Interstellar director Christopher Nolan says he had a very particular vision for the robots

The director Christopher Nolan with the actor Matthew McConaughey on the set of Interstellar. Melinda Sue Gordon / Warner Bros

In his secrecy-shrouded sci-fi extravaganza Interstellar, the filmmaker Christopher Nolan does not only take audiences to outer space, but he also sends a couple of robots along for the ride – and they're not just on board to sweep the floors.

“The idea was that they’d been designed to put humans at ease during extended periods of time,” says Jonathan Nolan, the film’s co-writer and the director’s brother. “They’ve been programmed with a sense of humour and variable levels of honesty.”

A particularly acerbic robot named TARS (voiced by Bill Irwin) accompanies a team of astronauts led by Cooper (Matthew McConaughey) to find a new home for humans after an ecological disaster wrecks Earth.

The writer-director Christopher Nolan talks about his very particular vision of what he wanted the robots to be, their artificial intelligence and their importance to the film’s story. What did you hope to achieve with the robot characters?

I wanted a more realistic approach to what a robot would be. I didn’t even call them robots in the script. I referred to them as “articulated machines” because I wanted my crew and everybody to stop thinking of your standard idea of a robot. I wanted to have a machine in the film that was like a piece of gear – very tough, very resilient – that had been designed for whatever purpose best suited it.

How did you approach the design of TARS? He’s different from robots we’ve seen in films.

As we pushed the concept further, it became a very minimalist appearance that disguises very complex functionality. My idea was to remove any trace of anthropomorphism, so it doesn’t have a face. It doesn’t have arms and legs. It does have a voice and therefore a personality. The great Bill Irwin, who was puppeteering and voicing TARS, was able to give an inanimate, non-human object a personality.

For their shape, were you inspired by the monolith from 2001: A Space Odyssey?

I think, in its science-fiction context, inevitably your mind goes to that – and that's fine by me. Definitely, the spirit of 2001 hangs over the film. It was one of our aspirations to pay homage to that film. It also relates strongly to the architecture of Mies van der Rohe. As we homed in on the idea, I asked my designer [Nathan Crowley], who's a very big fan of modern architecture: "What if we designed a robot as if Mies van der Rohe designed a robot?" I think he really nailed it.

The robots help to drive the story forward. How important was that to you?

In my brother’s draft, he was really into robots and artificial intelligence. What I wound up focusing on was the issue of why you need human beings on this mission. The robots are presented as being physically superior to humans and able to lift heavier things and follow orders perfectly. We kept coming back to the idea of intuition, human adaptability and innovation. That’s driven by a survival instinct, which a robot can’t have. That makes the robots very important in the story. They take on their own incredible personalities, but they’re not human. They keep you thinking about what it means to be human.