pm EDT join Uncle Jim and his Treksperts as we take a look back at the Star Trek episode Assignment: Earth. Original air date :29 March, 1968. The 26th episode of the second season it was based on a story by Art Wallace and Gene Roddenberry. The episode features Robert Lansing as Gary Seven, Teri Garras Roberta Lincoln, and Barbara Babcock as Beta 5 Computer and Isis' cat. Let's See What's Out There.