Muppets in Space was an early concept for a Muppet movie with a science fiction theme. In August 1998, Jerry Juhl told Muppet Central that in 1996, he and Kirk Thatcher had separately begun to develop movie ideas for the Muppet characters' next feature film. Thatcher's movie concept was about the Muppets as space travelers in a sort of wacky, Muppetized Star Wars universe. Juhl's script was about Gonzo and UFOs, which would later become the 1999 film Muppets from Space.
In a 1998 installment of Ask Henson.com, it was announced that Henson's next Muppet movie would be Muppets in Space! The original description for the film was that Kermit would be mistaken for the long lost leader of an alien civilization, and the Muppet gang would set out across the universe to save him. However, after the initial announcement, The Jim Henson Company decided to pursue Juhl's UFO concept for their next project instead. Kirk Thatcher's original screenplay, Muppets in Space was put aside for further development of the other project, initially titled "Star Gonzo." Columbia Pictures later decided to rename that project Muppets from Space.
As for Thatcher's unused Muppet space traveling film, it has yet to see the light of day. However, Jerry Juhl remarked, "I hope someday Kirk's movie gets made, because it is really funny."