Inertial Compensators

[BackworldTraveller]

Inertial Compensators seem to exist on a traveller ship.

How much of the ships acceleration do they counter?

If you don't offset all the acceleration, how much energy does the ship save?

 

[kilemall]

I always handwaved them as part of the M-drive, both power and space.


One could I suppose use various grav vehicle lifter cost and power structures to define how much power it is taking to effectively provide an attraction or repulsion effect, but I would tend to shy away from that being any kind of standard thing to cut power to.



Objects flying around during maneuvers would be lethal, and letting go of the ship's floor or walls in zero-G means an imminent impact with the back wall bulkhead at Gx10 m/s.


Unless you handwave the maneuver field itself is propelling everything along equally.



More interesting if it's not something that ever changes or is out of sync with the M-drive, unless there is an odd failure or the computer/bridge is destroyed and the crew is trying to accel out of the way of burning up on reentry or Large Rocks using just engineering inputs. No connection to the artigrav field, so ugly can happen.



So a lot depends on what YOU want to happen and what obstacles/choices YOU want for drama/game purposes.

 

[MThompson016]

In GURPS Traveller, Starships provides the following information on page 40.
GTL 8-9 compensators are up to 3g (TTL8-11)
GTL 10-12 compensators are up to 6g (TTL12-15)
GTL 13 compensators are up to 9 g (TTL 16+)

Mongoose 1st does not provide limits.

 

[AnotherDilbert]

Inertial Compensators seem to exist on a traveller ship.

How much of the ships acceleration do they counter?

All of it, up to a specified maximum.

CT said:

Tech level requirements for maneuver drives are imposed to cover the grav plates integral to most ship decks, and which allow high-G maneuvers while interior G-fields remain normal.

MT clarified:

Inertial Compensators: Inertial compensators, when installed, allow hlgh-G maneuvers while interior G-fields remain normal. Inertial compensators negate the effects of inertia, so the occupants of a moving craft have no sensation of motion.

TNE FFS was of course a bit more detailed:

Artificial gravity G compensators create an artificial gravity field in direct opposition to the axis of acceleration, thus negating the acceleration(up to the limit of the artificial gravity field). Compensated Gs is the number of acceleration or evasion Gs negated by the compensator. The amount of Gs which can be compensated vary by tech level as shown on the table below.

That's all we know.

If you don't offset all the acceleration, how much energy does the ship save?

Negligible? MT and TNE specified inertial compensators as a separate component. It used a set amount of power, regardless of how much of the acceleration it removed, i.e. a 1 G ship used as much power as a 6 G ship.

 

[Fovean]

I too have always subsumed inertial compensation into the operation of the maneuver drive.

Playing MgT 2e these days, where ship Power points have been brought back. I play that the Maneuver drive actually generates twice it’s rating, for example Thrust 2 (2G) as well as 2G for inertial compensation. So if the 2G M-Drive needs 20 Power, you could cut the grav plates and get an extra 10 Power out of it or up to Thrust 4.

It came about from trying to reconcile a Thrust 1/1G ship refueling from a 2G gas giant.

Obviously you reduce compensation for additional Thrust or Power at some risk to the crew. Vacc suits, acceleration couches/benches, G-drugs and the like all help the crew counteract the effects of uncompensated g-forces IMTU.

 

[whartung]

TNE has Artificial Gravity compensators, and G-Tanks. They're limited by TL. Basically 1G at TL 10, and +1 up to 9G at TL20.

The artificial gravity is .005 MW per cubic meter of the ship (so for a 100 ton ship, thats 7MW).

There's details about strapping in to couches and differences between maneuver Gs and evasion Gs.

 

[Grav_Moped]

I too have always subsumed inertial compensation into the operation of the maneuver drive.

Playing MgT 2e these days, where ship Power points have been brought back. I play that the Maneuver drive actually generates twice it’s rating, for example Thrust 2 (2G) as well as 2G for inertial compensation. So if the 2G M-Drive needs 20 Power, you could cut the grav plates and get an extra 10 Power out of it or up to Thrust 4.

It came about from trying to reconcile a Thrust 1/1G ship refueling from a 2G gas giant.

Obviously you reduce compensation for additional Thrust or Power at some risk to the crew. Vacc suits, acceleration couches/benches, G-drugs and the like all help the crew counteract the effects of uncompensated g-forces IMTU.

It's not necessary to have maneuver Gs > planet Gs to skim a gas giant.

Put the ship in an elliptical orbit (or, rather, a segment of one) with the perigee inside the atmosphere. This only requires thrust greater than aerodynamic drag (instead of greater than local G) -- keep the speed up and momentum will carry the ship back out of the atmosphere after the skimming pass. Atmospheric entry will be at hypersonic speed, and isn't a trivial task.

For MgT, it'd be Average difficulty check against Pilot skill to fly a safe skimming track (or use atmospheric operations rules).
Someone could assist through an Average difficulty Astrogation skill check to optimize the track (and there should be plenty of time available to bring the difficulty on this roll down quite a bit). Sensor ops, again at average difficulty, can also assist by forecasting "weather conditions" along the plotted skimming track.

Marginal failure indicates having to abort the skimming run with only half of the normal fuel load (either too high a track to scoop properly, or too low and it's necessary to climb out to avoid overheating the hull).
Average failure indicates having to abort the skimming run without collecting any fuel.
Exceptional failure indicates severe hull overheating or turbulence -- ship takes damage (I'm not confident in my understanding of MgT combat to figure out how severe it should be, but this should be a major crisis). Pilot skill check (no time modifiers allowed, stat is DEX) to mitigate damage, Engineer (maneuver drive) skill can assist by enabling maneuver drive overload operation to escape situation. Probably also destroys or at least damages the fuel purifier.

Of course, if the ship has enough maneuver Gs to hover, it can skim at subsonic speed and make this an Easy task.

 

[Condottiere]

It's mostly handwaved.

The general assumption is that the manoeuvre drives create a counter inertial compensation field; problems arise with the addition of reactionary rockets to the mix, either by themselves, or as afterburners.

In theory, you could accelerate at twenty five gees, so the question would be how do you compensate for that? Missiles and torpedoes certainly could hit fifteen gees, so why not other spacecraft?

 

[AnotherDilbert]

The general assumption is that the manoeuvre drives create a counter inertial compensation field; problems arise with the addition of reactionary rockets to the mix, either by themselves, or as afterburners.

No, it's specifically a separate component, the same technology that maintains a constant 1 G gravity in weightless space.

Tech level requirements for maneuver drives are imposed to cover the grav plates integral to most ship decks, and which allow high-G maneuvers while interior G-fields remain normal.

MT and TNE considers it a life support system.

 

[Fovean]

It's not necessary to have maneuver Gs > planet Gs to skim a gas giant...

...For MgT, it'd be Average difficulty check against Pilot skill to fly a safe skimming track (or use atmospheric operations rules).

This kind of blows away the High Guard trope... if it’s so easy that it’s Average, and has no negative effect on thrust/acceleration why do we need naval ships higher up in orbit guarding the skimming ships?

Of course, if the ship has enough maneuver Gs to hover, it can skim at subsonic speed and make this an Easy task.

I guess this is how lurking SDBs do their lurking?

Not trying to be snarky. Just exploring ways to keep some player-facing drama in the mix.

As regards grav plates, MgT doesn’t explore that level of crunch so hand-waving them into the M-Drive makes the most sense to me. If grav plates are Life Support I suppose one could add an entry to the Basic Ship Systems breakdown but still the most logical place to find the needed Power without revamping the whole system seems to be the M-Drive.

 

[Grav_Moped]

This kind of blows away the High Guard trope... if it’s so easy that it’s Average, and has no negative effect on thrust/acceleration why do we need naval ships higher up in orbit guarding the skimming ships?

If it was much more difficult than that, nobody would ever do it. Keep in mind that ships that rely on wilderness refueling have to do it 25 times a year. Small risks add up over multiple iterations.

They still need protection. A skimming run has a very predictable track. A 1G ship is committing most of its thrust to overcoming drag, and so doesn't have much if anything left to evade incoming fire. Ships with more acceleration are still having to fight gravity and are speed-limited by the atmosphere.

I guess this is how lurking SDBs do their lurking?

Not trying to be snarky. Just exploring ways to keep some player-facing drama in the mix.

Pretty much. I suppose they could descend until conditions are dense enough to provide buoyancy, if that's above the ship's crush depth.

As far as drama, you could declare it to be a bit more difficult while reducing the likely consequences of failure (or providing more options to escape or mitigate those consequences). Keep the option of catastrophe lurking in the background, though, for dramatic effect.

MgT has rules for atmospheric operations; look to them for guidance.

Classic (LBB2, HG) had it as a risk-free operation, except in the background text for Azhanti High Lightning -- and even that was meant to justify the ship having fuel shuttles.

As regards grav plates, MgT doesn’t explore that level of crunch so hand-waving them into the M-Drive makes the most sense to me. If grav plates are Life Support I suppose one could add an entry to the Basic Ship Systems breakdown but still the most logical place to find the needed Power without revamping the whole system seems to be the M-Drive.

 

[BackworldTraveller]

The FFS table of 1G at TL-10 and slowly increasing gives a tech limit to Gs

The Mongoose basic power for the ship includes life support so presumably includes Dampers.

There will. I think, be a difference in effectiveness between compensating for expected G (drives) and unexpected G (which FFS seems to include Evading, but presumably also includes atmospheric turbulence and impacts).

 

[AnotherDilbert]

As regards grav plates, MgT doesn’t explore that level of crunch so hand-waving them into the M-Drive makes the most sense to me. If grav plates are Life Support I suppose one could add an entry to the Basic Ship Systems breakdown but still the most logical place to find the needed Power without revamping the whole system seems to be the M-Drive.

Yet MgT2 allows 16 G rockets without any adverse effects on crew performance. You don't need an M-drive to enjoy the effects of inertial compensators.


This probably implies that inertial compensators are part of the hull:

Non-Gravity Hulls: Basic hulls include artificial gravity, using grav plates to ensure a normal gravitational environment for the comfort and convenience of the crew. Hulls can be built cheaper without artificial grav plating, using specific configurations that allow the hull to constantly spin in order to generate gravity if it is desired.

Note that artificial gravity and inertial compensators are exactly the same thing, except that inertial compensators can act in a many directions.

 

[Fovean]

This probably implies that inertial compensators are part of the hull...

Thanks for the reference. I guess the answer to the OP, in MgT anyway, is you gain no additional Power by turning off the compensation since it would seem it is not being tracked.

Regarding high-burn thrusters, they’ve never popped up but in the back of my mind I’ve seen them as being uncompensated IMTU. So very risky and generally limited to short bursts.

 

[Condottiere]

1. System Defence Unterwasserboote obviously don't want to give the game away, so will likely find a nice play to lay low, or proceed stealthily without stirring up the surrounding environment; buoyancy is achieved through lifters.

2. While I'm by no means an expert in Tee Five, it does get mentioned a couple of times:

Inertial Compensation. Because the technology is not gravity-based, Thrusters do not include inertial compensation. If required, it must be supplied independently (installing Lifters is sufficient)

3. I'm guessing hull configuration determines maximum gravitational force, due to the intrinsic need to keep said hull intact.

4. Black globe opens up another avenue of thought, in that it's mentioned most hulls have inertial compensators.

5. Impact is turned into energy, so inertial compensation could essentially be turning motion within the hull into energy, like an automatic watch.

6. Or maybe turning external force into energy.

7. Though what happens you retrofit a new faster manoeuvre drive onto a hull which used to have a slower one installed: rip out all the gravitational plating and reinstall new ones?

8. Or default inertial compensators can handle every gravitational force from one to twenty five.

9. Compensators. Integral to Maneuver Drives, Gravitic Drives, and Lifters is an inertial compensation component which counteracts the effects of acceleration on occupants of the ship.

10. Looks like the installation of lifters is integral to having inertail compensation onboard.

11. Honourable mention must go to gravitational motors for dirtside based vehicles: if they can go faster than one gee at technological level nine, you'd think spacecraft designs should be able to do that as well.

 

[AnotherDilbert]

9. Compensators. Integral to Maneuver Drives, Gravitic Drives, and Lifters is an inertial compensation component which counteracts the effects of acceleration on occupants of the ship.

Yes, in T5, not in any earlier edition I know of.

 

[AnotherDilbert]

I guess the answer to the OP, in MgT anyway, is you gain no additional Power by turning off the compensation since it would seem it is not being tracked.

Presumably it is part of Basic Systems. You might save a few Power per 100 Dt hull by turning artificial gravity off, but it is not defined how much.

Regarding high-burn thrusters, they’ve never popped up but in the back of my mind I’ve seen them as being uncompensated IMTU. So very risky and generally limited to short bursts.

Perhaps, it is not really defined in MgT. But if you can make 25 G craft that does not kill its crew instantly, I assume it's compensated.

 

[whartung]

This kind of blows away the High Guard trope... if it’s so easy that it’s Average, and has no negative effect on thrust/acceleration why do we need naval ships higher up in orbit guarding the skimming ships?

The issue here is that gas giant skimming has never been defined beyond stray sentences that "ships skim gas giants". There's not a lot detail to the maneuver.

One speculation regarding the High Guard is that even if the process is trivial to perform, it doesn't mean that the ship is not much more vulnerable to attack when in the situation. It can figuratively be considered a "pants down" position and one you'd rather not have to fight out of.

Your sensors could be blind, comms compromised, weapons systems on lock down. You have to climb out of the gravity well, etc.

So, depending on the duration, perhaps tactical and effective surprise can be achieved against a skimming ship.

Thus, the "High Guard" to keep watch, slow down the attackers, notify the skimming ship to abort their run and get out of the hole.

What's necessary is the combat DMs that make the ship particularly vulnerable during skimming to attack from "on high", or attack from below via SDBs climbing out of the atmosphere.

The actual run doesn't have to be difficult, but that doesn't mean the environment isn't dangerous when folks start trying to poke holes in you.

 

[Fovean]

Presumably it is part of Basic Systems. You might save a few Power per 100 Dt hull by turning artificial gravity off, but it is not defined how much.

Fair enough. But that makes me want to build gravitic engines out of inertial dampers. If the average ACS M-Drive needs 20-40 Power for its Thrust rating, a few points of Power to counteract that is an order of magnitude better.

Le Sigh. Forty years later and we still haven’t figured this out

 

[Fovean]

The issue here is that gas giant skimming has never been defined beyond stray sentences that "ships skim gas giants". There's not a lot detail to the maneuver.
...
Your sensors could be blind, comms compromised, weapons systems on lock down. You have to climb out of the gravity well, etc.

True, which is what led me down my particular rabbit hole.

My table occasionally likes some game mechanics to hang their actions on, since we don’t actually live in the 57th Century. The ones we’ve come up, some of which I noted above, make them happy and give us a verisimilitude lacking in the RAW.