Lori Garver spearheaded the NASA program that paved the way for SpaceX to return human spaceflight to the United States after a decade-long wait. In her new book and in a recent interview she reflects on that success, the controversial cast of characters driving this new space race, and the cultural issues that permeate the aerospace industry at large.

And the former NASA deputy administrator, when asked by CNN Business how SpaceX’s future might play out, had a message for Elon Musk: Don’t trip on your ego, adding that the perils and politics of spaceflight are already potential risks to the company’s future.

In her new memoir, “Escaping Gravity,” Garver wrote about her feelings watching the success of NASA’s Commercial Crew Program, the initiative that brought about the first privately owned human spacecraft that culminated in SpaceX’s historic 2020 astronaut launch.

“SpaceX has a huge lead and is running faster than any of the competition, including all the big aerospace companies,” she wrote. “To me, that is both fantastic and scary at the same time.”

She adds that, “[e]scaping gravity is not a simple maneuver and in the coming years it will be impossible to beat it safely every time. The private sector will have to answer to its customers for missteps that lead to bad outcomes. Only time will tell if they will be given the opportunity to correct their errors and continue as NASA has been allowed to do in the past.”

In an interview with CNN Business, Garver also said she was disheartened to read recent reporting alleging toxicity within SpaceX’s corporate culture amid Musk’s erratic behavior on Twitter and a broader “bro culture,” as she put it, that permeates the aerospace industry.