You just answered your own question.
Goku can't breath in space, nobody can because is vacuum.
But Goku can survive the absence of atmosphere, and Frieza has no problems in outer space.
The amount of time is a mystery, because in Dragon Ball he went to the moon, but again
how is possible for someone to survive in space but drown under water or choke to death? (there are parts in Frieza's saga
when Frieza tries to wash him "As a monkey as Goku is" in a lake.)
In my own opinion, Goku never really tried if he can (and Toriyama simply forgot).
Some parts aren't clear if saiyans can survive in space, or simply the elite and siayan professional soldiers can and
the normal warriors can not.
In the end, nobody is stupid to tries to stop a bullet even if he has a bulletproof vest.
Except for the Dragon Ball part, in Dragon Ball Z he didn't need to get out in space.
