Almost a month has passed since the SpaceX Falcon 9 exploded, and no one was sure why. SpaceX, however, now has something to clarify about the explosion.

Let us take a look at what exactly happened.

On September 1st, a SpaceX Falcon 9 rocket exploded during a routine test, and the company still isn't sure why.

Two days before it was set to launch a satellite into orbit, the Falcon 9 was on the launch pad at NASA's Kennedy Space Center in Florida, preparing for what's known as a static fire test.

It's used to test a rocket's engines before launch to make sure everything's working properly. Normally, the rocket is strapped to the launch pad and fuelled, and the engines are fired for a few seconds.

The engines are then shut down, and the rocket is considered ready for launch.

This time, things weren't so simple. While the rocket was being fuelled for the test, it suddenly exploded, destroying the rocket and the $200 million satellite it carried.

The satellite called Amos-6 was owned by the Israeli company Spacecom, and Facebook was going to use it to bring Internet to regions of Africa.

When the fireball happened, the engines were shut off, and there seems to have been no other source of heat that would have ignited it. 

SpaceX has had a lot of recent successes with their booster landings, but they've experienced failure before.

Last June, a Falcon 9 exploded while carrying $110 million worth of cargo for NASA.

But with that accident, SpaceX was able to find the problem and fix it.

According to space.com, SpaceX in an official announcement said:

"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. 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. "

SpaceX CEO Elon Musk is calling this the most complicated disaster they've ever had, and he's even asked that anyone with pictures or videos of the explosion send them to SpaceX to help their investigation.