Happened at lower than designed altitude, so the drag was high (due to air density).
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wiztecy
Active Member
Very informative link about the investigation:
Virgin Galactic rocket plane deployed braking system prematurely | Spaceflight Now
Virgin Galactic rocket plane deployed braking system prematurely | Spaceflight Now
rolosrevenge
Dr. EVS
wiztecy
Active Member
Well, the pilot prematurely unlocked the feathering (step one of deployment), but didn't authorize nor do the 2nd step which told the tail to rotate or actual deployment of the feathering. The mechanism did it on its own after step 1/unlock occurred. Sounds like a bug in the logic or short in the switch/mechanism used in step 2.
All this should be automated. Although it sounds like there's a bug in the logic, if automated, the unlock would not have happened until they reached peak altitude or when the engines have been cut off. Once they're in orbit the feathers can stay deployed until needed for re-entry. Which from all the pics I've seen it does, feathers deployed in orbit.
Here is an interesting discovery channel program outlining the program. 1.5 hours long.
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It appears the speed of deployment in the media release was classic news information fubar. The tail feathered, uncommanded they are saying, during the powered ascent stage. A big no-no as the ship is not designed to be accelerated with the rocket in the feathered attitude. Aerodynamic pressure dissesembled the aircraft before the pilots were able to shut down the rocket motor, if they even tried.... Looks like there definitly needs to be a way to prevent the tail moving into the feathered position if the rocket motor is making smoke!
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Interesting side note is that Rutan designed Space Ship One to be the safest re-entry vehicle to date. Idiot proof re-entry, just feather the tail and the ship will automatically orient itself(no matter what attitude its in) for maximum drag and maintain that position until the aircraft slows to sub-sonic speed and then transition back to glide/airplane mode. And it appears that this safe re-entry system may be implicated in a powered ascent accident.
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Interesting side note is that Rutan designed Space Ship One to be the safest re-entry vehicle to date. Idiot proof re-entry, just feather the tail and the ship will automatically orient itself(no matter what attitude its in) for maximum drag and maintain that position until the aircraft slows to sub-sonic speed and then transition back to glide/airplane mode. And it appears that this safe re-entry system may be implicated in a powered ascent accident.
It would be amazing if early feathering wasn't accounted for in the most basic safety control systems. That is what safety systems are for. You account for things that will create fatal "anomalies" and place blocks against that happening whether a human being is involved or not. In this instance there seems to be three critical errors that occurred that allowed this to happen. 1. A lack of a safety system to prevent premature activation. 2. The pilot activated the system prematurely and the system allowed it. And fatally: #3 the system activated the feathers improperly, at an improper time, and at an improper speed.
Why would you even need to unlock the feathers at all until you reach the pinnacle of your flight? They are obviously a clear point of instability for the craft. They are a critical step in the flight process but only after the powered phase. Safety programming should have been in place to prevent this from happening.
Hindsight is 20-20, but yeesh this seems like a clusterfrack. This was supposed to be a tourism ship and safety should be #1 with safety redundancies built in.
Why would you even need to unlock the feathers at all until you reach the pinnacle of your flight? They are obviously a clear point of instability for the craft. They are a critical step in the flight process but only after the powered phase. Safety programming should have been in place to prevent this from happening.
Hindsight is 20-20, but yeesh this seems like a clusterfrack. This was supposed to be a tourism ship and safety should be #1 with safety redundancies built in.
rolosrevenge
Dr. EVS
It it was this sort of failure, it's much easier fix than the rocket motor or something fundamentally wrong with the design. A second Spaceship II may yet carry tourists into space, though a manned dragon capsule with a reusable first stage may make it first.
It also calls their risk analysis process into serious question. That something as basic as this could possibly happen implies to me that a whole lot of other things could also possibly happen, and it means that they're going to be spending a LOT of time convincing the authorities that large sections of the design don't have to be revisited or redone.
Maybe I'm wrong, and I hope I'm wrong but....
zag2me
Member
As terrible as this is, fatal crashes tend to make things much safer in the future.
It sounds like they have a good idea on what happened so lets hope it improves the project in the years to come.
It sounds like they have a good idea on what happened so lets hope it improves the project in the years to come.
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