SpaceShipTwo Unity takes off for Flight Test from New Mexico on Dec. 12. Photo: Virgin Galactic

Virgin Galactic shares dropped 17% on Monday after a test flight over the weekend failed to reach space when the vehicle’s rocket motors did not ignite. 

The Dec. 12 test was a powered flight for SpaceShipTwo Unity, Virgin Galactic’s suborbital vehicle which is designed to carry space tourists. When SpaceShipTwo was released from its carrier vehicle VMS Eve about 45 minutes into the flight, the ignition sequence did not complete and its rocket motor did not fire. 

Virgin Galactic reported Monday that the onboard computer which monitors the propulsion system lost connection, which triggered a scenario that halted the rocket motor’s ignition. This system is designed to default to safe state if power or communication with sensors is lost, Virgin Galactic said. At that point, pilots CJ Sturckow and Dave Mackay flew the vehicle back to Spaceport America in New Mexico where it landed safely. The company is conducting post-flight analysis.

CEO Michael Colglazier said in the Monday release that this test flight will be repeated, and followed by another test fight with mission specialists before a test flight with founder Richard Branson. 

“Our spaceflight system [is] purposely designed to enable our pilots to safely glide back to the Spaceport at any point during the flight profile. Seeing firsthand how our pilots brought Unity in for a picture perfect landing after an off-nominal condition confirmed this approach.  I am even more confident that this is the level of safety that consumers will want and will be expecting from us,” Colgazier said, framing the test as an affirmation of the vehicle’s safety features. 

This was Virgin Galactic’s first rocket-powered flight test since a successful flight in Feb. 2019. The company completed two glide tests earlier this year.

Virgin Galactic said in recent quarterly results that it expected to fly Branson in the first quarter of 2021. It is unclear how this test failure will impact that timeline and its timeline to start commercial service. Shares closed at $32.04 on Friday and dropped to a close at $26.47 on Monday.