A SpaceX rocket undergoing pre-launch testing has catastrophically aborted, culminating in a gigantic explosion and the loss of the Spacecom Amos-6 satellite payload that was due to add Facebook’s Free Basics services to sub-Saharan Africa, as well as home broadband to parts of Europe and the Middle East. SpaceX said vaguely that an “anomaly” was to blame, and that there were no injuries. The Falcon-9 rocket’s anomaly “originated around the upper stage oxygen tanks and occurred during the propellant loading of the vehicle. We are continuing to review the data to identify the root cause,” it said. Facebook CEO Mark Zuckerberg noted that he was deeply disappointed by the explosion, but that Facebook “remains committed to our mission of connecting…