or they don't develop a lot of thrust.

Pick the answer that suits you and have fun with the implications (From "we need an ATV for this moon, there isn't enough gravity for an air raft" through "OMG my grav belt is stuck at full on, I hope I hit a Lagrange point otehrwise I';ll be heading through the outer system in a couple of years" to the ever popular "Haha pirates, try and board when the airlock has a 20g field pointing straight out")

 

[Rikki Tikki Traveller]

Here are the guidelines that I use:

Gravity Lifters (Air/Rafts etc) allow you to go out to Low Orbit. I define Low Orbit as 1/10th of the diameter of the planet, so for Earth it is about 800 miles. For other worlds you just take the size of the world in hundreds of miles.

To reach Low Orbit, a lifter can climb 100 km/hr, so it takes a number of hours equal to the Size code to reach Low Orbit.

Just as a quick note, the Earth's atmosphere essentally ends at a much lower limit. The ISS orbits at about 100 miles (just under actually).

Beyond that, the Maneuver Drive must be used. So a shuttle that wants to go to the Highport (usually located in Geostationary orbit), you need an M-Drive.

The Maneuver Drive works. Everywhere. I don't worry about limits on it. The Maneuver Drive automatically incorporates Lifters for landing/hovering etc.

Hope that helps!

 

[pasuuli]

Don't know if this has ever come up before, but I am curious as to what the limits of grav technology are. That is, I was wondering what the minimum and maximum gravity conditions gravbelts and grav vehicles (i.e. air-raft, g-carriers, etc.) are able to function in... what minimum gravity is needed for them to work effectively...what maximum gravity the technology can handle and so forth. Also, when controlling gravity aboard a starship or non-starship, what is the maximum gravity that can be generated internally (assuming safety protocols or whatever are overridden and the crew want the gravity to exceed 1G for some reason)? Up to the individual GM or is there some precedent set out there by some game designer or physicist? :?

The working concept is: grav vehicles and belts and the like can take you up a distance of 1 planetary diameter -- for rockball worlds at least.

Internal pseudo-gravity is probably dependent upon the GM and the species for which the craft was designed. The GM would have to rule on how easy it is to override safeties or enable security controls which would rapidly toggle the interior gravity between +G and -G...

 

[silburnl]

I would guess a probably premise would be that there has to be a gravitic field to interact with.

Yup. Watch out for habitats spun for centripetal 'gravity' - antigrav won't help you there (this is a minor bit of colour in Consider Phlebas - minor for the reader that is, not so minor for the poor schlub who missed the safety briefing...).

Regards
Luke

 

[Rikki Tikki Traveller]

The CT Traders and Gunboats listed internal gravity as being adjustable from 0.1 - 2.0 G (The Empress Marava Far Trader).

Seems like a reasonable range for internal gravity to me. You can also shut it off completely to get Zero-G.

BUT, it I like to use the fact that the Inertial Compensators are tied to the Grav Plates, if you turn off the Grav Plates, you loose Inertial Compensation, so all those walls just became floors at whatever acceleration the ship is undergoing at the time... But that's just me.

 

[GamerDude]

The CT Traders and Gunboats listed internal gravity as being adjustable from 0.1 - 2.0 G (The Empress Marava Far Trader).

Seems like a reasonable range for internal gravity to me. You can also shut it off completely to get Zero-G.

BUT, it I like to use the fact that the Inertial Compensators are tied to the Grav Plates, if you turn off the Grav Plates, you loose Inertial Compensation, so all those walls just became floors at whatever acceleration the ship is undergoing at the time... But that's just me.

and, they become the place your remains will be found spattered if the change in acceleration while not having intertial comps/dampeners online.

I can imagine even being strapped into a couch or acceleration chair is only a modest help under such conditions...being pushed into a harness or back into a chair can be almost as bad as being tossed across the room.

 

[Rikki Tikki Traveller]

Yep!

As the Referee, I felt there was no reason to explain to the players the consequences of their actions.

They turned off the Grav Plates while accelerating at 3gs. They all took fall damage immediately (they fell many meters at 3gs) and then couldn't move under the 3g acceleration pinning them to the back wall while they took additional damage due to the high G load.

Several of them died before they were able to cut the acceleration.

Physics is a bitch sometimes.

 

[BP]

Don't know if this has ever come up before...

It has :lol:

As Rikki Tikki Traveller, mentioned, some non-MGT sources made comments.

I look at the 'reasons' to know this and used to use 'upto 10Gs' for internal starships if someone wanted to use gravitics in 'creative' ways inside a starship (after overriding the safety).

I chose this 'arbitrary' number for several factors
-Not likely to directly kill (nominally >50g for that) though fall checks can result in broken neck, etc.
-Likely cause unconsiousness (GLOC) in one combat round (suited or not) - stat check.
-Even really quick changes - not likely to kill directly.
-Assume battle dress can compensate for circulation issues.

For over 5 G when passes consciousness check - check for blackout (or use level of success) only (no vision, but conscious).

 

[GamerDude]

The working concept is: grav vehicles and belts and the like can take you up a distance of 1 planetary diameter -- for rockball worlds at least..

Looking over the MGT Core book, air rafts and other vehicles can "go to orbit".

In searching the book, the "Interplanetary Transit Times Table" on page 145 gives "Surface to Orbit" as the example for a distance of "10,000 km" so I would that as the limit for grav vehicles.

For the grav belt, the text doesn't say it can go to orbit, and with a top speed of 300kph it would take over 30 hrs to reach an altitude of 10,000km, and it only has a power duration of 12 hrs.

 

[Sir Brad]

your best bet to find the Info you need is to get your self a copy of "Fire Fusion & Steel" for TNE and a copy of the Construction rules for Megatravller.

then don't forget Solamani do it a net 20% worse than the Baseline for that TL (heck the Men of Sol reached a general TL-11 before they got to work right) and Drone do it 10% better than the Baseline.

 

[BP]

...For the grav belt, the text doesn't say it can go to orbit, and with a top speed of 300kph it would take over 30 hrs to reach an altitude of 10,000km, and it only has a power duration of 12 hrs.

Good point - though orbit could be just to the edge of space (< 200 km) or a low orbit (under 2000 km for earth) - so that would be in range (though getting back down - or rather the landing - could be a problem with the latter ... )

The 10,000 km Surface to Orbit given in Traveller - I assumed was referring to typical orbital station - with geostationary orbits (over 3x out) also a possibility. Ships could orbit much closer...

 

[Treebore]

After reading some Gravitic Theory I would say the magnetic drives create a large magnetic field of strong polarity, and no matter how weak the magnetic fields it interacts with, the strength of its own field determines how much it "repels" which translates to its speeds.

I remember reading some old Sci Fi novels who based space travel on magnetics, I'll have to dig them up and see what I think of them now.

 

[BP]

After reading some Gravitic Theory I would say the magnetic drives create a large magnetic field of strong polarity, and no matter how weak the magnetic fields it interacts with, the strength of its own field determines how much it "repels" which translates to its speeds.

I remember reading some old Sci Fi novels who based space travel on magnetics, I'll have to dig them up and see what I think of them now.

Treebore, guessing you mean gravitic in place of magnetic :?

But the idea of gravity acting like magnetism - i.e. polarized with the magnetic poles being replaced by gravitic poles of attraction/repulsion sounds plausible for Traveller gravitics.

The gravitic 'propulsion' being generated irrespective of the existing local strength - i.e. the force (accelleration) due to 'gravity' is directionally controlled.

Traveller also seems to use anti-gravity. I recall somewhere that M-Drive 'thrusters' were explained as reactionless drives that also appear to lightup due to ionizaton (to explain the pretty ship pictures )

 

[GamerDude]

Traveller also seems to use anti-gravity. I recall somewhere that M-Drive 'thrusters' were explained as reactionless drives that also appear to lightup due to ionizaton (to explain the pretty ship pictures )

I can't remember if this was in GT or T20 or even CT, but it I heard it as Contragravity.

The diff as I remember it is "anti-gravity" means canceling gravity and "contragrav" pushes against gravity.

Of course that's a fuzzy recollection at best.

 

[EDG]

FF&S had "contragrav" (CG lifters) that cancelled out gravity - but they only worked in a gravitational field and didn't provide thrust (you could use them to lift off from a planet though).

It also had (as an optional technology) Thruster plates, which were the previously standard Traveller M-Drive that essentially worked by pushing against a plate on the ship (which if you think about it, is somewhat akin to using a ship-mounted spotlight to power a light sail).

 

[BP]

... (which if you think about it, is somewhat akin to using a ship-mounted spotlight to power a light sail).

(Someone else's I hope!)

 

[GamerDude]

FF&S had "contragrav" (CG lifters) that cancelled out gravity - but they only worked in a gravitational field and didn't provide thrust (you could use them to lift off from a planet though).

Cool...

Forgive my not recognizing it, but what is FF&S?