Virgin Galactic's SpaceShipTwo has crashed in the Mojave Desert after suffering what the company called "an in-flight anomaly" during a test flight conducted by Scaled Composites, Virgin Galactic's partner.

Two crew members were onboard. The California Highway Patrol reported 1 dead and 1 injured after the mishap, according to AP, and a spokesman for the Kern County sheriff's office confirmed that the co-pilot was killed.

The spokesman said that said the pilot had ejected from the craft and was found near one of the debris fields. He was taken to Antelope Valley Hospital with moderate to severe injuries.

At a press conference, a shaken Virgin Galactic CEO George Whitesides said, "Our primary thoughts are with the crew and families."

"Space is hard," he added. "Today was a tough day. We're supporting the investigation. We're going to get through it. The future rests on hard days like this."

At the same conference, an emergency response official reported that a helicopter was on standby during the test flight and was able to quickly airlift the injured pilot to the hospital. Officials were unable to comment on the injured pilot's condition.

Executives were unable to provide any additional detail about the cause of the crash, but did confirm that SpaceShipTwo's engines had been tested on the ground.

Roughly two hours after the accident, Richard Branson tweeted:

Thoughts with all @virgingalactic & Scaled, thanks for all your messages of support. I'm flying to Mojave immediately to be with the team. — Richard Branson (@richardbranson) October 31, 2014

Virgin Galactic and Scaled Composites executives confirmed at the press conference that Branson was on his way to the site and would arrive Saturday morning.

Just after 10 a.m. PDT today, ground controllers at the Mojave Spaceport lost contact with SpaceShipTwo, an experimental space flight vehicle. The incident occurred over the Mojave Desert shortly after the space flight vehicle separated from WhiteKnightTwo, the vehicle that carried it aloft. Two crew members were on board SpaceShipTwo at the time of the incident. WhiteKnightTwo remained airborne after the incident. The FAA is investigating.