An unmanned SpaceX rocket on a cargo mission to the International Space Station exploded shortly after liftoff on Sunday in Florida.
The Falcon 9 rocket from entrepreneur Elon Musk's space firm exploded shortly after it took off at 10:22 a.m. in Cape Canaveral.
NASA Launch Commentator George Diller said on the space agency's live blog that they had confirmed the rocket had broken up, but it's not clear yet exactly what went wrong.
Musk tweeted that SpaceX is working to figure out what went wrong.
He later tweeted that the issue was with the oxygen tank.
SpaceX and NASA officials said at a press conference they are still investigating.
The rocket was trying to bring supplies and a docking port to the astronauts at the space station, the Associated Press reported.
The ISS later tweeted out pictures of some of the materials lost.
People on Twitter said the explosion was heard in Daytona Beach and caused windows to shake.
Astronaut Scott Kelly, who is currently in space, said he watched the failed launch from the station.
Other NASA astronauts shared their sadness at the failed launch.
The failed launch is a big setback for NASA and is the second consecutive cargo shipment to be destroyed.
Orbital space company's Antares rocket blew up last October on its way to the space station, and a Russian supply ship burned up entering the atmosphere last spring.
SpaceX has previously launched cargo ships to the space station seven times successfully, the AP reported.
In April, the company also suffered a failure after it attempted to land a rocket on a barge.
But NASA and SpaceX executives struck an optimistic tone in an afternoon press conference, characterizing the event as a "hiccup," not a disaster.
"We've always assumed we would lose a space vehicle every so often. Space flight is very hard," Michael Suffredini, NASA's ISS program manager said.
They said SpaceX followed all safety procedures and there is no risk to anyone on Earth or the astronauts in the space station.
While they were sure not to downplay the significance of the lost rocket, Suffredini said that NASA and all the scientists would learn from the experience and be better for it.
"It's not whether you stumble or fall, but it's what you do after," he said.
Stephanie McNeal is a social news editor for BuzzFeed News and is based in New York.
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