Musk said the company thinks it has "gotten to the bottom of the problem" that led to an explosion on a Florida launch pad in September that destroyed a Falcon 9 rocket and a communications satellite.
Musk said in an interview on CNBC that it "looks like" SpaceX will start launching again in mid-December. He described the cause of the explosion as something that has "never been encountered before in the history of rocketry."
Musk provided few specific details but said it "basically involves a combination of liquid helium, advanced carbon fiber composites and solid oxygen, oxygen so cold that it actually enters solid phase."
"This was the toughest puzzle to solve that we've ever had to solve," he said.
Hawthorne-based SpaceX said last week it had narrowed its investigation of the explosion to one of the composite-overwrapped pressure vessels that store helium to pressurize the rocket's second-stage liquid oxygen tank.
The company said Friday that it is continuing to make progress on the investigation.
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11:04 a.m.: This article was updated to include a comment from SpaceX.