This is "Outerscope" a puppet-serial aired in the 70s during the VEGETABLE SOUP program on PBS. I remember the later less-nightmarish version vividly, probably having buried the above version deep in my subconscious. It was about a group of ethnically diverse kids having adventures in a spaceship they built in an old junkyard or vacant lot, can't recall exactly. What a great
According to tvrage VEGETABLE SOUP aired weekdays from September 1975 to December 1978. Here's a blog post by Nick Sagan that covers some history of VEGETABLE SOUP, "Outerscope," and, "Outerscope 2." This page from IMDBpro provides some names of perpetrators...er, people that contributed to the VEGETABLE SOUP program.