Here you go.....
A previous generation of Skynet's, (I cannot remember if it was the previous generation, or the one before that, were slated to be launched by the Space Shuttle, starting in 1986. Payload Specialists had been picked for these four launches, one from the British Armies Royal Signals Corps, one from the RAF, one from the Navy and one for the descendent manufacturer of the new ones, Marconi.
Then the Challenger accident happened, So Ariane 4's lanuched them. Prior to this, US launchers had been used for previous Skynet's, presumably the Shuttle was to be an extension of that arrangement, since the late 1960's.