Ice

[Rossoneill]

I have a question
On an icebound planet my players want to use ships lasers to bore into the ice near an old arcology (From the gateway Modules from T4 which i am using in T20)
I was thinking that the ice would be very refractory and the clouds of steam would render the lasers almost worthless as i was thinking they would act like an anti laser aerosol and scatter the laser .
Is this logical or even possible ?
Plus they need to do this fast as the inhabitants will probably notice them on radar or even visual
If it takes excessive time the inhabitants will notice, if its fast probably not in time to react.
Please give me your facts and opinions as i need to run this part this friday
Thanks

 

[far-trader]

How deep and how big is a question/problem too.

Besides weapons lasers are more about damage than quiet neat holes if that's what you're after. If all they need is a quick big hole in the ice and they have missiles that might work better.

I think given the amount of heat a starship generates you could make an argument for it simply being able to melt into the ice if that gets the job done

Ah, there it is! Pg. 158 T20 Handbook, Substance Armor Rating and Thickness table, text below on breaching, and the SI table next page should give you the rules you need

 

[Rossoneill]

They are trying to make a hole big enough to lower the 300 ton starship into then blow a hole in side of arcology to enter with the ship

 

[parmasson]

Are they x-ray lasers?
Anything powerful enough burn a hole in the heat resistant hull of a starship can melt the ice. As for the aerosol effect that might limit the effectiveness to a few miles. I think that the superheated steam from the guns alone will melt the ice. Of course all of this is IMHO and backed by little more than speculation.

What I would ask myself as referee is this, would it be more fun to have them caught by the authorities or get in undetected?

 

[Badbru]

I'd allow it in my game because that is essentially how they skim fuel from ice bodies or polar ice caps or frozen ice covered worlds imtu. Read somewhere about heating carbonaceous asteroids or space rocks and sucking up the released hydrogen and other vapours for asteroid belt refueling. YMMV.

What I'd question was how big and how safe that hole was before they flew a ship into it.

 

[Rossoneill]

They are standard T12 ships lasers
The arcology is roughly 5 km wide by 500 km long
and 10 or so levels
It is in a rift in the earth
Over the centuries the sides filled in with snow that became hardened ice
The inhabitants are tech 5 to 6 droyne and humans engaged in a war of countless centuries over who stays and who goes .
The humans who arrived during the second imperium decided the droyne should leave some centuries ago
The ship needs to get to the Ancients jump tunnel pad on the ground floor of the Arcology .
The blowing the hole basically cuts the adventure to 1 hour of play instead of several weeks .

 

[parmasson]

How about this
Player: " I activate the lasers and keep a close eye on how fast and deep I am drilling."
Rossthree the Ref. <clears throat> "The lasers are working great. Just as you get to within 10 meters of your target depth everything on the screen goes dark. Sensors are working fine and the laser is still firing but your depth seems to be the same."
Players: Oh sh** a black globe you gotta be kidding me!? Now what do we do!
Ref: <bland smile>

The lasers have activated a black globe device that was part of the Arcology's defensive systems. (you didn't think that the jumpgate was the only piece of technology still on down there did you) The players should be glad that the TL-22 disintegrator beam and meson guns don't work any more.

Now somebody has to get down there crawl through that natural cave formation and turn it off. Sure you could keep firing and might overload the BG but it could blow up and take your way home with it. Now you have to stash the ship somewhere out of sight and come back for it later if it is still there!

 

[parmasson]

The BG device protects everything above the old "ground" level. Now the PCs must approach the city from underneath. I just so happens that there is a natural cave formation 30km to the south that leads down etc . . . .
If you want to be really evil a high TL nuclear damper is activated and zaps the ship's power plant offline causing a scare until the PCs discover the effect is not permanent.

 

[aramis]

A BG will overload on the atmosphere, Parmasson... Kaboom!

If the players are canon-familiar, they'd recognize it as post TL20 technology.

Based upon MT weapons, and 3G3, that's about 535 gigajoules per shot, or 125.554819694 Giga TC Cal's. 1 cubic meter will use roughly 1 megacal per degree, with some hiccups, one being 8 cals, We need at least 100 degrees, and lets assume 150 for safety. so 160 or so MegaCals per cubic meter, or about 700 cubic meters per shot; cut that in half due to atmospheric scatter and superheating the steam. There WILL be explosions at that rate... the steam will expand some 25:1 or more. (My FD Time says 28.5:1 for water to steam from fire fighting.)

In short, there will be a sudden recoil as the 350m colum of steam just jumped from 1Atm to 25-28atm, and it will line up upon the laser....

 

[parmasson]

BG overload on the atmosphere? Damn, what book is that from?

 

[aramis]

Read the Bk5 pg 42 description
Here are some key phrases:
"Since a black globe absorbs all energy, a ship withits field on is protected from all fire."
Note it says all energy, It later mentions that includes preventing maneuvering.
"Energy striking the black globe is diverted to the ship's capacitors." Tells us where the energy goes.
"If a black globe absorbs energy and the ship's capacitors are already full, the ship is destroyed."
"No energy may be removed from the capacitors while the screen is on." So in hundred percent situations like you describe, the field's energy is going to just continue to climb.

It stops missiles, so it also must be absorbing kinetic energy. Therefore, even a slight breeze will start filling the capacitors, as will gravity...

Simple logic. (In a later book somewhere there is mention that BG's and planets = Exploding BG.)

 

[mike wightman]

Put another way, switch across to using a white globe to defend the arcology

 

[parmasson]

The B.G. simply continues to absorb all the ambient energy and then boom! White globe it is then.
Just think of all the half functional and very dangerous equipment down there.

 

[Badbru]

The trouble with any globe is precisely that, IT IS A GLOBE. At some point, unless the Arcology is a grav city, the globe will come into contact with the worlds surface (especially true if your arcology is partially buried in ice) upon contact with the world it will do what it does ie absorb energy. Specifically all the kinetic energy of the massive object that is the world travelling through space orbiting its star.
Even a size one world is a hell of a bullet!

From Fire, Fusion, & Steel pg 60;

"If an erected forcefield comes into contact with large quantities of matter ( a vehicle of 50 Displacement tons or greater, a large asteroid, a planet, etc.) the generator is immediately overloaded and destroyed, and its HPG sink immediately suffers a catastrophic detonation, causing 1d20 critical hits. As the field attempts to drain all of the kinetic energy of the large mass, cooling to absolute zero, energy is drawn from the entire mass to be drained by the globe, rapidly overloading the generator, as it cannot possibly contain all of the energy in a system that large."

YMMV, however this was taken from the description prior to the construction sequence for both Black and White Globes.

 

[parmasson]

Don't have FF&S.

Yep that's what the rules say but if I want to do something else to help the story along I do it. So perhaps the ancients had some half-globe system or something. It is up to the ref how their universe works. If you want to be a bit more on the letter of the law side go for it.
Me, I play loose and fast with the rules sometimes. To each his own!

 

[aramis]

At which point you've gone beyond the TL22 defined technology. Which still has only globes.

It may be possible, but it isn't possible with the technology of the OTU.

 

[parmasson]

Perhaps these ancients had access to even more fabulous technology!
Unobtainaium reflector coils
Quite a loooooong stretch but what the hey, it’s a plot devise.

 

[Rossoneill]

Thanks for all the ideas everyone
I think i will put reinforcing beams under the ice from the Arcology to the side of the rift .
If they continue to attack the beams then the side of the arcology starts to buckle endangering 1,000s, up to millions of the inhabitants

 

[aramis]

Originally posted by Parmasson:
Perhaps these ancients had access to even more fabulous technology!
Unobtainaium reflector coils
Quite a loooooong stretch but what the hey, it’s a plot devise.

Devise is a verb, meaning to come up with.
I believe the word you meant was device.

When you use plot devices without thought for the setting, you rob your players of the ability to comprehend their universe.

 

[mike wightman]

Why not have the arcology built with an outer layer of TL17 coherent bonded superdense armour, or TL19 plastic armour, that the ship's lasers just can't penetrate?