Experts say Virgin Galactic ignored several safety warnings prior to fatal crash

Days after Virgin Galactic spaceship exploded over California's Mojave Desert, experts and the United States authorities have said that Virgin chief Sir Richard Branson ignored repeated safety warnings prior to the crash.

One of the experts claimed that the space tourism company was playing a deadly game of "Russian roulette" and that one of its flights had to end in disaster, reported The Daily Star.

Carolynne Campbell, a rocket propulsion specialist at the International Association for the Advancement of Space Safety (IAASS), also said that she had first raised alarm over the perils of using nitrous oxide-propelled engines as long ago as 2007.

Three crew members were also killed in the same year when a tank of the gas exploded in a warehouse at the company's American headquarter.

The Federal Aviation Authority and National Transportation Safety Board have now said that they will consider expert testimony in their joint investigation into the cause of the SpaceShipTwo explosion which killed co-pilot Michael Alsbury, 39, and severely injured pilot Peter Siebold, 43.