A private, unmanned spacecraft under NASA suffered a catastrophic failure when it exploded shortly after takeoff from Virginia on Tuesday evening. No one was injured.

The Antares rocket, which is operated by Orbital Sciences, went up in flames just six seconds after launch from NASA's Wallops Flight Facility. The rocket was carrying a Cygnus spacecraft that was supposed to deliver supplies to the International Space Station on a routine mission. One-third of that cargo was made up of science experiments.

The exact cause of the explosion is still unknown. However, the Orbital Sciences team wasn't tracking any issues prior to launch. The private space company says it will conduct a thorough investigation starting immediately, including of the debris that was scattered around the area during the explosion.

"It is far too early to know the details of what happened,” said Frank Culbertson, Orbital’s executive vice president in a statement. “As we begin to gather information, our primary concern lies with the ongoing safety and security of those involved in our response and recovery operations."

NASA officials said the facility and launchpad suffered damage, but they don't yet know the extent of it.

This launch was part of Orbital Sciences' $1.9 billion contract with NASA to deliver cargo to the ISS through 2016. NASA officials said this type of event is built into the contract and the launch will be made up at a later date. NASA also contracts with SpaceX for similar supply missions. NASA officials said all is well on the space station, and the astronauts are OK on their supplies for now.

The Cygnus spacecraft was loaded with 5,000 pounds of cargo that included science experiments, food, clothing and other equipment for the astronauts on the ISS. It was set to rendezvous with the space station on Nov. 2.

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It was scheduled to be parked at the ISS for five weeks. Astronauts would have then loaded trash onto the Cygnus to be burned up in Earth's atmosphere.

A Russian supply ship is set to launch to the ISS on Wednesday. SpaceX is scheduled to fly a cargo load in December.

A lot of science experiments were on board. They made up ONE THIRD of the cargo. Big loss. #Antares — Amanda Wills (@AmandaWills) October 28, 2014

The rocket "suffered an accident shortly after liftoff," a NASA launch official said on the livestream shortly after the blast, at 6:22 p.m. ET.

Doppler radar shows the explosion of the #Antares rocket. No injuries reported according to @NASA pic.twitter.com/ugY57LZgve — Matt Daniel (@mattdanielwx) October 28, 2014

Planet Labs, an Earth imaging startup that had 26 satellites on board, said simply, "Space is hard."

"While this will not have a huge impact on ... Planet Labs, space is hard and our hearts go out to our fellow space innovators," the company wrote in a statement.

The Antares rocket sits on the NASA Wallops Facility launchpad in Virginia prior to launch. Image: NASA

The explosion sent a fireball into the darkness on a night when space buffs all along the eastern seaboard of the U.S. had hoped to catch a glimpse of the rocket blasting into space.

Additional reporting by Jonathan Ellis.