Elon Musk issued yet another incredibly ambitious timeline.

During a Q&A at the SXSW festival on Sunday, Musk said SpaceX will be ready to fly its Mars rocket in 2019.

“We are building the first ship, or interplanetary ship, right now,” Musk said. “And we’ll probably be able to do short flights, short up and down flights, during the first half of next year.”

Musk previously said he hopes SpaceX’s BFR, or Big Falcon Rocket, will be able to land on Mars in 2022. The first missions will send cargo to the Red Planet. Eventually the BFR will host convoys of people and their belongings. The ultimate goal is to establish a Mars-based colony.

The BFR could also fly people from city to city on Earth in incredibly short time spans, touting that it would take 30 minutes to hop from New York to Shanghai.

Musk is known for underestimating how long his major endeavors will take. The company’s Falcon Heavy rocket, which enjoyed a historic inaugural launch last month, was promised a 2013 debut.

Musk admitted as much about his deadlines with a sarcastic comment from the SXSW stage.

“People have told me my timelines are ‘optimistic,'” he said. “I’m trying to ‘recalibrate.'”