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Whistling Past The GraveyardThe Ares graveyard, that is. Mark Whittington once again proudly demonstrates his ignorance about space technology. Some would be embarrassed by it, but never Mark. Now, I'm not adroit at deciphering the somewhat arcane language of NASA documents, though I've read my share of them. But the numbers that Jon quotes is under a column called "Current Analysis" which is to the right of a column called "TPM REQT." That suggests, just drawing on an ability to read the English language, that the numbers quoted are a snapshot in time and do not reflect where the folks working on Constellation expect to be when the Orion and Ares start flying. Therefore not quite as alarming as Rand, Jon, or the mysterious person who calls himself "Anonymous Space" would like to imply. You're right. You are not adroit (though there's nothing "arcane" about this particular document). Of course it's a "current analysis." That's the only kind of analysis that one can do in the present. When it's redone in the future, that analysis will be the current analysis. And the current analysis says that the LOC/LOM are nowhere near what was originally promised for the vehicle (just as was the case for the Shuttle). There are no obvious ways to improve it--the hazards that lower it to those numbers are essentially intrinsic to the design, and probably not mitigatible within the mass budget. There is also no obvious way to "expect" something different in the future. This reality is almost certainly the reason that the Preliminary Design Review was delayed into next year. It should also be noted that, despite the mythology about how "safe" the Saturn/CSM were, we were damned lucky to not lose a crew during Apollo. Had we flown a lot more missions, it's almost guaranteed that we would have. Had the oxygen tank that exploded in Apollo XIII occurred on the way back, we would have lost the crew, no matter how innovative and responsive ground control was, no matter how many times Gene Kranz declared that failure was not an option. Sometimes, failure happens. And one of the reasons that space costs so much, the way NASA does it, is that when failure isn't an option, success gets outrageously expensive. But it gets better: Putting it another way, it is so of like suggesting that the LOM probability for SpaceX's Falcon 1 will be %100 just because the first three test flights have all failed to achieve orbit. No, that is not "putting it another way." That is saying something entirely different and utterly irrelevant. If he's attempting to do a Bayesian probability of future Falcon success based on its history, the next flight would have a 75% chance of failure, not a hundred percent. But there's a big difference between making an empirical estimate from past performance, and an analytical estimate based on a probabilistic risk analysis, the latter of which is where the Orion/Ares LOC/LOM numbers come from. Ares hasn't flown yet, so it's absurd to compare it to Falcon's actual record. 0 TrackBacksListed below are links to blogs that reference this entry: Whistling Past The Graveyard. TrackBack URL for this entry: http://www.transterrestrial.com/admin/mt-tb.cgi/10189 10 CommentsLeave a comment
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Thanks Rand. I saw Mark's post and just rolled my eyes. The snapshot in time bit is disingenuous, because if you look on pages 63 and 65 IIRC, they also show where those numbers were a while ago. And several of the numbers are trending downward. Those that are trending upward are still well below where they were supposed to be.
But what would I know?
~Jon
While it may be true (excluding the Apollo 1 ground fire) Apollo had no loss of crew, it did suffer a loss of mission with Apollo 13.
So what was the crewed Saturn V's actual LOM number, 1 in 10 or so?
despite the mythology about how "safe" the Saturn/CSM were
Does anyone think that strapping a potential bomb to your ass is safe? They took some amazing risks in the 60's. Too bad the vocal public (my personal code words for the lunatic left) doesn't understand that risk is part of progress. We have become so risk averse that we are almost at a standstill.
" Of course it's a "current analysis." That's the only kind of analysis that one can do in the present. When it's redone in the future, that analysis will be the current analysis."
In others, Rand Simberg agrees that I'm right. How this tracks with his ad hominem smear is something of a puzzlement.
Rand Simberg agrees that I'm right.
No, Mark. But if that delusion gets you through the day, I doubt if I or anyone else will talk you out of it.
For a far more rational discussion of this subject, I would go here:
http://forum.nasaspaceflight.com/index.php?topic=14198.0
Mind, I enjoyed the sight of several engineering types setting Jon straight by pointing out how meaningless those LOC/LOM numbers are. I am, of course, vindicated.
I am, of course, vindicated.
Yes, Mark. There, there. Of course you are.
You don't understand either side of a technical discussion, so you just agree with the one that you imagine fits your own prejudices.
"Had the oxygen tank that exploded in Apollo XIII occurred on the way back, we would have lost the crew, no matter how innovative and responsive ground control was, no matter how many times Gene Kranz declared that failure was not an option."
Why? Too little total oxygen remaining before the explosion?
"Why? Too little total oxygen remaining before the explosion?"
No lifeboat. On a nominal Apollo mission, the LM upper stage gets left in lunar orbit. Had the explosion happened on the trip back, the CM would have had 15 minutes of battery life...and the astronauts would have had nowhere else to go.
Mark,
Once again, you just don't get it. As several others have pointed out, if the current numbers are completely useless (they aren't), then the numbers generated in the ESAS study which were based off of even less real information are even less relevant. There is absolutely zero reason to believe that some study done in 90 days before *any* detailed engineering is going to be closer to the mark than the results of over 3 years now of development effort. While it is reasonable to assume that the design will eventually improve over time (in spite of the fact that the paper linked actually showed most of those numbers decreasing from the last time they were computed), is it really reasonable to assume that it's going to improve by orders of magnitude? More importantly, now that it's no longer clear that the vehicle will be any safer in practice than the EELVs, and is provably not sooner or cheaper...what's the point again?
Sure, we can continue to pour billions of dollars and roll the dice and see if it happens to end up as rosy as the ESAS guys painted it originally. But I thought you were against "hope" as a policy prescription.
~Jon