Author Topic: Falcon 1 - Post Failure thread (Read 134921 times)

Tap-Sa · « **Reply #120 on:** 03/25/2006 02:02 pm »

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Jim - 25/3/2006 4:36 PM

The FTS for this launch was only set up to shut down the engine.

Do you have any specifics on how this happens? Cutting the propellant flow by operating the valves, or something more rapid like shaped charges pinching the lines?

Avron · « **Reply #121 on:** 03/25/2006 02:25 pm »

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InfraNut - 25/3/2006 9:31 AM

In hindsight the blanket quick fix seems a bad idea. As someone else pointed out velcro can have very varying adhesion, so a single or a few tests cannot be relied upon to guarantee it will come off at a similar force. Also the blanket itself may be glued to the rocker by freezing condensation. The blanket should have been removed PRIOR to launch for predictable results and to have a chance to correct any problem.

Based on this, my best guess is that the insulation blanket seem the more likely root cause, and that either

(1) the skewed and unstable aerodynamics as the rocket gained speed exceeded the limitation in TVC course correction capacity or the "high frequency" changes went outside what the flight control algorithm could handle properly, or

(2) In the last step(s) of ripping loose, the blanket whipped the engine till something broke. Possibilities for how the emgine could have been damaged are too many to list guesses, even constrained by what we see happen. There are more direct damages and also indirect damages leading to loss of control and leading to RSO/auto flight termination.

I was expecting the blanket to be "ripped off" prior to launch say at the T-30 sec mark... winched off..

I look forward to see what Spacex comes up with next to solve the blanket issue..

Unfortunatly the entire flight sequence did not pan out as planned, however... No-one cannot say that they did not Launch..

Looking forward to a successful flight next time... I just hope we dont have to wait long for that.

Avron · « **Reply #122 on:** 03/25/2006 02:27 pm »

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braddock - 25/3/2006 8:30 AM

There have been so many positive expressions of support in the forums since the failure.

I have just sent to SpaceX Media Relations a page and a half worth of your supportive sentiments, to be forwarded to the SpaceX team.

Thanks.. if you get any feedback, it would be nice to hear..

Jim · « **Reply #123 on:** 03/25/2006 02:30 pm »

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Tap-Sa - 25/3/2006 9:02 AM
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Jim - 25/3/2006 4:36 PMThe FTS for this launch was only set up to shut down the engine.
Do you have any specifics on how this happens? Cutting the propellant flow by operating the valves, or something more rapid like shaped charges pinching the lines?

Just by operating the same valves that shut it down on the launch pad for static firings. This is standard for all vehicles operating from US gov't ranges.

For vehicles with destruct packages, The "Arm" command shuts down the engines and the "Destruct" command sets of the charges

gladiator1332 · « **Reply #124 on:** 03/25/2006 02:41 pm »

While I would love to have seen a successful launch, I believe a failure on the first mission is better than say, 20 missions from now. They can fix this thing early and get Falcon off the ground. Also, this will serve as a reminder to SpaceX and all of the other private initiatives that this stuff isn't easy and the road to space can be bumpy.

I'm sure they always were aware of this, but sometimes silly mistakes happen. But it is these types of mistakes that can bring a program down.

So far the private industry has gotten lucky. This is the first real failure we've seen, however, the SpaceShipOne flight where it did those rolls all the way up was a bit close.

Jim · « **Reply #125 on:** 03/25/2006 02:45 pm »

I think everybody is getting "wrapped around the axle" wrt the blanket. Rockets are very rugged vehicles considering the regimes they fly through. Pieces of cloth (not foam) are not going to damage it. If it were to, then the act of staging, jettisoning the fairing or the intented shutdown of an engine with the associated shock events would greatly damage the vehicle. Also the asymmetrical forces with the blankets would be small compared to any wind shear the vehicle would experience.

As everybody has seen, an "event" occurred around the engine section. Whether this was cause or effect remains to be seen. Anything else is speculation (which we all have fun doing)

One of Spacex's downfalls may be using a remote island in the RTS for a launch site. There may not be any range tracking cameras (like at the Cape or VAFB) that could help with the investigation. Less is not always better

Tap-Sa · « **Reply #126 on:** 03/25/2006 02:56 pm »

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Jim - 25/3/2006 5:30 PM
Just by operating the same valves that shut it down on the launch pad for static firings.

OK that voids my guess about the orange flame being nominal part of FTS. Just a bit hard to believe that the engine actually blew up, shared InfraNut's sentiment that Elon has enough brainpower in his company to render 'basic' failures like unscheduled chamber disassembly about as unprobable as in mature vehicles.

Sure would like to see ground video of the ascending vehicle, how much the blanket was banging the engine, did it cought fire, did it divert exhaust etc.

Exci · « **Reply #127 on:** 03/25/2006 03:10 pm »

First part of message posted at:
http://kwajrockets.blogspot.com/

From Elon this morning:

"Preliminary Fault Analysis
The good news is that all vehicle systems, including the main engine, thrust vector control, structures, avionics, software, guidance algorithm, etc. were picture perfect. Falcon's trajectory was within 0.2 degrees of nominal during powered flight.

However, at T+25s, a fuel leak of currently unknown origin caused a fire around the top of the main engine that cut into the first stage helium pneumatic system. On high resolution imagery, the fire is clearly visible within seconds after liftoff. Once the pneumatic pressure decayed below a critical value, the spring return safety function of the pre-valves forced them closed, shutting down the main engine at T+29s.

It does not appear as though the first stage insulation played a negative role, nor are any other vehicle anomalies apparent from either the telemetry or imaging. Falcon was executing perfectly on all fronts until fire impaired the first stage pneumatic system."

Chris Bergin · « **Reply #128 on:** 03/25/2006 04:26 pm »

Welcome to the the new users to the site....as Exci carried out, if anyone brings information from other sites on to here, only post a sample of their content, with a URL. If it's a specific URL, then post that alone, as we have a policy here of adhering to copyright and accreditation.

I know a lot of the 400 new users over the last 12 hours or so are here for the video of the failure, but hang around and look at the various things we cover here. We're a young site and we'll be happy for your company.

Flightstar · « **Reply #129 on:** 03/25/2006 04:45 pm »

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Exci - 25/3/2006 10:10 AM

However, at T+25s, a fuel leak of currently unknown origin caused a fire around the top of the main engine that cut into the first stage helium pneumatic system.

It does not appear as though the first stage insulation played a negative role, nor are any other vehicle anomalies apparent from either the telemetry or imaging. Falcon was executing perfectly on all fronts until fire impaired the first stage pneumatic system."

If that is the case, then they have problems. It would have been much easier to bypass what may now require a recertification of the Falcon propulsion system, as opposed to ensuring you don't have an insulation blanket slapping against your pluming.

hyper_snyper · « **Reply #130 on:** 03/25/2006 04:48 pm »

^^Why would the engine need to be recertified? Wouldn't they just need to find the leak and plug it?

Flightstar · « **Reply #131 on:** 03/25/2006 04:53 pm »

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hyper_snyper - 25/3/2006 11:48 AM

^^Why would the engine need to be recertified? Wouldn't they just need to find the leak and plug it?

It's only my opinion, but the lanuage used by Elon suggests they'll need to do a lot more than just finding the leak and plugging it. Certainly warrants more than patching it up.

NASA_Twix_JSC · « **Reply #132 on:** 03/25/2006 04:55 pm »

We're into speculation territory here remember folks, but I too would have been 'happier' if the blanket was the cause.

Damon Hill · « **Reply #133 on:** 03/25/2006 04:57 pm »

Hopefully enough of the engine can be recovered to pinpoint the leak's origin
and determine the cause. Mechanical/acoustical vibration and internal
resonance (sometimes referred to as POGO) is a common issue plaguing
engine development.

It'd be nice to see the tracking camera footage; the rocketcam's view at
best was just frustrating, if not misleading.

Otherwise, I'm not discouraged by this setback. The fix should be straightforward
and Spacex will sensibly review all of the flight data and apply lessons
learned.

Jim · « **Reply #134 on:** 03/25/2006 05:23 pm »

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NASA_Twix_JSC - 25/3/2006 11:55 AMWe're into speculation territory here remember folks, but I too would have been 'happier' if the blanket was the cause.

Since everbody is speculating. How about this: due to the rudimentary or lack of flame deflector, debris or flash back struck the vehicle at launch?

Tap-Sa · « **Reply #135 on:** 03/25/2006 05:33 pm »

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Exci - 25/3/2006 6:10 PM
On high resolution imagery, the fire is clearly visible within seconds after liftoff.

I wonder if webcast got a glimpse of this. Check out the video in FTP section, at about T+3s which is 14 seconds from start of the clip. A bright puff appears in the upper section of the engine.

DaveS · « **Reply #136 on:** 03/25/2006 05:54 pm »

It's leaking RP-1 alright! Leak starts at approx. T+1 second and forms a dark band around the very base of the RP-1 tank structure and the leak point is directly facing the camera.

DaveS · « **Reply #137 on:** 03/25/2006 06:02 pm »

As an interim quick fix, I suggest putting an protective cowling over the Merlin engine plumbing so that the plumbing is protected from these kind of events.

It has always worried me that something could damge the exposed plumbing and cause a failure of the engine.

amon · « **Reply #138 on:** 03/25/2006 06:09 pm »

That's what I was asking about last night when I said I thought I saw venting in line with the camera just below the interstage. I was thinking it might be the pressurant tanks though, not an actual fuel leak.

R&R · « **Reply #139 on:** 03/25/2006 06:26 pm »

The down time could be longer given that they only have a small group of people doing a lot of tasks. There's a reason Delta and Atlas have those "standing armies". Lucky for SpaceX they don't have several rockets already finished at the launch site or on the pad and what they have is still at the factory. It puts them in the best place to make the changes.