Elon Musk wants to send you to Mars — cheaply — and tonight plans to unveil the latest design of SpaceX's forthcoming rocket system designed to do just that.

The launch system, which is known as Starship, may stand about 390 feet tall, stretch 30 feet in diameter, and have enough space and fuel to carry 100 people and 150 tons of cargo to the red planet at a time. Musk also envisions a later version that's several times larger.

"Starship will allow us to inhabit other worlds," Musk tweeted on Friday, later adding: "To make life as we know it multiplanetary."

Those facts and figures about Starship may be outdated, though, since they're based on Musk's presentation about the system from more than a year ago.

Read more: SpaceX is eyeing these 9 places on Mars for landing its first Starship rocket missions

But starting at 9:15 p.m. ET on Saturday, Musk should present the newest Starship plans and details from SpaceX's rocket development and launch site in South Texas. He plans to address a small group of employees, journalists, local supporters, and residents of a nearby hamlet called Boca Chica Village.

Though SpaceX is hosting the roughly hour-long talk at a remote coastal area about 20 miles east of Brownsville, the closest major city, the company is broadcasting the event live online. You can watch Musk's presentation using the YouTube player below.

Read more: Elon Musk is about to unveil SpaceX's new Mars spaceship prototype in Texas. Here's what we know so far.

The backdrop for the event will be Starship Mark 1 (Mk 1): a towering stainless-steel prototype of the system that the company finished building on Friday. The ship follows the construction and several launches of a 60-foot-tall prototype, called Starhopper.

Starship Mk 1 weighs about 200 tons (without fuel), stand about 164 feet tall, and it will be powered by three car-sized Raptor rocket engines. Some are even calling the test ship the largest upper-stage rocket ever made — though it technically needs a giant booster, called Super Heavy, to meet that distinction.

Regardless, Mk 1 may launch more than 12 miles high as soon as October or November, according to Musk,

Musk has been tweeting out new details about Starship weeks ahead of the presentation tonight, including major changes to the vehicle's steerable canards or wings. Kimi Talvitie — a SpaceX enthusiast, software engineer, and artist — pooled those details into a 3D model that shows how the spaceship might use those devices to safely guide itself back to Earth, or some day land on and help populate planet Mars.

Musk will likely have more to say than that about the system, though, and the company's vision for using it.

So tune in to the YouTube livestream starting around 8 p.m. ET.

This story has been updated. It was originally published at 11:15 a.m. ET on September 28, 2019.