Speaking of blockbuster space movies, has anybody out there not seen "Star Wars" yet? If so, don't worry--the folks at Lucasfilms and 20th Century-Fox are planning on giving you lots of chances to catch up with everybody else. Or, more to the point, they're going to provide lots of opportunity for those people who have only seen the space opera twice, and might like to see it three or four more times. Starting next month, we're in for over a year of "Star Wars" saturation, continuing through the release of "Revenge of the Jedi." First, videocassettes of the film will become available in June, for a three-month rental only. After that, they'll continue to be available for rent, but will also be sold on videocassettes and videodiscs. For those with no home video equipment, the film will then be rereleased to theaters for a while. After that--and pending the completion of current negotiations--it will be screened on cable TV on a "pay-per-view" basis. Next February, it will be released to the pay TV networks: Showtime, the Movie Channel and others, although so far not Home Box Office, the field's leader (which is reportedly balking at the high price tag). Then, the following year--we're talking about 1984 now--the film will make its way to commercial television, where CBS has already paid $25 million for the rights to infiltrate any last pockets of resistance. "Star Wars" has already made over $185 million; estimates at how much money it will bring in with this next round of exposure start at an additional $60 million and go upward from there.