Freeware releaseOn June 25, 2004, Vivendi made Ground Control a free download (460MB) in order to promote the release of Ground Control II: Operation Exodus.
ReferencesOne of the main characters in Ground Control is a one Major Tom. This is probably a reference to David Bowie's Space Oddity:
This is Ground Control to Major Tom...
Server shutdownThe official Sierra game servers were shut down on 1st November 2008.
Information also contributed by Sciere