New York (CNN Business) The rocket and spacecraft at the center of Elon Musk's plan to colonize Mars could fly humans into orbit within one year — and cost billions of dollars less than he once predicted.

The SpaceX CEO said two years ago that it would cost between $2 billion and $10 billion to develop the hardware needed to trek millions of miles across deep space.

Musk said Saturday he now believes the cost will come in on the low end of that spectrum —"probably closer to a two or three [billion] than it is to 10," he told CNN Business' Rachel Crane during an interview at SpaceX's facilities in Boca Chica, Texas where Musk also unveiled the 160-foot-tall rocket prototype.

During an hour-long presentation on Saturday about the next steps, he also said the first passengers could board Starship and travel to orbit within a year.

The prototype, welded together in one month, indicates the activity that's taken place over the past 10 months as engineers ramped up development of Starship.

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