SpaceX isn’t completely sure what caused its Falcon 9 rocket to explode on the launch pad on September 1 and destroy a $200 million Facebook satellite in the process, but it is pretty sure something was wonky with one of the rocket’s helium tanks.

In the first update in nearly three weeks, SpaceX announced Friday that evidence suggests “a large breach in the cryogenic helium system of the second stage liquid oxygen tank took place.”

In the days after the explosion, there were questions of whether a foreign object played a part in the crash. SpaceX CEO Elon Musk floated the possibility: “Particularly trying to understand the quieter bang sound a few seconds before the fireball goes off. May come from rocket or something else,” he posted to Twitter on September 9.

Still, the helium tank anomaly only explains part of the story — SpaceX isn’t sure what the exact cause of the incident was. During normal prelaunch testing on September 1, the Falcon 9 rocket carrying that AMOS-6 communications satellite when it blew up on its launchpad at the Kennedy Space Center at Cape Canaveral Air Force Station in Florida.

Musk, the Federal Aviation Administration, the Air Force Public Affairs Agency, and NASA have still not ruled out that something external to the rocket’s system could have caused the explosion.

The company, which is based in Hawthorne, California will continue to “build engines, tanks, and other systems as they are exonerated from the investigation.”

Also in the update: “SpaceX confirmed that the recent crash is in no way related to the explosion of their CRS-7 model in July 2015.”

Musk has called the September 1 crash the “most difficult and complex failure” in the company’s 14-year history.

While the investigation is ongoing, SpaceX also announced on Friday that it very well could be launching rockets again as soon as November. (For some perspective, it took nearly six months after the June 2015 explosion.) SpaceX made sure to point out the two explosions were not related: “We have exonerated any connection,” the company says.

“Our number one priority is to safely and reliably return to flight for our customers, and we will carefully investigate and address this issue,” COO Gwynne Shotwell told Inverse earlier this month. Shotwell said at the World Satellite Business Week Conference on September 16 that she hoped the company would be able to launch again in November.

On Tuesday, Musk will be in Guadalajara, Mexico at the International Astronautical Congress, where he’ll lay out his vision for colonizing Mars. Rumor is that Musk will introduce more about the so-called SpaceX BFR (Big Fucking/Falcon Rocket) rocket, which would launch from Earth the Mars Colonial Transporter, the name of the interplanetary spacecraft that would take humans to Mars.