CT Only: Jump Torpedoes

[Fovean]

As I understand it, there was a lot of talk back in the day about jump torpedoes being exactly that - torpedoes, as in armed munitions. Along with the near-c rock debate it seemed the fan base was intent on working up ways to destroy worlds/stations from a parsec+ away.

That was before my time, mind you but I do hazily recall many discussions on it.

 

[boomslang]

So perhaps someone can share with me the game braking impact of the Jump Torpedo.

One effect is that is removes -- or at least dramatically lowers -- the floor on how much FTL travel (and communication) costs.

Assuming for the sake of argument that one can build a viable Xboat and the infrastructure to support it, there is a non-trivial amount of overhead that must be paid both at startup and as an ongoing cost to operate such a system.

The smallest common starship is the Type S/J, and they are not exactly cheap to purchase (at least when new).

I think another one of the reasons is so that a TU does not have routinely-unmanned starships. Although Xboats can Jump without anyone aboard, this is not the standard operational procedure; a crewman seems to be required to at least monitor the drives and computer throughout the duration of the flight, and robots are not considered appropriate to the task.

At the end of the day, I suspect the 100dt limit is much like the 100-diameter limit: you could probably push your luck and ignore it in a pinch, but Jumping is not as safe an activity if you ignore the well-established guidelines. Jumping something under 10dt may be like Jumping inside the 10-diameter limit: pretty much a guaranteed failure. Maybe the "Jump Bubble" around anything less than 100dt has too small a surface area to adequately dissipate the Jump energy under all conditions, or something like that.

 

[coliver988]

an idle thought: as tonnage is based on enclosed volume regardless of density, perhaps the jump torpedo has a ballon-like structure that inflates to 7m (about 1436m³ and is thus 100dTons...post jump, the balloon gets pulled back in.

Still not in MTU, but it could be a way around that 100dTon limit.

 

[boomslang]

an idle thought: as tonnage is based on enclosed volume regardless of density, perhaps the jump torpedo has a ballon-like structure that inflates to 7m (about 1436m³ and is thus 100dTons...post jump, the balloon gets pulled back in.

I considered something like this back in the day.

It would still need 10%dt of fuel per parsec, though -- you would need a drop tank or similar.

You could burn the fuel and charge it in the launch tube, then quickly shove it overboard, and while it scoots out to 100d from your ship, it could deploy its large, gossamer Jump grid.

Still sounds like more trouble than it's worth, though.

 

[coliver988]

I considered something like this back in the day.

It would still need 10dt of fuel per parsec, though -- you would need a drop tank or similar.

You could fuel and charge it in the launch tube, then quickly shove it overboard, and while it scoots out to 100d from your ship, it could deploy its large, gossamer Jump grid.

Still sounds like more trouble than it's worth, though.

so, a jump torpedo system requires a jump torp with a jump drive (and honestly, as with the XBoat maneuver is optional), a computer able to handle the jump (and carry the data you want carried), a comm system, the jump balloon and drop tanks. A ship could carry multiple jump torpedoes and a single reusable drop tank that gets recovered post-jump. Similar to the XBoat Tender. So I can see a Jump Torpedo Tender that requires a bit less in terms of resources.

It still does not address if a person is required or not for the actual jump, and there have been some really fun discussions along those lines over the years.

It would change the TU a good bit but perhaps it is something that is far more expensive than a regular XBoat for some reason, so used sparingly, and not publicly known. Other than that Leviathan ship

 

[Condottiere]

Assuming that there is no minimum volume for a stable transition, and engineering is a one tonne minimum.

Automated would remove the need for a bridge.

So, maybe five tonnes.

As I recall, my manned design was twenty five tonnes as the smallest viable starship.

But current canon is hundred tonne volume minimum, and ten tonne jump drive default minimum.

 

[Proneutron]

an idle thought: as tonnage is based on enclosed volume regardless of density, perhaps the jump torpedo has a ballon-like structure that inflates to 7m (about 1436m³ and is thus 100dTons...post jump, the balloon gets pulled back in.

Still not in MTU, but it could be a way around that 100dTon limit.

Except now you need a J-Drive spec'ed for 100 tones. Which would be too big to fit in the Torp.

 

[mike wightman]

Has anyone ever considered that the jump message torpedo - which according to CT77 fits in a standard missile rack - is launched while in jump space?

 

[Proneutron]

Has anyone ever considered that the jump message torpedo - which according to CT77 fits in a standard missile rack - is launched while in jump space?

No because without its own jump field it wouldn't survive.

 

[mike wightman]

It obviously generates its own jump field - all you need for that is a network of cables and a lanthanum jump coil...

 

[Proneutron]

It obviously generates its own jump field - all you need for that is a network of cables and a lanthanum jump coil...

And a jump drive. See specs for smallest JD possible in the rules

 

[whartung]

One effect is that is removes -- or at least dramatically lowers -- the floor on how much FTL travel (and communication) costs.

You think, at the Imperial scale, or Sector scale, or Subsector scale, or even star system scale that these costs matter a wit?

For example, do you think in the non-jump torpedo universe that the cost of a "Stargram" (or whatever the unit of interstellar communication) is dramatically different than in the jump torpedo universe?

That there are communications in the current universe that aren't happening because they cost too much? Communications of any actual import (vs casual "Hey Sally, it's me Betty. Todd and I just landed on Regina and, boy, the drinks sure are strong here! <3 Kisses, Betty")?

How much of society is stratified by the cost of communication in the current universe that wouldn't be in the jump torpedo universe?

Simply, if JT comms are cheaper than X-Boat comms, they're stlll no faster, and any cost savings aren't impactful to how people live or how business is done.

 

[boomslang]

You think, at the Imperial scale, or Sector scale, or Subsector scale, or even star system scale that these costs matter a wit?

Yes, actually I do, now that you ask.

Costs always matter to someone somewhere, eventually.

 

[Grav_Moped]

Assuming that there is no minimum volume for a stable transition, and engineering is a one tonne minimum.

Automated would remove the need for a bridge.

So, maybe five tonnes.

As I recall, my manned design was twenty five tonnes as the smallest viable starship.

But current canon is hundred tonne volume minimum, and ten tonne jump drive default minimum.

LBB5'81:
Minimum drive size is 1Td from small craft design rules.
Computer is downrated 1 model number when replacing a small craft bridge; downrate it two for replacing a starship bridge.
This violates the following rules: the 100Td size limit, starship bridge size, and starship crew requirements.

Cylinder hull configuration chosen for space-efficient stowage. Consider using a streamlined hull configuration instead if space is not at a premium.

1Td MCr4   J6 Jump Drive (limited to J1 by computer size)
1Td MCr3   Pn 14 (1 EP) Power Plant (TL-15)
1Td MCr1   5G Maneuver Drive (Agility 0)
1Td        Fuel
3Td MCr18  Computer Model/3 (effectively Model/1)
    MCr0.7 Hull (cylinder, includes fuel scoops for gas giant skimming)
-------------Totals-----------------------------------------------
7Td MCr16.7

Performance is J1/5G, endurance is 4 weeks.
Assume sufficient autonomy to refuel at gas giants as needed to reach a programmed destination.
Consider house-ruling that the Jump Drive is hardened to operate on unrefined fuel, as it is a J-6 drive operating at J-1.

It could be up to 2Td larger (hull cost goes up by MCr0.2) and still have fuel for J1, but would then have only 4G acceleration. This 2Td additional payload could include fuel, each ton of which would provide an additional parsec of un-refueled range. (It's still limited to J1 by the computer, which can't be upgraded because of energy point requirements.)

EDIT TO ADD: This design elides fuel use a bit, assuming that the 1%*Pn power plant fuel use scales down. If not, computer is a Model/2bis and the fuel tankage is 2Td with no change to the cost. Fuel use changes to 1.25Td/Jump (Jump fuel plus 1 week powerplant fuel) with three weeks reserve fuel.

 

[boomslang]

It could be up to 2Td larger (hull cost goes up by MCr0.2) and still have fuel for J1, but would then have only 4G acceleration. This 2Td additional payload could include fuel, each ton of which would provide an additional parsec of un-refueled range. (It's still limited to J1 by the computer, which can't be upgraded because of energy point requirements.)

Freight and/or low berths would be typical payloads, you are thinking?

 

[Grav_Moped]

Freight and/or low berths would be typical payloads, you are thinking?

Low berths (especially emergency low berths) would be a good option.

Or with a half stateroom*, it's the smallest possible starship.

I kinda like this. Scout mustering out benefit instead of a Type S, for a solo campaign?


* use half a starship stateroom double-occupancy instead of a small-craft stateroom, for its improved life support system.

 

[Proneutron]

For example, do you think in the non-jump torpedo universe that the cost of a "Stargram" (or whatever the unit of interstellar communication) is dramatically different than in the jump torpedo universe?

No because electronic storage is cheaper than dirt. There would be no significant cost difference in communication. Same for people moving.

 

[Grav_Moped]

It could be weaponized, but not well and not cost-effectively.

9Td version, payload is 2Td fuel. Ram target, Jump on impact. Misjump then carries 20Td of target ship into a misjump with the drone. (Less fuel means smaller Jump field and thus less damage.)

Mind you, the target only has to dodge a 4G missile.

...that costs MCr17.

 

[Grav_Moped]

Also, if you're also willing to break the power requirement rules, upgrade the 9-ton version to a Model/4 computer, add 1Td fuel, and it can do Jump-2 for just MCr12 more!
(This is about the cost of a Type S Scout Courier, though...)

 

[mike wightman]

And a jump drive. See specs for smallest JD possible in the rules

Nope.
The jump drive is to open the rift into jump space. The jump field that protects the ship is something to do with the hull cable network and the lanthanum coils.

Remember that we are talking about a jump torpedo that predates a lot of the rules that would come later - even the MWM article on jump drives.

At the time of the 77 CT rules where jump torpedoes are a thing the minutiae of the jump drive had not been filled in - all that is mentioned is the hull grid and lanthanum coils from early library data.

So it is possible that the jump torpedo, rather than being able to jump all by itself and thus need all that jump fuel etc. consists of nothing more than the grid and coils necessary to protect it from jump space, plus the usual stuff such as a battery, comms, a computer...

it has to be launched from a ship in jump space, or how about a jump drive equipped ship opens the rift, fires the torpedo and then doesn't itself jump - so the torpedo requires a jump drive equipped ship.

There is only one CT era adventure that mentions jump torpedoes beyond the 77 rules and sadly that doesn't get into the details plus it was written by Games Workshop rather than GDW, so we are free to speculate on such things.