News Virgin Galactic SpaceShipTwo accident during powered test flight

[Andy44]

Yes, but SS2 is not a launch vehicle, it's a self-propelled payload which carries passengers. For obvious reasons it had better be at least safer than, say, STS was.

As bad as this accident was, there is the very small consolation of it happening now rather than after passengers start flying.

 

[Keatah]

No. Spaceship 2 had had several previous flights. This was the first flight with either a new engine or a new fuel mixture. I am not sure which.

I know for fact it had a different propellant, Nylon. Nylon and a thermoplasticized polyamide.

I would guess the engine had been partly redesigned to accommodate the change. But, essentially, it was still a solid rubberized fuel.

I would also guess and assume the vibrations got out of hand, engine got into resonance, and vibrated itself to pieces.

 

[Cosmic Penguin]

Those that compares Antares/Cygnus with this one needs to remember that:

- All "traditional" orbital launch vehicles of today have an average success rate of only 90-95%.
- With oxygen-rich stage combustion engines such catastrophic failures shortly after liftoff are actually "within one's imaginations" with previous incidents. Look at one of my nightmares....
- Had Antares been carrying a manned spacecraft on top the LAS would surely have enough time to pull it away.

And SS2? It was supposed to provide a very high rate of safe operations, given its nature of flying passengers with very quick turnarounds. Yet the program run into so many troubles (not the least of which a 2007 test of the original rubber hybrid engine exploded killing 3 engineers), and that Virgin Galactic has been under enormous pressure to fly someone to 100 km ASAP (remember that Richard Branson has declared recently that he is hoping to fly on SS2 by early next year? Apparently Virgin Galactic's other shareholders, like a certain Middle East investment fund, were more than unhappy with the serious delays). And yet I still cannot predict such an accident on the very first flight with the new nylon based hybrid engine that should have reduced the oscillation problems with the previous engine.

Antares blowing up is at least within one's probable scenarios. SS2 disintegrating in mid-air on the other hand....

 

[Urwumpe]

I know for fact it had a different propellant, Nylon. Nylon and a thermoplasticized polyamide.

I would guess the engine had been partly redesigned to accommodate the change. But, essentially, it was still a solid rubberized fuel.

I would also guess and assume the vibrations got out of hand, engine got into resonance, and vibrated itself to pieces.

It could also be the case, that the solid fuel cracked and there was a chamber pressure transient - thats a very common problem with both solid and hybrid rocket engines, but solids are now designed to reduce the burn rate, when the chamber pressure increases, while hybrids would need active control over the oxidizer flow rate to compensate.


Since the only wreckage parts visible are the rudders and the elevons, I would also rather believe in the report that the engine assembly exploded.

http://www.parabolicarc.com/

 

[Keatah]

WTF? WTF? Quote, "A safe re-entry back into Earth's Orbit?"
Quote, "Somebody saw somebody trying to eject from that device." WTF? WTF?
There's more no doubt..
https://www.youtube.com/watch?v=jleTH5qly5o

Coolness..
https://www.youtube.com/watch?v=2x9PBidbwPs

 

[N_Molson]

Crew death = catastrophic failure.

Actually, it's a miracle that one of the crewmembers managed to bail out.

Never liked that thing too much I must say...

 

[Evil_Onyx]

Virgin Galactic crash: Branson vows to continue space project - BBC

The video has some photos of the breakup.

It is a sad day for commercial spaceflight.

 

[Unstung]

The Planetary Society seems to have provided some new information regarding the crash, at least that I haven't read about.

It is not yet clear what caused the accident. At the press conference, Scaled Composites president Kevin Mickey confirmed the flight was the first to substitute a plastic-based solid fuel for the motor's previous rubber-based compound. "This was a new fuel formulation. It had been proven and tested on the ground many times."

Several other news sources are referenced in the blog.

There's some more detail at SpaceNews.

[Stuart] Witt (the "chief executive of Mojave Air and Space Port") said he saw nothing unusual during the test that would lead him to conclude there was a problem. “I detected nothing that appeared abnormal,” he said. “It wasn’t because something did happen, it was what I was not hearing and not seeing. If there was a huge explosion, I didn’t see it.”

At the press conference, Mickey confirmed that the flight was the first to use a new hybrid rocket motor. Previous powered test flights, most recently on Jan. 10, featured a motor that used hydroxyl-terminated polybutadiene, a form of rubber. In May, Virgin Galactic announced it was switching the motor to a polyamide-based plastic.

Some of the engine's behavior leading up to the explosion has been described by NASA Watch.

According to CNN, SpaceShipTwo's engine started and ran for a few seconds but then stopped. It then restarted and exploded.

 

[Urwumpe]

Looks like the oxidizer tank got pushed forward in a piece of wreckage from the centerbody... but remained largely intact ... at least at the front dome

 

[ADSWNJ]

A somber and deep comment on that NASA site from a user jmach:

That desert is littered with the bones of test flights to get us where we are today in aerospace. The best way to honor them, and anyone who was injured or perished on this flight, is to push on. Prayers to the families, and Godspeed to Virgin Galactic.

 

[jroly]

Do you think it may have been due to the hybrid propulsion they use? My understanding VG have been heavily criticized because of it and is the main reason they have had delays.

 

[Urwumpe]

Do you think it may have been due to the hybrid propulsion they use? My understanding VG have been heavily criticized because of it and is the main reason they have had delays.

yes. The direct failure cause was very likely the engine.

But no, the problem is not their decision to use hybrid engines at all. It is a unknown technology in the scale that is needed for such a spacecraft. But such a kind of engine has properties that are very advantageous for the application... it makes really sense to try getting the technology developed at a larger scale.

 

[MaverickSawyer]

Actually, it's a miracle that one of the crewmembers managed to bail out.

They didn't bail out. The crew lack ejection seats, and it happened too quickly for them to depressurize the cabin and manually egress. I hate to say it, but the cabin disintegrated around them and threw them free.

 

[rhoude57]

8ndeed. The Spaceship Two is not equipped with ejection seats, only an escape hatch. Also, the test pilots were not wearing pressure suits. For test flights, it is customary for test pilots to don parachutes, as was the case for this flight. @MaverickSawyer is probably right. The ship probably disintegrated and the chutes deployed automatically at the set altitude.
http://www.universetoday.com/115873...irgin-galactics-spaceshiptwo-flight-accident/

 

[garyw]

Photos of the breakup

More debris

They didn't bail out. The crew lack ejection seats, and it happened too quickly for them to depressurize the cabin and manually egress. I hate to say it, but the cabin disintegrated around them and threw them free.

If the stories are true of the co-pilot still being strapped into his seat when it hit the ground then, yes. I think you're spot on that they were thrown clear of the explosion with the pilots chute auto-deploying and saving his life.

 

[Cosmic Penguin]

The NTSB is about to do a press briefing about the crash in Mojave - turn to ABC Bakersfield or NBC for live coverage.

 

[Cosmic Penguin]

The NTSB is about to do a press briefing about the crash in Mojave - turn to ABC Bakersfield or NBC for live coverage.

OK it looks like the investigation team just arrived so nothing to report about the facts yet. Apparently this is the first time NTSB is in lead of investigation about a "space launch failure" (they have participated in the investigation of the Challenger and Columbia accidents).

Next briefing later today.

 

[boogabooga]

8ndeed. The Spaceship Two is not equipped with ejection seats, only an escape hatch. Also, the test pilots were not wearing pressure suits. For test flights, it is customary for test pilots to don parachutes, as was the case for this flight. @MaverickSawyer is probably right. The ship probably disintegrated and the chutes deployed automatically at the set altitude.
http://www.universetoday.com/115873...irgin-galactics-spaceshiptwo-flight-accident/

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.

 

[Urwumpe]

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.

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.

 

[boogabooga]

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.

I never said that they should be wearing pressure suits. That isn't the problem. The problem is being suddenly and instantaneously without a spacecraft.

I'm sure Richard Branson has already hired someone to figure out how to serve champagne in zero gravity for his elite clientele. As for being fun, I was under the impression that XCOR and Copenhagen suborbital were going with that sort of strapped in, "wright stuff" sort of astronaut adventure experience.

That's the way I'd go, if I had a choice. Sorry, but staying at Ted Turner's four star luxury spa and resort the day before being launched into space strikes me as... sissy. Sorry. Either have a relaxing vacation, OR have an adventure.