Jill Ireland, b. 1936 in London. I didn’t know she was English. She married David McCallum (Ilya in Man from U.N.C.L.E.) in 1957, they divorced in 1967, and the next year she married Charles Bronson! I didn’t know any of that, or that she and Bronson did a lot of movies together. Reagan gave her the Medal of Courage in 1988 because she suffered from breast cancer and had testified before Congress about medical costs. She died of breast cancer in 1990, and in 1991 Jill Clayburgh played her in a tv movie. (Mem Alpha, Wiki) 

The 50ish leader of the misguided planetary society (which in this case is an earth colony where spores make people into happy dopes). The dialogue played up the perfect physical health of the spore dopes, including the leader’s, of course; but the actor died of a heart attack the month after the episode was shown. Born in 1918 in Babylon, N.Y. He was the sheriff in To Kill a Mockingbird and a general in Fail-Safe (the Cold War nuclear showdown thriller that was overshadowed by Dr. Strangelove). (Wiki here.)

Earl Grant Titsworth again, a.k.a. Grant Woods, the stunt man who died in a motorcycle accident. Different episode than “Side,” though:

Random helmsman: Dick Scotter. Don’t think he had any lines, but good-looking:

Almost a regular:  Lieutenant DeSalle appeared in this one and in “Squire of Gothos” and “Catspaw.” That’s two from season one plus the first episode to be shot for season two. Don’t think he ever did much, was just on hand and maybe said, “Aye, Captain” or the like. Did what looks like a respectable amount of work on Gunsmoke, Bonanza, Mission: Impossible, My Favorite Martian, etc. “Barrier’s final credit was the 1969 film Angel in my Pocket with Andy Griffith and Lee Meriwether. After leaving the acting profession, he became a legal officer for the US Coast Guard. As of 2007, he is a substitute teacher in northern Oregon.”