SpaceX announced today that it has completed its investigation of the September 1, 2016 incident that destroyed a Falcon 9 rocket and its payload and is ready to resume launches. The next launch, of 10 Iridium NEXT communications satellites, is scheduled for January 8, 2017 from the company’s west coast launch pad at Vandenberg Air Force Base, CA.

On September 1, a Falcon 9 rocket and its Amos-6 communications satellite payload were destroyed during a test two days before the planned launch. The rocket was being fueled for a routine static-fire test when something went awry, causing a fire and multiple explosions as shown in a video captured by USLaunchReport.com. In addition to losing the rocket and satellite, the launch pad, Space Launch Complex 40 (SLC-40) at Cape Canaveral Air Force Station (CCAFS), FL, was badly damaged.

SpaceX founder and CEO Elon Musk characterized it as the “most difficult and complex failure we have seen.” By October, the company determined that one of three composite overwrapped pressure vessels (COPVs) inside the rocket’s liquid oxygen (LOX) tank had failed. It said it had been able to recreate the failure “entirely through helium loading conditions” that “are mainly affected by the temperature and pressure of the helium being loaded.”

Today, the company said on its website the investigation was completed, although a single definitive cause was not identified. The conclusion is that one of the three COPVs failed “likely due to the accumulation of oxygen between the COPV liner and overwrap in a void or a buckle in a liner… The investigation team identified several credible causes … all of which involve accumulation of super chilled LOX or SOX [solid oxygen] in buckles under the overwrap.” Corrective actions “address all credible causes” and involve both short- and long-term actions. In the short-term, the COPV configuration will be changed to allow warmer helium to be loaded and helium loading operations will be returned to “a prior flight proven configuration…” In the long-term, the design of the COPVs will be changed “to prevent buckles altogether…”

The Falcon 9 has been grounded since September 1, delaying launches for commercial and government customers. At least one customer, Inmarsat, decided to switch to one of SpaceX’s competitors, Arianespace, to avoid further delays.

Most other customers have stayed with SpaceX and the upcoming launch is for Iridium, a communications satellite company that uses a constellation of 66 relatively small satellites to provide mobile communications to hand-held devices (essentially cell phones, but linked through satellites instead of terrestrial towers). Iridium is replenishing its constellation with a new generation of satellites, Iridium NEXT. The first 10 will be aboard the January 8 launch.

Via Twitter, Iridium said it was pleased with the announcement.

“Iridium is pleased with SpaceX’s announcement and targeted launch date of January 8 for the first #IridiumNEXT launch. #NEXTevolution https://t.co/zWdkK8FrLG — Iridium Corporate (@IridiumComm) January 2, 2017

These satellites are going into high inclination orbits, so must be launched from Vandenberg rather than the east coast so the flight path remains over the ocean instead of populated areas. SpaceX leases launch pads from the Air Force at Vandenberg (SLC-4E) and CCAFS (SLC-40), as well as NASA’s Launch Complex-39A (LC-39A) at Kennedy Space Center, FL, adjacent to CCAFS. It also has plans to build its own launch site near Brownsville, TX. The company has said little about when or if it will repair SLC-40. It can use LC-39A for east-coast launches of either Falcon 9 or the more capable Falcon Heavy now in development.