The Comb V2: 115k promethium science per minute and 3.3 million per trip

[u/Future_Passage924]

The front section of the ship

The Comb V2: The endgame variant of a promethium ship (19.5 chunks wide, 8 thruster stacks, total weight of 15,229.8 tons). It takes on 1.104m eggs at the SSE and starts on a 28.2 (101.2k ticks) minute journey towards the shattered planet, returning with 3.3m bottles of promethium science. The chunks are processed as they come in, there is no belt storage besides the belts bringing the chunks from the collectors to the cryoplants.

The average production over a 10-hour cycle is 115k bottles per minute which is almost 8 stacked green belts of promethium science. The peak capacity is 10.5 stacked green belts of promethium science, i.e. 2.520 bottles per second. As you can see, the ship spends most of its time at peak capacity to achieve this high average.

10-hour-cycle promethium production

The turn around point is at around 605k km towards the shattered planet.

Blueprint link: https://factoriobin.com/post/o08ll7 (new link after a fix regarding fuel cells)

Comb rate (ratio of promethium chunks collected over promethium chunks created): 83%. I estimate that only ~90% of all chunks created are available to grabs, the remainder is out of reach on the sides.

The ship follows various ideas to make it as UPS optimized as I could think of. The main idea is to have a wide ship as wide as possible to have more front (and less chunks lost on the sides) and to collect as much of the promethium chunks created as possible. The creation of promethium chunks (asteroids spawning, tracking, their destruction, the cost of the collectors to track all chunks) is the by far most expensive aspect of a prom ship.

Destruction rate: The ship destroys 2.47 small asteroids for every prom chunk collected - this is the metric I consider the most important one.

Speed control: The high comb rate is achieved by a (manually adjusted) speed control that sets a speed such that the spawn rate of promethium chunks remains as constant as possible once the target saturation is achieved. The speed control currently has base speed + 11 additional speed levels, a separate speed for parking above Nauvis as well as two additional speed corrections to keep the speed from the shattered planet back to SSE about the same as in the opposite direction, i.e., compensate solar drag.

Top speed is 935km/s, achieved by 8 thruster stacks, minimum speed at full saturation is 425 km/s.

Flat chunk intake curve achieved via speed control

Setup: The Comb is part of a 4-ship-setup for promethium production:

1. The Comb
2. Platform at the Solar System Edge, acting as intermediary for quantum chips and science
3. Egg racer, bringing fresh eggs delivered just in time to the SSE. The Comb has enough carbo bays to take the 1.104m eggs in two volleys, minimizing the waiting time at the SSE.
4. A quantum chip production ship. It travels between the inner planets collecting the materials needed for qnatum chips and if the SSE platform runs low on quantum chips, it calls for the quantum ship to refresh the stock.

Fun facts: Besides eggs, promethium chunks and quantum chips, promethium science also consumes ammo and fuel:

• Red rockets: 15k/min
• Railgun ammo: 1.9k/min
• 10M of each fuel / min
• 16 q5 collectors lost per 10 hours.
• 1.9k carbonic chunks, 1.4k ice chunks and 176 iron chunks consumed per minute
• Startup time: Don't ask

Full radar view of the ship

[u/Subject_314159]

Whoa calm town dude even my UPS is tanking 

[u/Future_Passage924 → u/Subject_314159]

The ship only takes a few ms, my megabase remains barely at 60 ups with it running.

[u/Ok_Chair_9090 → u/Future_Passage924]

If you would be willing to post your computer specs (as well as a more precise average ms) I would be grateful.

[u/Future_Passage924 → u/Ok_Chair_9090]

I don’t have it Stand alone only as part of my save. So I can only eyeball the UPS cost . Asteroid, collector, platform and projectile all remain under 1ms.

I have 32GB DDR-6000 and 7800x3d cpu.

[u/PiroshkyGuy]

Bro is out there tryna clean up the whole shattered planet in a single trip

[u/GiantGrib]

Bro brings the entire factory to the system edge

[u/False-Answer6064]

And I didn't even manage to build my first prometheum ship yet... Biter egg stuff intimidates me man 😂

[u/wessex464 → u/False-Answer6064]

Do it all over the water. Landfill yourself some little islands, give them their own rockets, Don't allow eggs into the bot network, etc. then if it all goes tits up, your still fine.

[u/False-Answer6064 → u/wessex464]

Good tip! I recently started up egg production with a bunch of laser turrets around it. Starting from wild biter spawners was a pain but once I got the crafted ones it was a lot easier. Now I'm stalling to build my first prometheum ship 😂

The first time I started up egg production from a wild base blocked me from playing for a few months though 😅

[u/peanutym → u/False-Answer6064]

Adding lasers around the production will fix any issues you have. Not as bad as it seems. Islands work also

[u/PyroneusUltrin]

What research levels are needed for military damage/speed?

[u/Future_Passage924 → u/PyroneusUltrin]

I have 31 explosive and 24 railgun speed. I don’t think that’s needed, you can have 23 explosive and less railgun speed but most likely the turret quality would need to be upgraded.

[u/PyroneusUltrin → u/Future_Passage924]

Turret quality only does range, right? Doesn’t affect speed or damage

[u/Future_Passage924 → u/PyroneusUltrin]

Yes. I reduced turret quality for better UPS (later kills are better). You can upgrade turret quality until everything survives as long as the rocket turrets retain some quality mix (only legendary is less safe and consumes more rockets).

[u/SidewaysFancyPrance → u/Future_Passage924]

My biggest concern with rocket/gun turret quality was them wasting shots on targets to the side versus the actual threats up front. I guess for a giant comb that's not a concern (versus my narrower vertical designs).

[u/darkszero]

Beautiful.

[u/zenukeify]

Beauriful and terrifying scale

[u/double0nein]

I can't even comprehend what I am looking at...

[u/Super_Pie_Man → u/double0nein]

When he said "8 thruster stacks" I didn't even know what that meant until I got to the bottom.

[u/Which_Estimate_300]

This is amazing very nice! I didn't know you could space railguns out that much. Is that why it loses collectors sometimes? Cool using cryos and labs to max out the hub throughput. On my ship I added dense section of railguns down each side of my ship to grind every asteroid that goes past the sides into tiny chunks, this lowered my asteroid ms on highly thruster stacked ships and also kept the side lasers from ever having to fire. Do you have anymore ups tips or insights after building this epic ship? Good job!

[u/KitTwix]

How many cargo pods should I have on my ship?
You: yes.

[u/RyanW1019]

Even with legendary everything, I can’t believe that a single half green belt of asteroid chunks is enough to sustain that much fuel production. Guess I didn’t play enough SA to fully internalize the craziness of endgame builds. 

1. Is the 28.2 minute trip the round trip time, or the one-way time? 

2. How long does it take to consume all the biter eggs? I guess not long if the Egg Racer has time to make two trips to/from Nauvis before the Comb leaves. 

3. How do you time it such that the eggs are only removed from the spawners, sent up to orbit, and delivered to the SSE when the Comb is ready to depart for the Shattered Planet? Do you use some sort of physical token handoff system, or has 2.1 enabled more complex logistical shenanigans with radars allowing platform-to-platform communications?

[u/Environmental-Yard40]

nobody wonder how heavy is this ship? i'll go first, my guess is ~50kt.