Musk Calls SpaceX Probe Of Sept. 1 Rocket Explosion “Difficult And Complex”

An image from NASA shows a fire burning after a SpaceX Falcon 9 rocket exploded during routine fueling.
ENLARGE

An image from NASA shows a fire burning after a SpaceX Falcon 9 rocket exploded during routine fueling.


Photo:

European Pressphoto Agency

More than a week after a Space Exploration Technologies Corp. rocket blew up on a Florida launchpad during routine fueling, company founder Elon Musk suggested investigators haven’t identified the likely cause and requested assistance from the public by providing recordings of the event that could assist the probe.

A series of messages from Mr. Musk on Twitter on Friday, believed to be his first public statements about the accident since September 2, said the probe is “turning out to be the most difficult and complex failure we have ever had in 14 years.”

SpaceX, as the Southern California company is called, lost a Falcon 9 rocket and a commercial satellite loaded on board in a fireball at Cape Canaveral Air Force Station.

In another tweet Friday, Mr. Musk said that before flames engulfed the nearly 230-foot booster and a series of explosions damaged the pad, “engines were not on and there was no apparent heat source.”

Investigators, among other things, are delving into whether something malfunctioned on the rocket or if there was a problem with the ground-based fueling system. Experts are combing through huge amounts of information, including video images and data detailing the status of various Falcon 9 systems.

For the first time, Mr. Musk revealed the probe also is delving into what he described in another tweet as an unusual sound that can be heard just before the explosion.

“Particularly trying to understand the quieter bang sound a few seconds before the fireball goes off,” he wrote, adding it “may come from rocket or something else.”

A SpaceX spokesman declined to elaborate.

In response to questions after the tweets the spokesman said in an email: “We are continuing to thoroughly investigate last week’s loss of Falcon 9, with support from the FAA, NASA, the U.S. Air Force and industry experts. Our priority is to safely and reliably return to flight.”

The National Aeronautics and Space Administration, SpaceX’s biggest customer, has experts participating in the probe, but the agency has declined to comment on the progress of the probe.

The Air Force, which intends to use the Falcon 9 rocket for future military launches, also hasn’t commented on the status of the investigation. A spokeswoman for the Space & Missile Systems Center, the Air Force’s acquisition arm for launch services, didn’t have any immediate comment on the service’s role in the probe.

Write to Andy Pasztor at andy.pasztor@wsj.com