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. 

Friday, May 17, 2019

Ultra-Tech Ultra-Gear: (Semi) Passive Support

In many ways the age of robotic exoskeletons is starting to become a reality. Powered exoskeletons are starting to come on the market for the medical field being used to assist in physical rehabilitation and to help nursing staff lift patients  as well as trails for ones to aid search and rescue and emergency response teams.

Sadly the one area that development is seemingly starting to drop off with many projects being canceled in the last three years is exoskeletons for military use and the reason is simple; inadequate power sources. Battery power just isn't there yet. While a hospital bound suit can get away with maybe two hours of operation on a single charge or can just be plugged into the wall, military suits can't be tethered in the field and are going to need to work for at lest 24hrs if not more to be practical. Even further some powered exoskeleton development teams worry about the more explosive properties of lithium-ion batteries being a danger on the battle field. On the other hand while internal combustion engines that can power a suit for a day can be made small enough to be practical,the noise they make along with their IR signature (if not an outright fire hazard) make it them hard to use without compromising a units position in ways that non-powered infantry would not be.

Powered exoskeletons are also very expensive do to their complexity so that's not helping things either.

Now that's not to saw that powered exoskeletons are never going to happen and in fact hybrid designs that use upcoming fairly quite micro-turbine engines to recharge a suits batteries when stealth isn't needed are being looked into at the technology matures and might renew interest in the near future. But for now, powered exo's are no longer as around the corner as we might have hoped. That's not to say that these limitations have not spurred some rather interesting work around, adversity is the mother of all innovation after all!

One area that has seen some innovation is the concept do to these limitations are in the concept of a passive exoskeleton. These don't let you carry more, move faster, or make you super human, in fact you're just as slow lugging around 100lbs in a passive exoskeleton as you are without one, in fact you might be slower as you have to lug the weight of the exoskeleton as well! What they do is through the use of smart load redistribution and shunting of the force of the weight towards the ground, they greatly reduce the metabolic impact of carrying said load by around a third. In other words you can carry a given load with greater comfort, for long and with less chance of injury! And all without needing a single double A battery! I think anyone reading this who has had to lug a full combat load across bad country can see the benefits of such a system! This of course potentially makes them much cheaper do to not needing on board computers to keep the suit from killing it's user and motors to power it.

Of course being a passive system there is a limit to how much such a suit can help out so some engineers decided to split the difference between a powered and passive exoskeleton and developed the concept of the quasi or semi-passive exoskeleton. A semi-passive exoskeleton uses the same basic concept of a full passive one but uses a limited power assist to help reduce the effects of carrying a heavy load much further then a passive suit could with current prototypes have the metabolic impact of lifting loads reduced by up to 80%! This of course is going to make them more complex and expensive then full passive exo's and they are gong to need a power source but they are going to be nowhere as expensive as a full powered exoskeleton and the power drain for exo's that can support a roughly 40kg load has been brought down to a little as two watts meaning that even modern batteries can power one for the better part of a day. 

All in all given the benefits I see semi-passive exoskeletons making for a good stop-gap till we can get a power source that can make powered ones more viable and given their price and low power needs. In fact do to their low cost and power needs I even see them being used to equip most military forces even well into TL 10 with powered suits still being limited to specialist roles (though still more common then in TL 9, TL 11's nano-suit might be the point where I can see cheaper down rated version being used as the stand issue military suit).

Ok, that's enough talking about them, let's see how mature TL 9+ version might work.

Semi-Passive Exoskeletons (TL 9)
Semi-passive exoskeletons use along with a effective load redistribution utilizing a rigged frame work to shunt some of the load into the ground that is further enhanced by a limited power assist. All this helps lower the metabolic impact of lugging around heavy loads by a large degree. In game terms, treat any load supported by the exoskeletons frame along with the weight of the exoskeleton as weighing 80% less when determining FP lost do to carrying said load. For example someone wearing a medium semi-passive exoskeleton while hauling a hundred pound load would be no more exhausted then if they were carrying a 24lbs load the same distane. Semi-passive exoskeletons also act as basic Load-bearing equipment (See High-Tech pg. 54).

Like the lower-body exoskeleton (Ultra-Tech pg. 181) a semi-passive exoskeleton consists of load-bearing back frame attached to a exoskeleton that goes around the hips and legs.

The full weight of both the exoskeleton and the carried load is till used to determine the other normal effects of encumbrance (Basic Set pg. 17) such as being slowed in movement speed, having a penalty to dodge, and any relevant skill penalties.

The Battlesuit skill limits both DX and DX-based skills (Basic Set pg. 192), as well as is used to don the exoskeleton which takes 18 seconds (or 3 at TL 11+ do to smart bio-plas straps). One a failed roll, the exoskeleton is still securely attached, just not in a optimum way and the metabolic effects of the load is only reduced by 2/3rds, on a failure by 5 or more or a critical failure the frame is so poorly fitted that FP lost is actually doubled instead of being reduced!

Semi-passive exoskeletons do require power to use to their full effect though they drain so little power that the often last several days on a signal power cell. They can be used unpowered but at reduced effectiveness, reduce the effective load by only 2/3rds (on a failed donning roll an unpowered frame simply acts a basic load-bearing equipment).

If attacked, semi-passive exoskeletons have HP based on their weight (see Basic Set pg. 558), HT 10 and DR 4. If rugged they have HT 12 and DR 8. Increase DR for normal semi-passive exoskeletons to 5 and the DR for rugged semi-passive exoskeletons to 10 at TL 10+.

Semi-Passive Exoskeleton, Light (TL 9): A light semi-passive exoskeleton designed for the to be used by industrial workers as well as the civilian outdoors market. Holds 30lbs. $1,500, 6.3lbs, 1B/35hrs. LC 4.

Semi-Passive Exoskeleton, Medium (TL 9): A heavier and ruggedized (see Ultra-Tech pg. 15) version of the light exoskeleton designed for heavy industrial, search and rescue, and fire fighting use. Holds 80lbs. $4,800, 20lbs, 1C/130hrs. LC 4. 

Semi-Passive Exoskeleton, Heavy (TL 9): Designed for military use (counts as being rugged,Ultra-Tech pg. 15), this heavy semi-passive exoskeleton can support a typical soldiers full loadout. Holds 150lbs. $9,100, 38lbs, 1C/70hrs. LC 3.

Multiply the weight and cost of a semi-passive exoskeleton by 2/3rds at TL 10, 0.5 at TL11, and by 1/3rd at TL 12. Increase power cell duration by 4 at TL 10, 8 at TL 11, and by 16 at TL 12.

Monday, May 6, 2019

Ultra-Tech Ultra-Quickie: How Much Explosives Are In a Ultra-Tech Warhead?

As any GM can account, sometimes PC's can get a little too clever for their britches and think outside the box.

For example: Let's say after disarming a bomb that was going to take out the presidents personal shuttle one of your players decides they're going to remove its explosive filler so they can repurpose it later.

Great! Smart lil bugger.... Now you just gotta figure out how much boom-boom is in this dang thing. Sure you can just pull a number out of your butt buuuut then you gotta hope you remember why you picked this number later if you have to do this again and hope no of your players are an "expert" on explosives and go, "Actually!"

Well good thing there is a way to figure how much explosives are in the warheads listed in Ultra-Tech!

First you just have to figure out how much a given warhead weighs and if you have read this blog post you should already know how to do this but to make your life easier I'll just give your the formula again.

Warhead weight = Warhead diameter (in mm)3 × 0.000002.

See Warheads R' Us for how I came up with this, my more observant readers might notice that this will give you same results as stating up a small warhead in GURPS Vehicles 3rd ed which in turn is the standard that Transhuman Space used for it's warheads (which in turn was a major influence on the 4th ed version of Ultra-Tech).

Now that you have how much the whole warhead weighs, we can now separate the explosive filler from the casing, fuse and other necessary components. 

To do that just take the warheads weight and multiply if by 0.78 annnnd boom! The product is the weight of the actual boomy part of the thing. Of course in real life this would vary based on what kind of warhead it was, how it was fused and so on this does at lest give you a good rule of thumb that is consistent and lines up with GURPS RAW.


Oh right.... you want to know how I came up with this, silly me. 

Well, if you open up your Basic Set to pg. 415 you'll see there's handy little formula to figure how much damage a given amount of explosives do. You just needed to know the weight and the explosives REF (relative effectiveness factor, or how powerful it is compared to the same amount of TNT).

Now let's look at a 100mm warhead which weighs 2lbs and a TL 9 HE warhead does 6d×5 cr ex.

To give a base line let's look at what 2lbs of TL 9 HE would do (I'll save you the crunch on this one but it's safe to say that TL 9 military explosives in Ultra-Tech are Plastex B/ Octanitrocubane) with a REF of 4).

Using the listed formula 2lbs of HE would do 6d × square Root of (2lbs × 4 × REF(4)) or 6d×5.56, which would normally be rounded to 6 but that would throw off the results. 

Now if we compare how much damage a 100mm warhead does compared to 2lbs of just HE that the warhead does only about 88% of the damage. Now since damage is based on the square root of the weight of the explosives, just convert that 88% to a decimal and square it which gives us a weight modifier of about 0.78. 

So this means that a 2lbs warhead should have 2lbs × 0.78 or 1.56lbs worth of explosives. So if I'm wright, if we plug 1.56lbs into the explosives damage formula we should get 6×5 and look at that, the formula gives us 6d×4.99 dice worth of damage. Bam! 

Oh, and another use for this knowledge is now you can swap out the plastex B and try out different types of explosives. For example, if we decided that we wanted that 100mm warhead filled with Nanoscale Thermite (Ultra-Tech, Too Pyramid 3/51 Tech and Toys III) we now knows that it can hold 1.6lbs worth which will burn for eight seconds and cost $320. 

I know this wasn't too big of a post, especially with how long I've been out of the game but rest assure I do have some more post in the works, two that give you more warheads to play should be done soon, with as well doing some major research into Robotech: The Next Generation/The Sentinels mecha and weapons so I should have more Ultra-Tech fun for you guys soonish.