BOCA CHICA VILLAGE, Texas — As Elon Musk, the founder and chief executive of SpaceX, says repeatedly, he created a rocket company because he wanted to colonize Mars. His fervent argument is that humanity must spread to a second planet as insurance for long-term survival.

“Which future do you want?” he asked near the start of a presentation on Saturday night at a launch site near the southern tip of Texas, during which he said the options were being “confined to Earth” or become a spacefaring species.

Mr. Musk said he hoped the audience agreed that humans should prepare for life elsewhere in the solar system as he delivered a progress report on Starship, a giant rocket that is the centerpiece of his ambitions.

[Read more from a Times interview with Elon Musk on SpaceX’s Starship.]

Standing before the prototype and an older rocket built early in the company’s history, he pledged that Starship would first take off to an altitude of 65,000 feet and then land, “in about one to two months.”