Elon Musk points to faulty strut as likely cause of SpaceX rocket failure

Elon Musk has identified the possible reason why SpaceX's Falcon 9 rocket exploded mid-air on June 28th. And he says there's a valuable lesson to be learned.

Musk said a faulty steel strut may have caused the rocket to fail two minutes after take-off from Cape Canaveral. The strut was holding a helium bottle in the liquid oxygen tank of the rocket.

The helium bottle, kept in place by two-feet long struts, was supposed to pressurize the second stage of the rocket.

"It appears that one of those struts broke free during flight," said the SpaceX founder and chief executive.

The faulty strut was identified afer probers analyzed sound from different sensors through triangulation.

Musk said the incident should not have happened, as the strut was designed to handle far higher pressure than it had gone through. "It appeared to be incorrectly made."

Musk though said this was just an initial assessment, and further investigation would be made.

To prevent such issue from happening again, different struts will be made in the future and tests will be conducted of each strut.

The struts were manufactured by an outside supplier and, with the failure, Musk said they might switch to a different one. The vendor was not identified.

Musk added the company had to be more vigilant, saying a culture of complacency among employees after seven years of successful launches might be partly to blame.

"When you've only ever seen success you don't fear failure quite as much. ... Now everyone in the company appreciates how difficult it is to get rockets into orbit successfully, and we'll be stronger for it," he said.

The Falcon 9 rocket was carrying 4,000 pounds of supplies and equipment to the International Space Station when it broke apart some two minutes after launch. It was Falcon 9's first failure in 19 flights.

Although the Dragon capsule carrying the payload had continued to communicate with SpaceX engineers, it did not survive the explosion. That is because it did not have an abort mechanism.

"If software had initiated the parachute deployment then the Dragon would have survived," Musk said.

Apart from the supplies, the first of two docking mechanisms for commercial crew capsules to be set up in the ISS was lost.

Musk said the delay would not affect the timeline for commercial flights, set to start in 2017. But he admitted it might change schedules for other customers.

"The fundamental nature of rocketry is that it is a case where a passing grade is 100 percent, every time. ... It's not possible to issue a recall or a patch or anything like that. From the moment of liftoff, it's 100 percent or nothing," said Musk.

Despite the mishap, he said customers and government regulators remained supportive of SpaceX.

SpaceX is the first commercial launch company to send cargo to the ISS and has a contract with NASA to fly its astronauts to the space station.

Recently, the company was also allowed to compete for Air Force national security launches.