News Virgin Galactic SpaceShipTwo accident during powered test flight

[MaverickSawyer]

Tourist flights, remember? Wouldn't be so much fun if the passengers would be strapped to their seats in full pressure suits. And not really trustworthy.

Not sure if you could even fit into that thing with a light-weight Russian pressure suit, but the crew of fighter jets also rarely wear such suits. Still, I am not sure if a pressure suit would make such a big difference.

It depends on the altitude they were at, and whether or not the suit retains pressure in such an event.

There was an SR-71 that broke up in flight in the mid/late 60's that kicked the crew out. Both of them were wearing pressure suits, and I know that the pilot survived the accident. I can't recall why the RSO bought it, but given the fact that the pilot was literally torn from his seat by the forces... :shrug:

Also, the USAF has a regulation about flying over 50,000 feet altitude: Pressure suits required. End of argument. Why don't they use them? Because of the increased pilot fatigue, reduced situational awareness, and decreased flexibility in the cockpit. And the fact that most aircraft in the inventory do NOT have the facilities for handling the suits the USAF uses nowdays: the David Clark suit like the ones used on the SR-71 and U-2.

 

[Quick_Nick]

There was an SR-71 that broke up in flight in the mid/late 60's that kicked the crew out. Both of them were wearing pressure suits, and I know that the pilot survived the accident. I can't recall why the RSO bought it, but given the fact that the pilot was literally torn from his seat by the forces... :shrug:

http://roadrunnersinternationale.com/weaver_sr71_bailout.html

 

[C3PO]

Tourist flights, remember? Wouldn't be so much fun if the passengers would be strapped to their seats in full pressure suits. And not really trustworthy.

Not sure if you could even fit into that thing with a light-weight Russian pressure suit, but the crew of fighter jets also rarely wear such suits. Still, I am not sure if a pressure suit would make such a big difference.

Exactly! Nobody expects motorsport-rated safety equipment in a production car. We could make cars/roads safe enough to almost eliminate the risk of a fatal accident, but it wouldn't be practical.

I've become almost immune to news reporters using words they don't understand when describing any event in space flight. (A so-called 'expert' on Sky News even talked about "suborbital altitudes". Anything from above ground to the edge of Earth's SOI can be suborbital.) It just shows that they have roughly the same level of interest in space as I have in 'reality TV'.

I think it's worse when they claim that accidents like this can jeopardize the future of space tourism. I don't remember anybody questioning the future of cruises after the Costa Concordia accident.

 

[Urwumpe]

There was an SR-71 that broke up in flight in the mid/late 60's that kicked the crew out. Both of them were wearing pressure suits, and I know that the pilot survived the accident. I can't recall why the RSO bought it, but given the fact that the pilot was literally torn from his seat by the forces... :shrug:

1966, Bill Weaver survived this, Jim Zwayer died. The cause of the accident was a classic inlet unstart during a high bank turn combined with an aft cg... happened in 75,000 ft at Mach 3.18.

Zwayer was likely killed by a broken neck, which was one of the many injuries that he received. Weaver only got some bruises and a small whiplash.

http://roadrunnersinternationale.com/weaver_sr71_bailout.html

 

[garyw]

Also, the USAF has a regulation about flying over 50,000 feet altitude: Pressure suits required. End of argument.

SS2 would have been at about 45,000ft when they ignited the rocket.

Holy crap. I'm shocked that there was a survivor. Even if there was no explosion and no jet stream, you don' want to be outside at 50 000 ft without a pressure suit. At all.

Being outside at 50,000ft without a pressure suit is no big deal. You'll pass out straight away and if you stay there like that, yes your brain will starve of oxygen and you'll die but in free fall you'll plummet through 14,000ft after a minute or two and regain conciousness as the higher pressure provides more oxygen. If you are on an automatic parachute then you just might survive it.

 

[N_Molson]

8ndeed. The Spaceship Two is not equipped with ejection seats, only an escape hatch. Also, the test pilots were not wearing pressure suits.

Then that's 10 times a miracle, truly.

Now, when you see all the things that a modern drone can do, you could expect those kind of test-flights testing new propulsion technologies to be unmanned.

Well, of course there's some romantism in having test pilots like during the X-15 era, and those people are professionnals who are fully aware that they are risking their lives each time. And the human ability to adapt to unforeseen events is without price.

Now, maybe a computer could have spared one live and avoid a catastrophic failure that is going to have a huge impact the program. :hmm:

 

[Kyle]

Sad news, it's been confirmed that Michael Alsbury was the pilot killed in yesterday's crash.

 

[Urwumpe]

Now, when you see all the things that a modern drone can do, you could expect those kind of test-flights testing new propulsion technologies to be unmanned.

No sensor in the whole universe is as accurate and as descriptive as the butt of an experienced test pilot.

 

[garyw]

test pilots also have more chance of bringing the ship home and remember than even today, modern jets still have engine trouble.

 

[Urwumpe]

Now, maybe a computer could have spared one live and avoid a catastrophic failure that is going to have a huge impact the program. :hmm:

Or maybe result in an otherwise possible and reliable technology being declared impossible by the flaws of the autopilot, after many millions lost to crashes caused by situation which a human pilot could have solved by his experience.

 

[Andy44]

Also, even if the primary purpose of the test flight was the engine, there are still lots of secondary objectives such as gathering more data on the vehicle's handling and cockpit instrument functionality and ergonomics, not to mention building up pilot logbook time. No computer can do that, and since the vehicle is planned to fly with people you need to test it for that, too.

The engine was run on the test stand multiple times with nobody in harm's way, at some point you have to fly it with people and accept the risk.

 

[rhoude57]

I'd be curious to see how representative the test stand conditions were vs those at altitude in the actual environment.

 

[Quick_Nick]

Sad news, it's been confirmed that Michael Alsbury was the pilot killed in yesterday's crash.

And the survivor is reported to be Peter Siebold.

 

[Urwumpe]

I'd be curious to see how representative the test stand conditions were vs those at altitude in the actual environment.

Likely not really comparable, but close enough. If you are lucky, you can test for different fuel temperatures. Sadly, simulating proper temperature gradients in the fuel as you can expect during a real mission would be really hard.

 

[rhoude57]

Likely not really comparable, but close enough. If you are lucky, you can test for different fuel temperatures. Sadly, simulating proper temperature gradients in the fuel as you can expect during a real mission would be really hard.

That's what I think as well. Replicating the cold soaking of the solid rocket fuel, then simulating the temperature and pressure gradients overlayed on the solid propellant burn rates, oxydiser feed rates and the perfomance of rocket engine components is one tough challenge.
Then, there is also the possibility of a manufacturing defect of either the solid fuel core or the casing.
Hopefully, there will be enough of the pieces found to discover the cause(s) of the "anomaly" (sic).

 

[Andy44]

Then, there is also the possibility of a manufacturing defect of either the solid fuel core or the casing.

That's the case in a lot of solid rocket failures. Hopefully they can find the pieces of the machine so they can look for things like cracks, etc., as well as looking over instrumentation data.

Also, if the manufacturers were thorough, photographs and documentation of the engine parts as they were assembled should be on file in case of investigations. That's how they found out why Apollo 13's O2 tank blew up and how the space shuttle's ET shed a large piece of foam on the 2005 Discovery return-to-flight mission.

Investigating anomalies is very interesting work, actually, although if fatalities and injuries are involved it kind of sucks the fun out of it some. Working on the Anteres launch vehicle program at least doesn't come with the heavy emotional cost of worrying about humans.

 

[ADSWNJ]

Hopefully, there will be enough of the pieces found to discover the cause(s) of the "anomaly" (sic).

"Anomaly" is such an innocuous word, ins't it? Like "mishap" (as used on the Antares explosion). Event, incident, transient, glitch ... it's just cold technical language, where we would otherwise use tragedy, disaster, etc.

For me, I reserve tragedy for a loss of life, so hence Antares was an explosion and VG SS2 was a tragedy.

 

[dman]

Quote There was an SR-71 that broke up in flight in the mid/late 60's that kicked the crew out. Both of them were wearing pressure suits, and I know that the pilot survived the accident. I can't recall why the RSO bought it, but given the fact that the pilot was literally torn from his seat by the forces...

Also, the USAF has a regulation about flying over 50,000 feet altitude: Pressure suits required. End of argument. Why don't they use them? Because of the increased pilot fatigue, reduced situational awareness, and decreased flexibility in the cockpit. And the fact that most aircraft in the inventory do NOT have the facilities for handling the suits the USAF uses nowdays: the David Clark suit like the ones used on the SR-71 and U-2. Quote

Found that pilots flying long hours at high altitude in U2 began to experience
decompression syndrome aka "bends" as low pressure in cockpit and suit
allowed nitrogen to come out of the blood

Caused memory blackouts as pilots literally forgot how to fly the plane

Fortunately no accidents

USAF responded by increasing pre breathe times before mission, increasing
cockpit pressurization from 29,000 ft equivalant to 15,000 ft equivalent

---------- Post added at 02:02 AM ---------- Previous post was at 01:48 AM ----------

Problem withany new technology is that requires long tedious and costly development process

SS2 is using a new un tried motor - its earlier cousin, SS1 development vehicle, experienced severe combustion instability with the solid rubber fuel

SS2 changed the fuel to nylon polymer - problem is in the nitrous oxide oxidizer

N2O can explode under certain conditions - couple years back a tank of the stuff
exploded during test killing 3 engineers

I suggested using a updated REDSTONE as booster for sub orbital flights as REDSTONE
design had been "wrung out"

Thread

http://www.orbiter-forum.com/showthread.php?t=34527

 

[Thunder Chicken]

Pressure suits are required if there is potential to be suddenly exposed to altitudes where the atmospheric pressure is less than the partial pressure of pure O2 required to maintain functioning. Even with a face mask feeding pure oxygen, at altitudes much above 50,000 ft the partial pressure of the oxygen is about the same as that in atmospheric air at around 15,000 ft.

Even though SS2 flew well above this altitude, pressure suits would likely not be much help in a catastrophic loss of vehicle event. Like the shuttle, the abort and egress options are very limited. The inherent assumption is that if the flight had to be terminated, the vehicle would need to be intact for the abort. Egress is not a viable option for a significant fraction of the SS2 flight profile. The survival of the one pilot was something of a miracle - a few more seconds of powered flight and the speeds and altitudes would have made survival all but impossible, pressure suit or not.

 

[Kyle]

Update to the status of the other crew member, Peter Siebold, apparently is "alert and talking with his family and doctors."

Great news in the light of everything else!

http://www.latimes.com/business/la-fi-virgin-galactic-crash-ntsb-20141101-story.html#page=1