75ºF

Broken strut likely cause of failed Falcon 9 launch, SpaceX says

Falcon 9 carrying 5,000 pounds of cargo lost

SpaceX Falcon 9 rocket explodes shortly after launch from Cape Canaveral

CAPE CANAVERAL, Fla. – SpaceX CEO Elon Musk said a broken strut is the likely cause of last month's failed Falcon 9 launch.

[RAW: Explosion | Home video | PHOTOS:  SpaceX rocket explosion]

Before Monday, Musk had said very little about what caused the explosion of the Dragon capsule, which was on a resupply mission to the International Space Station. 

In the nearly hourlong tele-conference, where he took questions, Musk explained why it's taken nearly three weeks to figure out why the mission ended in disaster.

Musk said they spent thousands of hours examining data, matching it precisely to the moment of failure to figure out what went wrong.

In the end, Musk said it was likely a 2-foot-long, 1-inch-thick steel strut that brought Dragon down.

"The strut holding down one of the helium bottles appears to have snapped and as a result releasing a lot of helium into the  upper-stage oxygen tank and caused an overpressure event quite quickly," Musk said.

Musk said that it's SpaceX's first failure in seven years and that this was an important lesson.

The earliest SpaceX would try to launch again would be September, Musk said, and added that the failure didn't impact the commercial timeline of SpaceX getting American astronauts back into space in the next two years.