Vote Your Canon #4: Jump Torpedos (consensus: NOT)

[mike wightman]

Begs the question of how you can fit a jump drive and fuel into something that weighs in around 50kg and can be launched from a missile turret. I mean, at that point we're talking 1/10th the mass of a sub-compact hyper alloy ground car.

The smallest jump capable message torpedoes are the Type-S Scout/Courier and the XBoat.
Anything smaller than 100 tons cannot jump.

The smallest manned craft...

 

[mike wightman]

Currently, overhead is five tonnes absolute, and minimum ten tonnes overall, subject to shrinkage due to increased technological difference.

For a manned craft...

 

[mike wightman]

If you're trying to be consistent with the LBB2 drive potential table formula ('77 rules), minimum possible size is in the ballpark of 5.6 tons. High Guard can do it in close to 5 tons at TL-15 if the 1Td drive and fuel (incl. powerplant) minimum sizes are kept.

For a manned craft...

ok I will stop posting that and point out that the message torpedo has very little to go on other than a name and what is mentioned in A4:
"Jump Message Torpedoes: Consists of little more than a jump drive, fuel and a
recording unit. 'J-Torps' are used to send messages by automatically broadcasting
a pre-recorded tape at the conclusion of their jumps."

It could be that 100t is the minimum size for a manned craft to have a stable handwavium, the message torpedo can have a much smaller jump drive because it is just a machine.

I'm pretty sure someone once suggested the launching ship must use its jump drive to open the jump portal and then fire the missile into it...

FF&S has no lower limit on jump drive size, I once designed a battlesuit with its own jump drive...

 

[Spinward Flow]

the message torpedo can have a much smaller jump drive because it is just a machine.

But but ... robot brains can't survive jumpspace!
Jumpspace needs an audience!
Handwavium!

 

[Grav_Moped]

But but ... robot brains can't survive jumpspace!

One specific "species" of robot in one novel couldn't. Nothing has been said about others, and Virus suggests otherwise.

Jumpspace needs an audience!

Thanks for citing my joke.

Handwavium!

Sure!

 

[infojunky]

I really don’t have any feeling yea or nay.

 

[Straybow]

Hmmm, if it's fired from a cannon, I don't think it would be called a torpedo.

Oh, canon.

The smallest J drive is 10 Td. Plus a power plant (4 Td), guidance computer (1 Td). That makes for a rather large "torpedo."

Nope. Just don't go there.

 

[Grav_Moped]

Hmmm, if it's fired from a cannon, I don't think it would be called a torpedo.

Oh, canon.

The smallest J drive is 10 Td. Plus a power plant (4 Td), guidance computer (1 Td). That makes for a rather large "torpedo."

Nope. Just don't go there.

You forgot the fuel. Yeah, if you're stuck with the drive potential table as written, it's a bit silly.

 

[robject]

Something that you CAN do is basically a "jump sled" kind of arrangement.
100 ton hull with jump drive, power plant, fuel, bridge and computer ... and then like a 40-50 ton small craft with 4 ton starship staterooms that (internally) docks with the jump sled and uses its maneuver drive to "tug" the jump sled around. Kind of a battle-rider(ish) arrangement with the crew living in the small craft.

I've used a 40 to 60 ton boat with 60 to 40 tons of drop tanks...

 

[robject]

Sure, but that "for now" has stood unchanged and even amplified for well over forty years. I wouldn't hold my breath waiting for it to change...

I agree... but I've been surprised before, so.

 

[Condottiere]

Force field creating virtual material volume.

 

[BackworldTraveller]

Assuming it were canon, the torpedo is fired off until it is at least 100d from the firing ship. Then it preps its jump. As it's a computer doing this (assuming the astrogation calcs are pre-done) this has to have a computer capable of doing so. This makes the jump torpedo quite big in the '77 book's rules. It then falls into jump-space and waits. Eventually it arrives out of jump space orientated in any direction and possibly anywhere - but it then has to successfully plot its position, look up the position of the target at the time it finds itself in, and plot a course between the two. This computer is getting bigger. It then heads to the target and pilots its way through the atmosphere...hoping to land on its target.

How many messages actually get through? Or crash into the delivery point at a substantial speed? Or get shot down by the target's point defence systems?

 

[whulorigan]

. .. and plot a course between the two. . . . It then heads to the target and pilots its way through the atmosphere...hoping to land on its target.

How many messages actually get through? Or crash into the delivery point at a substantial speed? Or get shot down by the target's point defence systems?

Why does it have to physically go to the location? Why can't it orient itself and transmit its message via a comm system?

 

[Grav_Moped]

My assumption has been is the volume of the starship varies by one percent while in jumpspace, the jump bubble destabilizes.

That's a decent way to nerf the "jump cutter with a balloon" munchkin trick. Besides, there has to be a reason for starship hulls to be so expensive, and bypassing that through using a party balloon kinda feels wrong.

 

[Grav_Moped]

Assuming it were canon, the torpedo is fired off until it is at least 100d from the firing ship. Then it preps its jump. As it's a computer doing this (assuming the astrogation calcs are pre-done) this has to have a computer capable of doing so. This makes the jump torpedo quite big in the '77 book's rules. It then falls into jump-space and waits. Eventually it arrives out of jump space orientated in any direction and possibly anywhere - but it then has to successfully plot its position, look up the position of the target at the time it finds itself in, and plot a course between the two. This computer is getting bigger. It then heads to the target and pilots its way through the atmosphere...hoping to land on its target.

How many messages actually get through? Or crash into the delivery point at a substantial speed? Or get shot down by the target's point defence systems?

Why does it have to physically go to the location? Why can't it orient itself and transmit its message via a comm system?

As I understand the concept (my implementation is slightly different), on jump exit the j-torp just sits there at 100D and broadcasts its message.

In '77 they arguably don't need a computer.

 

[Condottiere]

The other version is the expanding starship, much like your caravan expands while parked.

Or pop up, with or without the turret.

 

[Nathan Brazil]

Canon? Yes, but YOUR Charted Space buddies will never see them.

MgT Secrets of the Ancients has jump capable microdrone message torpedoes not reliant on portal technology.
Then again, they also have ansibles and Yaskodray can pop your past your n-space jump bubble and leave aboard his own ship which docks to yours mid-Jump during the week transit

 

[Grav_Moped]

Canon? Yes, but YOUR Charted Space buddies will never see them.

MgT Secrets of the Ancients has jump capable microdrone message torpedoes not reliant on portal technology.
Then again, they also have ansibles and Yaskodray can pop your past your n-space jump bubble and leave aboard his own ship which docks to yours mid-Jump during the week transit

Spoiler warning, dude!

 

[McPerth]

For a manned craft...

You have insisted several times on it, but I have never read about unmanned crafts to be free of this .limitation.

It could be that 100t is the minimum size for a manned craft to have a stable handwavium, the message torpedo can have a much smaller jump drive because it is just a machine.

It could, yes, but as I understand Travller universe (and, as always I may be wrong), it could also be that lower volumes cannot (for an yreason) create the entry into jumpspace....

I've never read '77 version (AFAIK it didn't reach Barcelona), so I can be too tainted for never had thi discussion, as al ltraveller versions I've had access to is 100 dton minimum for jump, period.

 

[McPerth]

But but ... robot brains can't survive jumpspace!

Where does this assertion come from? Many jump capable ships have robots, and they survive jumpspace.