Sent by BillR, who says “I know Scott Hilburn likes puns. A lot, in fact. But I don’t get this one.”
I don’t get it either. The GoComics comments do give a possible explanation, though IMO a rather feeble one — and not much like a pun.
Sorry, I spaced out for a minute
Comics I Don't Understand 
Might it have something to do with “pressing space” putting them into space?
I think Mark must have it. “Space” button is like an eject button?
There are a number of science fiction stories in which evil opponents and/or criminals are executed by being “spaced”. The comic would have worked a little better if the picture had made it more obvious that the hand pressing the space bar belongs to the man standing behind the chair. As it is drawn, his (left!) arm seems impossibly long.
How did he type the other spaces then?
@ Power – Either using “cartoon logic”, or by using Alt+032 on the numeric pad (which that tablet keyboard probably doesn’t have).
The space bar on a keyboard isn’t generally labeled. For the keyboard on the tablet, the key to put spaces between letters isn’t labeled. The tablet must also contain an eject button that is labeled “Space.” Mr. helpful pressed the latter. I blame the school system for not properly teaching our kids the difference.
Kind of looks like there are two space bars. He must have hit the wrong one.
Not launch, LUNCH!
I think we’re getting on to a correct explanation. It requires a number of caveats or subclauses, but I think TedD has captured the key ones: spaces in the text were inserted using a mostly-standard spacebar on the keyboard, unlabelled. The ejection system button, with a label “SPACE”, is distinct, and is what the second astronaut reached over and pressed.
As a programmer, I know to add a confirmation screen to say “Are you sure??” Maybe I could get a job with NASA.
What was it that turned one of them into a dog?
Obligatory “Where do Astronauts Hang Out?” cartoon here.
Why were they hanging around inside the no-longer-in-service Space Shuttle … in pressure suits of a type not actually worn in the Space Shuttle?
Yes, that sort of thing does bug me.
“Not launch, LUNCH!”
Thanks, Gilligan! (That phrase is exactly what I was thinking when I saw the comic).
For those too old or not old enough to have watched this: https://www.imdb.com/title/tt0072499/?ref_=fn_al_tt_2
Today’s “Rhymes with Orange” could have been a great launch/lunch gag: