SCRUB: SpaceX Falcon 9/Dragon COTS Demo (C2+) LAUNCH ATTEMPT 1 UPDATES

[oiorionsbelt]

Interesting, because SpaceX update said repairs are underway.

[Robotbeat]

FWIW, swapping "on the pad" is something that I think is pretty cool and quite an accomplishment. 

It is actually done in the hangar.

Swapping engines at the hangar. But I think other repairs can be done at the pad.

[majormajor42]

According to Mark Boucher, SpaceX has confirmed that the faulty valve was replaced last night, at the pad so it seems.

Edited: Clongton, a new static fire would need range clearances, yes? Can that  even be done tonight or tomorrow and still make the current launch time of Tuesday morning? (I'll take replies in discussion thread)

[clongton]

The faulty valve was replaced, at the pad so it seems.

Have they scheduled an engine fire to calibrate it?

[Antares]

Check valves don't need calibration, at least not by the end user.  They would pass some sort of acceptance test series by the vendor.

[mr. mark]

Space.com is reporting that the repairs have been accomplished.

http://www.space.com/15772-spacex-private-rocket-engine-repairs.html

"SpaceX engineers replaced the balky valve late Saturday, and are now inspecting the Falcon 9 rocket in preparation for a possible second launch attempt early Tuesday (May 22)."

[clongton]

Check valves don't need calibration, at least not by the end user.  They would pass some sort of acceptance test series by the vendor.

The engine, not the valve. Are they going to hot fire the engine to retest it with the new valve?

[ugordan]

Are they going to hot fire the engine to retest it with the new valve?

Obviously not since they're still talking about going ahead with the launch on Tuesday.

[MP99]

Check valves don't need calibration, at least not by the end user.  They would pass some sort of acceptance test series by the vendor.

The engine, not the valve. Are they going to hot fire the engine to retest it with the new valve?

But that would be a test of engine operation, not calibration.

cheers, Martin

[clongton]

Check valves don't need calibration, at least not by the end user.  They would pass some sort of acceptance test series by the vendor.

The engine, not the valve. Are they going to hot fire the engine to retest it with the new valve?

But that would be a test of engine operation, not calibration.

cheers, Martin

I know. Poor choice of words led to confusion.

[cuddihy]

My biggest concern is that there are 8 other identical check valves in the vehicle. I hope they plan to borescope all of them.

Bad idea unless inspection of the replaced valve suggests additional problems. You're more likely to do additional damage to the other currently good valves during the boroscope process than you are to find another problem.

[mr. mark]

Since repairs seems to have been made, what is the weather looking like for a Tuesday morning launch? Are we still looking at a 40% negative?

[ugordan]

30% chance of violation, but rdale would probably tell you even that is too pessimistic.

[rdale]

Yep - they are worried about cumulus cloud buildups but that isn't very common during the middle of the night.

[mr. mark]

 T - 34 hours 44 minutes and counting.... (maybe)

[Norm38]

Are they going to hot fire the engine to retest it with the new valve?

Obviously not since they're still talking about going ahead with the launch on Tuesday.

And given the circumstances that seems to be the best choice.  We've seen their abort process enough times to know they can shut down if needed.  Startup is the hot fire.  If the issue with the valve is cycle related, or related to a shutdown profile, then more testing at this point can only do harm.  Better to just attempt launch on schedule.

[sdsds]

We've seen their abort process enough times to know they can shut down if needed.  Startup is the hot fire [test].

Well phrased; it seems to accurately reflect the SpaceX approach.

[dcporter]

@elonmusk:

Simulations show launch ok with bad valve. Still, better to stop & fix. Recalling rockets after launch is not an option.

[robertross]

@elonmusk:

Simulations show launch ok with bad valve. Still, better to stop & fix. Recalling rockets after launch is not an option.

That kind of attitude shows maturity in the launch business. Very good call.
Thanks for passing that along.

[FinalFrontier]

Well that's unfortunate. That's really unfortunate.

Swapping is fine but that doesn't explain why the valve failed or what precisely went wrong with it. And that's not exactly a small or non critical valve, its a critical component.
 

I would like to make a few points on that.

1. They have not replaced the valve yet, so they have not done an analysis and learned why it "failed". Until that part has been removed and the analysis is done, everything is an educated guess. So there is no reason to be disappointed in them for this scrub.

2. They do not have to fully share the failure mode with us, only give a satisfactory answer to NASA on why they scrubbed.

3. Was the quote from SpaceX that it would have been a LOM if they had not scrubbed even accurate? That originally came very soon after the scrub from a SpaceX employee who's job it was to interface with the press and public. They are repeating what they have been told by other members of the team one would assume the managers pressed for answers on what just went wrong. It makes a nice quote, but did they at that point even know enough to make that statement?

Did not say I was disappointed in the fact they scrubbed, in fact just the opposite, I was saying I was concerned that it was this part that failed in terms of the next launch opportunity happening on time for the reasons I stated. Also, I wouldn't expect them to know right away what went wrong to cause the valve to fail, but I would expect them to investigate it and insure it can't happen again on the next window or cause something more severe.

2. No they don't, that's correct, and that's fine as long as they handle it.

3. Yes it was accurate it turned out that it was a propellant related check valve. They are very careful about putting inaccurate information out there I have not seen them do that even once so far. Also, don't know where your getting the idea that there was a SpaceX quote stating it would be an LOM,  thats totally ridiculous they never said any such thing. Nor did I say anything like that. I did however state that there was a possibility with this sort of issue (given that its a fairly important component) that it could potentially cause further failures, but to find out it would be a good idea to look into what caused the failure and how it could affect the vehicle if it happens again before flying again, not that "it WOULD be an LOM no matter what". Which they have since done, and have since determined that no, fortunately it would not be a large issue at all, but regardless the problem is resolved.

Where did you get this "SpaceX quote stating LOM" from? That never happened. Moving on.



All of that said it appears they did swap it out and are going to go ahead and launch again (based on the sims). So it would appear that, fortunately, failure of this competent cannot lead to something more severe like I mentioned earlier (shards of metal ect. note: took the example for that from the ssme sensor failures years ago where the sensors broke off inside the propellant lines).

So we will see how it goes on Tuesday. Still would like to know what caused that valve to fail.

Also, won't be discussing this further in this thread. If it comes up again I'll respond in the discussion thread so don't look here for my answer.