Space X is in the process of testing the crewed version of its Dragon space capsule that will be capable of ferrying humans to and from the International Space Station. The date for the first test with humans on board(initially scheduled for July) however, will need to be moved up, as the capsule suffered a failure during the activation of its engine abort SuperDraco thrusters and – Space X just confirmed – was destroyed.

The SuperDraco abort engines – which Space X famously produces via a metal powder bed fusion process – are designed to rocket Crew Dragon away from danger in the event of a launch emergency.

“We fired them [the Dracos] in two sets each for 5 seconds, and that went very well,” Hans Koenigsmann, vice president of Build and Flight Reliability at SpaceX, told reporters during a press conference on May 2nd. “And then, just prior, before we wanted to fire the SuperDracos, there was an anomaly and the vehicle was destroyed.”

Koenigsman also said that the initial data indicates that the anomaly occurred during the activation of the SuperDraco system. However, the SpaceX team doesn’t think the problem lies with the SuperDracos themselves. The engines have endured more than 600 tests at the company’s Texas facility and performed well during a 2015 “pad abort” test. The exact cause of the mishap remains under investigation, Koenigsmann stressed.

Crew Dragon and Space X’s cargo vehicle are very different, primarily because the robotic resupply vehicle does not have seats, windows or a life-support system. The Crew version is also the only one with SuperDraco abort engines. Although the actual crewed test may now slip to a later date, Space X will not have to rebuild the spaceship from scratch since several units of the capsule are in different stages of production.