
I've put down a requester chest and an inserter for the three main ingedients for the rocket itself (20x Low density structure, 20x Rocket fuel, 20x Rocket control unit) copy-pasted with Shift+click from the rocket silo.
I added the satellite (x5) requirement on the requester chest later (after the rocket was finished), but it wouldn't insert the satellite. Turns out the inserter is stuck trying to insert more Rocket fuel into the silo.
I know that assemblers were tweaked to allow more than 1 stack of an item in the input slot, but it doesn't work properly for rocket silos, as 24x Rocket fuel is already in the silo (stack limit is 10), but the inserter is trying to insert more and is stuck. (I've researched Inserter item stack size bonus 4, the highest one in vanilla).
I've attached the save. You can ignore the YARM (resource monitor) mod, it's the same behaviour without the mod.
tl;dr inserter trying to insert more items than the rocket silo is capable of holding
EDIT: removing the inserter and placing a new one does work (and that's what I did to continue this map), but it doesn't address the problems mentioned above.