This takes place on December 24, 2278, in 2254, in July 2258, on December 19, 2260, on August 12, 2260 and in 1260.
Zathras' line "You're the one who was" was later one of the phrases featured in the opening sequence of Season Five.
The blue spacesuit was on board the Discovery in 2001: A Space Odyssey (1968) and in 2010: The Year We Make Contact (1984), but never used there.