[nesnah]

Why no “Space Cadet”?

[Alas Babylon!]

Well, since the Space Force will be under the Department of the Air Force, just as the Marine Corps is under the Department of the Navy; the academy for the Space Force will be the Air Force Academy, as Annapolis is for the Marines.

What do you call a Marine-bound midshipmen? A Leatherneck?

Then I assume you can call a Space Force-bound Air cadet a “Space Cadet”.