NEW YORK - Elon Musk said that SpaceX will land on Mars in the next two years, a lofty goal for his space exploration company.

Musk said on Twitter that “the first Starships to Mars will launch in 2 years when the next Earth-Mars transfer window opens.”

The mission will be “uncrewed” and is meant to “test the reliability of landing intact on Mars,” the CEO said.

“If those landings go well, then the first crewed flights to Mars will be in 4 years,” Musk added.

Musk’s SpaceX has always planned on going to Mars, but his new timeline might seem overly ambitious. SpaceX’s Polaris Dawn mission — the first-ever private spacewalk — was supposed to launch last month but has been plagued by delays, including a leak in the equipment. That mission, while dangerous, is nowhere near as risky as a Mars landing.

Musk claims that once SpaceX is able to land on Mars, the “flight rate will grow exponentially from there, with the goal of building a self-sustaining city in about 20 years.”

“Being multiplanetary will vastly increase the probable lifespan of consciousness, as we will no longer have all our eggs, literally and metabolically, on one plane,” he said.