Saturday, May 25, 2019

Survivable Spaceships Quickie: I'll Try Spinning! That's a Neat Trick!

I don't think I need to convince anyone that the spaceships in GURPS Spaceships need more ways to stay alive in a fight and in fact I have already covered this topic before here and here.

Of course those were rather conventional ways of protecting a ship from over all damage. In today's post I cover two more ways to protect your ship, specifically from energy weapons, that are a bit more out there. 

Not today good sir! In this post we're gonna cover how NOT to taste that rainbow! Also, have you played Children of a Dead Earth yet? If not, why come? 

Yeah, that's the theory in a nutshell... or at lest a spinning one
Rotating Your Defenses (Rotating Armor)
During the 80's there was a real look into using DEWs (directed energy weapons, lasers and other pew-pews) to shoot down Soviet ICBM's as well as what could be done to protect them from said DEWs.

It was figured that it would take a laser just 10KJ per square centimeter to kill a typical Soviet ICBM but if you spun the armor on the ICBM so the laser couldn't dwell on one spot, that went up to 30KJ or more as the effective area the laser dwelled on increased and the spot hit had some time to cool. Quiet an effective increase. Of course there was a down side to this, the mechanisms needed to make the armor spin would add more mass meaning you would need to use thinner armor if wanted the same weight and the added complexity would increase cost. Thankfully the spinning also increased the effective slant of the armor against other attacks making up for the thinner armor against more physical attacks along side the increased effectiveness it has against beam weapons.

Another down side if the fact that spinning armor act like a gyroscope making it much harder for a ship to turn.

Adding a system of rotating armor cost as much as a given system of armor one size larger. It offers it's normal dDR against most types of attacks  but its dDR is treat as if it was an armor system three SM larger against burning, lasers, particle beams and other beam weapon types (with the exception of plasma guns). A ship that spins its armor is at +1 to it's SR (to a max of 5) but is also at -1 to it's Hnd.

Example:  A SM +7 ship is given a system of Nanocomposite armor. It gives its normal dDR of 15 against most attacks but against an enemy beam attack it's spinning armor effectively spreads the beams focal point out giving the ship and effective dDR of 50 vs lasers and other beam weapons! But do to the added complexity of adding a spinning mechanism to the armor, the system costs $5M rather then $1.5M. While spun its Hnd drops to -2 but its SR stays at 5.
Spin your ship's armor so you don't end up like this guy. You do NOT want to be this guy! Also play Children of a Dead Earth! 

But wait! There's more!

You can also cool your armor to increase it's protection as well!

Really Cool Armor (Actively Cooled Armor)
Another effective way to deal with beam weapons is to find a way to bleed off the thermal energy they deposit in the armor. In fact this is in fact the key feature of types of ablative armor that has been proposed for energy weapon defense, as the armor ablates it carries a lot of heat with it.

Well if this works, why not just run the ships cooling system through its armor? Well nothing, well outside of the fact that coolant used to handle normal ship functions isn't hardcore enough to handle the intensity that military grade energy weapons hit with, it would boil off way before it could shunt enough heat to save the armor. So what we need is a more hardcore level of coolant. How hardcore? Well molten tin has been suggested as possible candidate, Ultra-Tech examples might use more exotic materials.
Like this. But Bigger. And using molten metal instead of water. But you know what?
This thing would let you run Children of a Dead Earth at a butter smooth frame rate!

Other then that, the idea behind this system isn't that different from a water cooling loop you might used to cool your PC,  it's just a heat pump on a larger scale.

Actively cooled armor coolant can be used just as normal coolant as well, each tank of it extends a ships operational time by 10 times at TL 9, by 15 times at TL 10, by 20 times at TL 11, and by 30 times at TL 12.

Each system of actively cooled armor needs a fuel tank system of armor coolant to work. Each tank treats a given armor system as having the dDR of a ship five SM larger (if you also add rotating armor, increase this to eight SM larger!) against burning, lasers, particle beams and other beam weapon types (with the exception, once again, of plasma guns). Of course this is only for as long as the tank of coolant holds out! How long a tank can protect a system of armor depends on how powerful the attack is and the TL of the coolant. Against a weapon with the output equal to a major battery of the same SM as the armor system, a tank of coolant will last 10 shots at TL 9, 15 shots at TL 10, 20 shots at TL 11, and 30 shots at TL 12. Against larger or smaller beam weapons, increase or decrease how long a given tank last by the ratio of the attacking beams output against what the output for a major battery of the same SM as the armor system that is being hit. If you have more armor systems then tanks of coolant then divide how many shots it can survive by the number of armor systems its protecting, round down. If you have more tanks of coolant then armor systems then increase the number of shots by the difference, also round down. Armor coolant costs $1,000 a ton.

Example: If we decided to instead add a tank of armor coolant to protect our TL 10  SM +7 ship, its dDR 15 of nanocomposite armor would now give dDR 100 vs. beam weapons, dDR 300 is it also rotated! This is of course only so long as its coolant holds out! Being a TL 10 ship, its coolant can hold out against 15 100MJ shots, or 45 30MJ ones. This could of course be increased by adding more tanks of coolant. A single SM +7 tanks of coolant costs $15,000 to fill. 


  1. Replies
    1. Yeah, just life has been extra crazy as of late. I've got several posts on the back burnner, just haven't had the time to work on them.