Joel Kowsky/NASA Doug Loverro, who led NASA's human spaceflight division, has resigned after just six months on the job. Loverro quit a week before SpaceX is scheduled to launch its first passengers — two NASA astronauts — on a mission called Demo-2. In an email to NASA employees, Loverro referenced an unspecified "mistake" in risk-taking that led to his resignation. Ars Technica reported the mistake is "not related" to SpaceX's first crewed mission, but seemingly NASA's Artemis program to return humans to the moon's surface. An industry veteran told Business Insider that NASA's interim replacement "has the experience and judgement to shepherd human spaceflight through the coming weeks." Visit Business Insider's homepage for more stories. In a shock to the rocket-and-spaceship industry, NASA's human spaceflight chief abruptly resigned on Monday.