SpaceX’s Falcon 9 rocket, supposed to carry the AMOS-6 satellite into orbit this weekend with Facebook’s payload among others, exploded during a routine test.

Facebook, along with its partner Eutelsat, leased Ka-band capacity on the satellite which is operated by Spacecom. The capacity was earmarked to provide mobile broadband to remote parts of sub-Saharan Africa.

The launch was scheduled for early Saturday. SpaceX was conducting a so-called static fire test where the rocket’s engines are ignited while the vehicle is stationary, a standard procedure. The AMOS-6 satellite was loaded on the rocket at the time. No casualties were reported.

Elon Musk, the founder and CEO of SpaceX, tweeted yesterday: “Loss of Falcon vehicle today during propellant fill operation. Originated around upper stage oxygen tank. Cause still unknown. More soon.”

Mark Zuckerberg, Facebook CEO, was in Africa this week, presumably not by coincidence, and talked about the imminent launch, just shortly before the explosion.

The social media giant previously said it expected the additional coverage to come online in the second half of 2016. There was no statement about any changes to this schedule, although Zuckberberg posted on his social media site: “As I’m here in Africa, I’m deeply disappointed to hear that SpaceX’s launch failure destroyed our satellite that would have provided connectivity to many entrepreneurs and everyone across the continent.”

The Facebook chief noted that the company also had alternative technologies such as its Aquila drones or Project Aries, a terrestrial technology that aims for spectrum efficiency.