Author Topic: What failed at T-0 to cause that Fireball and Heavy Black Smoke?  (Read 20542 times)

Offline Lars_J

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Yes, that small (relatively speaking) grab arm fell off the strongback, that has been pretty clear for days now.

As one can see here (http://www.spacex.com/assets/img/20090105_strongbackfull.jpg), it is pretty flimsy looking compared to the rest of the strongback. They should be able to make it sturdier in plenty of time for the next launch - 7 months away. (COTS2 is currently set for July 15)

It should not be a big deal. They are learning the ground process details as they are moving along.

Offline MP99

Watch at full resolution, the high-def mission highlights video from the SpaceX website.  At 22-24 seconds you'll see from the downward-camera view in the upper left; the right side gripper arm fall off.

Agreed, seems very clear to me.

Also worth noting that Falcon is pretty much the whole plume height above the lightning towers a this point, so wasn't in any danger (assuming no chance that the arm could have been liberated earlier).


The following is just an educated engineering guess with no data behind it besides watching that video, so it's worth exactly what you are paying for it. :)

It looks like the arm just fell streight down at the acceleration of gravity. It wasn't twisting or moving laterally. That suggests to me that it wasn't torn loose by blast or over pressure. I wonder if it is actually a vibration problem? the engine note, could have setup a harmonic in the truss of the tower that amplified and found a week spot in one of the hinges. It could have been a high cycle fatigue failure in one of the turnbuckel connections.

Well, I don't have an engineering background, but...

Its interesting that the arm comes free just at the point where our view of the strongback is about to be eclipsed by the plume. Suggests to me it was simply blown off by the plume.

cheers, Martin

Offline Nomadd

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 If they want to handle the problem NASA style, a few dozen pressure/heat sensors going to a simple recorder shouldn't be too much trouble next time. You can get some pretty hard to predict spikes from different fronts reinforcing each other in places.

Offline JayP

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Watch at full resolution, the high-def mission highlights video from the SpaceX website.  At 22-24 seconds you'll see from the downward-camera view in the upper left; the right side gripper arm fall off.

Agreed, seems very clear to me.

Also worth noting that Falcon is pretty much the whole plume height above the lightning towers a this point, so wasn't in any danger (assuming no chance that the arm could have been liberated earlier).


The following is just an educated engineering guess with no data behind it besides watching that video, so it's worth exactly what you are paying for it. :)

It looks like the arm just fell streight down at the acceleration of gravity. It wasn't twisting or moving laterally. That suggests to me that it wasn't torn loose by blast or over pressure. I wonder if it is actually a vibration problem? the engine note, could have setup a harmonic in the truss of the tower that amplified and found a week spot in one of the hinges. It could have been a high cycle fatigue failure in one of the turnbuckel connections.

Well, I don't have an engineering background, but...

Its interesting that the arm comes free just at the point where our view of the strongback is about to be eclipsed by the plume. Suggests to me it was simply blown off by the plume.

cheers, Martin

I was talking about the video from across the lagoon. Admitedl  its  low quality, but you can see that the base of the vehicle is about 50 feet above the tops of the lightning tower when the arm begins to fall. It was in the plume for a good 2 seconds by that time. Of course it might of taken that long for the plume effects to actually rip the arm off, but it still looked like a streight fall. I would have expected a latteral component if it was due to blast forces.

Unless SpaceX releases a report (very unlikely) I doubt we'll ever know what happened.

Offline zaitcev

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I prefer to call it "western" or "west side" arm, because right and left depend how you look at it.

Offline Steve_the_Deev

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As an experienced engineer in MPS we never had a QD/Umbilical have a blowing leak and then catch fire.  We tested all our components for just about every failure mode possibility prior to each flt.  (Yes, Manned programs I admit are much tighter than Unmanned.)  So based on my experience the Falcon 9 QD failure is what it is...a Failure. It is not a nothing issue from my perspective.  If I were a Falcon Prop Engr do you think I wouldn't go.. "Oops I wonder what the Hell happened ?"  Of course they did and they know it is a failure.  If I run this through a Failure Modes Effects Analysis (FMEA) the Falcon 9 can have a serious failure maybe loss of mission because of the FMEA mode "QD Failed to sep" and they would have to assign a "loss of vehicle" to the FMEA Tables, that's just how it is.  Or if they have a condition where by the QD has failed internally then gushes externally flooding the side of the rocket with fuel or LOX that could lead to loss of mission in the worst case scenario as well. That is always the worst case result to design to. I have to tell ya'll,  being heavily involved for 2 years non-stop in the Post Challenger MPS redesign all our QDs were scrutinized by my team (me and my NASA counterpart) and the results were presented to NASA LVL 2 and 3.  Any failure mode that was Crit Lvl 1, of which MPS was 90%, reqd massive testing efforts to prove the components would not fail.  So far MPS has never had that type failure although our GOX and GH2 FCVs got scarily close!  So for Shuttle MPS it WAS a big deal in the FMEA analysis for a QD to "fail to check" or "failure due to rupture",  that is where I'm coming from. I am overly conservative for any type leak be it grnd or worse flt components. Yep we had to look at all possibilities and that is why I take the Falcon 9 failed QD as an off nominal event.  I bet the engineer in charge of that component will make sure it doe not happen again. Think about this, the GUCP leak on STS-133 happened BEFORE liftoff and look how much attention it got!! A leak is always a big deal.

Offline zaitcev

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First or second Falcon 1 flight had off-nominal upper stage umbilical disconnects too, that were plainly seen on video. They clearly fixed that up but never mentioned it in any PR. Note that it's only half of the picture anyway. We will never know if Falcon 1 or 9 had any issues with detaching first stage umbilicals though.

Offline ugordan

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First or second Falcon 1 flight had off-nominal upper stage umbilical disconnects too, that were plainly seen on video. They clearly fixed that up but never mentioned it in any PR.

It was clearly mentioned in the post-flight report that listed all the anomalies of the launch.

http://www.spacex.com/F1-DemoFlight2-Flight-Review.pdf
« Last Edit: 12/30/2010 06:12 PM by ugordan »

Offline awatral

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It was clearly mentioned in the post-flight report that listed all the anomalies of the launch.

http://www.spacex.com/F1-DemoFlight2-Flight-Review.pdf


Do you know if SpaceX has released Flight Review document for any other flight?


Offline ugordan

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I'm not aware of any if they did. The closest to a report like this is this AIAA paper on F1 flight 4 which goes into more details on the mission than I've seen elsewhere.

Offline ugordan

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Here's an image I ran across showing the erector, taken about a month after launch:
http://commercialspace.pbworks.com/f/AIAA%20Tour%20to%20SpaceX%20SLC40.jpg

Shows the extent of the charring from the fireball and that the remaining grip arm was removed from the erector.

Offline apace

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Here's an image I ran across showing the erector, taken about a month after launch:
http://commercialspace.pbworks.com/f/AIAA%20Tour%20to%20SpaceX%20SLC40.jpg

Shows the extent of the charring from the fireball and that the remaining grip arm was removed from the erector.

Assuming that's a photo of the employees, it is noteworthy that they aren't all kids.  Plenty of old silverbacks in that shot. 

http://www.solarnavigator.net/animal_kingdom/animal_images/gorilla_silverback_zoo_dreamstime.jpg

The photo has a filename of AIAA... so, it's not a photo of SpaceX employees...

Offline ugordan

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It's not a photo of the employees.
http://commercialspace.pbworks.com/w/page/16189410/Past-Front-Pages-and-Headline-News-Items

Possibly the only SpaceX employee in the image is Scott Henderson at far right.
« Last Edit: 01/27/2011 03:52 PM by ugordan »

Offline zaitcev

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Jeff Foust snapped a photo of the strongback raised without the gripper arms. I can understand that they took the arms off in order to repair them, but why raise it then?
http://yfrog.com/h645243368j

Offline beancounter

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Jeff Foust snapped a photo of the strongback raised without the gripper arms. I can understand that they took the arms off in order to repair them, but why raise it then?
http://yfrog.com/h645243368j

Just a guess but perhaps they've decided that the gripper arms are not the most effective or efficient way of holding the booster upright and are devising an alternative that can be used on both F9 and FH.  SpaceX are pretty hot on standardisation where possible.
Beancounter from DownUnder

Offline ugordan

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I can understand that they took the arms off in order to repair them, but why raise it then?

For some reason, the erector is raised to vertical now and then so this is not that unusual for them. During a pad tour before C1, Scott Henderson said they were doing some tests on it.

Online edkyle99

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Here's an image I ran across showing the erector, taken about a month after launch:
http://commercialspace.pbworks.com/f/AIAA%20Tour%20to%20SpaceX%20SLC40.jpg

Shows the extent of the charring from the fireball and that the remaining grip arm was removed from the erector.

Rather than calling that "charring", I would call that a deposit of products of combustion.  If the paint had been charred or burned severely, the steel beneath would have subsequently oxidized (rusted).  The structure itself, the portion visible, looks to be undamaged. 

 - Ed Kyle 
« Last Edit: 04/30/2011 12:37 AM by edkyle99 »

Offline Cherokee43v6

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Jeff Foust snapped a photo of the strongback raised without the gripper arms. I can understand that they took the arms off in order to repair them, but why raise it then?
http://yfrog.com/h645243368j

Wasn't this Friday, the day the stage supposedly had just arrived?  Perhaps that is the 'out of the way position' when taking delivery of large components.
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