Author Topic: SpaceX Falcon 9/Dragon CRS SpX-1 MISSION GENERAL DISCUSSION  (Read 633902 times)

Offline Ben the Space Brit

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Re: SpaceX Falcon 9/Dragon CRS SpX-1 MISSION GENERAL DISCUSSION
« Reply #500 on: 10/08/2012 11:16 am »
Really, a lot depends on the actual cause of the 'anomaly'.

If it was an engine failure (and subsequently RUD), then F9 Block 1 is grounded until a fix for Merlin-1C is identified and implemented.  The fact that this happened after acceptance tests and a static fire with no pre-warnings of a fault would raise issues about the engine's overall reliability.

However, if (as boinc suggests up-thread), the engine shut down after the bell contacted with debris, perhaps the side aerodynamic cover coming off, then it is just a case of double-checking the securing of the covers.  Are more rivets or welds needed? Is there an issue with metal fatigue?

An engine problem could impact on the schedule for SpX-2, but a structural issue might not.
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Offline alexterrell

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Re: SpaceX Falcon 9/Dragon CRS SpX-1 MISSION GENERAL DISCUSSION
« Reply #501 on: 10/08/2012 11:17 am »
Will this engine failure have any impact on future operations?

Of course it will. It's only logical to assume the vehicle is grounded until anomaly investigation is performed and corrective actions identified/implemented.
It probably will be grounded but I disagree that that is the logical step.

An anomaly ocurred and therefore without corrective actions may occur again. However, if the anomoly did not endanger the mission (within allowable levels) then there is no logical reason to delay the next launch.

I assume there is a period of analysis after which a decision is made on wheter to launch the next mission before corrective action is taken or after. 

Offline hrissan

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Re: SpaceX Falcon 9/Dragon CRS SpX-1 MISSION GENERAL DISCUSSION
« Reply #502 on: 10/08/2012 11:19 am »
Next step is to identify a failure which could knock out all engines, including an analysis of how well the correction software (and hardware) performed (it appears to have done its job). Could one engine failure plus a computing failure lead to LOM.

SpaceX would I'm sure love to get their hands on the engine shielding for the neighbouring engines. Did it contain all the damage - or were neighbouring engines lucky to survice (saved by the bell)? Did they get some high resolution pictures? Or will they be able to recover this stage?

What happened when the engine failed to the vehicle flight path. Was there a shock to the system which might damage other equipment? I assume they have accelerometer telemetary to measure just that.

Lots of analysis to do but this failure does demonstrate the safety of the rocket.
Another reason for reusability. :) If the rocket did not explode completely, you could investigate hardware after you get it back to Earth.

Offline ugordan

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Re: SpaceX Falcon 9/Dragon CRS SpX-1 MISSION GENERAL DISCUSSION
« Reply #503 on: 10/08/2012 11:23 am »
However, if the anomoly did not endanger the mission (within allowable levels) then there is no logical reason to delay the next launch.

I shudder to think that we've come to a point where a potential engine RUD is not labeled as a mission-endangering event. Just like Delta IV a couple of days ago, they might have been lucky this time. If you don't treat this as a major anomaly that it is, you're back to "normalization of deviance".

Offline Lol

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Re: SpaceX Falcon 9/Dragon CRS SpX-1 MISSION GENERAL DISCUSSION
« Reply #504 on: 10/08/2012 11:23 am »
There is no particularly good reason to think that it will be done by then, either.
Quite contrary.

Few reasons for that.

In most cases(>50%) root cause of rocket failure was determined in well under 3 months.
SpaceX is vertically integrated, most work done by them and they are quite independent of supply chain. 

For example, Falcon 1 Flight 3 failure was investigated and corrective measures were taken, so Flight 4 occurred less then 2 months after Flight 3.

Why do you assume root cause analysis and corrective action will be as trivial as that?
Trivial? I never said that. Please stop imagining things.

But what is your reasons for assuming that it wont be done by next year?
« Last Edit: 10/08/2012 11:25 am by Lol »

Offline ugordan

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Re: SpaceX Falcon 9/Dragon CRS SpX-1 MISSION GENERAL DISCUSSION
« Reply #505 on: 10/08/2012 11:33 am »
But what is your reasons for assuming that it wont be done by next year?

Because this wasn't a trivial software timing issue that could have been fixed in a couple of minutes like your other example. An engine that went through an engine acceptance test and at least two stage acceptance tests and which, during development, accumulated several thousand seconds of firing time apparently let go spectacularly. If you believe this to be a quick fix, that's your right. I am not nearly as optimistic as you that even if RCA is done swiftly that corrective actions will be possible on such a short order.

Online Robotbeat

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Re: SpaceX Falcon 9/Dragon CRS SpX-1 MISSION GENERAL DISCUSSION
« Reply #506 on: 10/08/2012 11:35 am »
That they survived this flight wasn't luck. It was excellent engineering.
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Offline Harold KSC

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Re: SpaceX Falcon 9/Dragon CRS SpX-1 MISSION GENERAL DISCUSSION
« Reply #507 on: 10/08/2012 11:39 am »
Catching up. These guys are scary. Need to stop dodging bullets before they put a crew anywhere near this LV.

That they survived this flight wasn't luck. It was excellent engineering.

"Excellent engineering" avoids the anomaly from happening. What next, the vehicle blows up and you'll praise their excellent FTS? :)
« Last Edit: 10/08/2012 11:40 am by Harold KSC »

Offline alexterrell

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Re: SpaceX Falcon 9/Dragon CRS SpX-1 MISSION GENERAL DISCUSSION
« Reply #508 on: 10/08/2012 11:41 am »
However, if the anomoly did not endanger the mission (within allowable levels) then there is no logical reason to delay the next launch.

I shudder to think that we've come to a point where a potential engine RUD is not labeled as a mission-endangering event. Just like Delta IV a couple of days ago, they might have been lucky this time. If you don't treat this as a major anomaly that it is, you're back to "normalization of deviance".
But isn't it progress where a potential engine RUD is not a mission endangering event? Where we can treat this specific failure mode (if it can be found out) in the same way as an airline treats an enegine failure.

The cautionary principle means no more flights until either:
1. The cause of the engine failure is identified and fixed
2. It is proven this is not a Mission Endangering Event.

Of course, the key to (2) would be to analyse the engines and see whether it was luck or good design that saved the vehicle. That may not be possible. (Where is the engine now?)



Offline peter-b

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Re: SpaceX Falcon 9/Dragon CRS SpX-1 MISSION GENERAL DISCUSSION
« Reply #509 on: 10/08/2012 11:46 am »
The cautionary principle means no more flights until either:
1. The cause of the engine failure is identified and fixed
2. It is proven this is not a Mission Endangering Event.

Given that there are only two (?) more flights of this engine design scheduled, the engine-out capability has been demonstrated, the engines and stages have already been constructed, and the flights are unmanned, I wonder if it'll be cheaper for SpaceX to fly them anyway (even with slightly higher insurance premiums) than to modify/rebuild the engines/stages...
Research Scientist (Sensors), Sharp Laboratories of Europe, UK

Offline Ronsmytheiii

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Re: SpaceX Falcon 9/Dragon CRS SpX-1 MISSION GENERAL DISCUSSION
« Reply #510 on: 10/08/2012 11:54 am »
Given that there are only two (?) more flights of this engine design scheduled, the engine-out capability has been demonstrated, the engines and stages have already been constructed, and the flights are unmanned, I wonder if it'll be cheaper for SpaceX to fly them anyway (even with slightly higher insurance premiums) than to modify/rebuild the engines/stages...
That would be normalization Of Deviance, which as we have seen is a deadly combination.  Better to just stop and fix it now, as whatever might be wrong with Falcon 9 1.0 might be able to occur on 1.1 as well.

Offline docmordrid

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Re: SpaceX Falcon 9/Dragon CRS SpX-1 MISSION GENERAL DISCUSSION
« Reply #511 on: 10/08/2012 11:56 am »
The cautionary principle means no more flights until either:
1. The cause of the engine failure is identified and fixed
2. It is proven this is not a Mission Endangering Event.

Given that there are only two (?) more flights of this engine design scheduled, the engine-out capability has been demonstrated, the engines and stages have already been constructed, and the flights are unmanned, I wonder if it'll be cheaper for SpaceX to fly them anyway (even with slightly higher insurance premiums) than to modify/rebuild the engines/stages...

I believe CRS-2 is the sole remaining F9 v-1.0/M1C flight, the next being an essentially new bird: the Q1 2013 flight of F9 v-1.1 from Vandenberg.
« Last Edit: 10/08/2012 11:59 am by docmordrid »
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Offline krytek

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Re: SpaceX Falcon 9/Dragon CRS SpX-1 MISSION GENERAL DISCUSSION
« Reply #512 on: 10/08/2012 11:57 am »

Just saw this on NewSpace Watch. No idea if it has been posted already.

http://spaceref.biz/news/viewsr.html?pid=42263

Quote
According to a statement provided to NASAWatch by Elon Musk at SpaceX:

"Falcon 9 detected an anomaly on one of the nine engines and shut it down. As designed, the flight computer then recomputed a new ascent profile in realtime to reach the target orbit, which is why the burn times were a bit longer. Like Saturn V, which experienced engine loss on two flights, the Falcon 9 is designed to handle an engine flameout and still complete its mission. I believe F9 is the only rocket flying today that, like a modern airliner, is capable of completing a flight successfully even after losing an engine. There was no effect on Dragon or the Space Station resupply mission."

Offline VatTas

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Re: SpaceX Falcon 9/Dragon CRS SpX-1 MISSION GENERAL DISCUSSION
« Reply #513 on: 10/08/2012 12:00 pm »
Looking at the slow-motion Youtube video, the double view, righthand rocket cam... at T+1:30 as indicated in the video.

Is it a trick of the lighting or does the entire skin of the vehicle deflect "inwards" just above the center of the frame?
Somehow everybody on the thread is ignoring this. That's clearly deformation, not some trick of light. It appears to happen several seconds after engine 1 problem (note that external and on-board camera views are out of sync). It's interesting what might have caused this? This must have been some considerable force acting to cause such effect.

Offline ugordan

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Re: SpaceX Falcon 9/Dragon CRS SpX-1 MISSION GENERAL DISCUSSION
« Reply #514 on: 10/08/2012 12:03 pm »
I believe CRS-2 is the sole remaining F9 v-1.0/M1C flight

+ Jason-3 for NASA.

Online Robotbeat

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Re: SpaceX Falcon 9/Dragon CRS SpX-1 MISSION GENERAL DISCUSSION
« Reply #515 on: 10/08/2012 12:04 pm »
Catching up. These guys are scary. Need to stop dodging bullets before they put a crew anywhere near this LV.

That they survived this flight wasn't luck. It was excellent engineering.

"Excellent engineering" avoids the anomaly from happening. What next, the vehicle blows up and you'll praise their excellent FTS? :)
They're bound to get an engine failure, so designing your rocket to work with an engine failure is a good idea.

I do computer storage engineering as a part time job. We often have hard drive failures, but because we use RAID, we haven't ever totally lost any data. Part failure is inevitable. System failure is not. How your system deals with part failure shows your true engineering capability.
« Last Edit: 10/08/2012 12:15 pm by Robotbeat »
Chris  Whoever loves correction loves knowledge, but he who hates reproof is stupid.

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Offline VatTas

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Re: SpaceX Falcon 9/Dragon CRS SpX-1 MISSION GENERAL DISCUSSION
« Reply #516 on: 10/08/2012 12:12 pm »
Screen captures showing dent appearing in the interstage.
(very noticeable when you switch between these two pictures in some picture viewer)
« Last Edit: 10/08/2012 12:14 pm by VatTas »

Offline ugordan

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Re: SpaceX Falcon 9/Dragon CRS SpX-1 MISSION GENERAL DISCUSSION
« Reply #517 on: 10/08/2012 12:16 pm »
We often have hard drive failures, but because we use RAID, we haven't ever totally lost any data.

Come on. Hard drive failures don't have the tendency of destroying other hard drives when they fail. I cannot believe how you can say that one occurence of a engine anomaly not resulting in LOV proves the vehicle is robust. By the same token STS-27 "proved" that Shuttle will survive tile damage.

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Re: SpaceX Falcon 9/Dragon CRS SpX-1 MISSION GENERAL DISCUSSION
« Reply #518 on: 10/08/2012 12:27 pm »
We often have hard drive failures, but because we use RAID, we haven't ever totally lost any data.

Come on. Hard drive failures don't have the tendency of destroying other hard drives when they fail....
actually, yes it does. The rebuilding process really stresses the drives and can cause another hard drive to fail much earlier, which is why you have RAID 6 and synchronous mirroring.


Before this flight, SpaceX had flown more Merlins than Atlas V has flown rd180s. There is no evidence SpaceX has a higher than industry standard level of engine failure. But they are the only folks who can survive engine failure and still complete the mission. To hold another view is to have a bias in systems engineering towards systems without redundancy, which are simpler and will thus have a lower incidence of per mission parts failures, but will have higher system failure rates than a properly engineered redundant system.
Chris  Whoever loves correction loves knowledge, but he who hates reproof is stupid.

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Offline Chris-A

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Re: SpaceX Falcon 9/Dragon CRS SpX-1 MISSION GENERAL DISCUSSION
« Reply #519 on: 10/08/2012 12:27 pm »
Screen captures showing dent appearing in the interstage.
(very noticeable when you switch between these two pictures in some picture viewer)

That is a umbilical connection point for the upper stage.

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