Author Topic: SpaceX Falcon 9/Dragon CRS SpX-1 MISSION GENERAL DISCUSSION  (Read 624819 times)

Offline Dave Huntsman

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Re: SpaceX Falcon 9/Dragon CRS SpX-1 MISSION GENERAL DISCUSSION
« Reply #540 on: 10/08/2012 02:34 pm »
Quote
Exactly. They have lots of telemetry and video both from the vehicle and from the tracking camera. The idea that they would fly again without analysing and correcting this issue is frankly ridiculous.

That brings up another question, though: I'll hazard a guess that launch video will prove significant in diagnosing what happened. Yet, if I am not mistaken, launch video was not a Go/No Go requirement for launch.  After they institute a fix(es) before next flight, will they also have to insist that launch video systems- and sufficiently clear weather - also be launch constraints for flight? If so, that could end up being one of the bigger impacts from this.
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Offline marsman2020

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Re: SpaceX Falcon 9/Dragon CRS SpX-1 MISSION GENERAL DISCUSSION
« Reply #541 on: 10/08/2012 02:51 pm »
At this point as far as we know, Orbcomm ended up in the 200kmx330km orbit?

I hope their business as a satellite communications provider doesn't like...depend on having operating satellites in the correct orbits or anything.

Offline woods170

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Re: SpaceX Falcon 9/Dragon CRS SpX-1 MISSION GENERAL DISCUSSION
« Reply #542 on: 10/08/2012 03:00 pm »
What a shame...  This thread was perfectly good up to page 24. And then we got 13 pages mostly filled with assumptions, uneducated guessing and armchair engineering.  :(

Thank goodness the big boss on this forum writes his articles based on hard facts only.
« Last Edit: 10/08/2012 03:01 pm by woods170 »

Offline Robotbeat

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Re: SpaceX Falcon 9/Dragon CRS SpX-1 MISSION GENERAL DISCUSSION
« Reply #543 on: 10/08/2012 03:01 pm »
Exactly. They have lots of telemetry and video both from the vehicle and from the tracking camera. The idea that they would fly again without analysing and correcting this issue is frankly ridiculous.
I never claimed they wouldn't analyse it -- in fact I'm sure they're doing just that, in great detail. I merely suggested that it might not be cost-effective to correct it for exactly one final flight of the model of engine that failed. I.e. the cost of LOM on SpX-2 multiplied by the probability of the same issue both recurring and resulting in LOM, might be less than the cost of effectively rebuilding an entire Falcon 9 LV. I'm 100% certain that any necessary changes will be introduced to new build Falcon 9s and the Merlin 1D engine.
I bet they will do what they need to do, actually. If this had been an actual full failure, they would really be paying for it, so they will reduce that risk as much as they can, even if just for a single flight.
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Offline Jim

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Re: SpaceX Falcon 9/Dragon CRS SpX-1 MISSION GENERAL DISCUSSION
« Reply #544 on: 10/08/2012 03:03 pm »
As for whether this CRS-1 event will impact the CRS-2 launch: it's almost certain that somebody now has a lot more work to do between now and then! I hope they are open about it. Can anyone confirm the investigation will need to fully include the range operator (USAF) at a minimum? Does NASA pay for insight into this at all?

No need for USAF as range operator but maybe USAF as potential user.  Via the NLS contract, NASA has insight.

Offline Jim

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Re: SpaceX Falcon 9/Dragon CRS SpX-1 MISSION GENERAL DISCUSSION
« Reply #545 on: 10/08/2012 03:04 pm »
Why did the second stage roll control thruster only fire (repeatedly) in one direction?

Normally you see it burn aprox. equally amount of times (about 45 degrees left/right).

Any thoughts?
 

because it was correcting the attitude.

Offline edkyle99

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Re: SpaceX Falcon 9/Dragon CRS SpX-1 MISSION GENERAL DISCUSSION
« Reply #546 on: 10/08/2012 03:10 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.

This is just Max-Q pressure effects, in my opinion.  We've seen parts of the Shuttle External Tank (or fairings on the ET), and other rockets I believe, deflect in similar ways.  These rockets are flexible!

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Offline edkyle99

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Re: SpaceX Falcon 9/Dragon CRS SpX-1 MISSION GENERAL DISCUSSION
« Reply #547 on: 10/08/2012 03:13 pm »
At this point as far as we know, Orbcomm ended up in the 200kmx330km orbit?

I'm going to wait a day to see how Space Trak sorts things out. 

 - Ed Kyle

Offline Jim

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Re: SpaceX Falcon 9/Dragon CRS SpX-1 MISSION GENERAL DISCUSSION
« Reply #548 on: 10/08/2012 03:15 pm »
I'm going with a nozzle failure.

Lots of exposed tubes on a Merlin 1C. How humid has it been at the pad?

I worry about rocket engines rusting away. I don't like to see launch vehicles rolled around outdoors too often. Just put them on the pad and fire them off, don't expose them to the elements.

Nozzle failure would not have those affecs.  Rusting?  That is never an issue, even if sat on the pad for a year.

Offline Jim

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Re: SpaceX Falcon 9/Dragon CRS SpX-1 MISSION GENERAL DISCUSSION
« Reply #549 on: 10/08/2012 03:16 pm »
Simply amazing that this (explosion) didn't turn into a a loss of mission.  They'll probably call it a success because it "proves" the robustness of their design.

I call it by the skin of their teeth!


No, they got the same benefit as Delta IV did recently.  They had excess performance.

Skin of their teeth or not, I am very impressed.  Whether you want to call it an explosion or not the event looked very energetic and big chunks of the rocket got blown out into the slipstream and other big chunks fell off.  Falcon 9 just kept on trucking.

Offline Tcommon

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Re: SpaceX Falcon 9/Dragon CRS SpX-1 MISSION GENERAL DISCUSSION
« Reply #550 on: 10/08/2012 03:16 pm »
At this point as far as we know, Orbcomm ended up in the 200kmx330km orbit?

I'm going to wait a day to see how Space Trak sorts things out. 

 - Ed Kyle

"Falcon 9 did not make its second upper stage burn, and the Orbcomm satellite is being tracked in low orbit instead of its elliptical target orbit."
http://www.facebook.com/jsrpage/posts/10151048911726680

Offline Jim

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Re: SpaceX Falcon 9/Dragon CRS SpX-1 MISSION GENERAL DISCUSSION
« Reply #551 on: 10/08/2012 03:19 pm »

Bottom line, there was no LOM and SpaceX gets paid for cargo delivery.  There aren't bonus points awarded for perfection.  Personally, I am skeptical of theories that rely on a fundamental design flaw for a system that has made orbit 4 times now.

The Merlin is designed to be inexpensive and reliable enough.  The rest of the SpaceX validation process and ultimately the engine out capability of Falcon 9 are designed to weed out bad engines and mitigate the effects of a failure like this one.

Wrong on many counts.
There are penalty points for successful missions with problems
4 flights does not prove a design.
And the last sentence is unsubstantiated.

Offline Jim

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Re: SpaceX Falcon 9/Dragon CRS SpX-1 MISSION GENERAL DISCUSSION
« Reply #552 on: 10/08/2012 03:20 pm »
*If* this was a RUD event for engine 1 - Would this be the first time a LV has survived an "engine RUD" and still delivered the payload successfully?

I'm wondering about that too.  Did we witness an historic first tonight?

No, there is nothing historic about it.

Offline Jim

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Re: SpaceX Falcon 9/Dragon CRS SpX-1 MISSION GENERAL DISCUSSION
« Reply #553 on: 10/08/2012 03:21 pm »
It obviously *looked* pretty serious and Spacex confirm early engine shutdown.

I'll note that concerns about aerodynamic forces shredding the engine nozzle tend to be about the engine at *sea* level, not when the engine, or rather the nozzle on it reaches (or exceeds) its designed altitude. On that basis the idea that the engine was starting to spin down (smoky exhaust suggesting unburnt RP1) and the unbalenced aero forces tearing the nozzle off seem unlikely.

If it was a full on RUD event this could be Spacex's *finest* hour.

Engine is not just shut down early, it's *destroyed* (if correct).
Primary mission goes to completion.
Secondary mission also appears to have successfully been carried out.

As others have asked, has a mission *ever* survived that much damage and still succeeded?

No LOM, No LOV and I suspect (but cannot prove) had it been a crewed Dragon no LOC (I can imagine ways to kill the crew which leave the capsule intact but I can't believe they would not be picked up in design or test).

I also suspect ISS crew will be taking a *very* detailed look over the whole of Dragon looking for damage before they commit to berthing.

The key issues are design flaw Vs fabrication flaw and how to correct and/or detect it.

No doubt a lot of telemetry is being chewed through right now and I hope NASA don't get cold feet over Dragon and CRS. while shocking I believe the results will be of *huge* benefit to the programme.

Wrong, this is not a finest hour.  They just got lucky.  A performance critical mission would not have the same out come.

Offline Jim

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Re: SpaceX Falcon 9/Dragon CRS SpX-1 MISSION GENERAL DISCUSSION
« Reply #554 on: 10/08/2012 03:22 pm »
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".

bingo

Offline Jim

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Re: SpaceX Falcon 9/Dragon CRS SpX-1 MISSION GENERAL DISCUSSION
« Reply #555 on: 10/08/2012 03:23 pm »
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?

Wrong.  You have no basis for your points

Offline Lurker Steve

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Re: SpaceX Falcon 9/Dragon CRS SpX-1 MISSION GENERAL DISCUSSION
« Reply #556 on: 10/08/2012 03:30 pm »
It obviously *looked* pretty serious and Spacex confirm early engine shutdown.

I'll note that concerns about aerodynamic forces shredding the engine nozzle tend to be about the engine at *sea* level, not when the engine, or rather the nozzle on it reaches (or exceeds) its designed altitude. On that basis the idea that the engine was starting to spin down (smoky exhaust suggesting unburnt RP1) and the unbalenced aero forces tearing the nozzle off seem unlikely.

If it was a full on RUD event this could be Spacex's *finest* hour.

Engine is not just shut down early, it's *destroyed* (if correct).
Primary mission goes to completion.
Secondary mission also appears to have successfully been carried out.

As others have asked, has a mission *ever* survived that much damage and still succeeded?

No LOM, No LOV and I suspect (but cannot prove) had it been a crewed Dragon no LOC (I can imagine ways to kill the crew which leave the capsule intact but I can't believe they would not be picked up in design or test).

I also suspect ISS crew will be taking a *very* detailed look over the whole of Dragon looking for damage before they commit to berthing.

The key issues are design flaw Vs fabrication flaw and how to correct and/or detect it.

No doubt a lot of telemetry is being chewed through right now and I hope NASA don't get cold feet over Dragon and CRS. while shocking I believe the results will be of *huge* benefit to the programme.

Wrong, this is not a finest hour.  They just got lucky.  A performance critical mission would not have the same out come.

I assume you shouldn't consider secondary satellites placed in the wrong orbit a success either.

Offline krytek

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Re: SpaceX Falcon 9/Dragon CRS SpX-1 MISSION GENERAL DISCUSSION
« Reply #557 on: 10/08/2012 03:30 pm »
So the second stage failed to restart?  That sounds bad.

Offline tigerade

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Re: SpaceX Falcon 9/Dragon CRS SpX-1 MISSION GENERAL DISCUSSION
« Reply #558 on: 10/08/2012 03:33 pm »

I assume you shouldn't consider secondary satellites placed in the wrong orbit a success either.


Has that been confirmed?

Also, any status on the GNC door? 

The silence is deafening.

Offline mduncan36

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Re: SpaceX Falcon 9/Dragon CRS SpX-1 MISSION GENERAL DISCUSSION
« Reply #559 on: 10/08/2012 03:35 pm »
So the second stage failed to restart?  That sounds bad.

I doubt it "failed" but simply couldn't restart due to fuel depletion from the longer burn to get Dragon into orbit.

I know everyone here want's to figure out what happened but would it not be made easier by waiting for just a bit of detailed information?

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