no tech for oxygen ksp rss ro rp0

[Flying dutchman]

hello,

 

i'm stuck in my ro career because i can't add oxygen to the servicemodule tank in the ui menu. it just says: no tech for oxygen. but when i go in to sandbox it is available for the same tank.

problem is there is no way to research or to unlock this to my knowledge. 

 

please help :$

[Flibble]

You need to unlock Crew Survivability in the tech tree. That should then unlock oxygen for service modules.