An expert on rocket propulsion has urged Sir Richard Branson to "give up" on his Virgin Galactic project and said the crash over the Mojave Desert was not a surprise.
Carolynne Campbell-Knight, from the International Association for the Advancement of Space Safety (IAASS), said the company should stop its attempts to take tourists into space.
They should stop, give up. Go away and do something they might be good at – like selling mobile phones. They should stay out of the space business.
Carolynne Campbell-Knight, IAASS
Ms Campbell-Knight claimed she contacted those involved in the project in 2009 or 2010 to raise concerns about the type of fuel used. This came after an explosion in 2007 during tests on a rocket motor killed three workers.
Claims have now emerged that those warnings were ignored and that SpaceShipTwo, which crashed on Friday killing one of its co-pilots, was testing a new, plastic-based rocket propellant for the first time.
Sir Richard, who flew on Friday to the Mojave Desert airfield that was home to Virgin Galactic’s experimental flights, said he was “determined to find out what went wrong” and learn from the tragedy.