[Space/Spaceships] TL9 nomad fleet - playable?

[teviet]

Originally Posted by David Johnston2

Reaction drives can't do that. Not enough delta-v

Unless it's an antimatter or conversion drive, but even then you need at least 63% of your ship's mass to be fuel before you'll get delta-v greater than c.

TeV

[Anthony]

Originally Posted by David Johnston2

Reaction drives can't do that. Not enough delta-v

Well, for a sufficiently lenient value of relativistic, sure they can. At 30 km/sec (roughly the earth's orbital velocity) you've got a time dilation of 1.000000005, which is measurable.

[Johnny1A.2]

Originally Posted by cccwebs

The need for multiple fuel tanks is probably the most limiting factor for non-superscience "nomad" fleets. Reaction mass and the replacement of reaction mass would probably significant gameplay sessions on their own, and the heading of the fleet would probably be based on where the next resources are located.

Alternatively, one could handwave some high-tech equivalent of sailing, maybe the ships can tap into some motive force radiating out of the galactic central black hole or something, some superscience force we don't even know about today. This gives the advantage that the ships don't need fuel tanks, and gives the GM a nice arbitrary fudge factor as needed, since whatever is that fleet rides, like sailing ships with wind, is dependent on a natural force that may be inexhaustible but is also not necessarily always there when you need it.

"The gravitocosmic flow remains too low to break orbit..."

[Johnny1A.2]

Originally Posted by cccwebs

Come to think of it, in a setting without reactionless thrusters, the ships of the fleet would be built to reduce the amount of transport required between them. Having to shuttle people and goods routinely between various ships would eat away at reaction mass. If reaction mass supplies ever dwindles down low enough, ships that could not be at least minimally self-sustaining would suffer dire consequences.

I always figured a fleet like that would actually tend, over long voyages anyway, to precisely match velocity and run connecting tubes from ship to ship, or some equivalent.

[Johnny1A.2]

Originally Posted by teviet

Unless it's an antimatter or conversion drive, but even then you need at least 63% of your ship's mass to be fuel before you'll get delta-v greater than c.

TeV

Er...did that come out the way you intended it? Or are you using 'c' to mean something different?

[sir_pudding]

Originally Posted by Johnny1A.2

Er...did that come out the way you intended it? Or are you using 'c' to mean something different?

Presumably you'll want enough delta-v left to decelerate.

[teviet]

Originally Posted by Johnny1A.2

Er...did that come out the way you intended it? Or are you using 'c' to mean something different?

Actually Δv (the product of acceleration times endurance, i.e. what you get out of the rocket equation) can be greater than c, it's just that your actual velocity v is not the same. Instead you have:

v/c = tanh( Δv/c )

That is, if you accelerate at 1g for 2 years you have a Δv of 2c, but an actual speed of tanh(2)=0.964 times c. If you continue to accelerate for another year you have a Δv of 3c and an actual speed of tanh(3)=0.995 times c.

TeV

[Johnny1A.2]

Originally Posted by teviet

Actually Δv (the product of acceleration times endurance, i.e. what you get out of the rocket equation) can be greater than c, it's just that your actual velocity v is not the same. Instead you have:

v/c = tanh( Δv/c )

That is, if you accelerate at 1g for 2 years you have a Δv of 2c, but an actual speed of tanh(2)=0.964 times c. If you continue to accelerate for another year you have a Δv of 3c and an actual speed of tanh(3)=0.995 times c.

TeV

Thanks, obviously I read that in terms of resulting relative velocity, and so it didn't seem to make sense. Thanks for the clarification.

[Sword-dancer]

A nomadic culture?

A culture of nomadic traders?

They travel and trade most of their ships are merchant vessels, they ´ve maybe a home planet to gather, built ships and such things, they let repair their ships in dockyards of the system they trade with?

[vicky_molokh]

Originally Posted by Ulzgoroth

True, if you're using reactionless STL drives. (And usually true for FTL.)

If you're reactionless, though, you won't need much fuel tankage.

So the necessary systems for a universal ship would be:
3x armor (you could do 3/2 or 3/3 armor, but it might be a bad idea.)
1x habitat (More than enough room for the ship's crew)
1x open space
1x factory
1x stardrive
1/2 fusion reactor (or 1 fission)
1/3 control room
1/3 reactionless drive
1/3 hangar
1/3 refinery

I've filled at most 9 and a third systems here. More than half the ship is left to be filled with fuel tanks, cargo stores, more of the aforementioned systems, and whatever else you see a need for. Actually, the open space is optional...you could also go Total Life Support on the cabins, and you'd still have more cabins than workspaces.

I'd build the 'basic' flagship somewhat differently. My choices are heavily influenced with not being used to 1/3 systems. Here's my take:

TL 9^
dST/HP 700
HT 14
Hnd/SR -4 / 5
setting)
Move 0.1G/c (can be improved with more/better drives)
LWt 1,000,000 (assuming SM+14)
Load 175,114 (given by ss.xls)
SM+14 (scaleable, but taken 14 in case there is no artificial gravity generators in the
Occ 1,140+0SV (assuming SM+14 yadda yadda)
dDR 150
Range 1x
Cost around $83.01 B (excluding two systems that are left unspecified)

Front:
1. Armor - Advanced Metallic Laminate, 150dDR
2. Control Room, Computer: C9 Comm/Sensor: 12 Stations: 40 [2]
3. Habitat, 6,000 Cabins [2] (unspecified; need to figure out the ratios and life support; either way, at least 3k people should live there)
4. Cargo Hold (primarily for food and other necessities), 50,000 Tons
5. Unspecified
6. Unspecified
Center:
1. Armor
2. (!)Weapon Battery - Medium 3 Weapon Mounts (or whatever, but need at least some weapons) [2]
3. Cargo Hold, 50,000 Tons (raw materials and/or parts for smaller craft, but also other stuff depending on needs)
4. (!)Factory - Fabricator $50,000,000/Hr (general-purpose) [2]
5. Hangar Bay Launch: 2,000 ton/min / Cap.: 30,000 Tons (linked to factory!) [2]
6. External Clamp (for docking ops)
Rear:
1. Armor
2. Fuel Tank 50,000 Tons of Hyperspace Fuel
3. (!) Reactionless Engine - Rotary or some other appropriate 0.1G [2]
4. (!) Stardrive - Hyperdrive or some other, FTL-1 [2]
5. (!) Mining facility (for fuel and other stuff) 5,000 Tons/Hr [2]
6. (!) Refinery 15,000 Tons/Hr (for fuel and other stuff) [2]
Core:
1. Open Space, 100 Areas (5 Acres) [2]
2. Power Plant - Fusion, 2 Power Points [2]

Note that unless modified with another reactor, such a ship can only operate two of the following systems at a time: STL, FTL, weapons, Mining, Refinery, Factory. Not a big deal outside emergencies, but there might be situations where either the first three or the last three need to be active at a time. It's would also be very convenient to refine the materials, build stuff, and accelerate simultaneously after a mining operation.