SpaceX is leading the investigation into the cause of its massive rocket explosion last week, a probe that involves some 20 people from industry, NASA, the Air Force and the Federal Aviation Administration.

More than half of the members are from outside the company, according to an industry official with knowledge of matter who is not authorized to speak publicly about an ongoing investigation. They will have access to raw data and the ability to analyze it independently.

The setup of the investigation is similar to the probe that looked into SpaceX’s rocket explosion last year, when a rocket hired under a NASA contract headed for the International Space Station exploded a couple minutes into flight.

At the time, members of Congress said they had “serious reservations” about SpaceX leading the probe and they expressed concern over whether the "investigation and engineering rigor" being applied would be sufficient to prevent further mishaps.

Under FAA regulations, launch providers handle investigations when there is no loss of life, injury or outside property damage. The aerospace company now known as Orbital ATK, which lost a rocket in 2014, also led its own investigation.

On Thursday, SpaceX’s Falcon 9 blew up while it stood on its launch pad at Cape Canaveral Air Force Station moments before a test firing of its engines. No humans were on board and no one was hurt. It was scheduled to launch a commercial satellite. On Twitter, SpaceX founder Elon Musk said the blast occurred while crews were fueling the rocket and that it originated around the upper stage’s oxygen tank.

It’s unclear how long the investigation will take or how long it would be to repair the launch pad.

After its rocket exploded last year, SpaceX was grounded for six months before it flew again. In the wake of last week's explosion, NASA said it was sticking by SpaceX, which it has hired to eventually fly astronauts to the space station. The agency said it remains "confident in our commercial partners."