Elon Musk, the founder of the rocket company SpaceX, has "aspirational" plans to launch people to Mars in 2024 and ultimately colonize the red planet.

To make the roughly six-month one-way journey, Musk and his engineers have dreamed up a 347-foot-tall launch system called the Big Falcon Rocket, or BFR. The spacecraft is designed to have two fully reusable stages: a 19-story booster and a 16-story spaceship, which would fly on top of the booster and into into space.

SpaceX employees are now building a prototype of the Big Falcon Spaceship at the Port of Los Angeles. Gwynne Shotwell, the company's president and COO, reportedly said Thursday that the spaceship may start small test-launches in late 2019.

Several official graphics of the spaceship's internal structure exist, but none show exactly how the ship would be equipped for Mars. So spaceflight-loving artist Nick Oberg created his own illustration of how the vehicle might look and function on the inside.

Oberg is a 29-year-old scientist at the University of Groningen in the Netherlands, where he's working toward a PhD in astrophysics. But he used some spare time to make what he calls an "imaginative" cutaway drawing of the BFR spaceship. It includes detailed sketches of hydroponic greenhouses, messy crew cabins, and even a person pooping on a zero-gravity toilet.

Oberg posted the cross-section illustration to Reddit in June, and it found its way onto Twitter — where Musk saw and liked the artwork.

"It was really out of impatience that I made this, because I can't wait to see what SpaceX is going to do with its mission," Oberg told Business Insider. "I was also excited to show other people what was happening, to make it seem more real. It's like a magic trick that's too good: It seems to go over people's heads. You can say, 'We are going to build a giant rocket ship,' but most people don't understand. I thought illustrating it would help."

Here are the key parts of Oberg's full drawing; the captions he gave each one are above the images, and additional explanations from him are below.