An unmanned NASA-contracted rocket exploded early Tuesday evening along the eastern Virginia coast, causing a huge fireball but no apparent deaths.
According to NASA, the Orbital Sciences Corp.'s Antares rocket and Cygnus cargo spacecraft were set to launch at 6:22 p.m. ET from the Wallops Flight Facility along the Atlantic Ocean. It was set to carry some 5,000 pounds of supplies and experiments to the International Space Station.
"There was failure on launch," NASA spokesman Jay Bolden said. "There was no indicated loss of life."
Bolden added, "There was significant property and vehicle damage. Mission control is trying to assess what went wrong."
Video shows the rocket rising into the air for a few seconds before an explosion. It then plummets back to Earth, causing more flames as it hits the ground. NASA tweeted that the failure occurred six seconds after launch.
Ed Encina was among those who watched it happen from about three miles away in the remote resort area.
"You immediately thought that everything was fine, because you see the big launch, and it brightened up the sky," said Encina, a Baltimore Sun reporter. "And then all of a sudden, you see a big fireball."
Encina recalled a loud boom that caused "your feet (to) shake a little bit," as well as flames enveloping a roughly 100-yard area around the launch pad in a marshy area with brush.
CNN iReporter Dymetria Sellers -- who watched from a drawbridge because the NASA visitors station was at full capacity -- recalled a "breathtakingly beautiful" site when the rocket ascended, followed by mass confusion as flames lit up the early nighttime sky moments later.
"About 30 seconds later, we could hear and feel two booms reach us, and it was apparent the rocket had exploded," she said.
Mark Kelly, a former NASA astronaut, explained that such a colossal fire was to be expected.
"It takes a lot of propellant to take a spacecraft of that size moving 25 times the speed of sound," Kelly told CNN, explaining how fast the rocket should have gone on its way to the space station. "So when it fails, it's usually pretty catastrophic."
The launch had been scheduled for Monday, but that was scrubbed "because of a boat down range in the trajectory Antares would have flown had it lifted off," according to NASA. Coast Guard spokesman David Weydert said the boat that triggered the postponement was 40 miles offshore.
It was a different story Tuesday. Just before liftoff, the space agency reported "100% favorable" weather and "no technical concerns with the rocket or spacecraft being worked."
After the explosion, the launch director said on NASA's feed that all personnel were accounted for and that no injuries were reported.
He added the spacecraft contained "classified ... equipment," and that there was a need to maintain the area around the debris field for investigative and potential security reasons given what was on board.
About one-third of the spacecraft's cargo consisted of material for scientific investigations, including a Houston school's experiment on pea growth and a study on blood flow in space.
There was about the same amount of cargo for supplies for the space station's crew, including more than 1,300 pounds of food.
It adds up to a big loss, and it wasn't immediately clear if a new mission will be added to compensate. Still, that doesn't mean the space station's six-person crew will go hungry in the meantime.
They still have goods on board and will get more soon: A Soyuz resupply spacecraft stocked with cargo and crew supplies is set to launch Wednesday from Kazakhstan. And SpaceX, a private company, should have its own fifth mission later this year, including more supplies and a laser instrument to measure pollution, dust and other aspects of the atmosphere, according to NASA.
NASA won't directly send anything up to the space station. That's because, since the end of the space shuttle program, it has relied on private companies to bring materials to the space station, albeit using NASA facilities for launch.
Orbital's first such commercial supply mission, in fact, was in January out of the Wallops Flight Facility. The Virginia-based company has a $1.9 billion contract with NASA to make eight flights to the space station under the space agency's commercial supply program.
Tuesday's launch was supposed to be the fourth flight for Orbital until it ended, as the company acknowledged in a statement, in "catastrophic failure."
"We will conduct a thorough investigation immediately to determine the cause of this failure and what steps can be taken to avoid a repeat of this incident," said Frank Culbertson, the general manager of Orbital's Advanced Programs Group. "As soon as we understand the cause, we will begin the necessary work to return to flight to support our customers and the nation's space program."
Live coverage of the mission was available on the Wallops Ustream site
Launch coverage on NASA TV began at 5:45 p.m. EDT NASA TV streaming video, downlink and scheduling information
More information about International Space Station.