I had that video in my feed at one point too. It wasn't bad. Short version. It was BRIEFLY brought up by NASA to bring Big Bird on a shuttle launch for a publicity stunt but the logistics were really difficult. Jim Henson studios had a policy with Sesame Street and the like that they didn't want to say "this is the puppeteer/actor for Big Bird". Any photo or video clip showing Big Bird's actor out of costume would have not been allowed. If you get by those hurtles, the Butterfly Effect may have led to an additional safety check preventing the Challenger disaster.