What does the idiom, he is a couch potato mean?

This idiom means, someone who spends little or no time exercising and a great deal of time watching television.

Explanation:

This idiom is supposed to have originated in the 1970's in America by a comic artist who drew two idle and inactive characters, who he called "Couch Potatoes."

the apollo program, also known as project apollo, was the third united states human spaceflight program carried out by the national aeronautics and space administration (nasa), which succeeded in landing the first humans on the moon from 1969 to 1972.