Elon Musk says he splits his time between Tesla and SpaceX depending on the 'crisis of the moment'

• Elon Musk is CEO of four companies, but says he splits most of his time between Tesla and SpaceX.
• Musk said at The Wall Street Journal conference that his time is typically spent solving the "crisis of the moment."

Elon Musk said he's constantly juggling his work at Tesla and SpaceX.

As the richest man in the world and the CEO of multiple companies, including Tesla and SpaceX, Musk said he tries to split his time evenly between the two companies, but it depends on "the kind of crisis of the moment."

"I triage the tasks and try to do the things that are most useful or where I'm most needed – it varies from one week to the next," he said on Monday at The Wall Street Journal's CEO Council Summit.

Musk said that he works seven days a week and some "pretty crazy hours." Historically, the CEO has said he has worked up to 20 hours a day. In 2018, Musk said on the podcast Recode Decode that his work at Tesla and SpaceX sometimes drove him to sleep on his factory's floor and work over 120 hours a week. Though, the CEO said later that year that he scaled back to 80 to 90-hour work weeks.

"Nobody ever changed the world on 40 hours a week," Musk said at the time.

Most recently, Musk has had to focus his attention on a "crisis" at SpaceX. During The Wall Street Journal conference, Musk said that SpaceX's Starship spaceship has consumed a large portion of his time.

In November, Musk said that SpaceX planned to launch Starship into orbit by January or February. On Monday, Musk expressed doubt as to whether Starship would be able to launch in 2022 at all.

"This absorbs more of my mental energy than probably any other single thing," he said. "It is so preposterously difficult, that there are times where I wonder whether we can actually do this."

Musk expressed concern over SpaceX's progress with the engines for the Starship rocket last month. Over Thanksgiving weekend, Musk sent a company-wide email saying SpaceX faces a "risk of bankruptcy" if it cannot achieve a flight rate for its Starship rocket of at least once every two weeks in 2022. As a result, Musk and SpaceX employees worked over the holiday weekend to fix the engine-production issue.

Tesla and SpaceX are not the only companies in which Musk is heavily involved. The billionaire is also the CEO of Neuralink, a company that is developing implantable brain chips, and The Boring Company, a tunnel-construction company.

Much like Tesla and SpaceX, Musk's other two companies also have lofty goals. Musk has said that he plans for Neuralink to begin implanting chips in human brains within the next year. Similarly, The Boring Company is working on multiple hyperloop projects in Las Vegas and California.