Putting things into space isn’t an easy thing to do. The amount of energy required to reach orbital speeds means that we really only have one option available to us: strapping whatever it is to a giant barrel of explosives and setting light to it. Whilst the science of this is now well understood it doesn’t mean that we’re immune from mistakes, especially those which arise from the inherently complex systems that these rockets have become. Indeed just last week we saw the even a long time space contractor, one with numerous launches under its belt, can suffer a catastrophic accident without any indication that things were going to go wrong. Unfortunately tragedy has struck another private space venture with Virgin Galactic’s SpaceShipTwo crashing, killing one of the test pilots.
This unfortunately isn’t the first tragedy to befall this project. Back in 2007, shortly after their X-prize winning journey and subsequent partnership with Virgin, Scaled Composites had a fatal accident that killed 3 of their engineers. Whilst this wasn’t a flight accident, it was a catastrophic failure of the nitrous oxide tank that the ship uses, it did make many people question just how safe this kind of craft could be made. To their credit the subsequent 7 years were incident free with the prototype undergoing numerous tests both in the air and back down on the ground. Last week however that streak was broken when the VSS Enterprise broke up over the desert in California, killing one of the pilots and destroying the craft.
Initial reports centred on the fact that SpaceShipTwo was testing a new fuel mixture which could have potentially exploded causing the craft to fail. For a motor like the one in SpaceShipTwo, namely a hybrid rocket engine, this is highly unlikely as the fuel doesn’t have the same capability to combust explosively as its liquid cousins do. Had the changes been with the oxidizer or tank design then I’d be more inclined to blame them for failure. Indeed current reports have shown that the motor has been found fully intact at the crash site, indicating that a mid air explosion was not the cause of the crash.
Investigators are now focusing on the events leading up to the crash, including the possibility that the wings were unlocked too early into their flight. SpaceShipTwo has an unique system for its re-entry, it’s wings fold up in a process called feathering that ensures it comes back down belly-first. Engaging this system is a 2 stage process, requiring the pilots to first unlock the wings and then engage the feathering process. Initial reports have suggested that the wings were unlocked during powered ascent although it’s still too early to say if that was the cause of the crash or not.
To his credit Richard Branson has committed himself to the project even in the face of this disaster which means we’ll still be seeing SpaceShipTwo make flights into space sometime in the future. This will definitely set them back but I’m sure that the new versions of the ship will ensure that an event of this nature cannot happen again. It’s an unfortunate reminder that things like this still carry some form of risk with them and those who dare to be on the frontiers like this really are risking their lives for our greater good.