Just made a new account just to immortalize this head-canon, and I'll probably be proven wrong soon, but I have a new head canon regarding S.W.O.R.D.
After S.H.I.E.L.D. was reformed and reintroduced as a government agency in 2017 under Jeffrey Mace's leadership, S.W.O.R.D was introduced at the same time as a subagency under S.H.I.E.L.D., akin to the comics, with the main and express purpose of preventing another Battle of New York scenario and defending Earth against such things, and also as acting as a NASA reverse-engineering alien tech and for getting humans out to the stars. It's essentially akin to how the DOD has the NSA under it's direct command.
Edit: Yo-Yo references "SPEAR", which didn't exist, but said that SPEAR was a space division, leading more to that idea.
Edit 2: SWORD helped out with making Zephyr One space capable. Just a headcanon.