Divine Angel said:

btm said:

On the subject of space ships in sf, why do so many characters in sf films smoke cigarettes on spaceships — an environment with critically limited oxygen? In a lot of films about submariners, the characters smoke, too, even though oxygen is also in extremely limited supply. The Hunt for Red October is a prime example.

How else would you the character is cool, or stressed, or just had sex?

Or the passage of time, thinking when they have a long ash