I’ll start off with the first episode of Gerry & Sylvia Anderson’s Space: 1999.

Space: 1999: Season 1 Episode 1 - “Breakaway” (1975)
https://www.youtube.com/watch?v=Y6BXaGEuqxo - from the Shout! Factory YouTube channel (50 mins long - 1080p)

Synopsis:
Commander John Koenig, the new commander of Moonbase Alpha, leads the investigation of a mysterious disease at the station and uncovers evidence of a far greater looming disaster.

Directed by Lee H. Katzin.

Cast:
Martin Landau & Barbara Bain.

Trivia:
The show was originally conceived as a new season of Gerry & Sylvia Anderson’s UFO (1970). Consideration had been made to produce the series in Hollywood, but it was decided Britain would be more cost-effective.

IMDb link (for episode 1)
Wikipedia article (for entire series)

Some additional information about Shout! Factory:
A diversified multi-platform media company devoted to producing, uncovering, preserving and revitalizing the very best of pop culture, Shout! Factory’s entertainment offerings serve up first-run feature films, original, contemporary, and classic TV series, animation, live music and comedy specials. Shout! Factory owns and operates Shout! Studios, Scream Factory, Shout! Factory Kids, Mystery Science Theater 3000, Timeless Media Group and Shout! Factory TV.