Virgin Galactic’s SpaceShip Two has experienced an “in-flight anomaly” over the Mojave desert, according to reports. CNBC said the craft was released for free flight about 50,000 feet above sea level on Friday morning, when it exploded shortly after firing its rocket engine, which it hadn’t done in more than nine months. No casualties have officially been reported. Stu Witt, the director of the Mojave Air and Space Port, said SpaceShip Two blew up and came down in pieces near Koehn Lake.

Two pilots are needed in the cockpit in order to fly SpaceShip Two. Today’s test was meant to provide Virgin Galactic with necessary data to one day provide public suborbital trips to the edge of outer space, which officially begins 62 miles above Earth. More than 700 people have already paid the $250,000 ticket fee for a ride, but today’s tragedy will no doubt be a huge setback for any future plans.

Since SpaceShip Two’s last flight, Virgin Galactic reportedly switched up the plane’s fuel mixture from a rubber-based compound to a plastic-based mix, according to CNBC; the new mixture was meant to boost performance of the rocket’s engine.

Below is Virgin Galactic’s official statement:

Virgin Galactic’s partner Scaled Composites conducted a powered test flight of SpaceShipTwo earlier today. During the test, the vehicle suffered a serious anomaly resulting in the loss of the vehicle. The WhiteKnightTwo carrier aircraft landed safely. Our first concern is the status of the pilots, which is unknown at this time. We will work closely with relevant authorities to determine the cause of this accident and provide updates as soon as we are able to do so.

This is a developing story, so we’ll update as we know more. An ABC 7 Tweet reported a rescue crew carrying a person from the wreckage on a stretcher to a chopper; another report said one fatality has been confirmed, while the other pilot is listed in critical condition.

It seems to be a dire scene out in the desert right now, and a huge tragedy for the pilots involved. Tweets about the incident are still flooding in, and we’ll update as we learn more.