SpaceX has begun “serious development” of a new rocket that it plans to use to start colonizing Mars in the 2020s, company founder Elon Musk announced Sept. 29.

SpaceX has already ordered tooling and started erecting a facility to assemble the rocket, Musk said at the 68th International Astronautical Congress in Adelaide, Australia. The company has also been testing a new main engine, the Raptor.

The rocket will be fully reusable, with the booster returning to Earth about 20 minutes after launch. The company already has experience with such Earth landings, having completed 16 of them since 2015 with the booster for its existing Falcon 9 rocket.

The new rocket’s spaceship, which loosely resembles NASA’s former space shuttle, will be 48 meters (157 feet) long and will include the upper stage and the payload bay. Under the company-funded effort, SpaceX intends to start building the spaceship in about the second quarter of 2018 – or in about six to nine months — and launch it for the first time in about five years.

“We believe we can do this with the revenue we receive for launching satellites and for servicing the [International] Space Station,” Musk said.

SpaceX’s initial Mars goal is to land at least two cargo-carrying spaceships on the Red Planet in 2022, placing power, mining and life-support infrastructure there to support future flights. Four missions – two with crew, two with cargo – are to follow in 2024.

Ultimately, Musk wants to use the new rocket to create a city on Mars. An artist’s rendering of his concept is posted on Instagram.

Musk said the rocket could have several other uses. It could put satellites into orbit, transport crew and cargo to the space station, collect space debris and set up a lunar base.

“It’s 2017; we should have a lunar base by now,” Musk opined.

The rocket could also provide high-speed travel on Earth, carrying people to any point on the planet in less than an hour, Musk said. For example, a trip from New York to Shanghai would take 39 minutes.

SpaceX refers to the new rocket as “BFR” but did not clarify whether the acronym stands for “Big Falcon Rocket” or something else.