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SpaceshipTwo crashes shortly after Mojave test flight

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Re: SpaceshipTwo crashes shortly after Mojave test flight

#241

Post by neurotech1 »

robryk wrote: post #221
neurotech1 wrote: post #191

Earlier quoted context omitted.

Your forgetting the countless times that a test pilot has saved the aircraft/spacecraft from destruction. If it was unmanned and flown by computer, it would have been a fireball. At least one shuttle flight would have been lost if the crew didn't fly manually to correct for a malfunction. STS-4 PIO'd on landing and would have crashed if auto-stabilization wasn't overridden by the pilot.

According to wikipedia, it was STS-3 that had (autoopilot-induced) oscillations during landing. The description on Wikipedia seems to imply that they were expected (the autopilot was being tested) and that the dangerous condition was due to the autopilot being left partially engaged after the test.

Correct. There was also an pitch stabilization system that malfunctioned due to the misconfigured (partially engaged) autopilot. Point remains that the pilots flying skills in the cockpit saved the orbiter.

Re: SpaceshipTwo crashes shortly after Mojave test flight

#243

Post by marze »

termain wrote: post #215
marze wrote: post #195

Earlier quoted context omitted.

"1. They didn't stay with rubber/nitrous." This you believe so strongly because a news story stated it? Wait for the accident report. It will say "rubber".

Aviation Week reported it back in May. So, yes. I'll keep an eye out for the accident report. http://m.aviationweek.com/space/new-fuel-boost-spaceshiptwo

Well you could be right, but it is very hard to imagine that being true since the plastic hybrid has only been tested once on the ground. Doing a flight test so soon would be totally insane. In any case, the disaster was undoubtably a result of inadequate ground testing.

Problems like these are almost always the result of management pushing things faster than the engineering progress warrants.

Re: SpaceshipTwo crashes shortly after Mojave test flight

#245

Post by Turing_Machine »

melling wrote: post #148
Turing_Machine wrote: post #107

Earlier quoted context omitted.

"x The Alaska crab program doesn't come to a complete stop for a couple years while there's an investigation" Neither will Virgin Galactic. "You don't need to go to Congress and request an additional $1.7 billion for another ship." Neither does Richard Branson.

Perhaps, you haven't noticed but I'm using this accident to discuss our national space program. Virgin Galactic has a plane that goes to 62 miles/100km. While this is great, in the short-term, it doesn't help our space program. Btw, you don't think they need to revisit safety to assure their customers that it's not a one way trip? Do they even have a second plane? There's not a chance that there will be a commercial…

"Btw, you don't think they need to revisit safety to assure their customers that it's not a one way trip?"

Not from what I'm seeing. No one is planning to cancel their reservation. I wouldn't, if I had one.

Re: SpaceshipTwo crashes shortly after Mojave test flight

#246

Post by marze »

DanBC wrote: post #76
marze wrote: post #69

Earlier quoted context omitted.

Some say this is an "inevitable" result of pushing boundaries. No. This is the result of a poorly managed program. What they are doing is much easier than the Apollo program, which was well managed and had no in-flight failures that resulted in loss of life, while accomplishing an infinitely harder task. This is a tragedy, obviously. But the program is about six years behind schedule, been going for 10 years. The mos…

> Apollo program, which was well managed and had no in-flight failures that resulted in loss of life The flaws in Apollo One were so severe the three crew died on the launchpad. Describing that tragedy as "no in-flight deaths" is accurate but misses some important information. http://en.wikipedia.org/wiki/Apollo_1

True. But it is almost pointless to compare these two programs since Apollo was so much more complex.

To put it in perspective, Apollo flew on a rocket with five engines producing 1,500,000 lbf thrust each, on the first stage alone. By contrast, the Virgin motor produces 60,000 lbf thrust for 70 seconds.

The Apollo program had a safety culture configured so that if anyone identified a safety issue, they became responsible for the problem and responsible to sign off that it was corrected.

Re: SpaceshipTwo crashes shortly after Mojave test flight

#247

Post by termain »

marze wrote: post #243
termain wrote: post #215

Earlier quoted context omitted.

Aviation Week reported it back in May. So, yes. I'll keep an eye out for the accident report. http://m.aviationweek.com/space/new-fuel-boost-spaceshiptwo

Well you could be right, but it is very hard to imagine that being true since the plastic hybrid has only been tested once on the ground. Doing a flight test so soon would be totally insane. In any case, the disaster was undoubtably a result of inadequate ground testing. Problems like these are almost always the result of management pushing things faster than the engineering progress warrants.

I think it's also possible that a bad fuel grain slipped through whatever QA process they had. You might count that as insufficient ground testing, though.

"Problems like these are almost always the result of management pushing things faster than the engineering progress warrants."

Coincidentally, we were talking about such an instance today at work, the Conestoga 1620. As relayed to me, the "low frequency noise" mentioned in the wikipedia post was a low frequency structural mode that was missed because management didn't want to pay for a high enough fidelity finite element analysis.

https://en.wikipedia.org/wiki/Conestoga_%28rocket%29

Re: SpaceshipTwo crashes shortly after Mojave test flight

#248

Post by Raptor22 »

yongjik wrote: post #214
ceejayoz wrote: post #83

Earlier quoted context omitted.

> Space travel is awesome, but so is living, and right now we are not living in a way that is sustainable over the short term. Space travel is fundamental to the human species living sustainably in the long term. Correcting greenhouse gasses doesn't help us if the next day we find a planet-killer asteroid is a few weeks away.

I don't think you fully appreciate just how difficult space travel is, especially the kind of space travel where you found a colony that will sustain itself after the Earth is hit by an asteroid . The required scale of technology/economy comfortably puts it in "at least several centuries from now, if we're incredibly lucky and/or devoted". In this regard, the comment about CO2 is actually much more pertinent than it…

> The required scale of technology/economy comfortably puts it in "at least several centuries from now, if we're incredibly lucky and/or devoted".

We went from not flying anything heavier than air to going to the Moon in 66 years. If we really really wanted to, we could go to Mars in thirty. This is a problem of priorities, not technologies (although the technological problems are real, they are not insurmountable).

Re: SpaceshipTwo crashes shortly after Mojave test flight

#249

Post by chrisweekly »

Tangent: I think it's safe to say that HN -- on this thread in particular -- is populated by many people who are deeply interested in space travel.

I'd like to recommend everyone select as their next book for pleasure reading Andy Weir's "The Martian".

Here's my GoodReads review:

It's not high-brow literature by any stretch. But it's not about the writing per se, it's about the story. I challenge anyone to read it without caring what happens to the protagonist. I recognize that he (and perhaps by extension the author?) may be borderline juvenile on a few occasions... but for me it hardly detracted from the reading experience. On the contrary, I was sufficiently immersed in being on Mars in the shoes of this bold and lonely astronaut that the book per se disappeared nearly the entire time I read it. Pausing to re-read a noteworthy turn of phrase or analyzing it as literature might well have detracted from the author's intent. The story is the thing. For me, the writing got out of the way. And I'm glad it did. This is an extremely well-researched, gripping, exciting page-turner. If you are remotely interested in space travel, imho it's a must-read.

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