NBC, thinking they had a potential winner, had commissioned a new set of Space Ghost cartoons from Hanna-Barbera as part of the 1981 Space Stars series. I guess the thinking was they had gotten some positive numbers from combining reruns of the original series with Frankenstein, Jr. a few years earlier, but waited too long to pull the trigger. When they did, Space Stars was part of an action-packed lineup that also included Spider-Man & His Amazing Friends & Kid Super Power Hour with Shazam!. Of the three adventure shows, only Spidey was retained the following season. Go figure.
Here, then, is an offering from 1981, as Space Ghost (Gary Owens) meets his doppleganger from a parallel universe, Space Spectre. The mistake in the casting was not having Owens double up and voice Spectre as well as Space Ghost. Instead, Spectre's voice is that of John Stephenson, who also voices a galactic patrolman in pursuit of the villain. Minute mistakes like that, apparently, proved to be costly.......
Edit: 7/14/14: The video has been deleted. The only other copy available has a Spanish overdub, which we can't use.
As noted, Jan & Jace's confusion would've worked better had Owens voiced Space Spectre.