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Old 10-19-2020, 07:23 AM   #11
DataPacRat
 
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Default Re: [Spaceships] Statting a STL Interstellar Probe

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Originally Posted by AlexanderHowl View Post
Solid state objects still need maintenance, though it is a more modest requirement, especially when they are exposed to cosmic radiation for thousands of years.
Any ideas on what such maintenance would consist of? I'm trying to guesstimate how small a maint-bot would do any good, or if I could get away with some relatively-highly-redundant microbot swarms.


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In addition, most governments will not allow people to build and launch interstellar probes without permission, and they would definitely not give someone without substantial resources permission to do so.
The flufftext already includes a line that the most difficult part of the build was getting approval from a relevant government agency. :)


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I am confused about the endgame for the character though. Assuming that the ghost was stored in the cargo hold, who are they thinking would boot them up in the future? We had enough trouble recovering programs from 25 years ago, I cannot imagine the difficulties that would exist for a civilization 10,000 years in the future, especially if they are nonhuman. At best, the probe would probably end up as a museum exhibit without anyone realizing that there was a copy of an archaic ghost trapped within.
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Another concern is that a SM+2 probe at TL11 would have a 'control room' with a Complexity 6, which is only good enough for a ghost of a rat, not the ghost of a human, so the entire vanity project would be rather pointless.
In this setting, a ghost can run in a computer that fits inside a human skull. In SS, a one-system cargo hold on a SM+2 ship can hold 100 lbs. The ship's computer may not be able to run a ghost, but there shouldn't be a problem fitting enough compute for one - or nine or ten, for decent redundancy.


Latest new thought: I'm trying to convince myself that the 'maw' from SS7 doesn't /really/ have to go in a front space; plenty of critters are arranged differently, like starfish. (I'm thinking of doing the maw to digestive system to refinery setup, to grab up-to-20-lb rocks to melt into front armor.)
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Old 10-19-2020, 07:24 AM   #12
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Default Re: [Spaceships] Statting a STL Interstellar Probe

At 0.01g, a trip to Alpha Centuari would take about 41 years and reach a maximum velocity of around 0.2 c, according to the omnicalculator.
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Old 10-19-2020, 11:29 AM   #13
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Default Re: [Spaceships] Statting a STL Interstellar Probe

For the sake of discussion, here's my current draft of the probe. I've thrown in a couple of anti-micrometeor lasers (though with the downscaled power plant, I need to stat up a capacitor), and some armor-rebuilding machinery. And I still haven't decided which option to use for maintenance needs.

(The setting uses somewhat different numbers for computer complexity and storage space, and size of a ghost, but that's a whole other issue I don't feel like getting into today.)


* SM+2: LMass 1 ton, Length 5 yards, dST/HP 7, Hnd/SR ?0/4?
* TL10, THS-style (plus ^ drive + power plant)
* Unstreamlined
* Design Switches:
- Advanced Computers
- Exposed Radiators
- Accelerator Tube Limits
- Slower Industrial Systems
- Pyramid 3-34 Armor/Volume tweak; 15 armor systems, dDR*2.3
* Systems:
- Fore: 6x Steel Armor, $1,200, dDR 0.5*6*2.3=dDR 6.9
- Aft: 6x Iron Armor, $720, dDR 0.3*6*2.3=dDR 4.14
- Centre: 3x Iron Armor, $360, dDR 0.3*3*2.3=dDR 2.07
- Centre: Maw, crushing: 8d6-1 crushing damage (dDmg 1d-1), $1k
- Centre: Digestive System, crushing: capacity 0.01 tons (20 lbs), dDmg 0d+2/20sec, $500
- Centre: Weapons, Medium Battery of 2, beam (UV laser): 100 kJ, dDmg 1d ea, $4k, 0.015 tons (30 lbs) cargo space. Range 700/2,000 miles
- Core: Control Room: $2k, Comm/sensor TL-9=1, Computer C5+1=C6
- Core: SM+0 Power Plant, Perpetual Motion: 0.1 PP, $600
- Core: SM+0 Rotary Reactionless Engine: req 0.1 PP, $50, 0.01G accel
- Core: SM+0 Refinery: req 0.1 PP, 0.0015 tons/day (3 lbs/day; 200 days for 6 full systems of armor), $100 [melt crushed asteroid into replacement armor]
- Core: 7x SM+0 cargo spaces: 7*0.005=0.035 tons (70 lbs)
* Cargo Holds (120 lbs):
- THS p141 Microframe: 10 lbs, $10k, C7 (can run two ghosts), storage 10,000 TB (1,000 TB dedicated to 10 copies of a ghost; 9,000 TB dedicated to cultural and historical database)
- Maintenance bots. (Robots? Microbot swarms?)
* Total cost: $20,530
* Range before needing to rebuild fore armor:
- 0.01c: 345,000 years, or 3,450 light-years
- 0.1c: 345 years, 34.5 light-years
- 0.2c: 41.4 years, 8.28 light-years
- 0.3c: 13.8 years, 4.14 light-years
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Old 10-19-2020, 11:32 AM   #14
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Default Re: [Spaceships] Statting a STL Interstellar Probe

Why not just build a ramscoop on it ? seems to take care of most ablation issues... not sure what you would do with the mass, since both the engine and the power plant don't seem to need it.
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Old 10-19-2020, 11:46 AM   #15
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Default Re: [Spaceships] Statting a STL Interstellar Probe

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Why not just build a ramscoop on it ? seems to take care of most ablation issues... not sure what you would do with the mass, since both the engine and the power plant don't seem to need it.
Cost, mainly; $100k for a SM+2 ramscoop kind of blows away rhe garage-scale budget I'm aiming for.
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Old 10-19-2020, 01:18 PM   #16
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Default Re: [Spaceships] Statting a STL Interstellar Probe

Question for the crowd: How many repair microbot swarms provide a good balance between having enough to keep the probe working, and minimizing cost?

A given repair swarm costs $250 plus $250 per model of equipment it can fix, up to a maximum of 4. Going over the systems in the probe's current draft, it looks like 9 different skills are needed: Armoury (Heavy Weapons), Armoury (Vehicle Armour), Electronics Repair (Computers), Mechanic (Fuel Cell), Mechanic (Reactionless Drive), Mechanic (Refineries), Mechanic (Robotics), Mechanic (Vehicle Type, for digester), Mechanic (Zero Generator). (Plus Computer Programming and Electrician, but repair swarms don't have those skills as an option, so we'll pretend they're part of computer repair.) So an absolute minimum of 3 swarms is in the cards, and a minimum cost of $3k. (Each swarm repairs things much slower than a human, but I'm not worried about speed.)


Also, would it be reasonable to build a repair swarm whose target model of equipment is another repair swarm? If so, then something like setting Swarm A to fix Swarm B, which can fix Swarm C, which can fix Swarm A, could be enough to let the whole pile-of-cards keep on keeping on for the target duration; that is, at least one of the three swarms is still working, then it could bootstrap to full self-repair functionality. ... Though I'm still tempted to have 2 of each swarm, for the usual benefits of redundancy. More than 2, and I start wincing at the price.
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Old 10-19-2020, 05:12 PM   #17
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Default Re: [Spaceships] Statting a STL Interstellar Probe

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Originally Posted by DataPacRat View Post
(I'm thinking of doing the maw to digestive system to refinery setup, to grab up-to-20-lb rocks to melt into front armor.)
However, you have to match velocity with said rocks. Colliding with them at 0.01c will spoil the whole day.
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Old 10-19-2020, 06:10 PM   #18
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Default Re: [Spaceships] Statting a STL Interstellar Probe

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Originally Posted by johndallman View Post
However, you have to match velocity with said rocks. Colliding with them at 0.01c will spoil the whole day.
Of course, given its reactionless drives and perpetual-motion engine, the vessel can slow down and speed back up as much as it likes. Even if it has to slow to a dead stop relative to where it originated, that only costs it 2 years (and typically it’ll be picking rocks much closer to its own velocity).

As for maintenance, if you’re alright being a bit abstract, give it an engine room, then take a look at the progression on larger vehicles to work out how many workspaces you’ll actually need (it will be fractional for each component that needs such). Now pay for Total Automation for that many workspaces. The 5% mass (and additional cash) sacrificed to the engine room represents the inefficiency suffered for working at such a small scale (normally, the automation machinery - ‘bots, charging station, microfabricators, etc - is such an insignificant portion of the ship’s mass that you need only worry about cost, but with such a small vessel, the mass is more of an issue).
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Old 10-19-2020, 06:39 PM   #19
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Default Re: [Spaceships] Statting a STL Interstellar Probe

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Originally Posted by Varyon View Post
As for maintenance, if you’re alright being a bit abstract, give it an engine room, then take a look at the progression on larger vehicles to work out how many workspaces you’ll actually need (it will be fractional for each component that needs such). Now pay for Total Automation for that many workspaces. The 5% mass (and additional cash) sacrificed to the engine room represents the inefficiency suffered for working at such a small scale (normally, the automation machinery - ‘bots, charging station, microfabricators, etc - is such an insignificant portion of the ship’s mass that you need only worry about cost, but with such a small vessel, the mass is more of an issue).
With four SM+2 systems and four SM+0 ones, that looks to be 0.00044 workspaces, which when totally automated cost $2,200; plus $300 for the engine room. I'm quite willing to throw in the total automation costs, as a way to help sane-ify stretching the Spaceships system down to this scale. (I could even flufftext them as a variety of dedicated microbot swarms, to best fit with the TL.)

Where this approach breaks down, though, is that the engine room likely requires a full workspace itself, which would add $5M to the cost, well beyond the available budget. (It's hard to draw a curve when a SM+9 engine room requires 2 workspaces, while SMs +5 through +8 all require 1.) If there's a solution to that, I'd be quite happy to throw this in, too, as you suggest.
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Old 10-19-2020, 08:28 PM   #20
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Default Re: [Spaceships] Statting a STL Interstellar Probe

Time to double-check my math on micrometeor detection.

Assuming we're using the Control system C6 computer; using 3e-based THS numbers, a NAI-4 costs $250, and a C6 skill set software for Electronics Operation (Sensors) M/A costs $500, and offers a skill of 15.

Spaceships rules for passive sensors give pretty abysmal chances of detecting a SM-10 dust grain; SM (-10), Time 20-second turn (+0), Range 151-250 miles (-32), Telescopic vision (+1), Observation in plain sight (+10), In Space (+24), IR Signature (+0), total -7. More than 500 miles, and it drops to -10, effectively an auto-failure. With a dust-grain travelling at 10 miles/sec, or 200 miles per 20-second turn, With a skill of 15-7=8, that's only a 25.9% chance of making the detection roll at 200 miles, and a 16.2% chance at 400 miles, for an overall chance of 37.6%.

Active sensors offer much more promise. With a Scan rating of 1, base radar range is 20k miles; but radar only detects human-sized or larger objects. Imaging radar can detect smaller things, but the base range is 2k miles, at which range there's a -0 to skill. At up to 4k miles, rolls are -2; 8k miles, -4; 16k miles, -6; 32k miles, -8; and 64k miles, -10. For a dust-grain travelling at 10 miles/sec, between 32k and 16k miles from the probe, the grain will take 1600 seconds, or 80 20-second turns. As far as I've found, there aren't any size penalties to 4e active-sensor rolls; so during each turn, the NAI gets to roll at 15-8 = 7, each roll having a 16.2% chance of success, meaning the odds of at least one of the 80 rolls succeeding are 99.9999276%. Even at 0.01G, that gives plenty of time for the probe to ease out of such a grain's path; and/or to take 10 potshots with the lasers as the grain approaches within 2,000 miles.

If I'm wrong and SM does affect active sensor rolls, then as the dust-grain travels from 4k to 2k miles, the AI gets to roll 10 times at 15-2-10=3, for a 0.5% chance of success per roll (with a 4.889% chance of making at least one roll); and then 10 times at 15-10=5, for a 4.6% chance of success per roll (and a 37.56% chance of making at least one roll).

Depending on which rules are in play, then either micrometeor impacts are effectively a non-problem, or this tiny ship will probably get hit by any aimed its way. Since larger ships have better sensor scores, and SS7 bothered discussing the dangers of such dust-grains, then the latter option seems more likely. But I'm still a bit confuzzled about 4e sensor-operation rules... eg, do high speeds make an object easier to detect, as was the case in 3e/Vehicles? IIRC, 10 miles/second is 17,600 yards/second, which would add something like +23 to detection rolls, more than offsetting the -10 from SM...

... Is anyone up to clearing my befuddlement here?
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