SpaceX Falcon 9 v1.1 - Dragon - CRS-5/SpX-5 -Jan. 10, 2015 - DISCUSSION

[pippin]

The 9th launch of the 1.1 should be getting rid of such things, no?  What slipped through Hawthorne and McGregor and manifested itself at the major test before launch?

I remember a rocket that for it's 28th flight (8th in the Heavy configuration) had some valve problems (among other non vehicle related problems on that day) that conducted to a one day slip.

Yea, but that was due to a non-standard (exceptionally long) launch campaign, these type of things will probably happen to every LV from time to time when you do something that you don't do often. That's different from issues in your bread-and-butter standard campaign.
Plus, I'm pretty sure someone at ULA will be thinking about solving the valve issue, too, now that it happened twice IIRC.

[Antares]

Random component failures are a sign of poor quality or inadequate testing.  I believe the same thing about the Delta valves.  As an industry, we seem to accept this.  I don't know why.  The individual steps of rocket science are not rocket science.

[PreferToLurk]

Anyway, I don't think many here are upset that SpaceX delayed the launch after discovering the anomaly -- they are upset at the anomaly.  Anyway, I imagine Musk is just as upset if not more. For someone that wants gas and go reusability, not being able to solve these "little" hardware problems once and for all must drive him crazy more than it does any of us space voyeurs. 

[mvpel]

As to valves, SpaceX is already working diligently in that area:

SPACEX LAUNCHES 3D-PRINTED PART TO SPACE, ...

On January 6, 2014, SpaceX launched its Falcon 9 rocket with a 3D-printed Main Oxidizer Valve (MOV) body in one of the nine Merlin 1D engines. The mission marked the first time SpaceX had ever flown a 3D-printed part, with the valve operating successfully with high pressure liquid oxygen, under cryogenic temperatures and high vibration.

Compared with a traditionally cast part, a printed valve body has superior strength, ductility, and fracture resistance, with a lower variability in materials properties. The MOV body was printed in less than two days, compared with a typical castings cycle measured in months. The valve’s extensive test program – including a rigorous series of engine firings, component level qualification testing and materials testing – has since qualified the printed MOV body to fly interchangeably with cast parts on all Falcon 9 flights going forward.

[Chris Bergin]

This had wandered into general Falcon stuff, so I trimmed those posts out via magical powers and then merged them into the - guess what! - general Falcon thread.

[Jimmy_C]

I just was wondering how well the static fire test a few days ago would apply to the launch date. Might different weather conditions cause valves and seals to act differently? Or are the local conditions pretty consistent; because, it's operated at cryogenic temperatures? Or maybe it's only operated within design tolerances? Sorry to bother. Just a fan wondering how things worked. Have a good holiday!

[IslandPlaya]

I just was wondering how well the static fire test a few days ago would apply to the launch date. Might different weather conditions cause valves and seals to act differently? Or are the local conditions pretty consistent; because, it's operated at cryogenic temperatures? Or maybe it's only operated within design tolerances? Sorry to bother. Just a fan wondering how things worked. Have a good holiday!

I think this is a good question. However, all that can be tested, has been tested before lift-off. If there is any further anomalies then we will get a scrub or a kaboom! Or something in-between.

[kevin-rf]

I think this is a good question. However, all that can be tested, has been tested before lift-off. If there is any further anomalies then we will get a scrub or a kaboom! Or something in-between.

Anomalies != Kaboom

Anomalies can range from benign to catastrophic.

[Comga]

I think this is a good question. However, all that can be tested, has been tested before lift-off. If there is any further anomalies then we will get a scrub or a kaboom! Or something in-between.

Anomalies != Kaboom

Anomalies can range from benign to catastrophic.

I think that's what he meant by "something in-between".

[deruch]

Will there be an additional static fire before the launch on Jan. 6th?

I know they've already had 2, one incomplete.  Will there be a 3rd to ensure that everything is working properly after the longish delay?

[king1999]

Will there be an additional static fire before the launch on Jan. 6th?

I know they've already had 2, one incomplete.  Will there be a 3rd to ensure that everything is working properly after the longish delay?

The second one was successfully, why would they do another one? Static fire actually put stress to the hardware. And rockets are not grocery, they don't become rotten in two weeks.

[laika_fr]

 forecast

wind gusts : 25 km/h
max wave height : 2.5 meters

 

[deruch]

The second one was successfully, why would they do another one? Static fire actually put stress to the hardware. And rockets are not grocery, they don't become rotten in two weeks.

I asked because the latest updates from the update thread (linked below) hadn't said anything about the results of SpaceX's data review post-static fire.  SpaceX obviously did something between the two static fires.  The "nominal" 2nd fire suggesting that it was better than the first but not necessarily that it was a total fix.  That might only be established by the data review.  If there was any additional work done on the rocket during the 2 week stand down, a 3rd static fire would be perfectly reasonable. 

I'm aware that the F9 isn't going to "go bad" because it was put back on the shelf for a little bit.  But if Elon is really claiming that they'll be able to reuse a recovered (actually flown) stage I find it hard to believe that the stress of a 3rd static fire should represent a significant risk.  Of course, if it's not necessary any additional risk is unwarranted.

Per L2, the Falcon 9 v1.1 is back up at her SLC-40 Pad for another Static Fire attempt to gain additional engineering data.
(emphasis added)

Good news boys and girls! Per L2, the Second Static Fire has been conducted and was nominal.

Now for the caveat: Nominal means they got the routine duration of the Merlin 1Ds firing and that she enjoyed a good countdown to get to that point. They then review the data from the firing, which isn't immediate, but it's already a better situation than the previous attempt.
(emphasis added)

[archipeppe68]

Here it is my contribution to such topic.

Ciao
Giuseppe

[Silmfeanor]

Here it is my contribution to such topic.

Ciao
Giuseppe

You have made a tiny mistake - the interstage between 1st and second stage stays attached to the 1st stage all the time - it is not jettisoned.

[archipeppe68]

Here it is my contribution to such topic.

Ciao
Giuseppe

You have made a tiny mistake - the interstage between 1st and second stage stays attached to the 1st stage all the time - it is not jettisoned.

Many thanks for the tip, I've missed it.
I will collect all other (if even) inputs and I will update the drawing.

[Tomness]

Here it is my contribution to such topic.

Ciao
Giuseppe

You have made a tiny mistake - the interstage between 1st and second stage stays attached to the 1st stage all the time - it is not jettisoned.

Many thanks for the tip, I've missed it.
I will collect all other (if even) inputs and I will update the drawing.

 i am prettty sure you have it right, b/c SpaceX wants to get where the interstage stays but its jettisoned atm.

[rokan2003]

No, it's not jettisoned. The grid fins are attached to the interstage.

[Lee Jay]

No, it's not jettisoned. The grid fins are attached to the interstage.

Are the grid fins used during the reentry burn?  I thought they'd be used between the reentry burn and the landing burn (not sure when, but between).

[Norm38]

^^^ SpaceX might not even know that yet.  The fins have been referred to as "hypersonic" so maybe.  It'll come down to how much stress they'll see and what they're capable of.  But anything that increases drag reduces the amount of fuel needed to slow down.
There are still three burns yes?  Initial boost-back burn, a supersonic retro burn before Max Q, and the final landing burn.  If the grid fins were incredibly effective, maybe the middle burn is shorter, or not needed at all?

But that would be a bonus.  Right now the fins' main job is to augment the RCS.  I wouldn't be surprised if they were conservative this flight and didn't deploy the fins until after Max Q.