SpaceX – Launch Vehicle Failure • Hacker News Board

Re: SpaceX – Launch Vehicle Failure

#341

Post by Ntrails » Mon, Jun 29, 2015, 8:55 AM UTC

Retric wrote: post #334

nhstanley wrote: post #333

Earlier quoted context omitted.

"Why did you want to climb Mount Everest?" "Because it's there. Everest is the highest mountain in the world, and no man has reached its summit. Its existence is a challenge. The answer is instinctive, a part, I suppose, of man's desire to conquer the universe." - George Mallory

That's a great reason to be the first to climb Everest, but it seems lacking to be the 4,000th.

Why do people run marathons? It's a personal challenge. Hundreds of thousands of people do non-record breaking runs which are pain, suffering and followed by elation at success.

That he was the first was a big part of it, but the reality is remove the words "never been climbed" and the sentence still works. Climbing everest, running a marathon, [insert challenging sports thing here] - each person strives within their own measure and tries to exceed their own expectations.

Re: SpaceX – Launch Vehicle Failure

#342

Post by nanofortnight » Mon, Jun 29, 2015, 10:56 AM UTC

thearn4 wrote: post #88

n_coats wrote: post #49

Earlier quoted context omitted.

I saw two big puffs of smoke and initially thought it was the boosters releasing.

It did looks like it was close to the point of stage separation. But we'll see soon what the SpaceX's engineering analysis is.

Yes it was close to meco.

Re: SpaceX – Launch Vehicle Failure

#343

Post by phkahler » Mon, Jun 29, 2015, 2:29 PM UTC

robzyb wrote: post #319

phkahler wrote: post #313

Earlier quoted context omitted.

>> "That's all we can say with confidence right now. Will have more to say following a thorough fault tree analysis." You're supposed to do the fault tree analysis before you build the rocket Elon. The safety critical systems on your car have these done. Or perhaps they never did one for over pressure because it seems implausible for the pressure to increase.

> You're supposed to do the fault tree analysis before you build the rocket Elon. How can you do a fault tree analysis before things go wrong? Maybe fault tree analysis means something different to you. According to Wikipedia, it is "a top down, deductive failure analysis in which an undesired state of a system is analyzed using Boolean logic to combine a series of lower-level events." There needs to be an undesirabl…

>> How can you do a fault tree analysis before things go wrong?

Formal fault tree analysis has been used byt the nuclear power industry for decades. You may consult the "Fault Tree Handbook" also known as NUREG-0492 which can be found here:

http://www.nrc.gov/reading-rm/doc-collections/nuregs/staff/s...

It has been adopted in parts of the auto industry for at least a decade (I was directly exposed to this).

You start with a preliminary hazard analysis based on what could go wrong and work backward through the system to identify things connected to the component in question that would lead to the undesired outcome. You'll build a large binary circuit where the inputs are events or problems and the output is a failure. The tools can do an analysis to determine what combinations can lead to that failure. If the simplified boolean expression contains any single terms, you have a single point of failure that will lead to the undesired outcome. You then redesign the system so that no single point failures lead to disaster.

THIS ANALYSIS HAS TO BE DONE BEFORE YOU BUILD IT TO BE ANY GOOD.

I always liked this way better than the more common "faulure modes and effects analysis" or FMEA, which makes you try to determine system-wide consequences of component failures - often down to individual resistors. These do find problems at design time, but IMHO it's too much work. With a fault tree you get to treat larger assemblies as a component.

Re: SpaceX – Launch Vehicle Failure

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Post by akhilpo » Mon, Jun 29, 2015, 2:41 PM UTC

India's ISRO sent a mars mission for around $70 million. That was including the payload i think. How is $60 million cheap for just a launch vehicle?

Re: SpaceX – Launch Vehicle Failure

#345

Post by trjordan » Mon, Jun 29, 2015, 4:24 PM UTC

joezydeco wrote: post #291

humbledrone wrote: post #270

Earlier quoted context omitted.

Average cost for successful launch: * United Launch Alliance: $110 million * SpaceX: $63.5 million ($60 million * 18 total / 17 successful) So SpaceX saves you $46.5 million per successful launch. If we assume that 1/18 SpaceX launches fail, then in the long run SpaceX wins as long as your typical payload cost is less than $46.5 * 18 = $837 million. If we assume that the cost to replace the payload for a failed launc…

Does this formula apply to manned spacecraft? What's the payload value of an astronaut? (Not trying to be snarky here, just thinking that the 1/18 vs 0/83 comparison seems moot when you have humans on board)

At some point, yes, there is a monetary value to human life. During the early days of space flight, it was something like $1 million per astronaut. These days, it's up to something more like $50 million per astronaut (inflation would put it as more like $7 million).

I don't have my original source on this, but here's a good article discussing that and the concept of "mission success": http://reason.com/archives/2012/01/26/how-much-is-an-astrona...

Re: SpaceX – Launch Vehicle Failure

#346

Post by darkmighty » Tue, Jun 30, 2015, 6:14 AM UTC

ams6110 wrote: post #299

dewarrn1 wrote: post #232

Earlier quoted context omitted.

So with a 5.5% margin the $1.6 billion contract would be expected to yield $88 million in profit? Given what I'm assuming are large R&D expenditures on top of launch-related costs, I wonder whether the business is sustainable.

5.5% profit, if reliably realized, is sustainable. It's comparable to a conservative investment return. That said, most businesses strive for more than that.

Yea where I live I get 7% (over inflation) on treasury bonds (it's kinda insane here, but 5.5% does seem like a low value). I assume all missions are fully insured to prevent bankruptcy with such low margins?

If it is so I would imagine simply improving the reliability track of the vehicle to lower insurance would have a very large effect on profitability. If they could eventually tank the insurance partially/completely in house (given a low chance of failure) that would be even better.

Re: SpaceX – Launch Vehicle Failure

#347

Post by PieterCVoges » Tue, Jun 30, 2015, 6:26 AM UTC

Just wondering... Why don't they use the new V2 Dragon with it's escape/abort system in all future resupply missions? At least they should be able to save the very expensive lab supply equipment, instruments, experiments, etc. Just fit it with the current V1 Dragon attach system for ISS docking.