[Spaceships] Dealing with Cheap World-Killers?

[Anthony]

Given your 'infosphere' logic, precognitive sensors are entirely reasonable and resolve the issue of range completely, because you're detecting based on temporal range rather than physical range (which is zero).

[DataPacRat]

Originally Posted by ericthered

that's an interesting table I didn't remember! Your numbers are off though: its 3 per month at .9c, for 36dDR per year, which makes things tougher, and you may have to throw a wad of armor rather than a giant rock, or at least make it bigger (and thus more expensive). Or slow down (giving your foes a bit more time to react, and a longer payoff time.

Stone armour is 7 dDR per space, so if all 6 front spaces are rock, that's 42 dDR, enough for the run. (Edited my reply with the corrections.)

Originally Posted by ericthered

What will all of those particles do to your stealth? If you've got a steady trickle of small explosions on your bow that may negate all your fancy stealth technology. It certainly will make it much harder to have a stealth coating in place at the time you arrive.

It's an interesting point.

Hm... with the slower industry toggle, a SM+9 fabricator produces $150k per day, enough to cover the full cost of the cheap world-killer's $50M stealth coating every 333 days. (And since only the front is being ablated, it can re-cover that area every 111 days, which is shorter than the run-up time.) Said factory costs $150M, plus $10M for a SM+9 fission reactor, bringing the cheap world-killer's cost up to $894M - still under the target $1B.

[David Johnston2]

Originally Posted by DataPacRat

Stone armour is 7 dDR per space, so if all 6 front spaces are rock, that's 42 dDR, enough for the run. (Edited my reply with the corrections.)



It's an interesting point.

Hm... with the slower industry toggle, a SM+9 fabricator produces $150k per day, enough to cover the full cost of the cheap world-killer's $50M stealth coating every 333 days. (And since only the front is being ablated, it can re-cover that area every 111 days, which is shorter than the run-up time.) Said factory costs $150M, plus $10M for a SM+9 fission reactor, bringing the cheap world-killer's cost up to $894M - still under the target $1B.

How does it apply the replacement coating?

[DataPacRat]

Originally Posted by David Johnston2

How does it apply the replacement coating?

TL10 Repair microbot swarms, set to repair one model of equipment (ie, "stealth coating") are pretty cheap. Or maybe the attackers are paranoid enough to include some combat-bots to fend off any would-be rocknappers, and let them do maintenance during the acceleration phase.

[David Johnston2]

Originally Posted by DataPacRat

TL10 Repair microbot swarms, set to repair one model of equipment (ie, "stealth coating") are pretty cheap. Or maybe the attackers are paranoid enough to include some combat-bots to fend off any would-be rocknappers, and let them do maintenance during the acceleration phase.

So you'll need to include a cargo hold for raw materials.

[ericthered]

You don't have 111 days to apply the coating: you have as long as it takes the coating to be ablated. You've got to deploy the coating right before you impact, and I don't think it will last very long.

If the ablation damage is evenly distributed with time, it ablates one human scale point of DR per day. If the impacts are not hitting armor, that's 3d6 damage per day, or about 10 damage a day, or 1 damage per 2.5 hours. I don't know how much punishment a stealth surface can take, but that's a lot of damage, and you've got to apply the surface in under the time it takes to ablate.

The other issue is that the collisions won't just destroy your stealth gear, it will generate light and radiation on your bow. If the armor ablates completely away you are loosing 5,000 tons every two months or so, or around 80 tons of mass per day. Even if only half of the DR loss is mass loss, that's still 40 tons of mass per day lost to space in energetic collisions.

[Anthony]

The other problem is that it's quite unlikely that stealth will actually work at velocities sufficient to cause ablation.

[DataPacRat]

Originally Posted by David Johnston2

So you'll need to include a cargo hold for raw materials.

The current build:

* Cheap World-Killer:
   - SM+12: 100,000 tons, length 200-400 yards
   - Unstreamlined
   - TL10, no superscience other than "Singularity Drive" and "Vacuum Energy" Power Plant
   - Airlocks, auxiliary power systems, Landing Gear, Routine equipment
* Design Features:
   - Stealth Hull (-8 to detect): $50M
   - Chameleon Hull (-4 to see): $35M
* Design Switches:
   - Exposed Radiators
   - Accelerator Tube Limits
   - Slower Industrial Systems
   - Pyramid 34: Armor Volume (19 armor systems: dDR * 3.6), -2 effective SM when being targeted or attacked
* Systems:
   - Front:
      6 * SM+12 Armor, Stone: dDR 7*3.6 (minus a SM+9 armor, subtracting dDR 2*3.6)
      - [Hull] SM+9 Hangar Bay: cap 100 tons, launch 50 tons/minute, $300k
   - Central:
      6 * SM+12 Armor, Stone: dDR 7*3.6 (minus a SM+9 armor, subtracting dDR 2*3.6)
      - SM+9 Weapons, Medium Battery: 3 UV Lasers, Turret, 300 MJ: dDmg 3dx5, $15M
   - Rear:
      5 * - SM+12 Armor, Stone: dDR 7*3.6
      - SM+12 Standard Singularity Drive: Total Automation (replace 10 workspaces with $50M), $500M, accel 0.5G
   - Core: (1 SM+12, 2 SM+11, 2 SM+10, 3 SM+9)
      - SM+12 Cargo Hold: 5k tons
      - SM+11 Control Room: Computer C9, Sensors 10, 15 control stations, Total Automation (replace 3 workspaces with $15M), $60M
      - SM+11 Cargo Hold: 1.5k tons
      - SM+10 Cargo Hold: 500 tons
      - 2 * SM+9 Cargo Holds: 2*150 tons
      - 3 * SM+9 Power Plant, Reactor, Fission: 75 years, $3M
      - SM+9 Fabricator (to rebuild stealth coating on fore sections): $150k/day, $150M

- TL: 10^
- dST/HP: 300
- HT: 13
- Hnd/SR: -4/3
- Move: 0.5G/c
- SM: +12
- LWt: 100,000 tons
- dDR: 144/144/126
- Occ: 0
- Load: 7,300 tons
- Cost: $884M
- Notes:
   - At 0.9c, impacts with a force of 2,521 teratons of TNT - 25 times that of the dinosaur-killer asteroid.
      - 0.9c collision damage: 6d * 3 * dST 300 * 167,654 mps = 905,331,600d dDmg (average damage roll: 3.1B)
   - Can be manufactured by SM+12 robofac in 88.4 days. Takes 622.5 days to accelerate to 0.9 c, over 0.75 light-years. (And takes 873 days to go out 0.75 ly.) Total time to doom, if built and launched from in-system: 4 years, 123.9 days
   - Cargo:
      - TL10 Repair microbot swarms and hives (to repair / reapply stealth coating), $500 ea
      - TL10 Combat Androids ($200k ea)
      - TL10 Walking-Tank Warbots ($200k ea)

(And time for another set of errands, see y'all in a few hours.)

[Fred Brackin]

Originally Posted by DataPacRat

R

At .9c, the relativistic mass increases to about 2.3x normal.

That effective increase in mass would change the detection point from 700 light-seconds to 1000.

As to how long you a destroyed world-killer needs to expand the figures i used yesterday of 500 km per second for the expansion velocity were not complete WAGs. Rather they were a factoid I didn't have time to source then.

https://en.wikipedia.org/wiki/Thermo...usher_ablation

.....has the outer layers of an exploding nuclear weapon expanding (and/or imploding) at roughly that speed. So it's something like a ballpark number.

There will be no "fragmentation" of the world-killer's mass. No two atoms of it will remain in contact with each other. Individual atoms at .9c are effectively cosmic rays but .9 c is actually a fairly moderate velocity for cosmic rays. They shouldn't penetrate deeply though an Earth-like atmosphere.

There should also be interaction with the planet's magnetosphere but those effects would be getting complicated to predict. However, even interception at 10 seconds before impact should be at 9 light-seconds of distance or circa 1,6 milion miles of distance and that should indeed be beyond the magnetosphere's boundary.

That takes us to how many interceptors we need. Looking at Spaceships 3 for the mroe detailed rules we can work out that missiles of 28 cm or less have an endurance of 330 seconds and 32 cm+ missiles have double that. So we want 32 cm missiles at $1m each.

If you detect at 1000 light-seconds that's 1100 seconds before impact. If you launch at only a few seconds after that you can have a 32 cm missile that burns for 660 seconds and then coasts for another 320 seconds and still impacts the world-killer at 100 seconds before planetary impact.

That would have us putting ourkiller-killers 90 light seconds out making for a sphere 33.5 million miles in diameter with a surface area of an intimidating sounding 3.5 billion square miles. However, one of our 32 cm killer-killers can cover an area of about 500 thousand square milles (please, check my math!) so that looks to me like we only ned 7000 killer-killers to cover a sphere with intercept 100 seconds before impact.

$7 billion might sound like a lot to spend on missiles but if you think you can get by with interception twice that close you only need to spend 1/4th that much money.

[martinl]

Originally Posted by DataPacRat

I'm putting together a setting that's roughly TL10, no FTL or other superscience save for two items, which are close enough to what Spaceships calls a Singularity Drive and a Vacuum Energy plant that I'll just swipe the stats....

Anyone have any ideas for how the remainder of potential world-killers might generally be dealt with? .

Your society has ~free energy tech and has not destroyed itself. Thus either
1. Institutional guardians have kept ahead of the many diverse and innovative malefactors this whole time
or
2. There are no malefactors.

Other folks seem to be working on 1, but allow me to suggest 2 instead. Some time in the past there was a very bad Whoopsie where life was nearly wiped out by bad actors with WMDs, and ever since it has been a universally accepted tenant that all beings capable of this are Fixed.

This does not have to be dystopian if you don't want. High tech superpsych and supercomputer science can be handwaved as easily as superphysics. Perhaps it is just corrected by doctors at birth and programmers at AI inception as a matter of course.

"Why wouldn't I include the 'don't massacre folk' fix? It's been standard for three centuries for a very good reason."

Then any PCs get a taboo trait (Can't massacre folks). This might restrict normal PC activity a little, admittedly, but watching the players argue for the ability to do atrocities should be fun at least.

Then of course they discover the villain found a way around it.