Factorio Forums

Hi devs! Many players use belt weaving / braiding / layering to store prometheum asteroids, because it's the most efficient storage per tile. When you see players do this, do you feel that everything is working and balanced as intended? Or does this feel like an unfortunate workaround?

I'm the sort of player who prefers to play "as intended". For example, I stopped using LDS shuffle and asteroid upcycling long ago, as soon as you mentioned that they felt unintentionally overpowered. Would you kindly share your thoughts on prometheum storage?

Thanks!

*cough* spoilage *cough*

edit:
I typed this half as joke, half serious, because I don't expect such a drastic change to even be considered.
Meaning, making prometheum chunks spoilable in a medium amount of time.
But thinking about it more, if it spoiled to stone and/or uranium or even more different items (a bit like recycling on Fulgora), it would be super cool to make everything fully in space lategame. It could even have a long freshness for this to be an interesting feature.

Spoil into Uranium? Nah - Promethium should EXPLODE!

This is not a joke; I would love to see this Mechanic in the base game to discourage storage. Promethium Science already requires a dangerous-to-handle item (Biter Eggs); why not double-your-fun?

Quite drastic, but I like that, too.
I prefer my suggestion. But maybe we could process excess promethium into different things before it spoilsexplodes, similar to how asteroid reprocessing works.
A bit useless, since you could always just chuck it off the platform anyway.

in all seriousness, unless you also make sure that recycling to liberate biter eggs from module is also prevented or discouraged somehow, this won't really be sufficient.

at least, that is my understanding.

In a space of 16 tiles, a Cargo Bay can hold 20 Stacks times 50 Productivity Modules to a stack divided by Recycling factor 4 divided by 10 Biter Eggs per Promethium Science Pack Recipe times 10 Packs per Craft = 250 Science Packs. Overgrowth yumako/jellynut soil improves this a bit (20 Stacks * 100 Stack size * 10 Eggs per Soil / 4 Recycling / 10 Recipe * 10 Output) to 5000 Science Packs. Legendary Cargo Bays increase this to 12,500 / 16 Tiles = 781 Science Packs per tile.

The same Cargo Bay can hold only 20 Promethium Asteroid Chunks; not enough for even a single Craft (25 required) - or 50 with Legendary Quality, which yields 1.25 Science Packs per tile. Using weaved belt storage gets about 25 Asteroid Chunks per Tile (I am sure a denser design exists), enough for one craft of 10 Science Packs per tile.

I have tried a design which Recycles excess Promethium Asteroid Chunks during the return trip after running out of Biter Eggs using Quality Modules; this gives a nice bonus of Uncommon/Rare chunks for Quality science which I craft on-orbit using Quality Eggs (not recycling Overgrowth soil).

Factorio 2.1 gave a small buff to prometheum storage since we now have the ability to send cargo between space platforms. You can just send it to a space platform specifically made for crafting prometheum science.

It would be nice to have an official statement on prometheum storage just for closure.

sgoeg wrote: Tue Jul 21, 2026 6:51 pm Factorio 2.1 gave a small buff to prometheum storage since we now have the ability to send cargo between space platforms. You can just send it to a space platform specifically made for crafting prometheum science.

I hate to be the bad guy here, but that is not true now is it?
The actual crafting was usually done by just one or two Cryogenic Plants on the ship and a couple inserters? Putting that on another platform is hardly an improvement, if you think about how slow platform-to-platform logistics are for this purpose, if you can only send a couple chunks each time and it takes 25 for one craft of Promethium Science Packs.

The actual reason why people built giant buffers was so they don't have to do the opposite: Transport hundreds of eggs to the edge of space, because spoilage makes them a huge thread. The update has not changed anything about this incentive structure. Most people will still want to bring as many chunks home as they can, i.e. they weave belts. It's like before.
It seems to me, that transferring the Promethium chunks to another platform (presumably over Nauvis) has no noteworthy benefit and a bunch of downsides (especially throughput). Or am I missing something?