San Francisco: One person was killed and another badly injured when Virgin Galactic's SpaceShipTwo exploded over southern California's Mojave Desert after takeoff on a test flight, the California Highway Patrol said.
The spacecraft normally flies with two pilots.
"During the test, the vehicle suffered a serious anomaly resulting in the loss of SpaceShipTwo," Virgin Galactic said on Twitter Friday.
The company said it was working with authorities to determine the cause of the accident.
NBC News said witnesses saw at least one person in a parachute near the Mojave Air and Space Port shortly after SpaceShipTwo took off from the facility attached to an aircraft.
The explosion occurred after SpaceShipTwo detached from the airplane and activated its motor.
Virgin Galactic intended to offer would-be space tourists the chance for a suborbital ride on SpaceShipTwo, which is designed to return to earth as a glider.
The company's founder, British billionaire Richard Branson, had hoped to be part of the first commercial flight of SpaceShipTwo next year.