Federal investigators have been looking for answers in California's Mojave Desert, the site of Virgin Galactic's fatal SpaceShipTwo trial flight, according to MSN News.
The biggest question is whether or not the new hybrid rocket fuel used was a safe combination and if Virgin knew how unstable the fuel was. Typically, rocket fuel is carbon-based, but SpaceShipTwo was using a new system of nitrous oxide and plastic, according to MSN News.
"The debris field indicates an in-flight breakup," Christopher Hart, acting chairman of the U.S. National Transportation Safety Board (NTSB), told Reuters. "We'll know that for certainty when we look at all the sources we have."
Investigators have said a full investigation could take up to a year.
A lead expert on hybrid propulsion for the International Association for the Advancement of Space Safety (IAASS), Carolynne Campbell, told The Guardian nitrous oxide is "mild, gentle stuff" when used in a dentist's office as "laughing gas," but in a rocket engine, the gas is "extremely unpredictable - it has a bit of a devil in it."
Six months ago, Virgin Galactic described nitrous oxide as "benign" and stable" on its website, but the gas was a contributing factor in a 2007 spaceport explosion, Campbell told The Guardian.
"They knew that three people were killed by this stuff, and yet they persisted in presenting it as safe, stable and benign," Campbell said.
British rocket scientist Geoff Daly has been very critical of Virgin's space endeavors, according to MSN News. In small quantities, Daly said nitrous oxide is safely used in drag racing.
"It's still very poorly understood in large quantities ... The temperature of the fuel is critical," Daly said, according to MSN News. Daily had reportedly warned the Federal Aviation Authority (FAA) last year of an impending disaster. Daily also cited what he called major design flaws in the spacecrafts structure.
Founder of all things Virgin, Richard Branson, released a statement on Virgin Galactic's webpage saying, "We understand that everyone is anxious to understand what happened on Friday; certainly no one wants to know more than we do. However, as we have made clear, Virgin Galactic is not in a position to comment on the incident itself or the test flight. The National Transportation Safety Board (NTSB) is in charge of the investigation and we are cooperating fully with their work. All inquiries should be directed to them."
The statement later says, "Now is not the time for speculation. Now is the time to focus on all those affected by this tragic accident and to work with the experts at the NTSB, to get to the bottom of what happened on that tragic day, and to learn from it so that we can move forward safely with this important mission."
