There are some things I just can't figure out.
Take for example Planet of the Apes. Spun off from the 1968 movie of the same name and its subsequent sequels, it was meant to anchor CBS' Friday night lineup in 1974, but, surprisingly, it lasted just one season.
The one constant to Apes in correlation to the movies was the presence of actor Roddy McDowell, who played a different character, Galen, as opposed to the roles he played in the movies. This time, there were two astronauts (Ron Harper & James Naughton) instead of just one in the original story. You had a killer theme, composed by the incomparable Lalo Schifrin, to set the mood. Just what went wrong?
How about the fact that Planet was airing directly opposite Sanford & Son over on NBC? You wonder how could a 3 year old sitcom get the better of a sci-fi series based on a popular series of movies. Well, back in those days, viewer habits were harder to break. It was Sanford, after all, that ultimately did in ABC's Brady Bunch, and would remain strong for another couple of years.
Jpwrites uploaded a sample open & close. You'll note that Mark Lenard (ex-Star Trek, Here Come The Brides) was in the cast of this series as well.
Story consultants Joe Ruby & Ken Spears are better known for their cartoon work. At the time, they were also working at DePatie-Freleng, which got the next crack at the Apes franchise with a Saturday morning cartoon that also failed to connect with the viewers the very next season, and it would mark the end of Ruby & Spears' association with DFE, as they returned home to Hanna-Barbera the year after that.