SpaceX's Falcon 9 rocket, meant to launch a satellite this weekend, exploded on the launch pad at Cape Canaveral, Florida around 9:07AM ET. The explosion occurred during the preparation for the static fire test of the rocket's engines, and no one was injured, according to SpaceX. The blast reportedly shook buildings "several miles away."

The company confirmed to The Verge the loss of the Falcon 9 an hour later. Initially SpaceX said the explosion was caused by an "an anomaly on the pad," which resulted in the vehicle's loss. Later, the company clarified that the problem originated around the oxygen tank of the Falcon 9's upper stage — the top portion of the vehicle. Something happened while propellant was being loaded into the Falcon 9, but it's still unclear if the rocket is to blame or if it was a problem with the launch pad equipment.

Video of the event confirms the explosion started toward the top of the vehicle.

SpaceX was getting the Falcon 9 ready to launch the Amos 6 satellite, a communications probe for the Israeli satellite operator Spacecom. The satellite was meant to provide internet to parts of sub-Saharan Africa as part of Facebook's Internet.org initiative, and the social media company partnered with Eutelsat to lease the satellite from Spacecom. In 2012, Spacecom purchased Amos 6 from satellite manufacturer Israel Aerospace Industries, in a deal worth an estimated $195 million.

"We are disappointed by the loss."

"We are disappointed by the loss," a Facebook representative said when reached for comment by The Verge, "but remain committed to our mission of connecting people to the Internet around the world."

The mission was scheduled for 3AM ET Saturday. Before all launches, SpaceX conducts a static fire test, in which the rocket's engines are turned on while the vehicle is constrained. It's a routine procedure the company has done many times before. This time around, it seems that something caused an explosion on the launch pad just before that test got underway.

The 45th Space Wing, the US Air Force unit that commands the Cape Canaveral Air Force Station (CCAFS), is responding to the explosion. "There are no known casualties. There's no threat to public safety, and our emergency management teams are on site responding," Bryan Purtell, a representative for the 45th Space Wing, told The Verge. An additional statement from the unit asked the public to avoid the area: "CCAFS Emergency Management is providing the initial on-scene response. Roadblocks will be set up in and around CCAFS, so we ask that you avoid the entrance to the Air Force Station until further notice. We will provide updates as they become available."

Photo of the explosion at the SpaceX launch site at Cape Canaveral this morning. pic.twitter.com/RWUKLGq6v4 — Mike Gruss (@Gruss_SN) September 1, 2016

This explosion comes at a pivotal time for SpaceX. The company has been in recovery mode after a major setback last year, when one of its Falcon 9 rockets exploded during launch in June. After that, SpaceX took a six-month hiatus but returned to spaceflight in December with the successful launch of the Orbcomm-2 satellite. The company even landed the Falcon 9 rocket for the first time afterward — a feat it had been trying to perfect for the past year. Since then, SpaceX has experienced a string of successes with its rocket launches and landings.

And the company has big plans for the future. SpaceX is working toward the first launch of its Falcon Heavy rocket later this year, a giant vehicle that will provide even more thrust than the Falcon 9. And in late 2017, the company plans to launch NASA astronauts to the International Space Station for the first time, part of the space agency's Commercial Crew Program. On top of all that, SpaceX recently announced plans to send the first private spacecraft to Mars in 2018. But depending on what caused today's explosion, SpaceX's plans could run into delays.

Update 12:18 PM ET: Updated with comment from Facebook.

Update 1:23PM ET: The article was updated to include a new statement from SpaceX about what caused the explosion.

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