How much Hydrogen does a Trillion Credit Squadron need?

[Limpin Legin]

So, if an entire Trillion Credit Squadron passes the same star system and needs to refuel by skimming, i) how much fuel would it *likely* require and ii) how much Hydrogen can the star provide as fuel? Yeah, it's a subjective-wacky question because it depends on the exact makeup of the squadron and it depends on why the entire squadron was passing the same Star, at the same time, in the first place. But supposing, hypothetically, what would the answer look like?

On a deeper level, the amount of Hydrogen a Star has available is not recorded or calculated in Traveller star systems. Hydrogen is always inferred as being infinitely abundant. But shouldn't a Star have a sort of "Hydrogen Endurance Points" (HEPs) that can be used to determine whether a Star has enough fuel to give any passing by skimmer? When the HEPs are reduced to zero, possibly due to Trillion Credit refuelling, then the Star's core will shrink under gravity and become a red dwarf, and much later, possibly a white dwarf.

Might that impact the logistics of something like the Fifth Frontier War, should one side run out of Hydrogen availability? (Instead of automatically assuming both sides got access to an infinite abundance of Hydrogen via skimming.)

I haven't found anything that tells me that a Squadron doesn't use unrefined skimmed fuel on every occasion. But that might be a well justified answer, if someone can provide suitable evidence and the numbers add up.

 

[AnotherDilbert]

You don't skim from the star, but from a gas giant or ocean.

If the fleet skims every week for a few centuries, the difference might be measurable (not noticable). Barely.


It's not a practical problem.

 

[Condottiere]

Probably somewhere between half to three quarters of a megatonne.

 

[Tobias]

No, for all practical purposes, hydrogen is in infinite abundance.
A fleet of one hundred 500 kton dreadnoughts requires mabye 300 million cubic meters of hydrogen per jump. That sounds like a lot, but it's nothing. The humble Baltic Sea could refuel that fleet 20 million times before it ran dry (which it would not, because water from the North Sea would flow in.)

 

[agentwigggles]

Couple million years from a Saturn like gas giant?
This question pops up every and then.
I get why. The scale of planets is beyond human ability to be intuitive about it.
The amount of hydrogen on earth or saturn is a finite amount.
And when a ship uses that for fuel it is removed from the planet.
Ergo ships can empty a planet.

But the ratio the scale is as such that a tigress takes basically no hydrogen. We're talking like 0.00 (couple more zeros) 01 percent of the hydrogen it has.

 

[J. L. Brown]

Other folks have already answered, and very well, but I will take a stab at it also.

A single (empty) dTon of usually costs 50000 credits; using a 'Dispersed Structure' configuration or 'Non-Gravity Hull' (rules are not clear on how to stack these) can get the costs down to 25000 Cr/dTon, and a 'Light Hull' option can drop that to 20000 Cr per dTon. So 1000000000000 (a trillion credits) buys (at most) 40 million dTons of (empty) starship hulls. If that forty million dTon fleet refuels for a jump-6, they will need 24 million (2.4x10^7) tonnes of hydrogen.

Earth has about 1,386,000,000 (1.386x10^6) cubic kilometers of water; with a billion (10^9) cubic meters per cubic kilmeter, Earth has 1.386x10^15 cubic meters of water. Each cubic meter is a (1000000g) tonne of water; water is molecular weight ~18, ~16 of that is Oxygen, then other ~2 is hydrogen. So each tonne of water is 111111g of hydrogen; nine cubic meters of water is equal to one dTon of hydrogen.

The fleet requires 2.16x10^8 cubic meters of water to refuel. It can refuel 6416667 times from Earth before our water is gone; if a fleet like that it refueled in an hour, it would take 732 years to deplete the water on Earth. Jupiter has a mass of ~318 Earths; the sun has a mass equal to approximately 333,000 Earths -- and both of those are 'mostly hydrogen', instead of mostly rock like the Earth is.

 

[Alaskan15]

This prompts a thought - What would it take for a ship to be able to refuel from a star and not melt or fry the crew? Obviously this will vary by the star, but what is the lowest TL at which you could reasonably design a ship that could do this, if they stuck to main sequence M & K stars, and nothing hotter or bigger? How much armor, how much Rad shielding, how strong an M drive, how powerful the grav-plates? Can anyone but the Ancients pull this off? If not, how many Ancient ships are still floating inside stars, overlooked by the lesser beings?

 

[Limpin Legin]

You don't skim from the star, but from a gas giant or ocean.

This prompts a thought - What would it take for a ship to be able to refuel from a star and not melt or fry the crew? Obviously this will vary by the star, but what is the lowest TL at which you could reasonably design a ship that could do this, if they stuck to main sequence M & K stars, and nothing hotter or bigger? How much armor, how much Rad shielding, how strong an M drive, how powerful the grav-plates? Can anyone but the Ancients pull this off? If not, how many Ancient ships are still floating inside stars, overlooked by the lesser beings?

Yes, I've accidently confused Gas Giants with stars. Well, that is sort of a 40 year old error, and nobodies noticed until just now . I did wonder why so I checked both GDW and Mongoose rulebooks , and some of the phrasing does seem to group stars with gas giants, and maybe that lead me to believe incorrectly. I mean, c'mon! - why are stars called "dwarfs" and planets called "giants"? Surely that in itself is instrumental to misunderstanding?
But even stars contain hydrogen, so thanks for persevering with the possibility that stars could be skimmed for some unrefined fuel. Yes heat is the obvious problem. Solar flares too. Maybe it would be possible to skim from solar plasma without getting quite so near to the star. But rules-as-written, cannot do that.

 

[Limpin Legin]

Other folks have already answered, and very well, but I will take a stab at it also.

A single (empty) dTon of usually costs 50000 credits; using a 'Dispersed Structure' configuration or 'Non-Gravity Hull' (rules are not clear on how to stack these) can get the costs down to 25000 Cr/dTon, and a 'Light Hull' option can drop that to 20000 Cr per dTon. So 1000000000000 (a trillion credits) buys (at most) 40 million dTons of (empty) starship hulls. If that forty million dTon fleet refuels for a jump-6, they will need 24 million (2.4x10^7) tonnes of hydrogen.

Earth has about 1,386,000,000 (1.386x10^6) cubic kilometers of water; with a billion (10^9) cubic meters per cubic kilmeter, Earth has 1.386x10^15 cubic meters of water. Each cubic meter is a (1000000g) tonne of water; water is molecular weight ~18, ~16 of that is Oxygen, then other ~2 is hydrogen. So each tonne of water is 111111g of hydrogen; nine cubic meters of water is equal to one dTon of hydrogen.

The fleet requires 2.16x10^8 cubic meters of water to refuel. It can refuel 6416667 times from Earth before our water is gone; if a fleet like that it refueled in an hour, it would take 732 years to deplete the water on Earth. Jupiter has a mass of ~318 Earths; the sun has a mass equal to approximately 333,000 Earths -- and both of those are 'mostly hydrogen', instead of mostly rock like the Earth is.

Couple million years from a Saturn like gas giant?
This question pops up every and then.
I get why. The scale of planets is beyond human ability to be intuitive about it.
The amount of hydrogen on earth or saturn is a finite amount.
And when a ship uses that for fuel it is removed from the planet.
Ergo ships can empty a planet.

But the ratio the scale is as such that a tigress takes basically no hydrogen. We're talking like 0.00 (couple more zeros) 01 percent of the hydrogen it has.

No, for all practical purposes, hydrogen is in infinite abundance.
A fleet of one hundred 500 kton dreadnoughts requires mabye 300 million cubic meters of hydrogen per jump. That sounds like a lot, but it's nothing. The humble Baltic Sea could refuel that fleet 20 million times before it ran dry (which it would not, because water from the North Sea would flow in.)

Probably somewhere between half to three quarters of a megatonne.

You don't skim from the star, but from a gas giant or ocean.

If the fleet skims every week for a few centuries, the difference might be measurable (not noticable). Barely.


It's not a practical problem.

Thanks everyone for your calculations. I suppose there is a hidden sub-question, here? All answers assume that hydrogen can be taken until the last teaspoon of hydrogen is mopped up - which is kind of fair, as that is what the original post assumes. But the hidden question might be how much hydrogen can be skimmed before it destroys the local planetary ecosystem? That too might seem a long time away, I suppose, but no harm in asking, for sure.

 

[MasterGwydion]

Thanks everyone for your calculations. I suppose there is a hidden sub-question, here? All answers assume that hydrogen can be taken until the last teaspoon of hydrogen is mopped up - which is kind of fair, as that is what the original post assumes. But the hidden question might be how much hydrogen can be skimmed before it destroys the local planetary ecosystem? That too might seem a long time away, I suppose, but no harm in asking, for sure.

Does a gas giant have an ecosystem to damage?

 

[Limpin Legin]

Does a gas giant have an ecosystem to damage?

Don't suppose there would be any plant life to destroy, but IDK if skimming would increase greenhouse gases, and increase planetary temperatures, and thus make future skimming operations hindered by high temperatures? Not only in terms of depleting hydrogen, but also pollution gained from frequent starship visits?

 

[ottarrus]

Does a gas giant have an ecosystem to damage?

Traveller has several life forms, including one acknowledged sophont race [and another one that hasn't been discovered yet in the MgT timeline], that live within GG atmospheres. So in an OTU sense, yes, there is.
Within the borders of the 3-I I presume that checking all bodies in a star system for life forms is a part of the IISS' job. But obviously mistakes occasionally get made. The standard procedure is that the Scouts set gas giants with confirmed lifeforms as off limits. Besides, it's SO hard to get chlorine jellyfish out of the purifiers
IMTU naval vessels could use such a gas giant so long as the 'trespass' and the reasons for it are written up in the ship's logs for later review.

 

[ottarrus]

Linked below is the canon official race that are GG natives, the Jgd-il-Jagd.
The second race is the Sheol, a GG dwelling race in the Spinward Marches that aren't discovered until after the 5FW.

Jgd-ll-jagd - Traveller

wiki.travellerrpg.com

 

[ottarrus]

Getting back to the basic question, the smallest gas giant in our Solar System is Neptune at 388 times the size of Earth [ roughly 24.5 km /16k miles diameter]. I submit to you that the entire Core Fleet in one spot would require thousands of years to deplete the atmosphere of just one such Small Gas Giant.

 

[MasterGwydion]

Traveller has several life forms, including one acknowledged sophont race [and another one that hasn't been discovered yet in the MgT timeline], that live within GG atmospheres. So in an OTU sense, yes, there is.
Within the borders of the 3-I I presume that checking all bodies in a star system for life forms is a part of the IISS' job. But obviously mistakes occasionally get made. The standard procedure is that the Scouts set gas giants with confirmed lifeforms as off limits. Besides, it's SO hard to get chlorine jellyfish out of the purifiers
IMTU naval vessels could use such a gas giant so long as the 'trespass' and the reasons for it are written up in the ship's logs for later review.

Thank you! Now I have to start adding a few more of these lifeforms to My games to make this interesting. Perhaps some in the TL-8 to TL-12 range.

 

[AnotherDilbert]

Thanks everyone for your calculations. I suppose there is a hidden sub-question, here? All answers assume that hydrogen can be taken until the last teaspoon of hydrogen is mopped up - which is kind of fair, as that is what the original post assumes. But the hidden question might be how much hydrogen can be skimmed before it destroys the local planetary ecosystem? That too might seem a long time away, I suppose, but no harm in asking, for sure.

Earths surface is 500 000 000 km², of which 360 000 000 km² water.

The top metre of water is 1 × 360 000 000 × 1000 × 1000 = 350 trillion m³ of water = 360 trillion tonnes of water.
Hydrogen is about ²/₁₈ of water by mass, so about 40 trillion tonnes of hydrogen = 40 trillion Dt of hydrogen.

A Trillion credit squadron is roughly 1 MDt of warship, at Jump-4 that is 400 000 Dt fuel needed.
40 trillion Dt / 400 000 Dt = 100 000 000 refuelings.

If nothing else happens the squadron can skim from the Earth every two weeks for is about 4 million years before taking the top metre of water, or about 4000 years before taking the top 1 mm (~¹/₂₅").

So, a squadron would take something like ten thousand years to change the Earth as much as nature does in a single year: insignificant...


Space is immensely big, even planets are really big.

 

[ottarrus]

Space is immensely big, even planets are really big.

Which is why the whole idea of one individual, or even a population less than one million people, 'owning' an entire world is ridiculous on its face.
Assuming a given world had a decent Size [say 4 or more at a guess], were I to drop a colony on the other side of the world from the original colonists, I effect their colony ZERO percent. Unless, of course, both colonies go looking for a fight. Then all bets are off.

 

[agentwigggles]

Thanks everyone for your calculations. I suppose there is a hidden sub-question, here? All answers assume that hydrogen can be taken until the last teaspoon of hydrogen is mopped up - which is kind of fair, as that is what the original post assumes. But the hidden question might be how much hydrogen can be skimmed before it destroys the local planetary ecosystem? That too might seem a long time away, I suppose, but no harm in asking, for sure.

For a saturn like planet?
Probably a couple million years.
This question pops up every now and then. I get why. The scale of the gas giants is so huge, that, that its beyond human ability to be intuitive abbout it.
The amount of hydrogen on Saturn is finite.
When a ship uses that for fuel, it takes that away from Saturn.
Ergo a Ship can cause damage to Saturn ecosystem.
But the scale is so far off, that a Tigress, takes basically no hydogren. We're talking like 0.00 (couple million more zeros) 1 percent of Saturn hydrogen.

 

[AnotherDilbert]

For a saturn like planet?
Probably a couple million years.

Saturn is 570 sextillion (billion trillion, 10²¹) tonnes of about 95% hydrogen.
That is 540 sextillion Dt hydrogen...

A 1 MDt squadron needing 400 000 Dt per refuelling could refuel a quintillion (billion billion) times before exhaustion.
It would take 50 trillion years to skim away even 0.1% of the gas giant.

 

[Alaskan15]

Linked below is the canon official race that are GG natives, the Jgd-il-Jagd.
The second race is the Sheol, a GG dwelling race in the Spinward Marches that aren't discovered until after the 5FW.

That is how many known sentient species there are. It was my impression that since detecting technologically primitive gas-giant intelligent life would be so difficult that the Scout Service has decided to restrict gas giant refueling from every gas giant with any multi-cellular life, just in case.

I thought that there was some note of this somewhere in CT canon, maybe a throw of X on Xd6 to see if refueling at a particular gas giant was restricted, although part of me suspects that this rule was more to stop players from always going for gas-giant refueling, needing less money, and then turning down all the jobs the Referee offers.