United Earth Space Corps

The United Earth Space Corps was briefly mentioned in dialog in the opening cutscene to the Halo 2 level, Cairo Station. It is most likely another branch of the UNSC.

Trivia

 * It shares its acronym, UESC, with the United Earth Space Council, which is humanity's primary body of government in Marathon.
 * Likewise, it's mentioning is most likely a nod to Marathon.