As SpaceX prepared to test fire the powerful engines of its Falcon 9 rocket, an explosion rocked its launch pad at Cape Canaveral Air Force Station Thursday morning, blowing up the rocket, making it the second the company has lost in a fireball in just over a year.

There were no humans on board, and no one was hurt. But the massive explosion could be felt for miles and a plume of dark, thick smoke hung over the coastline as emergency officials scrambled to assess the damage.

The accident came at a pivotal moment for SpaceX, the upstart company founded by Elon Musk that has for years been flying commercial satellites to orbit and cargo to the International Space Station for NASA.

Along with Boeing, SpaceX is now preparing to ferry astronauts for the first time to the station under a contract with NASA. The mission was slated to take place as soon as next year, but some officials say Thursday’s explosion is likely to prompt new scrutiny. The explosion came on the same day a government watchdog reported that human flights to the station could be delayed because of technical issues with the companies’ spacecraft designs.

Last year, a SpaceX Falcon 9 rocket—which would also be used to fly astronauts—blew up a couple minutes after liftoff during a cargo mission.

“This will always raise questions and possible delays, and certainly people redoubling their efforts on safety,” said Lori Garver, the former deputy NASA administrator.

Today, a SpaceX Falcon 9 rocket exploded at Cape Canaveral. Post reporters Joel Achenbach and Chris Davenport discuss the explosion’s effect on NASA, SpaceX and Elon Musk’s Mars plans.

Posted by Washington Post on Thursday, September 1, 2016

The explosion occurred at 9:07 a.m. as SpaceX was preparing to test fire the rocket’s engines ahead of the launch of a commercial satellite, reportedly valued at $195 million, that had been scheduled for early Saturday morning. The Falcon 9, towering some 230 feet high atop Launch Complex 40, was being fueled, when a fireball ignited around the upper stage oxygen tank, Musk said on Twitter. It was unclear what caused the mishap. Video of the incident shows a series of ignitions that engulfed the launch pad in flames.

In a statement issued Thursday afternoon, NASA officials said they "remain confident in our commercial partners and firmly stand behind the successful 21st century launch complex that NASA, other federal agencies, and U.S. commercial companies are building on Florida’s Space Coast."

Musk, the billionaire tech entrepreneur who also runs Tesla Motors, has laid out huge aspirations for his space company on an incredibly ambitious timeline. He plans to launch an uncrewed spacecraft in 2018 that would land on the surface of Mars, a planet he intends to colonize. At a space conference next month, he is scheduled to provide further details on how the company plans to get humans there by as early as 2025.

The company also hopes to launch by the end of the year the Falcon Heavy, a much more powerful rocket than the one that exploded Thursday. And it plans to fly for the first time one of the rockets it had recovered earlier this year in a landing.

But now SpaceX will be temporarily grounded while the investigation begins into what caused the explosion and repairs begin on the launch pad. After the explosion last June, SpaceX recovered quickly, returning to flight six months later. On that launch, it pulled off the first of its rocket landings.

In an interview in June, Musk said that as it works to get to Mars, “we’re going to make mistakes along the way.” The company has enjoyed tremendous support from people inspired by its successes, but he said that“when we occasionally fall down, we want their support. . .Support us when the chips are down. Fair weather friends are easy to come by. But the ones that really matter are the ones that support you when the chips are down.”

This year, the SpaceX successfully launched several more rockets, as it worked to churn through its growing backlog. And SpaceX was getting its momentum back, restoring confidence not just in the company, but in the notion that private companies, and not just governments, were capable of safely ferrying passengers to space.

Garver, the former NASA deputy administrator, said that after NASA’s setbacks, the country “continued to persevere, and I think in this case they will as well.”

She pointed out that NASA hired two companies—SpaceX and Boeing—to fly astronauts to the station so that it would have a backup in case something went wrong.

“We were always aware that both companies could see setbacks,” she said.

Separately on Thursday, NASA’s Inspector General released a report that said NASA’s “commercial crew” program to outsource human flights to the space station “continues to face multiple challenges,” this time because of concerns with the companies’ spacecraft designs. The IG said the issues “will likely delay the first routine flight carrying NASA astronauts to the ISS until late 2018 – more than 3 years after NASA’s original 2015 goal.”

Given the delays, the report said that NASA has had to extend its contract with Russia, which currently flies U.S. astronauts to the station, through 2018 at an additional cost of $490 million.

John Logsdon, the former director at George Washington University’s Space Policy Institute, said it was too early to say what the fallout of the explosion would be “because we don’t know what happened or why it happened and how long it’s going to be before they launch again.”

No matter what the cause, “it is certainly unfortunate for the broader future plans for SpaceX,” he said.

Some in the space industry said they thought SpaceX could recover quickly, especially if the problem was not with the rocket.

“We’re disappointed by what happened,” said Eric Stallmer, the president of the Commercial Spaceflight Federation. “But we’re confident they’ll find the root of the problem, and they’ll be back to flying soon.”

In a statement, Sen. Bill Nelson (D-Fla.) said: “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.”

The satellite that SpaceX was planning to launch Saturday was the AMOS-6, which would have been used in Facebook’s first attempt to provide the Internet to rural areas from space.

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