SpaceX said that in preparation for Thursday's engine firing — a test carried out a few days before every launch — "there was an anomaly on the pad resulting in the loss of the vehicle and its payload." No additional details were provided. It wasn't clear whether the rocket caused the problem or something else on the pad.
It's the same kind of SpaceX rocket used to launch space station supplies for NASA.
Buildings several miles away shook from the blast, and multiple explosions continued for several minutes — one right after another. Dark smoke filled the overcast sky. A half-hour later, a black cloud hung low across the eastern horizon.
TV cameras showed smoke coming from the launch pad nearly four hours later. The rocket was still standing, although the top third or so was clearly bent over.
The explosion occurred at Launch Complex 40 at the Air Force station, right next door to Kennedy Space Center. Kennedy emergency staff were on standby following the explosion. At the same time, personnel were monitoring the air for any toxic fumes. The Air Force stressed there was no threat to public safety in the surrounding communities.
The initial blast sent next-door NASA employees rushing frantically outside to see what happened. At first, it sounded like lightning, but was followed by the sounds of more explosions, then more and more.
Facebook spokesman Chris Norton said his company was "disappointed by the loss, but remain committed to our mission of connecting people to the internet around the world." Founder Mark Zuckerberg was in Kenya on Thursday, discussing internet access with government officials.
SpaceX is one of two companies shipping supplies to the International Space Station for NASA. The company also is working on a crew capsule to ferry station U.S. astronauts; that first flight was supposed to come as early as next year.
The California-based company, led by billionaire Elon Musk, had been ramping up with frequent launches to make up for a backlog created by a launch accident in June 2015. In that mishap, a support strut evidently snapped in the upper stage. The problem was fixed.
SpaceX was leasing the pad from the Air Force for its Falcon launches. The company is also redoing a former shuttle pad at Kennedy for future manned flights for NASA. The first crewed flight was supposed to take place by the end of next year. Boeing also is working to develop a crew capsule for NASA.
Sen. Bill Nelson (D-Fla.), whose single space shuttle flight ended 10 days before the Challenger disaster in 1986, said the SpaceX accident "reminds us all that space flight is an inherently risky business."
"As we continue to push the frontiers of space, there will be both triumphs and setbacks. But at the end of the day, I'm confident that our commercial space industry will be very successful," Nelson said in a statement.