I have a few memories audio taping One of Our Planets is Missing. However, I do remember - vividly - when it was cancelled. I was crushed when I tuned in at 11:00 that Saturday morning and was greeted by this announcement:
"Star Trek will no longer be seen at this time. Stay tuned for...WESTWIND!"
The only satisfaction I had was that it was done after 13 episodes. But my show was gone. I didn't see it again until Nickelodeon reran TAS in the 80's.