Looking for the name of a film

[desertrat]

It would be back in the late 70s/ early 80s. It was about a window in a laboratory which could look into the future. When they arrived in the future there was a desolate landscape where mutants roamed the earth. They (2 men and 1 woman)? find an area where the last of the earths survivors are building a rocket to escape the planet as they were running out of supplies and the mutants kept attacking to take them. The survivors had android helpers who could work but were programmed not to harm humans (even the mutants). I've seen lots of sci-fi repeated over the years but never this one. Sorry not much to go on. 

[Dagman]

I think this may be it, did they get caught in a time loop in the end?http://www.movieactors.com/ScienceFiction/t25.htm

[desertrat]

That was the one. Thanks very much.

[Dagman]

No probs desertrat!