if I mine and replace the output miniloader it doesnt happen again.
Seems like a bug in the miniloaders mod.
If I mine the Rocket Silo and place a Chest there, a Space Sience Pack flickers in there.
Video

Can be moved to Not a Bug.

I can not reproduce it in vanilla.
Okay... so it has to be a mod that causes this

I guess that too.
Tried to slow the game down at the moment it lauched the Rocket, but the Input Spot stays empty.

1. What did you do?

I tried to lauch Rockets and set the inserter to only insert the satelite when the output space science belt is empty.


2. What happened?

Output belt was not empty and in the Rocket Silo was still space Science. Inserter did not input the satelite , but the Rocket launched ...