The mod would cause this load-order race condition after the pleagos mod added barreling_machines as a required dependency:

Failed to load mods: ...-out _ /prototypes/updates/generate-tech-card-cooling.lua: 14: attempt to index local ‘science _pack’ (a nil value)
stack traceback:
..=out /prototypes/updates/generate-tech-card-cooling.lua: 14: in main chunk
[C]: in function 'require' _ _Krastorio2-spaced-out _/data-updates.lua:43: in main chunk
Mods to be disabled:
» Krastorio2-spaced-out (1.6.18) B Reset mod settings

I fixed it by adding this in the info.json dependencies list for this mod:
"? barreling_machines"

EDIT: nevermind that actually does nothing because I did something and the mod wasn't even loading anymore :sob:

EDIT 2: [FIXED] i fixed it by moving the require("fixes.tech_cards") line from data.lua to a new data-updates.lua file in the mod root. maybe ill make a pull request but im lazy

Doing that didn't get mine working, but 0.5.1 loads while 0.6.1 gives the above error. I don't know that it's actually tied to Pelagos because I've tried disabling that planet and loading but still get the error.

DonkW's fix worked for me. Needed to create a data-updates.lua file in the root.