Space Hero was a title held by a Starfleet officer at Starfleet Command's Fleet Operations Center, Sol Sector.
In January 2155, S. Bakula held this title. The title and the officer's name was listed on a directory placard. (ENT: "Demons", United Earth directory)
It was unknown what the job of a "Space Hero" entailed, though it was likely an honorary title for an officer who has distinguished him or herself in space missions. The reference was an in-joke reference to Scott Bakula for his portrayal of "space hero" (and starship captain) Jonathan Archer on Star Trek: Enterprise.