Dragon was destroyed just before the firing of its SuperDraco thrusters
Ars Technica » Scientific Method 2019-05-02
During a news conference Thursday in advance of a SpaceX supply mission to the International Space Station, the company's vice president of mission assurance, Hans Koenigsmann, provided some additional details about a failure with the company's Crew Dragon spacecraft 12 days ago.
In the company's most expansive comments to date, Koenigsmann said the "anomaly" occurred during a series of tests with the spacecraft, approximately one-half second before the firing of the SuperDraco thrusters. At that point, he said, "There was an anomaly and the vehicle was destroyed."
During the activation phase, the SuperDraco thruster system is pressurized, and valves are opened and closed. Since the accident there has been speculation that there may have been some issue with the composite overwrap pressure vessels, or COPVs, which store rocket fuels at extremely high pressures. The COPVs on Crew Dragon are different from those on the Falcon 9, and they would not have been overly stressed at that moment, Koenigsmann said. "I'm fairly confident that the COPVs are going to be fine," he said.