A space elevator sounds like science fiction, but scientists are still actively trying to make it a reality. Here’s what you need to know.

A space elevator is one of those ideas that sounds ultra crazy at first but when you learn more about it, it still sounds absolutely crazy but you can see the upsides. It’s exactly what it sounds like, a giant elevator that you get in down here on earth and step off of in freaking space. You’d need an anchor on earth which would serve as the loading station for the elevator car, a tether stretching into space for the car to travel along, and a counterweight way out in space to keep the tether taught.

Designs vary but it looks like the counterweight could have to be as far as 100,000 kilometers above the earth, more than a quarter the distance to the moon. Sounds nuts, but for some it’s not just a pie in the sky idea, it’s something they’re actively working towards.

In September of 2018 researchers from Shizuoka University in Japan launched an experiment to the International Space Station to test the practicality of one aspect of a space elevator. The experiment involves two tiny cubic satellites connected by ten meters of cable, with a small container moving along the cable with a motor. It’s a far cry from a full fledged space elevator, but the goal was to show that locomotion along a cable in space was possible.