SpaceX's December launch postponed until early January

SpaceX grounded its rockets for more than three months after September's Falcon 9 explosion, but they were supposed to end this year with a new launch on December 16th.

However, that launch has now been canceled, and SpaceX is looking at a new launch date in early January. On a blog posted on their website, SpaceX stated that they are completing the final steps necessary to safely return to flight.

We are finalizing the investigation into our September 1 anomaly and are working to complete the final steps necessary to safely and reliably return to flight, now in early January with the launch of Iridium-1. This allows for additional time to close-out vehicle preparations and complete extended testing to help ensure the highest possible level of mission assurance prior to launch.

Elon Musk said last month that the cause of the accident was "a combination of liquid helium, advanced carbon fiber composites, and solid oxygen," so it's not clear what they are investigating and if there might have been another problem with the Falcon 9.

In January, SpaceX should launch satellites for Iridium Communications, a company that provides communications services through a constellation of more than 60 satellites. Iridium previously stated that the launch would happen on December 16th, but now they are aiming towards early January.

The January launch should be just the first one that SpaceX will perform in the cooperation with Iridium since the company said they are, "replacing its existing constellation by sending 70 Iridium NEXT satellites into space on a SpaceX Falcon 9 rocket over seven different launches."