c. October 1986
A casting breakdown for the new series was sent out to agents, actors were put forward for consideration. Producers had their own wishlist and the shows Casting Director, Mary Jo Slater, reached out to the agents of those they had in mind directly. However, casting soon became a problem for one character specifically - Captain Rhon.
Rhon was - to all intents and purposes - a retread of Spock. A full Vulcan who had been in Starfleet for long enough that he had embraced some of humanities emotional quirks.
Producers wanted Yaphet Kotto for the role, but negotiations were proving harder than expected.
In contrast, the casting of the new First Officer, Commander Richard Kincaid, and Chief Medical Officer, Doctor Karen Hart, were the first two casting choices agreed, with Jenny Agutter signing on as Dr Hart whilst James Horan was recruited as the Kirk-like Commander Kincaid after studio chiefs determined that "(Billy) Campbell doesn't give the sense of someone you wanted to follow into battle ..." and Jonathan Frakes rejected the offer when his contract on Falcon Crest was extended.
Horan said in later interviews that he would become acutely aware during filming that he was the studios third choice for Kincaid.
Later, the character of Dr Hart was renamed (not an altogether unusual practice, in itself, but this rename happened the day filming was due to begin) and became Doctor Beverley Crusher. Similarly the intended relationships between Crusher and Chief Engineer Gage, and Kincaid and Cadet Helen Joyce were adjusted so that Kincaid became a mentor to Joyce rather than a lover, and the romantic relationship was between Kincaid and Crusher - allowing producers to broaden the age range in their casting of Chief Engineer Gage.
To that end, Gage became a grandfather figure to the crew and a contemporary of Captain Rhon, rather than a similar age to Kincaid and Crusher.
Roscoe Lee Brown was subsequently given the role as the final cast signing of the month, with three other regulars still to be cast and the negotiations with Yaphet Kotto still ongoing ...