Jump Drive

[AnotherDilbert]

The original rule that you could use it to power the ship makes a lot more sense, but it requires a much more detailed energy management sub-game for HG.

It makes sense, but unfortunately that is wide open to abuse, just like Emergency Agility.

E.g. take a rider with about PP-12, six for agility and six for weapons and screens. Using capacitors we can get by with PP-6 and some capacitors charged every few rounds by the otherwise unused PP in the tender/carrier (waiting in the Reserve).

Having half the PP (and fuel) makes the rider (and hence the tender) much small and cheaper. "Normal" designs will have no chance in comparison.

 

[BackworldTraveller]

...but both fuel and capacitors are necessary.

I vaguely recall that the fuel was necessary not just to provide an energy source, but to provide matter for filling the jump bubble to stop the micro-universe from collapsing through the hull. (No idea where that might be from though).

Also, at really high energy densities all sorts of things start to become conductive...keep the charge in the capacitors for too long and it ionises the air around the terminals and then - click - lightning? Ozone, Nasty nitrous oxides, and how much energy skipping about like a steam punk van-der-graff?

 

[Condottiere]

1. Again, this all seems edition specific.

2. Jump bubbles seem a relatively recent development.

3. I think it was the need to drain the capacitors to avoid blowing up due to the energy captured by the Black Globe, that required to explain the connection between capacitors and power plants; if the capacitors need a functioning power plant to drain their stores, then they aren't batteries.

Power plants create energy, but this seems a form of energy transformation, in which the power plant is the crucible.

Possibly, something to study in depth.

 

[willtron3030]

I vaguely recall that the fuel was necessary not just to provide an energy source, but to provide matter for filling the jump bubble to stop the micro-universe from collapsing through the hull. (No idea where that might be from though).

Using a "buffer medium" in the jump bubble isn't canonical, but I do use it.

:looks at forum title, sees "OTU":

... and that's all I should say about that.

 

[AnotherDilbert]

T4 is theoretically canon?

The fuel remaining in the jump drive's surge tank is used to create a thin hydrogen atmosphere around the ship during jump, which helps to delay the collapse of the jump bubble.

 

[mike wightman]

The folks that wrote that were misunderstanding what DGP had written about a bubble of normal spacetime in their Starship Operator's Manual. MgT continued to use it, T5 and now the MgT JTAS article drop it.

So it appears to be an error introduced by T4 authors.

 

[willtron3030]

T4 is theoretically canon?

Fair. I don't have T4. My oversight.

 

[AnotherDilbert]

Fair. I don't have T4. My oversight.

Agreed, it's obscure. I only brought it up because it seems to have inspired MgT to say strange things about the jump bubble.

 

[AnotherDilbert]

The folks that wrote that were misunderstanding what DGP had written about a bubble of normal spacetime in their Starship Operator's Manual. MgT continued to use it, T5 and now the MgT JTAS article drop it.

Eh? SSOM says nothing about venting hydrogen into the jump bubble?

Just like JTAS#24 it notes that some of the jump fuel is expelled as coolant.

So it appears to be an error introduced by T4 authors.

Well, it's published, so hardly an error. At most an alternate reality, like TNE?


Note that I don't see anything inconsistent between the different descriptions of the jump process, they are just not completely complete. CT, MT, & T5 doesn't say anything about what is expelled into the jump bubble or when.

 

[mike wightman]

For most things I consider the latest original work of MWM to be canonical for the setting.

His original Jump space article in JTAS 24 makes no mention of using hydrogen to fill a bubble, the ability to use a collector or antimatter plant similarly discounts a hydrogen filled bubble.

T5 makes no mention of a hydrogen bubble, and now that the original Jump Space article has been elevated to sainthood by the publication of MgT JTAS2 the hydrogen bubble is popped for the Third Imperium as imaged by Mongoose.

Now the caveat - referees are free to decide how things work in their own ATUs and bespoke settings so if you want a hydrogen filled jump bubble fine, but how do you explain collectors and antimatter powered jump drives not using hydrogen?

 

[mike wightman]

Eh? SSOM says nothing about venting hydrogen into the jump bubble?

Read what I said again. I am not claiming SSOM mentions a hydrogen filled bubble but it does mention a bubble of normal space surrounding the ship. I'll dig out the exact reference when i can get to the loft.

Note that I don't see anything inconsistent between the different descriptions of the jump process, they are just not completely complete. CT, MT, & T5 doesn't say anything about what is expelled into the jump bubble or when.

Nothing is expelled into the jump bubble or collectors and antimatter powered jump drives would not be possible.

 

[Condottiere]

Lanthanum grids don't require inflated jump bubbles.

Tee Five seems inclusive, whereas in the MongoVerse they went with the path of least resistance.

Also, jump bubbles probably require less maintenance, financial or otherwise.

 

[AnotherDilbert]

His original Jump space article in JTAS 24 makes no mention of using hydrogen to fill a bubble, ...

Exactly, it says nothing about it either way.

... the ability to use a collector or antimatter plant similarly discounts a hydrogen filled bubble.

The collector collects "particles" (i.e. matter), the antimatter plant can produce particles (i.e. matter) as a bi-product:

In reactions between protons and antiprotons, their energy is converted largely into relativistic neutral and charged pions. ...

Charged pions ultimately decay into a combination of neutrinos (carrying about 22% of the energy of the charged pions) and unstable charged muons (carrying about 78% of the charged pion energy), with the muons then decaying into a combination of electrons, positrons and neutrinos ...

https://en.wikipedia.org/wiki/Antimatter#Fuel

Either way there is some matter to expel into the jump bubble, if necessary.

Yes, it is contrived, but Collectors are contrived from the start.

T5 makes no mention of a hydrogen bubble, ...

Exactly, it says nothing about it either way.

... and now that the original Jump Space article has been elevated to sainthood by the publication of MgT JTAS2 the hydrogen bubble is popped for the Third Imperium as imaged by Mongoose.

I haven't read it, but I guess it says nothing about it either way?

 

[AnotherDilbert]

Read what I said again. I am not claiming SSOM mentions a hydrogen filled bubble but it does mention a bubble of normal space surrounding the ship. I'll dig out the exact reference when i can get to the loft.

This?

As the rift closes, the protective jump field "bubble" around the ship is also sealed. This bubble keeps out the strange physics of jumpspace, and serves to provide a safe region for the ship, where the normal physics of our universe operate. The bubble follows the contour of the jump grid exactly, and appears as a dull, gray, undulating "wall" about a meter from the surface of the ship's hull.

It says nothing about any atmosphere or expelling hydrogen?

How did the author of T4 FF&S misunderstand that to an deliberately created hydrogen atmosphere in the jump bubble?

 

[AnotherDilbert]

Lanthanum grids don't require inflated jump bubbles.

Separating jump fields into grids or bubbles is only T5, in earlier editions they are the same thing; the bubble is formed by the hull grid.

In T5 terms earlier editions only had jump grids.

 

[coliver988]

Lanthanum grids don't require inflated jump bubbles.

Tee Five seems inclusive, whereas in the MongoVerse they went with the path of least resistance.

Also, jump bubbles probably require less maintenance, financial or otherwise.

T5 posits 3 types of jump mechanisms:
Jump bubble creates a spherical field around the ship centered on the jump drive. This is how I understood jump drives to work.

Jump plates radiate their effects in overlapping globes. The step-child of the jump bubble and the...

Jump grid uses a mesh of wires that closely conforms to the shape of the hull.

There are cost and benefits to each one. Bubbles are the cheapest and easiest to repair but anything inside that bubble goes to jump with you. Plates are relatively easy to repair, just plop another plate down, but you don't have to worry about debris in your jump bubble. They are "a compromise between the cost of the jump grid and the misjump potential of the jump bubble".

So performance-wise you have good, better, best with corresponding costs and maintenance concerns.

 

[Grav_Moped]

This?


It says nothing about any atmosphere or expelling hydrogen?

How did the author of T4 FF&S misunderstand that to an deliberately created hydrogen atmosphere in the jump bubble?

Maybe it's just their handwave for the massive fuel requirements for Jump? If the fuel for Jump is more than the power plant could plausibly burn, where else might it be needed? And there you go.

First edition LBB2 had all of the fuel burned for a Jump processed through the Jump Drive.
First edition HG added the need for a power plant of at least Pn=Jn (and made Power Plants a central part of the shipbuilding system, and made them large at lower TLs).
Second edition LBB2 continued the Pn=Jn requirement without detailing power usage, but retaining the large Jump Drive.
Second edition HG didn't change from first edition.

I don't have T4 but I get the impression that from then on, the power plant did all the fuel use and the Jump Drive became merely a complex electrically-powered field generator that didn't actually have fuel flowing through it except maybe as coolant.

 

[mike wightman]

It's chinese whispers due to different authors.

MWM writes his jump space article clarifying how jump works (jump drive and power plant required) (note xboat as written is now completely broken design without rules fudges)

DGP authors add fluff in SSOM and mention a jump bubble.

T4 author adds hydrogen to the jump bubble - thus invalidating collector powered and antimatter powered jump ships.

MgT author goes with the fanon/T4 hydrogen jump bubble.

MgT reprints Annic Nova invalidating this paradigm.

T5 and the reprint of the jump space article in MgT JTAS 2 removes the need for hydrogen in the jump bubble.

 

[AnotherDilbert]

It's chinese whispers due to different authors.

In other words you have no idea where the T4 FF&S authors got their ideas, other than that text was added over time.


Just like JTAS#24 a normal jump procedure is described, i.e. using a fusion power plant. If the T4 description prohibits collectors, then JTAS#24 must too:

When the jump drive is activated, a large store of fuel is fed through the ship power plant to create the energy necessary for the jump drive. In the interests of rapid energy generation, the power plant does not work at full efficiency, and some of the fuel is lost in carrying off fusion by-products, and in cooling the system.

Yes, the power plant and computer requirement in LBB2'81 invalidated some LBB2'77 designs such as the Subsidized Merchant (Type M) or the X-Boat. Some of them were re-specified for LBB'81, some were not. So what, that happens with every new edition?

 

[AnotherDilbert]

Maybe it's just their handwave for the massive fuel requirements for Jump? If the fuel for Jump is more than the power plant could plausibly burn, where else might it be needed?

As far as I know the explanation from JTAS#24 is used, even in later editions:

When the jump drive is activated, a large store of fuel is fed through the ship ['s drives] to create the energy necessary for the jump drive. In the interests of rapid energy generation, the [drive] does not work at full efficiency, and some of the fuel is lost in carrying off fusion by-products, and in cooling the system.

I don't have T4 but I get the impression that from then on, the power plant did all the fuel use and the Jump Drive became merely a complex electrically-powered field generator that didn't actually have fuel flowing through it except maybe as coolant.

T4 said that the jump drive needed both power from the power plant and burned the jump fuel itself.