SpaceX may resume its rocket launches in mid-December, CEO Elon Musk said Friday in an interview with CNBC. The company had put its planned flights on hold in September after one of its Falcon 9 rockets exploded on the launch pad.

“I think we've gotten to the bottom of the problem. Really surprising problem that's never been encountered before in the history of rocketry, and it basically involves a combination of liquid helium, advanced carbon fiber composites and solid oxygen,” Musk said. “It's never happened before in history ... so this was the toughest puzzle solved that we've ever had to solve.”

The explosion at the launch site in Cape Canaveral, Florida, on Sept. 1 took place when the Falcon 9 rocket was being refueled. The blast not only destroyed the payload — a $200 million AMOS-6 communications satellite manufactured by the Israeli company Spacecom, which Facebook planned to use to expand internet access in sub-Saharan Africa — it also caused significant damage to LC-40 — SpaceX’s primary launch site.

In an anomaly update released last week, SpaceX said it had narrowed down its investigation into the mishap to “one of the three composite overwrapped pressure vessels (COPVs) inside the LOXm [liquid oxygen] tank.”

The setback triggered concerns that SpaceX — a company heavily reliant on commercial satellite launches as a revenue source — may lose some of its clients. Speaking to the Wall Street Journal earlier this week, Rupert Pearce — CEO of the British satellite communications company Inmarsat, which is one of SpaceX’s customers, said his company was “looking at alternatives” for future launches.

“No doubt SpaceX will fix the problems, but if you’re a customer time is money,” Scott Pace, director of the Space Policy Institute at George Washington University and a former NASA administrator, told the New York Times in September. “This will get customers looking at alternatives. It may give competitors an opening and slow down SpaceX.”