Sci-fi series of the recent past lead off this collection of TV programs to be released Tuesday on DVD.

• "Earth 2: The Complete Series" (Universal, 1994-95, not rated, $49.98, four double-sided discs). This sort of updated "Lost in Space" or "Robinson Crusoe On Mars" is less action-packed and more thoughtful than most modern sci-fi shows, but that works to its advantage. The pollution level of Earth is so bad 200 years down the road that people are forced to live in space stations, and their children are suffering. The plot kicks in when a scientist (Debrah Farentino) takes her sick son to another planet, hoping it will help him heal, but, of course, problems arise. Antonio Sabato Jr., Rebecca Gayheart and Clancy Brown are regulars; guests include Virginia Madsen, Kelli Williams, Tim Curry and Terry O'Quinn.

Extras: Full frame, 21 episodes, deleted/extended scenes, bloopers, one episode each of "Sliders" and "Cleopatra 2525," trailers, optional subtitles (English, Spanish), chapters.

• "Sliders: The Third Season" (Universal, 1996-97, not rated, $59.98, four double-sided discs). Quinn (Jerry O'Connell), Wade (Sabrina Lloyd), Arturo (John Rhys-Davies) and Rembrandt (Cleavant Derricks) continue to land in alternate universes while they try to get back home. There are some good episodes here, but the series starts to slip toward the end of the season as Arturo dies at the hand of an evil colonel (Roger Daltry). This also marks Wade's last season. Guests include Tommy Chong, Robert Englund and Corey Feldman.

Extras: Full frame, 25 episodes, bloopers, one episode each of "Earth 2" and "Cleopatra 2525," trailers, subtitle options (English, Spanish, French), chapters.

• "Cleopatra 2525: The Complete Series" (Universal, 2000-01, not rated, $49.98, three double-sided discs). This half-hour series (later expanded to an hour) is campy sci-fi in the manner of "Hercules" and "Xena," with futuristic Charlie's Angels trying to take Earth back from evil robots. The premise is amusing — Cleopatra is a stripper from 2001 who was cryogenically frozen after a breast-implant operation went awry and revived 500 years later. Produced by Sam Raimi (the "Spider-Man" movies) and starring Jennifer Sky as the title character and Gina Torres and Victoria Platt as her cohorts.

Extras: Full frame, 28 episodes, deleted scenes, making-of featurette, bloopers, one episode each of "Sliders" and "Earth 2," trailers, optional subtitles (English, Spanish), chapters.