Poseidon class water tanker (primitive early dropshuttle)

[kato]

Many ways of doing it.

One possible other approach to account for the inefficiency of a moving space station would be an engine size comparison (x 2.6), expanding that factor two-dimensionally for flow rate and multiplying by the relative input requirement (x sqrt(3)) between the tug and a space station that size. Would give us 11.44 tons/day at stationkeeping.

Or we just say that the entire stationkeeping under tow maneuver is tactical, and thus we apply tactical rates at a continuous 360 tons/day. ;)

[RunandFindOut]

Also .1g is WAY above the thrust needed to maintain position for station-keeping at a jump-point.  Gravity at either of the two standard system jump-points is something like .001g if I remember correctly and burning at .1g you'd only need to burn at long intervals.

[kato]

Gravity at either of the two standard system jump-points is something like .001g if I remember correctly

The sun's gravity is about 0.0059267g at 10 AU.

... and maintaining that at pure tactical expense with a x24 factor for the towed asteroid means 204.8267 fuel points per day or - for our 2130s dropshuttle tug - 13.655 tons per day.

[idea weenie]

Already doing that, both low-g and Hohmann transit. In the above model when the tug retrieves an asteroid it docks to it and gives it a push at 0.125g (the max it can run) for only 100 hours. It then floats without further acceleration for the next 36 days, before braking again for another 100 hours at 0.125g.

Good

Strategic fuel use in BT is calculated geometric, not squared btw.

It's mostly the fuel to keep the asteroid stable at the jump point that's high; 0.1g required for the combination of asteroid and tug weighing 97,500t means that it's burning the equivalent of 2.4g for the tug only, at a constant rate - and that means you're burning 13.5t per day nominal on fusion only.

Actually, distance traveled should be based on the square root of the ratio in acceleration,; not sure what you mean by geometric.

The basic distance formula, where you put in starting speed, acceleration, and time is:
D = (starting velocity) * Time + accel * Time^2 / 2

Starting velocity is zero, so that is removed:
D = accel * Time^2 / 2

I now get Time on one side, and everything else on the other:
D = accel * Time^2 / 2
2 * D = accel * Time^2
2 * D / accel = Time^2
Time^2 = 2 * D / accel
Time = sqrt(2 * D / accel)


Proof of time doubling:
setting accel = 1G
Time = sqrt(2 * D / 1)
Time = sqrt(2 * D)
Time = sqrt(2D)

Assuming accel is 1/4 G:
Time = sqrt(2 * D / .25)
Time = sqrt(2 * 4D / 1)
Time = sqrt(2 * 4D)
Time = sqrt(4 * 2D)
Time = sqrt(4) * sqrt(2D)
Time = 2 * sqrt(2D)

So if acceleration is quartered, that means time taken to travel the distance doubles.  Since fuel usage is equal to time * acceleration, that means fuel use is halved.

This is independent of ship mass or other properties.  A tug that is pushing an asteroid at .1G will take half the time and burn twice the fuel compared to the same tug pushing the same asteroid at .025G.

[kato]

ffs to continue this

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[ Porthos Rig Carrier / Civilian Spheroid Dropshuttle / 3000 tons / 2135 ]

1170.0 tons - Maneuver Engine (3/5)
  60.0 tons - Structural Integrity (10 SI)
  45.0 tons - Control Systems
  20.0 tons - Quarters (4 Steerage)
   2.0 tons - Armor (primitive - 21 points: 5n/5l/5r/6a)
   0.0 tons - Heatsinks (39 free)
260.0 tons - Fuel Tank (3900 fuel points, 5.64 tons/burn-day)
   5.5 tons - Fuel Pumps
   7.5 tons - 1.2 tons Consumables and 6.0 tons Spare Parts (for 2 months ea) + 0.3 tons bulk cargo (1 bay door - a)

(above - all from Poseidon base craft)

400.0 tons - Naval Tug Adaptor incl. add-on internal structure
800.0 tons - Mining Rig Bay (4 small craft bays) (2 bay doors - l/r)
  25.0 tons - Fuel Tank Extension (375 fuel points extra)
168.0 tons - Quarters (24 Second-Level)
  37.0 tons - Consumable/Spares/Bulk extension to 300% / 6 months overall, incl. single mining rig supply


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Porthos Notes:
- Equipment replaces water tank of Poseidon.
- May carry and deploy in houseruled large bay either:
- four individual small craft / fighters / vehicles / satellites up to 200t
- single mobile structures / space stations / advanced support vehicles up to 800t
  (for rules conformance assume disassembled carriage in cargo)
- Acts as multipurpose deployment and supply tender as well as fuel retrieval tanker for Aramis rig.
- May provide tactical auxiliary stationkeeping for spacecraft up to 90,000 tons for up to one day.
- May provide tactical recovery for spacecraft up to 72,000 tons over distances up to 5 AU (... for anything past one million km count your recovery time in weeks and
  months though).


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[ Aramis / Mining Rig / 800-ton Mobile Structure / ~50x50m footprint, four-hex / Single-Level (18m height) / 2135 - Tech Level C ]

Chassis Weight : 98.5 tons per hex (CF80 Fortress, nominal)
Internal Armor :  5.0 tons per hex (nominal for CF80)
Sealing        :  8.5 tons per hex (Environmental Sealing)
Motive System  :  4.0 tons per hex
Power  System  :  4.5 tons per hex (1.5 MP, fission)
Equipment      : 80.0 tons per hex

Hex A : Water Tank (28.7t)     : 33.0t
Hex A : 3x Fuel Tank (11.6t)   : 40.0t
Hex A : 8.2 days food/parts    :  1.0t
Hex A : Communications Gear    :  1.0t
Hex A : Backhoe (LCP)          :  5.0t

Hex B : Water Tank (28.7t)     : 33.0t
Hex B : 3x Fuel Tank (11.6t)   : 40.0t
Hex B : 12.3 days food/parts   :  1.5t
Hex B : Dumper (5 tons)        :  5.5t

Hex C : 6x Fuel Tank (11.6t)   : 80.0t
Hex D : 6x Fuel Tank (11.6t)   : 80.0t

Crew : 17 Enlisted + 3 Officers (20 total)
Cost : 20,115,900 C-Bills


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Aramis Notes:
- CF80 base vehicle costs 17,982,000 C-Bills sans 320t mounted equipment.
- Chassis weight and CF-discrete "internal armor" derived from dual tracked tractor/trailer combination.
- Dumper and Backhoe represent mining conveyor belt system with on/off mass flow capacity of light cargo platform.
- 5-ton minimum does not apply for MS fission engines. For fluff consider single 18-ton reactor spread over all four hexes.

Aramis Production:
- 11.5t fuel - one tank - produced per day (cap-off every 2.5 weeks at 200 tons).
- 28.75% production efficiency relative to available power.
- Asteroid with minimum 6.0% H2O required due to loading requirements.
- Supply reserves for 3 days beyond cycle onboard.

P.S. Operationally serve the L1 point of a gas giant in a system, in particular - due to distances involved - in otherwise already colonized M and K class systems. Aramis would be deployed on moons of the gas giant. For a K2V the L1 point of a gas giant beyond the snow line and proximity limit would be located about 0.184 AU or 27.5 million km from the planet, with a colony on a habitable planet 3.15 AU or around 5 days at 1g away.

[kato]

And for that Lagrange Jump Point:

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[ Athos Space Station / Civilian Space Station / 6000 tons / 2135 ]

  72.0 tons - Stationkeeping Engine (-/-)
  60.0 tons - Structural Integrity (1 SI)
   6.0 tons - Control Systems
  20.0 tons - Quarters (4 Steerage)
   2.0 tons - Armor (primitive - 21 points: 5n/5l/5r/6a)
   0.0 tons - Heatsinks (39 free)
260.0 tons - Fuel Tank (2600 fuel points, 0.282 tons/burn-day - stationkeeping for 30 months)
   5.5 tons - Fuel Pumps
   7.5 tons - 1.2 tons Consumables and 6.0 tons Spare Parts + 0.3 tons bulk cargo (1 bay door - aft)
1524.0 tons - Cargo

  35.0 tons - Quarters (7 Steerage) [replacing controls]
   4.0 tons - bulk cargo (1 bay door- fwd) [replacing controls]

500.0 tons - Grav Deck (>250m) [replacing engine]
400.0 tons - Small Craft Bays [replacing engine]
  89.0 tons - Consumable/Spares/Bulk extension / 12 months overall [replacing engine]
  15.0 tons - Small Craft Naval Repair Bay, Pressurized [replacing engine]
   0.0 tons - Heatsinks (18 free) [replacing engine]

2023.0 tons - Quarters (289 Second-Level - 58 Crew + 231 Passengers) [add-on tonnage - in grav deck]
617.0 tons - Consumable/Spares/Bulk extension [add-on tonnage - in grav deck]
350.0 tons - Lifeboats (50) [add-on tonnage - in grav deck]
   3.5 tons - MASH [add-on tonnage - in grav deck]
   0.5 tons - Small bulk Cargo [add-on tonnage - in grav deck]
   6.0 tons - Field Kitchens (2) [add-on tonnage - in grav deck]


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Athos Notes:
- Poseidon hull design in Pontos configuration rebuilt into space station by removing engine
- Replacement aft with stationkeeping engine, paired small craft bays and 270m diameter grav deck producing 0.33g at 1.5 rpm
- Grav deck arranged in three 250m long sections with about 96 quarters and 16 lifeboats each, additional equipment in connecting nodes between sections.
- intended primarily for transshipping, passenger transfer and general distribution purposes at Lagrange jump point
- retains stowage of 100 TEU (20' containers) from Pontos
- space stations do not have primitive engines.