SpaceX admits its spacecraft blew up in accident – but does not explain why

SpaceX has confirmed that one of its rockets blew up in a mysterious accident – but has not revealed what happened.

The company and its primary customer, Nasa, have spent the two weeks since a spectacular explosion of its new crew capsule saying very little about what took place.

Nasa expects to rely on the spacecraft to transport astronauts into space in the future, and its success is vital to the space programme. But it has revealed next to nothing about what exactly went wrong.

Now Hans Koenigsmann, vice president of flight reliability for SpaceX, admitted that there had been an "anomaly". But the company continued to be tight-lipped about the details of the problem.

The April 20 accident occurred on a landing zone at the Cape Canaveral Air Force Station as SpaceX was conducting a test of emergency thrusters designed to propel the capsule, dubbed Crew Dragon, to safety from atop the rocket in the event of a launch failure.

An attempt to test-fire the eight SuperDraco engines triggered the accident, demolishing the entire vehicle on a test stand, Koenigsmann told reporters at NASA's Kennedy Space Center.

"Just prior, before we wanted to fire the SuperDraco, there was an anomaly and the vehicle was destroyed," Koenigsmann said on Thursday. "There were no injuries. SpaceX had taken all safety measures prior to this test, as we always do."

The news conference was called ahead of Friday's scheduled launch of an unmanned resupply mission to the international space station using a cargo-only capsule built by SpaceX, the private rocket venture of billionaire entrepreneur Elon Musk.

When pressed, Koenigsmann declined to characterise the nature of the accident, including whether an explosion or fire was involved. NASA has likewise demurred when asked to describe the mishap.

A leaked video of the accident, which was acknowledged as authentic by a NASA contractor in an internal memo obtained by the Orlando Sentinel newspaper, showed the astronaut capsule blasting into smithereens. A pall of smoke was also widely observed rising over the launch pad from a distance at the time of the ill-fated test.

The Crew Dragon had been scheduled to carry US astronauts Bob Behnken and Doug Hurley to the International Space Station in a test mission in July, although the recent accident, as well as some other hitches in the vehicle's design, are likely to push that schedule to later in the year or into 2020.

"It's certainly not great news for the schedule overall, but I hope we can recover," Koenigsmann said.

The destroyed vehicle was one of six such capsules built or in late production by SpaceX, and the first flown into space. A SpaceX Falcon 9 rocket launched it without crew to the space station in March for a six-day visit before returning to Earth, splashing down safely in the Atlantic for retrieval.

"We have no reason to believe there is an issue with the SuperDracos themselves," Koenigsmann said, adding that the engines have been tested nearly 600 times in the past.

NASA has been awarded $6.8bn to SpaceX and rival Boeing Co to develop separate capsule systems to fly astronauts to space, but both companies have faced technical challenges and delays.

Additional reporting by Reuters