You know Red Dwarf. We know Red Dwarf. We all know Red Dwarf – it's practically a member of the family. But how well do you know it? Did you know it's 30 years old today?

We've gathered 12 more things you might not have realised about the evergreen sci-fi comedy.

1. Alfred Molina was originally cast as Rimmer

Steve Granitz/WireImage

It's pretty much impossible to imagine anyone but Chris Barrie in the role now, but Molina was actually cast before him.

It's not clear whether Molina left or was recast, but reportedly the producers were unhappy with Molina's demands for changes to the character.

2. The TARDIS makes a cameo

ganymede.tv BBC

Blink and you'll miss it. This little Doctor Who easter egg can be seen in series five's 'Demons and Angels', with the TARDIS casually hanging out near Red Dwarf's closed bay doors as Starbug hurtles past.

3. Kryten was almost Swedish

Joel Anderson

Robert Llewellyn considered both Swedish and American accents before settling on Kryten's weirdly endearing Canadian twang.

4. Series four was re-jigged thanks to the Gulf War

'Meltdown', the episode featuring historical figures battling each other in wax droid form, was originally planned as the series four opener. But the events of the Gulf War at the time (the episode was originally scheduled to air in February 1991) made the episode a bit tonally unfortunate, and so it was swapped out for 'Camille'.

The original order would also have meant that 'Dimension Jump', aka the introduction of Ace Rimmer, was the last in the series. Which would have made a lot more sense as a finale.

5. Grant and Naylor were worried that the Cat might seem racist

Not racist in himself, but racist as a portrayal, and it was thanks to this concern that the script found its way to Craig Charles.

"This was in the mid '80s, when everything was so PC," Charles told The Guardian. "I said, 'I don't think the part of the Cat is racist at all, but any chance of me coming in to read for the part of Lister?'"

6. An alternative version could have starred Hugh Laurie and Alan Rickman

The LIFE Picture Collection / Ron Galella / WireImage Getty Images

Laurie, who was starring as the buffoonish Prince George in Blackadder the Third at the time, was apparently in the running for Lister early on.

At that stage the vision for the character was very different – Doug Naylor has said that they had in mind a performance similar to Christopher Lloyd's in Back to the Future: "His brain was fried, he was slightly deranged."

Meanwhile, reports vary on whether Rickman auditioned for Lister, Rimmer or both, but he was definitely in contention.

7. There's a reason why Lister's pregnancy never got resolved

Grant and Naylor were as sensitive to sexism as they were to racism, and this became a problem as they sat down to write series three. The series' first episode was meant to resolve the series two cliffhanger, in which Lister ends up pregnant with twins thanks to some parallel-universe shenanigans.

But they simply couldn't work out how to actually deal with the pregnancy without coming off as sexist, and so eventually they scrapped the episode altogether. The episode's planned synopsis runs as a humorously sped-up Star Wars-style scroll at the beginning of series three's actual first episode, 'Backwards'.

8. Ace Rimmer was created to give Chris Barrie a break from playing gits

Grant Naylor Productions

Between Arnold Rimmer and Gordon Brittas, you can imagine why Barrie might have been yearning to play somebody less insufferable for a week, and so Grant and Naylor threw him a bone. A glorious bone, with great catchphrases and perfect hair.

9. Kochanski was re-cast at the last minute

Grant Naylor Productions

We're not talking about Chloe Annett, who replaced Clare Grogan once Kochanski became a main character in series seven.

Alexandra Pigg was originally cast to play Kochanski in series one, but shooting was delayed by an electricians' strike and she was no longer available after the strike ended. Her loss was Grogan's gain.

10. Craig Charles was the only cast member not asked to be part of the US remake

Ouch. While Robert Llewelyn was the only cast member who said yes, both Chris Barrie and Danny John-Jules were offered the chance to reprise their roles in the 1992 American remake of Red Dwarf.

Then again, the pilot was godawful and the whole thing has gone down in history as one of the great US remake horror stories, so Charles didn't exactly miss out on much.

11. You've already seen the Red Dwarf movie

Sort of. In a condensed form. The long, long, long stalled Dwarf movie was so close to getting off the ground, so many times – it was officially announced in November of 2000, after the BBC had declined to produce series nine. A script was written, and rewritten, and rewritten again. Storyboards were drawn. A filming date was announced. And then... Nothing but false starts.

But several key ideas from the movie did finally find their way to the screen in 2012, becoming the storyline for series ten's finale 'The Beginning'. Specifically, the character of Hoguey the Roguey and Rimmer's arc into becoming a capable leader were both apparently taken from a draft script.

12. It's not your imagination – Lister and Kochanski's relationship really is that confusing

In series one, Lister just has a crush on Kochanski and they've never actually dated. But Grant and Naylor rightly decided that this made Lister seem a bit, y'know, obsessive and pathetic, considering how much time he spends talking about her.

So in later series – and in the brilliant tie-in novel Infinity Welcomes Careful Drivers – history gets rewritten, and Lister and Kochanski did have a brief relationship before she dumped him.

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