International Space Station: 100KW for 68Td; about 2KW per 100Td, or 0.002MW per Td. We're in the ballpark now, and might be bang on if TNE only counts pressurized volume for life support power.
T5: Collector TL Stage Effects / Annic Nova Q.
- Thread starter Grav_Moped
- Start date
International Space Station: 100KW for 68Td; about 2KW per 100Td, or 0.002MW per Td. We're in the ballpark now, and might be bang on if TNE only counts pressurized volume for life support power.
AnotherDilbert
SOC-14 1K
Unless you want artificial gravity which adds another 7 MW per 100 Dt.
Of hull, or of volume with artificial gravity? This can make a big difference if you're trying to minimize energy consumption. I wouldn't expect FF&S to have made that distinction, but maybe they did.
It's like turning out the lights when you leave the room. It does mean you need to secure everything in the room before you shut off the grav (because it's also probably inertial compensation too).
But if you're running on minimal power (canon XBoat, maybe DA 1 Annic Nova as well), you probably aren't maneuvering much.
In that case, you only need it for the bed in your stateroom, the cockpit part of the bridge, workstations in the drive room, and a break room (for convenience, but mostly to prevent health consequences from long-term living in free-fall). Corridors and a lot of the rest of common spaces shouldn't need it except when under acceleration -- and if you've got power for the maneuver drive, you've got far more power than the artificial gravity uses.
AnotherDilbert
SOC-14 1K
I can't recall if FF&S specified, but MT specified you have to control the gravity in the entire hull IIRC.
This implies that you can't use artificial gravity to make moving cargo in a ship's hold easier (which is something called out in canon as possible, but not under MT) without really inconveniencing all the ship's occupants.
Again, I don't think they expected anyone to seek this level of granularity. As an RPG mechanic, extreme emergency power cutback requiring shutting off the pseudgrav and inertial compensation works well to convey dire straits.
As an edge case construction rule for ships that don't have a traditional powerplant (which in canon means basically the XBoat and Annic Nova*) it's unsatisfactory. I mean, yeah, it's playing rules lawyer to say you only need to pay the power cost for artificial gravity where you're using it, and don't have to where you're not. But I don't think it's an unreasonable ask. Wouldn't make a big difference for AN since so much of it is likely to be in continuous use (and the hydroponics deck would NOT react well to being put in 0G). It would for the XBoat, since there's so little actual crew space relative to the entire hull.
*except the LBB5 XBoat and MongT/T5 Annic Nova; they do have power plants.
The thing about power use for life support/environmental/gravity and batteries is more about the principle of Annic Nova itself: Other than for the pinnaces, it doesn't need fuel ever -- it's the perfect ghost ship. Changing that to "oh, it still needs fuel, just a tiny amount though" takes that away. And grandfathering it in without an in-universe explanation as is the case for the XBoat (if you're not using LBB5), means it probably has tech the authorities would not let the players keep once the adventure is done.
AnotherDilbert
SOC-14 1K
Not really. You have to install it for the entire hull, but can regulate field strength per room, at least according to CT S7.
It is also a necessary property of inertial dampers: in order to counteract the effects of a rotation of the ship some parts of the ship needs a stronger gravity field than others.
Condottiere
SOC-14 5K
1. The default setting for (Terran) humans is to keep the spaceship onboard environmental conditions to Earth norm, which would include smoothing out gravitational fluctuations.
2. In Einsteinianspace, interaction with it allows solar panelling to be unlimited energy, if somewhat rationed; if you could find something to interact with in jumpspace, for example movement, you could set up a windmill or turbine that can turn that kinetic energy into electricity that the ship systems could be pwoered on.
3. Compromisingly, there are fission reactors and cold fusion (though that may not have been invented in the MongoVerse).
2. In Einsteinianspace, interaction with it allows solar panelling to be unlimited energy, if somewhat rationed; if you could find something to interact with in jumpspace, for example movement, you could set up a windmill or turbine that can turn that kinetic energy into electricity that the ship systems could be pwoered on.
3. Compromisingly, there are fission reactors and cold fusion (though that may not have been invented in the MongoVerse).
The question then is whether it can be selectively shut off, or whether the field saturates the whole ship and can only be interrupted locally. In other words, whether or not turning off the gravity completely (including inertial compensation) in a 100Td cargo bay of a 200Td ship reduces the power draw by 7MW. Not that it matters much, most of the time -- if your ship is designed around having artificial gravity (non-tailsitter), any time you need grav and i-comp, you're already running a power plant with at least 250MW/100Td/G and that 7MW is just a rounding error.
A secondary question is whether this is a prerequisite for maneuver drive. That is, it may be that a LBB2/T5 Size A Maneuver Drive can only push 1,000 mass tons (rough equivalent of 100 displacement tons) at 20m/sec2 (2G) if the entire hull is contained in an artificial gravity field. (It's likely that even if you could turn all the gravity off when not accelerating, you'd probably still keep at least the fuel tanks under gravity to ensure proper fuel flow -- the SpaceX Starship test articles had issues with fuel slosh during the kick-flip maneuver.)
It's worth noting that the 7MW/100Td does not scale with maneuver drive rating. Since the power requirement is only about 2.8% of what a maneuver drive needs per G of acceleration, it's likely that increases in artificial gravity energy costs are just subsumed in the maneuver drive's power draw.
Last edited:
1. Yes. My meandering here is not about the default settings, but wandering off into edge cases where the baseline assumption of unlimited energy doesn't apply.
2. Might not even need to get that exotic. The jump capacitors needed for a Jump-1 hold 1.5 gigawatts per 100Td (High Guard + Striker), and that all ends up going into the jump drive. Recover even a tiny fraction of that from the waste heat, and you're set for the entire week in weird-space. The rules don't allow that, though.
3. I thought "Fusion+" tech was supposed to be cold fusion, but I may have misunderstood. I don't think MongT uses it, though. Radioisotope Thermal Generators (RTGs) ought to be able to cover heating, air conditioning, but probably not artificial gravity. Batteries would probably be lighter for use cases up to "months", RTGs would be for when you need "years" of power.
AnotherDilbert
SOC-14 1K
Presumably not. If we need to install it in the entire ship, we can presumably not just turn half of it off.
You are mixing CT and TNE freely here. TNE ships are not bound by any 250 MW/100 Dt limitation.
If you want to use basic assumptions from CT, then MT is a closer match, and basic artificial gravity would consume 95 MW/100 Dt.
No, in both MT and TNE artificial gravity is a separate system and works independently of the propulsion. You can have a rocket drive with inertial compensation or an M-drive without.
The 7 MW is from TNE that does not use M-drives, so that is a quite a reach.
I've built, and re-built, the ANNIC NOVA many times using T5. Each time is a little different.
I ended up preserving my sanity with these assumptions:
Bottom line: there's plenty of room to accommodate the elements of the text description. It's a very portable and forgiving ship design, once you deal with the power plant issue.
I ended up preserving my sanity with these assumptions:
- The A.N. is TL 16; it simplifies the Collector dilemma.
- I've also used smaller Collectors before -- e.g. C-2, C-2, and a C-1.
- The A.N. is a Dispersed Fusion+ design; no power plant necessary, but monthly starport checkups are a good idea.
- When porting a design, aim for the text description instead of the technical design sheet.
- And the 'best' is the enemy of the 'good enough'.
Bottom line: there's plenty of room to accommodate the elements of the text description. It's a very portable and forgiving ship design, once you deal with the power plant issue.
Last edited:
Seems like an average then.
Wait. TNE doesn't require Pn-1 minimum?
So it's 950KW/Td instead of 7MW/Td. Won't make a lot of difference if you have fusion power, really does if you don't.
Ok, but that goes back the first point: If it's not needed for the M-Drive, then why does it have to cover the whole ship? ("Rules say so" is an answer, but not a satisfactory one). You'd want grav in the fuel tanks and habitable spaces, and probably the cargo hold (but you could get away without it on a 1G ship if the cargo is properly blocked and braced). Again, it's down in the noise compared to how much energy the M-Drive uses.
If it's the 950KW/Td from MT, you're going to have M-Drives and 250MW/Td/G (or Jn) per 100Td.
That said, a flat-rate power draw regardless of external forces says a LOT about how artificial gravity works.
1. Any ship's artificial gravity field can maintain normal gravity against up to 6G external forces, regardless of the ship's M-drive capability. (Fixed power requirement and cost, 6G limit in the rulesets that have it.)
2. It's likely functions by making the area in its field selectably 0-1G in a specified direction regardless of outside forces. There is no inertial compensation involved, because the artificial gravity field completely isolates its contents from inertial forces. (Fixed power requirement.)
3. Acceleration higher than 6G causes the artificial gravity field to fail entirely, rather than "leaking through". (6G maximum possible acceleration in the rulesets with that limitation.)
Condottiere
SOC-14 5K
Inertial compensation might be a field effect, but artificial gravity seems very much local gravity plating.
AnotherDilbert
SOC-14 1K
Neither MT nor TNE has power plant numbers. You only need enough power in MW.
MT require 95 MW/100 Dt. TNE require 7 MW/100 Dt. TNE overall requires less power, but power plants produce less power, so it is balanced.
Yet, it is the only one I have.
Yes, it depends on TL. Higher TL inertial compensation can handle higher acceleration. It has been defined that way since LBB5 that introduced compensation.
No. If the inertial compensators can handle 6 G, then 2 G will be felt if the ship accelerates by 8 G. See TNE.
No.
OK
OK
Understood. I think it violates the "it has to make sense" heuristic but those are the rules.
I'm mostly ok with that, in that the rules limit on acceleration isn't based on F=MA (you can keep adding F to get more A), but on the physical limitations of the meatbags on board.
Many high-G ship deckplans are wrong then. A 6-G belly-lander needs 7G artificial gravity (vector sum of 6G pulling forward, 1G pulling toward the floor). And with strong enough drives, they could be 8G tailsitters instead before needing to add acceleration couches (7G forward vs 8G thrust nets 1G aft).
Which means high-G ships need to be tailsitter/skyscraper oriented, not belly-landers. Few are.
AnotherDilbert
SOC-14 1K
Vectors do not add that way. Orthogonal vectors only gets slightly longer. See LBB2 and Pythagoras.
For military use it has to compensate erratic evasive manoeuvres, not just steady acceleration:
FF&S said:
There are also "G tanks", basically wearing a G suit submerged in a fluid, so you can withstand another G without penalty if you are strapped in.
Right. It's about 6.08Gs, not 7. The fraction wasted in lateral (in the direction of the deck) force decreases with increased acceleration.
If the sum total of erratic evasive maneuvers is limited to the MD output (and it is, hence Agility as a concept), it's still hitting the same limit.
That almost mandates tailsitter deck orientation. Or separate seats for low and high G operation and the expectation that everything not tied down falls to the aft bulkhead very quickly.
Taken as a whole, this suggests that the classic limit of 6G involves tailsitters with G-tank control couches and -3G/+1G artificial gravity (2G uncompensated, 1G from the g-tank, and 3G from artificial gravity). Maybe artificial gravity is easy up to 3G and starts getting impossibly expensive and difficult above that?
Last edited:
Condottiere
SOC-14 5K
You'll be able to tolerate long term about one and a half gravities, so with inertial compensation of six, that's seven and a half gees, with the artificial gravity turned off.
In theory, acceleration couch compensates an additional gravity, and the gee tank two.
In theory, acceleration couch compensates an additional gravity, and the gee tank two.
