I’m very excited about the , mostly because it represents the first spacecraft being designed for general-use space travel that goes beyond Earth orbit, and, well, that’s exciting. Currently, SpaceX has built a rough steel full-size prototype called Starship Mark 1, which they plan to launch in a suborbital test flight soon, and an orbital flight soon after. It’s impressive as hell, but it’s important to remember it’s still basically just a shell with fuel tanks and engines. Here’s what else needs to happen.

The Mk1 prototype has three Raptor engines, with the final design to have six, and the massive Super Heavy rocket booster , arranged in rings, somewhat like the .

Starship is an : 160 feet tall, 30 feet in diameter, capable of hauling over 100 tons into orbit. That makes it the biggest rocket since the mighty Saturn V moon rocket, and the largest, most powerful rocket currently in development.

The Starship spacecraft itself will be the largest fully reusable spacecraft system ever, and, in plan at least, should prove to be a far more flexible system than the Space Shuttle, humanity’s only other reusable crewed spacecraft to date.

he can get the Mk1 to orbit quite quickly:

“This is going to sound totally nuts, but I think we want to try to reach orbit in less than six months.”

In case you’re wondering what SpaceX thinks a launch, orbital refueling, and booster recovery will look like from their Boca Chica, Texas spaceport, they’ve thoughtfully animated a little video showing everything:

Keeping very much on-brand for SpaceX CEO Elon Musk, the timetable from the first prototype to a full, crewed mission is surprisingly short. , with a passenger list of six to eight artists (and likely at least two qualified crew) for 2023.

In a webcast news conference tonight, Elon Musk revealed that the first paying customer to fly on…

That’s just a hair over three years away, and while SpaceX has been making impressive progress, there’s a hell of a lot to be done. A look inside the Mark 1 makes this very clear:

It’s mostly an empty shell, with engines, fuel tanks, and some control systems. This makes complete sense for a first prototype and is an absolutely necessary step that all spacecraft go through, but there’s a hell of a lot more that has to be done before Starship will be ready for a human crew.

Life support for a crew as large as the Starship is planned to be able to support is no joke, as Musk has suggested that the ship will be capable of carrying around 100 passengers.

There has never been a life support system that can accomodate that many people. The International Space Station generally supports six crew at a time, though a record of 13 people have been together at once (a few times, it seems), as you can see in this group photo here from STS-131 and Expedition 23 to the ISS in April of 2010:

So, the Starship will need a system capable of handling nearly 10 times that amount of crew. Oxygen, CO2 scrubbing, waste management and water reclamation, thermal management, the whole deal. For potential trips of multi-month durations, as Musk wants to send these things to Mars.

And that’s not even addressing the needs for heat shielding for re-entry, micrometeoroid protection, radiation protection, food storage and preparation, insulation, sleep systems, exercise systems, and so on.

While most of these problems are well-understood, we’re still talking about implementations at scales never attempted before, and it seems that every crewed spacecraft does some amount of re-invention to fit its own needs.

All I’m saying is that what we’re seeing here is very preliminary, but still very cool and extremely ambitious. I’m but I do have an idea about how SpaceX could get ahead if it really wanted to hit the 2023 artists-to-the-moon date.

SpaceX could cheat if it manages to develop a viable cargo-only version of the Starship, which would not need complex life support systems, and instead placed the crew in multiple Crew Dragon capsules, inside the cargo area of Starship.

Additional consumables like oxygen and water and other supplies could be added as well, along with a source of power for the capsules, but this could allow such a flight, as early as possible, without having to develop the necessary systems for Starship.

Of course, the crew wouldn’t be thrilled, as they’d be crammed into the relatively cramped capsules instead of the vast, airy Starship interior they’d been promised.

Crew Dragon has a roomy interior for an orbital ferry capsule, but it’s only intended for use for a few days at a time.

As you can see in that video tweeted from the ISS, once they get in the Crew Dragon there’s not that much room. It’s still way better than the Apollo capsules we went to the moon with decades ago, though, and it could certainly work.

Realistically, that’s the only way I can actually see Starship carrying crew by 2023—by carrying already-developed crew capsules as cargo. I’m hopefully confident that SpaceX will get there before too long, but I think we’re looking at the normal Musk pattern of overpromising here.

Still, none of that should detract from what an exciting idea this is. I hope they pull it off.