Two killed in blast at space tourism rocket firm

A huge explosion killed two workers and critically injured four others at a Mojave Desert airport site used by a pioneering aerospace company linked to Sir Richard Branson's Virgin Galactic space tourism business.

Last night's blast at a Mojave Air and Space Port building belonging to Scaled Composites, which sent the first private manned rocket into space, also left some toxic material, said Kern County fire captain Doug Johnston.

All the victims worked for Scaled, the Mojave, California-based builder of SpaceShipOne, the first private manned rocket to reach space.

Aerospace designer Burt Rutan, who heads Scaled but was away, rushed back to Mojave early today. He appeared emotional, hugging the airport manager and fire chief. His voice trailed off at times as he spoke to reporters.

No information about the victims was released because families were being notified.

Rutan said the blast did not involve a rocket firing but happened during a test of the flow of nitrous oxide through an injector during the testing of components for a new rocket motor for the upcoming SpaceShipTwo.

The nitrous oxide was at room temperature and under pressure, Rutan said.

Rutan gave little additional information about the test, but said it had been done safely many times during the SpaceShipOne programme and had been done once before for the SpaceShipTwo programme.

"We were doing a test we believe was safe. We don't know why it exploded. We just don't know," he said.

SpaceShipTwo is to be used for Virgin Galactic, which plans to offer £100,000 rides into space for tourists.

Authorities did not allow access to the blast site in a remote unpaved area about a quarter of a mile beyond an aircraft storage area.

Video news helicopters showed wrecked equipment and vehicles at the airport in the high desert north of Los Angeles, near Edwards Air Force Base.

Scaled uses nitrous oxide as an oxidiser in its rockets, which are tested at the airport. An oxidiser provides the oxygen that rocket fuel needs to burn. Scaled's website notes that "temperatures and pressures must be carefully controlled" during oxidiser transfers.

Two people were killed, four were critically injured and one received minor injuries, said Mark Corum, a spokesman for Hall Ambulance Service.

The injured were airlifted to Kern Medical Centre, about 45 miles from the airport.

The Mojave airport is where the Rutan-designed Voyager aircraft was built. It made history in 1986 when it achieved the first non-stop flight around the world without refuelling.

In 2004, Rutan's SpaceShipOne, funded by Microsoft co-founder Paul Allen, made the first privately-financed manned spaceflight by climbing more than 62 miles high on a suborbital journey above Mojave. SpaceShipOne went on to make two more flights to win the £5 million Ansari X Prize.

Rutan has since been developing SpaceShipTwo for Sir Richard, who is investing at least £100 million for a fleet of Rutan's spaceships.

Earlier this year he told a trade show the new ship would be ready within a year and, after a year of flight tests, would have its first commercial launch in 2009.

Rutan, who works secretively and stresses that safety will be the key to success of space tourism, has not publicly released a schedule for completion of the design, testing and first launch.

Aerospace and defence contractor Northrop Grumman owns 40% of Scaled and recently agreed to acquire the rest of it. The deal is awaiting regulatory approval and should close next month.

Northrop Grumman spokesman Dan McClain said the company had no comment on the explosion.