Late game Promethium ship design

[michal.don]

Hello, I also asked this at the Factorio discord, but I'd like to get as many good answers as possible, so posting here as well:

I am enetring the late game and scaling all the planetary science production right now. Currently, I have one Promethium ship running, just to get some Research productivity going, but it's a slow one, not getting that much science done. Eventually, I'm going to have to design a new one, or rather a new fleet of them. I'd appreciate some insight from somebody who built a late game Promethium ship, mainly regarding the bottlenecks and the core design issues.

My thoughts on that are as follow. As a rough first estimate, let's consider a ship that produces a full stacked turbobelt of Promethium science (240/s), on average. Let's consider a round trip time of half an hour. And let's consider that half of that time the ship would be able to craft the science. As far as machines go, two legendary cryoplants (8 lege prod 3s) with two beacons should suffice. Each would consume 200 promethium chunks a second (tough, but probably doable? ), 16 quantum procs a second (no problem) and 160 biter eggs a second (probably not that much of an issue as well).

Let's assume that I load the ship with eggs in Nauvis orbit, fly out, begin crafting beyond the Edge, turn around when the eggs are about half way depleted, stop at Aquilo, resuply the quantum processors, and fly to Nauvis to deliver the science.

If my numbers are correct, for this rate, and using this method, I would need 144 000 biter eggs (288 rocket launches) and 14 400 quantum processors (72 rocket launches) per trip, that would yield 432 000 science packs.

Are these numbers realistic? Am I missing something, are my estimations completely wrong in some regard (for example, is the 30 minute trip unrealistic for this number of science packs? Am I overestimating the portion of the flight when I'll be able to craft the science?) Are these numbers even realistic for one ship, or should I aim for more ships for this science rate?

Any insights much appreciated,
Michal

[Techjar]

Most of your math checks out, with the notable exception of the 200 prom chunks per second for each cryo plant. It's not really possible to get more than 120 per second, as it takes 8 legendary inserters to consume a whole turbo belt (60/s) of chunks, due to the lack of stacking. A cryo plant has 20 positions for inserters; 2 will be needed to pull science out at 144/s, 1 or 2 for eggs and quantums depending on how you handle them (the rates you calculated for those are way off, one bulk inserter is plenty capable of handling both), and that leaves 16 or 17 for prom chunks. So, the practical limit is 2 turbo belts of chunks.

What I ended up with in my design is 4 cryo plants making 576/s at peak, shipping 256k eggs (512 rocket launches) per trip and coming back with 768k science, and a round trip time of a bit under 40 minutes. Average science production per ship ends up being almost exactly 20k/m. You don't have to go with the same numbers of course, but several of your calculations do corroborate with my own, so you're on the right track. If you make the ship sufficiently fast you should be able to craft science for around 25 minutes before the eggs expire, so if anything you are underestimating that part.