How to fire atomic bomb? (Space Age)

[Grumpy Old Gamer]

because space bar isnt working and google only returns 6 year old results for the base game, not space age, even if I specify space age, the AI is too dumb to know the difference between rocket launcher and rocket silo apparently

[Fel]

It is an ammunition for the rocket launcher, and it is fired with space.

EDIT: To answer your added portion about google, the wiki pages starts with "Atomic bombs are very expensive alternative ammunition for the rocket launcher, rocket turret and the spidertron.", so I am not sure where you went for the information.

[creamcone]

You should try the button combination that allows you to hit friendly objects. I have it set to C, but I think it's something like shift+space by default.

[Fel]

Rocket launcher is a weapon that fires at the cursor directly, same as the shotgun for example.
It is only weapons with auto-aim like the guns that need that alternate firing method to hit friendly targets at the cursor.

In fact, you usually want to make sure you switch to a gun-type weapon when not in combat, to make sure that you don't blow up your factory if you press space by mistake.
It is even more important with nukes since they have a wide area of effect.