Scientists think they’ve figured out why a SpaceX Falcon 9 rocket blew up in a fiery explosion back during a static test on Sept. 1, destroying its payload along with it and throwing the entire program into chaos. Engineers have zeroed in on the rocket’s helium system, and the discovery could allow SpaceX to move forward after weeks of investigation into a complex problem that threatened to cause its lucrative commercial program grind to a halt.

The Falcon 9 rocket exploded on the launch pad in Cape Canaveral, Fla. on Sept. 1, and for a while engineers couldn’t figure out what caused the accident. The rocket was supposed to launch an Amos-6 satellite, which was destroyed in the accident. Engineers now think it was a breach in the helium system during the test that led to the failure. The system injects helium into the fuel tanks to keep them stable during the intense heat of the launch.

The Accident Investigation Team has spent weeks looking through 3,000 channels of data, examining debris from the rocket and reviewing the audio and video recordings from the event.

“At this stage of the investigation, preliminary review of the data and debris suggests that a large breach in the cryogenic helium system of the second stage liquid oxygen tank took place,” says a recent SpaceX statement. “[Updated 09/24: At this time, the cause of the potential breach remains unknown.] All plausible causes are being tracked in an extensive fault tree and carefully investigated. Through the fault tree and data review process, we have exonerated any connection with last year’s CRS-7 mishap.

“The teams have continued inspections of LC-40 and the surrounding facilities,” the statement continues. “While substantial areas of the pad systems were affected, the Falcon Support Building adjacent to the pad was unaffected, and per standard procedure was unoccupied at the time of the anomaly. The new liquid oxygen farm – e.g. the tanks and plumbing that hold our super-chilled liquid oxygen – was unaffected and remains in good working order. The RP-1 (kerosene) fuel farm was also largely unaffected. The pad’s control systems are also in relatively good condition.”