I have in 1966 23 set personel. I uppgraded their building and constrained by how many I could hire each year. And I also got the red symbol in left corner.
SwedeWolf
I was called Lill Sputnik (Little sputnik) as a baby in 58-59
If you are resuming a game saved on a previous version of the game, you'll still find that you cannot hire more individuals. That's because the game determines the hiring batches during initialization and stores that information as part of the saving process.
To sum it up: start a new game using 0.7.3 and you'll be able to hire more people for every department.
Cheers,
Ignacio Liverotti
Lead Developer of Buzz Aldrin's Space Program Manager
Polar Motion