When Steve Carell’s Mark Naird first arrives at the titular “Lunar Habitat” base, he is wearing a very bulky astronaut suit. He puts it back on later in the episode when he decides to go for a run near the base and is forced to wear the suit while doing so in order to maintain the false reality of the experiment being conducted by the episode’s astronauts. . An identical model of Mark’s costume is also worn in the same episode by Michael Hitchcock’s Jerome when he is forced to leave the habitat just to bring Mark back there.
Both times he wears it, the costume is humorously big on Carrell’s Space Force Commander, making him look even more out of place among the episode’s central astronauts. That said, beyond Carrell’s absurdity, observant viewers may also recognize the costume as that worn by “Stargate SG-1” characters. The Easter egg was noticed by Redditor u/crimsonxsecret, who wrote that they thought the costume looked “familiar” and posted a screenshot of Carrell’s Mark wearing it in “Space Force” on a photo of the same costume worn in a Season 5 episode of “Stargate SG-1” titled “Fail Safe”.
The fact that the costume is also the one that was worn in “Stargate SG-1” makes it all the funnier that Mark passes out in his after running, despite being repeatedly warned not to. do so by his colleagues.