Shared Timeline
2141 sits on one fan spine with Doom 3, DOOM (2016), Eternal, and Dark Ages.
Official DOOM releases do not ship one neat calendar that cleanly merges every game. Fans still try. The Fandom Shared timeline page is one such attempt to put Doom 3, DOOM (2016), Eternal, and Dark Ages on one spine.
Mercury Rising uses that spine as a creative challenge. The campaign sits in 2141, before Doom 3 (2145) and DOOM (2016) (2149), and tries to weave parallel threads — Betruger and Hayden, multiple Mars footholds, Hell as gateway — without pretending the job is easy.
Condensed from Shared timeline on the Doom Fandom wiki. Fan orientation aid — not an official Bethesda chronology.