(FILES)This May 29, 2014 file photo shows Elon Musk as he unveils SpaceX's new seven-seat Dragon V2 spacecraft, in Hawthorne, California.
AFP PHOTO / Robyn BeckROBYN BECK/AFP/Getty Images

Every time SpaceX prepares to launch a rocket, Elon Musk plays the role of a wedding officiant, shooting an e-mail to the entire company, urging employees to step forward if anyone has reason to call off the flight-- speak now or forever hold your peace.

No one did that last month, and the launch proceeded as it has many times before. But on this flight, the Falcon 9 rocket, laden with food and supplies for the International Space Station, but no astronauts, exploded two minutes into the flight—the most catastrophic failure of the space company’s history.

The explosion appears to have been caused by one small piece of hardware, Musk said Monday—a steel strut, two feet long and one-inch at its thickest point—on a towering 224-foot tall piece of complicated machinery, powered at liftoff by nine engines.

The piece failed, causing helium to over pressurize an oxygen tank in the second stage, which led to the explosion, he said.

But Musk also pointed to another possible cause, saying that as the company continues to grow it may have lost some of the inherent paranoia that fueled SpaceX in its early days, when it was unclear whether the Internet tycoon and his loyal band of rocket scientists would ever be able to reliably launch rockets into space.

The explosion was the “first time we’ve had a failure in seven years,” Musk said. “To some degree I think the company as a whole maybe became a little complacent.”

Musk is a notoriously hard-charging executive, who operates on little sleep, fires off tweets in the middle of the night and famously keeps his desk where everyone can see the insane hours he dedicates to his companies, which includes Tesla Motors.

He is an obsessive who sweats every launch, and wants his employees to as well, which is why he fires off the e-mail before each flight, telling his employees that if they blow the whistle on a problem they would be protected even if they go over their managers’ heads.

“They should call me immediately on my cell phone or send me an email,” he said.

In the call with reporters to discuss the results of the preliminary analysis of the explosion, Musk was every bit the rocket scientist he has become, detailing how a faulty strut designed to withstand 10,000 pounds of force buckled under 2,000.

But he also sounded as if he were giving a business-school lecture on how a successful startup can retain its innovative culture and edge as it grows into a corporate behemoth.

SpaceX has had an extraordinary string of success—winning contracts from NASA to fly cargo and, eventually, astronauts to the space station. It has forced one of its main competitors, the United Launch Alliance, the joint venture between Lockheed Martin and Boeing, to reconfigure its business to compete with SpaceX.

But after becoming a darling of the space industry, and an emblem of the New Space movement with one successful flight after another, he said he fears the company’s winning streak has perhaps softened it.

When the company lost a string of rockets in its early days, there were only 500 people working at SpaceX, he said. Now it employs 4,000.

“The vast majority of the people at the company today have only ever seen success,” he said. “You don’t fear failure quite as much.”

(The company did lose an unmanned test rocket, which exploded over Texas last year.)

The 20th email asking people to come forward doesn’t “resonate with the same force,” as it did when the company was small and scrappy and feared going out of business. “There’s Elon being paranoid again,” he said of the reaction.

But now they know the driving power of failure—and fear—“and we’ll be the stronger for it,” he said.

He wouldn’t detail exactly when the company would fly again—saying only that it would be “no sooner than September.”

The Dragon capsule that was carrying the space station’s supplies survived the explosion, Musk said, and was communicating with the control center until shortly before it crashed into the ocean. If it had been outfitted with additional software, the parachutes would have deployed Musk said, and the capsule could have been saved.

The capsule the company is developing to ferry astronauts to the station is equipped with thrusters that would have flown the astronauts to safety, he said.

The faulty strut is manufactured by a supplier, not SpaceX, Musk said. He declined to name the supplier.

He reiterated that the investigation into the explosion being conducted by SpaceX in conjunction with the Federal Aviation Administration and the NASA was still ongoing and that it could turn up causes other than a failed strut.

But for now, he said, “there doesn’t seem to be any other explanation that makes sense.”

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