Thankfully, nobody was on board, so there are no reported injuries.

Although SpaceX has had other failures before, this one is notable for a couple of reasons: it’s the first time a Falcon 9 model has failed at launch (after 18 successful missions), and this time the rocket was carrying 4,000 pounds in cargo for the ISS.

It was also carrying some units of Microsoft’s HoloLens headset for ISS astronauts, where the augmented reality device was to help them complete certain tasks – such as performing equipment repairs with the help of an expert from the ground or instructional animations.

Had the launch and resupply mission gone to plan, the Falcon 9 rocket was to try to land itself on a drone ship in the Atlantic Ocean. It’s a complicated but crucial step in Space X’s goal of creating a reusable rocket, but so far both attempts have ended in failure.

SpaceX’s next reusable rocket trial is scheduled for August 9, though there’s currently no word on whether today’s failure will affect the upcoming flight’s timing.

Update: Here’s a full video of the failed launch. Skip to about 3:17 if you just want to get to the explosion.

CEO Elon Musk also tweeted out to explain the cause of the failure: an overpressurization of one of its oxygen tanks.