Interstellar is one of my favorite movies of all time and the soundtrack to the movie, which is composed by Hans Zimmer, is simply jaw dropping. The strong organ presence in the soundtrack also really draw me to the music because I first learned to play the organ as a young child before later moving on to play piano and keyboards. So what's the story behind the Interstellar Organ? What organ was used and why did Hans Zimmer and Christopher Nolan (the director) end up choosing the organ as such a central instrument? Like everyone else today I did a bit of searching on the internet. Turns out the decision to use a pipe organ as a central instrument in the score was first brought up by Christopher Nolan and Hans Zimmer quickly jumped on the idea and the rest was history.
So why was specifically was the 1926 four-manual Harrison & Harrison organ in the Temple Church in London chosen? I couldn't find the answer to why that specific organ was chosen but I suspect it was for the amazing acoustics in the Temple church along with the relative notoriety of the Harrison & Harrison organ in the church. Keyboard Magazine published an interview that was done with Hans Zimmer and Hans had this to say about recording the organ in the Temple church for the movie soundtrack:
"Abbey Road Mobile set up a remote studio in one of the side rooms of the church. It wasn’t just the organ; we had the orchestra in there as well. So we had an enormous amount of microphones placed all throughout that church. But I think the main mics really were a few Neumanns, about 20 feet away. More were about 40 feet away from the main pipes."
"It was great being able to really use the space. Because an organ doesn’t exist outside its acoustic space, so you have to find the right space. The great thing about Temple Church is, it’s in the center of London but it’s completely isolated. There are just the law courts all around it, and it’s basically a pedestrian zone, so there’s no traffic noise."
The reason an organ in general was chosen was because of the scientific significance of the instrument (after all Interstellar was all about the science). A quote from an article in title "Why Interstellar's Organ Needs to Be So Loud" in the Atlantic I think says it all:
"As Zimmer recently told the Film Music Society, the organ was chosen for its significance to science: From the 17th century to the time of the telephone exchange, the pipe organ was known as the most complex man-made device ever invented. Its physical appearance reminded him of space ship afterburners. And the airiness of the sound slipping through pipes replicates the experience of suited astronauts, where every breath is precious (a usual preoccupation with sci-fi movies that is taken very literally in Zimmer’s music, which also features the exhalations of his human choir)."
I could go on and on about the details of how the soundtrack was made, but this short video does a great job of explaining it: