There was a nice attempt a bit over a decade ago to update some of the CGI to make it less dated and to retcon out some of the science and production failures. It also moved the show to 2099. https://www.youtube.com/watch?v=wPTZaSv9Bxk
There was no CGI used in Space: 1999, it's all practical model and optical effects. And as far as I can tell, it was all done on film, even though it was a TV show, so all of the effects shots could be rescanned for HD, or possibly even 4K.