NASA's human spaceflight chief has resigned a week before SpaceX is supposed to launch its first astronauts for the agency

• Doug Loverro, who led NASA's human spaceflight division, has resigned after just six months on the job.
• Loverro quit just 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 rather NASA's controversial lunar exploration program, called Artemis.
• An industry veteran told Business Insider that NASA's interim replacement "has the experience and judgement to shepherd human spaceflight through the coming weeks."

In a shock to the rocket-and-spaceship industry, NASA's human spaceflight chief abruptly resigned on Monday.

The departure of Doug Loverro, a former member of the Department of Defense's Senior Executive Service, who took command of NASA's Human Exploration and Operations Mission Directorate on December 2, comes at a critical time for the US space agency.

On May 27, SpaceX is scheduled to launch its first passengers — NASA astronauts Bob Behnken and Doug Hurley — on a roughly three-month mission to space called Demo-2. The test flight is designed to show NASA that SpaceX, the rocket company Elon Musk founded 18 years ago, can safely launch people into orbit aboard a Crew Dragon spaceship, dock with the International Space Station, and return the crew to Earth.

NASA Administrator Jim Bridenstine previously described Loverro as "a respected strategic leader" who was to help execute the space agency's Commercial Crew Program, which Demo-2 is a part of. He also managed an ambitious and controversial plan to land humans back on the moon in 2024, called Artemis.

"He is known for his strong, bipartisan work and his experience with large programs will be of great benefit to NASA at this critical time in our final development of human spaceflight systems for both Commercial Crew and Artemis," Bridenstine said in an October 16 announcement of Loverro's hiring.

SpaceRef published an all-hands email that Loverro sent to NASA's human exploration division on Tuesday, the day after he officially resigned.

"The risks we take, whether technical, political, or personal, all have potential consequences if we judge them incorrectly. I took such a risk earlier in the year because I judged it necessary to fulfill our mission," Loverro wrote mid-way through his email. "Now, over the balance of time, it is clear that I made a mistake in that choice for which I alone must bear the consequences. And therefore, it is with a very, very heavy heart that I write to you today to let you know that I have resigned from NASA effective May 18th, 2020."

He told his colleagues that he left "because of my personal actions, not anything we have accomplished together."

A former astronaut will carry the torch through Demo-2

Loverro did not specify the nature of his perceived mistake.

However, Eric Berger, the senior space editor at Ars Technica, reported that the apparent folly was "not related to Crew Dragon," which is the spaceship that's about to launch Behnken and Hurley. Rather, Berger said the mistake "seems to stem from" Loverro's selection of SpaceX, Blue Origin, and Dynetics for nearly $1 billion worth of lunar lander contracts for the Artemis program. (The agency is struggling for resources to execute the program.)

A spokesperson at NASA declined to comment on the matter.

Loverro's departure comes less than a year after the July demotion of Bill Gerstenmaier, who led NASA's human spaceflight division for nearly 15 years. Ken Bowersox, a former astronaut and the deputy associate administrator for NASA's human spaceflight division, is filling in for Loverro's role as he did following Gerstenmaier's departure.

Wayne Hale, an aerospace engineering consultant and retired NASA space shuttle program manager and flight director, says he was "surprised as anyone" to learn of Loverro's apparent ouster. But he did not express doubt about the agency's current position with Bowersox at the helm.

"I have great confidence in Ken Bowersox," Hale told Business Insider in a message, adding that he "has the experience and judgment to shepherd human spaceflight through the coming weeks."