Space Ship Two reported to have crashed
 

Missing after in-flight anomaly: http://rt.com/usa/201315-virgin-spa...-mojave-desert/


Bill

Tragic with the fatality and a definite setback for Virgin. If they come in threes, what is next?

http://www.nbclosangeles.com/news/l...nbcnews_taboola

Links to Virgin crash details:

http://www.theguardian.com/science/...in-crash-mojave

http://www.parabolicarc.com/

http://www.bbc.com/news/world-us-canada-29857182

http://www.reuters.com/article/2014...N0IK24220141031

https://www.youtube.com/watch?v=_OxITQ1JA_M

https://www.youtube.com/watch?v=JpwEY0TcKhQ

Breaking news Jerry

The crash site is directly west of California City, CA about 2 miles west of Hwy 14 near Red Rock Mountains.

http://goo.gl/maps/RDZZb

MTA and FAR:
http://goo.gl/maps/MRGrf

I have attached in-flight photos of the anomoly.

Is sad indeed. I was hoping that things were finally coming together for Virgin in this effort and that we'd be seeing paying customers heading into space in the near future, though I know they are some years behind their original plan for that goal.

I guess it is another reminder that some 50 odd years after humans first made it into space that getting there is still a difficult undertaking that allows little margin for error. If there were 'errors' in their system, I guess it better to wring those out now and not when you have a craft aloft full of people. Any loss though is tragic, and I'm sure the Virgin Galactic 'family' is pained to the core after the events of today.

I do hope though this setback will not deter them from their efforts. That would be the real tragedy to have them turn back in the face of this loss.


Earl

It appears the motor ignited, extinguished, then the motor (engine) system exploded.

There are several strong candidates for explaining the anomoly.

1. The motor experienced combustion instability resulting in a hard chuff exceeding the pressure limits of the casing.

2. Phase change of the N2O associated with the shut down or active turn off by the pilot. This anomoly would be similar to the accident during ground testing when a flow test resulted in the death of three propulsion engineers.

3. Associated with the unplanned or planned shut down, a water-hammer effect associated with the pressure fed system which may or may not have an effective reverse flow or pressure drop system (check valve).

4. Bulkhead failure.

5. Structural failure.

There was a large industrial N2O explosion at a port in TX over a decade ago associated with phase change on flow systems. The explosion was described as a detonation, but it is unclear if that is entirely true as no sensors were active to measure shock velocity. However the fracturing of concrete and steel structures indicated a detonation was at least in the realm of likely.

Tech Jerry

Clear photos and more details. I know the eyewitness Messier personally.

http://www.telegraph.co.uk/news/wor...pace-quest.html

http://www.parabolicarc.com/2014/10...ts-giant-leaps/

Attached is the Flight Track image for the event.

The surviving pilot is talking and will be able to assist with the investigation.

Another report from insiders says the motor exploded and blew both tails off. The main body entered ballistic.

This explains the mid-air disassembly but the lack of a large flash seems to be what is specific to hybrids. No fuel to intimately mix with the oxidizer leading to a white cloud and perhaps the flame we did see was the fuel grain in low pressure afterburn or the oxidizer impinging a body part made of fuel that kept the flame going after the case portion departed. It is not clear to me we have seen the combustion chamber in the main body wreckage photos. We certainly have seen the oxidizer tank in remarkably good shape. This reduces the detonation theory substantially.

Tech Jerry

Reasons #1 and #3 are looking good right now.

This failure, as tragic as it is, does (despite its aftermath) demonstrate the greater safety of hybrid rockets. Had SpaceShipTwo been powered by a liquid bipropellant rocket propulsion system, there would likely have been *no* survivors, or anything left of them or the vehicle except small fragments a few inches across. Also:

If I designed (or commissioned the design of) a "clean-sheet" manned orbital vehicle in which safety was the primary consideration (not requiring reusability), it would be a two-stage, LOX/paraffin hybrid (possibly pump-fed rather than pressure-fed, to reduce the tankage mass) launch vehicle, with a capsule on top. Since such a vehicle could not explode (detonate) as a liquid bipropellant or monopropellant rocket can (because a hybrid rocket's fuel and oxidizer can never completely mix all at once, due to their being in different states [one solid, one liquid]), a capsule's launch escape system need not have to be as powerful or high-acceleration as those of the Mercury, Apollo, and Soyuz spacecraft--it would only need to get a capsule out of the way of a malfunctioning hybrid launch vehicle. In addition:

Since the capsule would not have the propulsion system *inside* it (as was the case with SpaceShipTwo), even a failure such as the one that SS2 experienced would not destroy (or likely damage much, if at all) a capsule mounted above a hybrid launch vehicle, even if the escape system didn't fire. It would probably be like the final Apollo Little Joe II test (which became a *real* abort due to a control system malfunction), where the launch vehicle disintegrated and left the capsule (whose LES pulled it away for an otherwise uneventful landing).

The leading theory now is that the feathering mechanism deployed early: http://www.foxnews.com/us/2014/11/0...-investigation/

Darn those early deployments...



Bill

This is troubling, if you think about what those booms had to do in order to move at all in a Mach 1 slipstream. Yes, I realize that the atmospheric density was less at 45K than it is at sea level, but there's still a lot of resistance to overcome.

There's going to be a lot of rushing to judgement about the co-pilot unlocking those booms early, but thinking about that slipstream for a bit, that action shouldn't have made any difference at Mach 1 as it would have at Mach 1.4 or Mach 2, or higher. Granted, it facilitated the movement by taking away one layer of safety early, but that transition from M1 to M1.4 was only a matter of seconds at best.

What caused the break-up of the vehicle was that uncommanded feathering, and that requires the motive force of either hydraulics or electric motors. SOMETHING triggered a command that should not have been sent without that second lever being moved into position. Without that motive power, even if the booms had been "floating" without restraint, that slipstream should have actually forced and held the booms in their proper position throughout the powered portion of the flight.

Wings generate lift. If the booms with tails attached generated enough lift, it could have overcome the pressure of the control mechanism and they could have moved upwards. of course, there is drag on them making them want to move backwards, and there will be some angle of equalibrium.

Then you must consider the fuselage, which also has lift and drag. If the fuselage was forced upward or lifted upward, that would create huge aerodynamic loads.

Either the tails ripped off the fuselage, or the fulelage ripped away from the tails.