Gas giant mining

[whartung]

For "extremely high volume" transport of fuels from other star systems there are logistical challenges.

Using B5, a while ago, I did some tanker math. These are J3 tankers making round trips (thus 60% fuel consumed per round trip) for fuel delivery. My original premise was for deep space fuel caches.

TL	Free space for 1000 tons	Free space for 10000 tons
9	4.5%	7.3%
10	6.5%	9.3%
11	6.5%	9.3%
12	8.5%	11.3%
13	11.5%	14.3%
14	13.5%	16.3%
15	16.5%	19.4%

Simply, at TL 12, for example, a 10,000 ton tanker has 11.3% free space, or 1130 tons available for fuel delivery.

I find when you scale the 10,000 ton ship up to, say, 100,000 the percentages pretty much stay the same.

So, again, say, at TL12, if you wanted to support a freighter, you'd need a 1.2 to 1:1 times jump number tanker ratio to support that freighter (of similar size to the tanker).

 

[Grav_Moped]

Then there's the @Spinward Flow approach to interstellar fuel tankers: External fuel tanks (drop tanks if you must; otherwise just modular hull blocks that are fuel tankage) and internal cargo holds with collapsible tanks. On arrival at the offload point, empty the collapsible tanks, then the external tanks, then move the external tanks into the cargo hold to reduce the fuel requiremed for the return trip.

I'll leave the math to others.

 

[Spinward Flow]

These are J3 tankers making round trips (thus 60% fuel consumed per round trip) for fuel delivery. My original premise was for deep space fuel caches.

Kind of makes you wonder how J4+4 "works" for a place like Riftspan Station in the Great Rift to access to the Islands Cluster via J4.

With (reusable) L-Hyd Drop Tanks, it can be practical ... but without drop tanks, you're spending 80% of your displacement on jump fuel.
Bridge adds 2%.
J4 (custom LBB5.80) adds 5%.
M1 adds 2%.
PP4 adds 4% (TL=F) or 8% (TL=D) for drive ... plus 4% for power plant fuel.

Before adding crew staterooms and computer, you're already looking at 80+2+5+2+8+4=101% of your hull displacement @ TL=D ... so ... bye bye to your maneuver drive, because you're going to be delivering under 1% of your displacement to your destination.

TL=F makes things SLIGHTLY better ... your "deliverable tonnage fraction" is under 3% ... and if you ditch the maneuver drive entirely your deliverable fraction goes up to ... under 5%.

Note that without a maneuver drive on the starship tanker ... you're going to have to rely on "Tenders" to handle all maneuver tasking at each destination following a breakout (just like XBoats do).

 

[Grav_Moped]

Kind of makes you wonder how J4+4 "works" for a place like Riftspan Station in the Great Rift

Edit: See Post #46 for the proof of concept.

J4 ship. 2J2 outbound with carried drop tanks for both J2s, but the first J2 per formed with an additional set of expended tanks.

First J2 ends halfway there but with full tanks (less 1 wk power fuel). 2nd is at station. Drop tanks are then half full (J2 all-up, J4 for the core hull), ship tanks are full J4 and 2 wks power).

Ship does a J4 for home and leaves the half-full tanks behind as the resupply. They’re a full load for the next J4 ship passing through.

 

[Spinward Scout]

Therefore a plentiful supply of hydrogen needs to be obtained.

Why not just make a grav-platform with thrusters that sits/parks at the upper edge of a Gas Giant's atmosphere, that drops hoses or skims directly into the atmosphere itself? Eliminating the need for skimming ships. It's not like it will ever run out of fuel. Although I'm sure there could be a nice table for malfunctions.

 

[Grav_Moped]

J4 ship. 2J2 outbound with carried drop tanks for both J2s, but the first J2 per formed with an additional set of expended tanks.

First J2 ends halfway there but with full tanks (less 1 wk power fuel). 2nd is at station. Drop tanks are then half full (J2 all-up, J4 for the core hull), ship tanks are full J4 and 2 wks power).

Ship does a J4 for home and leaves the half-full tanks behind as the resupply. They’re a full load for the next J4 ship passing through.

Proof of concept:
Core hull -- Fleet Scout (199.5Td, J4/4G). LBB2 build.
Internal tankage, 120Td (J4, 4 wks Pn-4).
Payload drop tanks, 200Td.
First jump expended tanks, 80Td (hopefully recoverable after ejection, but that's not mandatory).

First jump:
Overall ship tonnage is ~480Td. Drive ratings at this tonnage are J1/1G (again, this is LBB2).
Jump (J2) while ejecting the 80Td tanks, retaining the 200Td tanks. Drive ratings are J2/2G upon tank ejection/Jumpspace entry.

Second jump, starts 2pc from origin:
Overall ship tonnage is ~400Td. Drive raings at this tonnage ae still J2/2G.
200Td drop tanks are still full, 10Td of internal tankage used for power during jump.
Jump (J2) while retaining 200Td tanks.

Arrival at mid-rift station, 4pc from origin:
Drop tanks have 120Td fuel remaining -- given to the station's stockpile, along with the tanks themselves.
Internal tanks have 100Td fuel (J4 + 2 weeks power) remaining.

Return to origin:
Jump (J4) on internal fuel. Will have ~10Td or so fuel remaining (1 week power) on jumpspace exit.

Repeat as necessary and/or desired. Each such trip leaves 1 full fuel load for a Fleet Scout at the station. Payload tanks may be configured as 1x80Td tank and 1x120Td tank, to allow repeating this process so as to be able to place sets of 120Td tanks at a depot/cache at the far end of the refueling chain. They will require refuelling there, but it does save having to contract for new tank construction at the far end.

Conclusion and suggestions for further development:
This works for the smallest practical LBB2 ship that can do J4/4G.

Due to scale efficiency in LBB2, it will therefore work with any larger LBB2 ship capable of J4/4G and a hull sized such that there is another hull of twice its size on the Drive Performance Table.

Due to the reduced size of drive components in LBB5 and the lack of a table dictating fixed hull size increments, it will therefore work with any LBB5 ship larger than 200Td.

 

[Grav_Moped]

Why not just make a grav-platform with thrusters that sits/parks at the upper edge of a Gas Giant's atmosphere, that drops hoses or skims directly into the atmosphere itself? Eliminating the need for skimming ships. It's not like it will ever run out of fuel. Although I'm sure there could be a nice table for malfunctions.

This has been done, kind of, in Star Wars. I think I've also seen it in a Traveller scenario, but I don't recall which one.

Include extensive drive redundancy, and you're good.

 

[aramis]

This has been done, kind of, in Star Wars. I think I've also seen it in a Traveller scenario, but I don't recall which one.

Include extensive drive redundancy, and you're good.

Secret of the Ancients. A13, IIrC

 

[Condottiere]

Also, zeppelins.

 

[Spinward Scout]

This has been done, kind of, in Star Wars.

Cloud City?

If you could make a Trans-Atmospheric Tower in a Gas Giant, that would eliminate any skimming for fuel. But I doubt the gravity would allow it. I could be wrong, tho. Depends on what you make the Tower out of. Arthur C. Clarke speculated that the center of Jupiter contained a diamond in 2061. So anything stronger than diamond "should" work.

 

[aramis]

Cloud City?

If you could make a Trans-Atmospheric Tower in a Gas Giant, that would eliminate any skimming for fuel. But I doubt the gravity would allow it. I could be wrong, tho. Depends on what you make the Tower out of. Arthur C. Clarke speculated that the center of Jupiter contained a diamond in 2061. So anything stronger than diamond "should" work.

Gravity at the cloud tops of Jupiter isn't that high... 2.45 G or so. Saturn's about 1.08 G.

 

[Grav_Moped]

If you could make a Trans-Atmospheric Tower in a Gas Giant, that would eliminate any skimming for fuel. But I doubt the gravity would allow it.

Consider it as a "Space Elevator" but without a lower anchor point, and possibly a large upper-end mass (a former asteroid) rather than the full counterbalancing tether cable. Oh, and with pipes rather than elevator tracks/motors. Pipes can contain grav generators to move unrefined fuel up the line without needing insanely high vacuum to pump up the material in a way not seen in the three millenia that have elapsed since the 1989 chart-topping hit by Belgian performers Technotronic, Pump up the Jam.

 

[Spinward Scout]

Consider it as a "Space Elevator" but without a lower anchor point, and possibly a large upper-end mass (a former asteroid) rather than the full counterbalancing tether cable. Oh, and with pipes rather than elevator tracks/motors. Pipes can contain grav generators to move unrefined fuel up the line without needing insanely high vacuum to pump up the material in a way not seen in the three millenia that have elapsed since the 1989 chart-topping hit by Belgian performers Technotronic, Pump up the Jam.

I'm sure that plays on every elevator ride. I just don't know how it would work without attaching to the actual "land" of the Gas Giant.

Gravity at the cloud tops of Jupiter isn't that high... 2.45 G or so. Saturn's about 1.08 G.

I was talking Gravity at whatever is at the center. It would need to connect somewhere.

 

[Condottiere]

Reverse gravity.

I suppose amplifiers at every storey.

 

[Spinward Flow]

Depends on what you make the Tower out of. Arthur C. Clarke speculated that the center of Jupiter contained a diamond in 2061. So anything stronger than diamond "should" work.

Current speculation is that the core of Jupiter ought to contain a significant amount of metallic H₂ in order to generate the planetary magnetic field ... which is the strongest in the solar system (stronger than even the local star's, Sol).

 

[Silverhawk]

@whartung answered before I could.

If you're industrializing the production in order to meet demand, you're probably looking at something akin to a kind of "bucket brigade" doing a sort of "pitch & toss" on orbital trajectories between locations. Rather than doing a powered fuel shuttle for every shipment, instead you've just got a lot of "unpowered tanks" that get filled up and accelerated onto a trajectory by a maneuver tug. Once the trajectory on the "throw" end gets finalized, the tug undocks from the tank and leaves the tank flying on an inertial trajectory towards a destination point (which gets reported). Same thing happens on the "far end" of the operation, except there it's more of a catch and retrieve for detanking. The tanks can then be filled with "whatever is needed for the return journey" (water, oxygen, nitrogen, whatever) and the tanks get "thrown" by maneuver tug back towards the orbit where they started from, completing the round trip.

Capital investment is needed for the maneuver tugs on both ends (will need some extras so you can have maintenance rotations without disrupting service) and the tankage infrastructure needed to "fling supplies" between both ends of the operation. The orbital trajectories of the unmanned tanks will be known to system defense boats (if any) so attempting to steal any of the (unattended and unmanned) tanks while on inertial orbit trajectories becomes something of a "steal from at own risk" type of venture (of course, some will still try it when desperate enough). There also the "mining station" and contracts with starport(s)/spaceport(s) to manage, along with all of the personnel needed to keep the party going.

I've been playing around with the idea that you would gather it into a large shipment maybe using modules and process it in flight. Segregate the useful impurities into their own module to sell assuming an industrial system or it could be transported to another system. Just haven't got the all the details on the ship and the modules. RL is being something of a pain.

 

[Spinward Flow]

I've been playing around with the idea that you would gather it into a large shipment maybe using modules and process it in flight.

An obvious(ly right) conclusion.

From a CT perspective, that would mean that you're probably looking at some sort of 200 ton fuel tank + a 200 ton capacity fuel purification plant as being the "minimum reasonable" unit of scale (simply because fuel purification plants below 200 tons capacity "aren't allowed" in CT).

In MgT, you would simply need a fuel purification plant sufficient to process an entire tank of fuel during the minimum transit time between source and delivery destination. The longer the transit time, the "slower" the purification process needs to be, reducing costs.



In CT, fuel purification takes 1 minute per ton for skimmed atmosphere off a gas giant ... or 10 minutes per ton for water skimmed from an ocean (or lake, or whatever). (LBB5.79, p32)

Consequently, in CT ... a 1000 ton capacity fuel tank filled by atmospheric skimming would require 1000 minutes (16h 40m) to purify/refine ... which in transit time terms is "nothing" when talking about interplanetary solar transfer orbits at 0G "unmanned" inertial navigation time frames.

In CT ... a 1000 ton capacity fuel tank filled by water ocean skimming would require 10,000 minutes (6d 22h 40m) to purify/refine ... which in transit time terms is "important" when talking about interplanetary solar transfer orbits at 0G "unmanned" inertial navigation time frames, but for anything that takes "1 week" or longer to complete the transit will mean that the fuel tank arrives at the destination fully purified.

 

[Grav_Moped]

I'm sure that plays on every elevator ride. I just don't know how it would work without attaching to the actual "land" of the Gas Giant.


I was talking Gravity at whatever is at the center. It would need to connect somewhere.

No, it doesn't have to connect at all! The center of mass needs to be high enough that the whole thing, collectively, is effectively in "geo"synchronous orbit -- give or take the gravitic drives helping it stay in place. Tidal forces stabilize the structure. A lower, faster orbit than synchronous might be preferable, where the lower-end's velocity is high enough for effective ram intake but low enough to avoid thermal damage to the structure from friction heating. This will require grav drives (not merely antigravity) to overcome aerodynamic drag.

It's hanging down (and extending up) from orbit, not standing on anything.

 

[Condottiere]

Fuel processors are dirt cheap, and take up very little volume.

 

[Spinward Scout]

No, it doesn't have to connect at all!

I didn't realize you could do it that way. That sounds much better. So no worries about that crushing gravity then.

I've been playing around with the idea that you would gather it into a large shipment maybe using modules and process it in flight.

I'd like 2 modules of Refined and a module of Unrefined, please? Just drop them off at my hangar.