I am trying to remember the name of a TV show in the late 70s, perhaps early 80s, in which a group of two or three people (there was a man and a woman) travelled between different sections of a large spaceship. The spaceship carried people from Earth. I seem to remember that the various sections of the spaceship (which were semi-spherical) contained different environments, and different ethnicities from Earth. Hence the protagonists found themselves in an unknown situation each time they entered a new part of the ship.
Can anyone help me to find out the name and suggest where I could get a hold of episodes?