Crash during game play

My first game. Cycle 880.

After loading, I extend gantries on middle rocket. Then I open access to oxylite, dupes fill solid oxidizer tank of middle rocket. Meanwhile I let middle rocket refuel.

Right rocket is ready for launch so I launch it, and after that I launch middle rocket too.

I finish vaccilation of Ellie near rockets. I also set up manufacturing of 5 batches of supercoolant.

Somewhere around 2/3 of cycle 880, the game crashes .

I don't use any mods, just clean game.

Output_log.txt is mentioning NullReferenceException for EquippableBalloon. I noticed that Ellie's balloon is hanging outside of vaccilator when she enters. Could it be that balloon that is crashing my game?

Output_log.txt and game save file are attached.

Povrly.sav