Well, there had already been a well-known US television series called Space Patrol
in the 1950s, so naturally Roddenberry wouldn't have used that name. There was also a British marionette-based show
of that name in 1963-4 (not from Gerry Anderson, and more realistic than his marionette shows) -- not to mention the German miniseries Raumpatrouille
, meaning Space Patrol
, which debuted only nine days after Star Trek
premiered in the US!