While SpaceX seems to be flying high to many outsiders, founder Elon Musk, in a companywide email sent the day after Thanksgiving, said the lack of progress toward the company’s Raptor engines puts SpaceX at a “genuine risk of bankruptcy.”

The letter, first reported by Space Explored and confirmed by CNBC, shows Musk’s frustration with the pace of Raptor engine production. (The Raptor is the engine that propels the Starship rocket.)

“The Raptor production crisis is much worse than it had seemed a few weeks ago,” he wrote. “As we have dug into the issues following the exiting of prior senior management, they have unfortunately turned out to be far more severe than was reported. There is no way to sugarcoat this. I was going to take this weekend off, as my first weekend off in a long time, but instead, I will be on the Raptor line all night and through the weekend.”

While Musk did not elaborate on “prior senior management,” Will Heltsley, former VP of propulsion, departed the company a week ago.

Musk said the bankruptcy risk was real “if we cannot achieve a Starship flight rate of at least once every two weeks next year.” He urged employees to return to work, despite the holiday weekend, saying, “Unless you have critical family matters or cannot physically return to Hawthorne, we will need all hands on deck to recover from what is, quite frankly, a disaster.”

SpaceX has a valuation of over $100 billion and employs 7,000 people. The company has launched a space tourism division and recently bested Jeff Bezos’s Blue Origin in a fight over a $2.9 billion NASA contract.