SpaceShipTwo Crash

[razark]

His attitude is that VG can't lead to anything more than that; and without complete changes to their approach, he's right.

Wrong.

VG starts making paying tourist flights. Demand for flights increases. Someone else sees how much money there is to be made. That someone find a way to do it cheaper/better. Innovation occurs. Human race wins.

It may not be the best way, but there's a good chance that the fact that VG is creating an new industry could lead to other companies getting involved and making vast improvements in the technology. Just out of curiosity, when is the last time you saw a Wright Company airliner?

[Kryten]

It may not be the best way, but there's a good chance that the fact that VG is creating an new industry could lead to other companies getting involved and making vast improvements in the technology. Just out of curiosity, when is the last time you saw a Wright Company airliner?

They aren't the only actors in this area. Jeff Bezos' Blue Origin have reached all of these points already; they've built a test suborbital tourism vehicle, they've developed an engine for it that both actually works and has utility for orbital spaceflight, and they've had their test vehicle turn into tiny pieces over the desert. They'd bothered to include an autopilot in their vehicle of course, so they're continuing with barely a blip.

[m_robber]

Press conference from the NTSB is interesting:

While they say they are not drawing any conclusions yet, it seems that the "feather" mechanism may have been the culprit rather than the engine / fuel. The co-pilot apparently unlocked the mechanism before he was supposed to. It deployed. However, no one actually activated it, as after unlocking it has to be activated by the crew.

[thorfinn]

Fuel grain and oxidizer tank are intact, with no breaches and no burn-through.

Seems like I might owe an apology to the rocket designers.

[facmanpob]

I don't often post here, but I felt I had to. I'm a bit saddened by all of the vitriol and rhetoric shown in the last 16 pages of posts. None of us here know the cause of the crash, although some here appear to think they do. The NTSB are releasing daily statements about their investigation, and the truth will out. So I'm going to keep my comments to what for me is currently the most important issue, extending my condolences to the family and friends of Michael Alsbury, and wishing Peter Siebold a speedy and full recovery.

[KasperVld]

I don't often post here, but I felt I had to. I'm a bit saddened by all of the vitriol and rhetoric shown in the last 16 pages of posts. None of us here know the cause of the crash, although some here appear to think they do. The NTSB are releasing daily statements about their investigation, and the truth will out. So I'm going to keep my comments to what for me is currently the most important issue, extending my condolences to the family and friends of Michael Alsbury, and wishing Peter Siebold a speedy and full recovery.

This, sir, is an excellent post. I think some introspection is in order when I read through the topic. Over and over the VG customers are described in awful ways, VG itself is slandered and posters seemingly think they know the cause of the crash. Some restraint is dearly lacking.

Like you I'll limit myself to condolences to the family of the deceased pilot and the wish for a full and speedy recovery for the injured pilot.

[Agricola]

It is amazing how some people are reacting to this, so much hate for Virgin Galactic without knowing any facts. So we heard today how the feathering mechanism deployed on its own, but even so that could not be the cause. Richard Branson has come out with a superb statement which also applies to a number of people here, "Rumours and innuendo from self-proclaimed experts can be put back in their box," he told the BBC.

[Streetwind]

That is pretty much why I didn't even bother to try participating in this discussion, or the one surrounding the Antares failure. I had my suspicions from the start that certain usual suspects would quickly turn the atmosphere hostile and irrational, and occasional peeks at the threads later-on only confirmed this. It sadly is a growing trend that has been going on for a while now, specifically in the science subforum.

Now, to add something of actual relevance: http://www.space.com/27637-virgin-galactic-spaceshiptwo-crash-feather-system.html

The article gives a good, professional summary of the press conference without speculating or overdramatising (for those of us who might be stuck at work).

Edited November 3, 2014 by Streetwind
Typos, typos everywhere

[Red Iron Crown]

The

has some interesting info. The tanks and engine were apparently intact. Apparently the feathering mechanism was activated at an inappropriate time.

Edit: Nuts, didn't notice this was linked above.

[Dkmdlb]

Let's let this thread be a lesson to us all about speculating on this kind of thing without having access to all the relevant information. Even now - the NTSB chairman said the information about the activation of the feathering system is ''a statement of fact and not a statement of cause."

So while it's probably just fine to speculate about causes and discuss possibilities, it is completely out of line to make accusations and definitive statements outside of what the investigation shows.

[Kryten]

The feathering mechanism has been emphasised as a safety feature before, and SS1 escaped a spin by feathering on at least one occasion. It's very likely the attempt at feathering was in response to another problem, but exactly what it might have been isn't clear at that point.

[Brotoro]

That doesn't seem likely, since they pilots did not order the feathering action to start (according to the NTSB). They only unlocked the feathering mechanism (apparently earlier than they were supposed to...but simply unlocking it is not supposed to activate the feathering).

Maybe I don't understand feathering, but I can't see why you'd ever want to activate feathering while the rocket motor is firing. Perhaps somebody who understands the SpaceShipTwo flight profile better than I do can explain.

[Kryten]

That doesn't seem likely, since they pilots did not order the feathering action to start (according to the NTSB). They only unlocked the feathering mechanism (apparently earlier than they were supposed to...but simply unlocking it is not supposed to activate the feathering).

They wouldn't have a chance. Complete breakup was within the next couple of seconds of pulling the lever.

Maybe I don't understand feathering, but I can't see why you'd ever want to activate feathering while the rocket motor is firing. Perhaps somebody who understands the SpaceShipTwo flight profile better than I do can explain.

Either they did it while panicking, remembering recommendations to use it in case of loss of control in earlier glide flights, or they were intending to turn off the motor before actually activating the mechanism.

[Soda Popinski]

There was a mention the feathering was suppose to be activated at Mach 1.4. In this case, the ship was going Mach 1. At first that doesn't make a lot of sense to me, but I figure Mach 1 at 15,000 meters would be very different than Mach 1.4 at 100km. At least if my understanding of aerodynamics from FAR and DRE are anywhere near accurate.

Additionally, I doubt the tail booms would stand up to a feathered position while undergoing rocket based acceleration.

Edited November 4, 2014 by Soda Popinski

[mrfox]

To shed a bit of relevance to the difference in risk levels between test flying and the finished products - note that both the Gulfstream G6 (a plaything for the rich, just like VG), and the Airbus A330 (one of the most sucessful and prolific large commercial jets today) both suffered fatal crashes with total hull loss during flight testing.

[Brotoro]

There was a mention the feathering was suppose to be activated at Mach 1.4. In this case, the ship was going Mach 1. At first that doesn't make a lot of sense to me, but I figure Mach 1 at 15,000 meters would be very different than Mach 1.4 at 100km. At least if my understanding of aerodynamics from FAR and DRE are anywhere near accurate.

Additionally, I doubt the tail booms would stand up to a feathered position while undergoing rocket based acceleration.

No, the NTSB guy said that *unlocking* the feathering mechanism was to be done at Mach 1.4...not that feathering was to be activated at that time (which requires an additional control input).

But I still don't know why you'd even want to unlock that mechanism until after burnout of the rocket motor.

[Cally]

Oh man, I really hope this doesn't damage the company.

Virgin Galactic and SpaceX are our last hopes for getting to space, and something like SS2 would be wonderful.

[Streetwind]

They wouldn't have a chance. Complete breakup was within the next couple of seconds of pulling the lever.

That's not what the investigation team said. Actually, there's sort of a timeline now availabe:

10:07:19 - Separation from carrier plane

10:07:21 - Ignition of rocket motor

10:07:29 - Pilot unlocks feathering mechanism

10:07:30 - Vehicle goes supersonic

10:07:31 - Feathering system deploys uncommanded

10:07:34 - Loss of telemetry feed

Source.

That doesn't rule out the possibility that it was deployed in response to some other anomalous event, perhaps by the flight computer being programmed to do so in case the sensors show XYZ is happening. And then that still doesn't mean it actually happened, but only that the flight computer thought it did (see: blocked sensor port on the F9R-Dev1 leading to autonomous activation of FTS despite no overt malfunction). Basically it's all speculation as of yet. The NTSB wouldn't even say with certainty that aerodynamic forces from the deployed feathering mechanism were the thing that ripped the plane apart - it's just the most likely explanation right now, because it is immediately obvious that this uncommanded and unscheduled deployment was very, very wrong. And the wings kind of did fall off first...

I also notice how very much the incident coincides with entering the transsonic regime, which usually comes with a sudden and major change in aerodynamic behavior. Did something happen at exactly this moment that would cause an unlocked feathering system to deploy itself? The system isn't usually unlocked until mach 1.4, when the plane is well stabilized in the supersonic airflow - perhaps there is a good reason for that?

Virgin Galactic and SpaceX are our last hopes for getting to space, and something like SS2 would be wonderful.

XCOR. Blue Origin. Sierra Nevada Corporation. Firefly Space. RocketLabUSA. Masten Space Systems. Copenhagen Suborbital. Look em up, especially the first two

And even Boeing, while being a hidebound oldspace company, is still a future commercial provider of private spaceflight - they have an exclusive (!) deal with Bigelow Aerospace to ferry passengers to a private space station using the CST-100 vehicle, should Bigelow get around to building such a station.

Edited November 4, 2014 by Streetwind

[Red Iron Crown]

Actually, there's sort of a timeline now availabe:

10:07:19 - Separation from carrier plane

10:07:21 - Ignition of rocket motor

10:07:29 - Pilot unlocks feathering mechanism

10:07:30 - Vehicle goes supersonic

10:07:31 - Feathering system deploys uncommanded

10:07:34 - Loss of telemetry feed

Amazing to me how quickly things can go sideways. Even if there was some sort of ejection system for the pilots I'm not sure they would have had time to activate it.

[Kryten]

But I still don't know why you'd even want to unlock that mechanism until after burnout of the rocket motor.

It turns out it's what was done in the

. It seems the supposed 'standard operating procedure' is anything but.

[Soda Popinski]

No, the NTSB guy said that *unlocking* the feathering mechanism was to be done at Mach 1.4...not that feathering was to be activated at that time (which requires an additional control input).

But I still don't know why you'd even want to unlock that mechanism until after burnout of the rocket motor.

Not really a surprise around here, but an interesting article. Altitude was a big factor, as it was at Max Q when the feathering occurred.

Because of the thinner atmospheric density, folding the wings that high up at Mach 1.4 would have produced less aerodynamic stress than folding them at a lower altitude at Mach 1, Stengel said.

According to Professor Stengel, had the feathering occurred 10 or 20 seconds later, in the thinner atmosphere, it would have survived.

http://www.nbcnews.com/storyline/virgin-voyage/expert-opinion-spaceshiptwo-wings-flipped-worst-possible-time-n241211