SpaceX Falcon 9/Dragon CRS SpX-1 MISSION GENERAL DISCUSSION

[CapitalistOppressor]

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!

S

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.

[meekGee]

This thread is a great example of why companies don't bother releasing info in the first place. Too many Internet experts.

hey!  I am NOT an expert!

But I'm having fun, and this thread is not a reliable source - it's a discussion thread....

[cordor]

looks to me was just ice falling off the rocket while passing max-q.

Did you bother to watch the slo-mo video?

That was certainly NOT just ice falling off!

ya, i watched both. the rocket just went supersonic at that point. things look funny is normal.

[Kabloona]

Thanks for posting the slo-mo video, Zephyrus.

I looked at the few frames just before the event, and I think I'm seeing significant combustion instability 3-4 frames ahead. That is consistent with both propellant flow changes (think a problem in the turbopump) but also with exterior flow disruptions (ice shearing off the fairing, or just plain MaxQ). And it's also possible that the combustion instability was caused by small variations in the manufacturing of the combustion chamber.

In either case, I think the combustion instability caused structural failure of the nozzle, followed by the fairing separation. I think the large triangular object in the exhaust stream is the fairing, not the engine nozzle.

I believe that the turbopumps continued to spin for some time thereafter, because I don't think the volume of propellants dumped into the exhaust could have come out without them - tank pressurization shouldn't have delivered that volume all by itself. So I don't think the TP let go.

If I'm right, the impact on schedule might be significant, as inherent combustion instability problems take time to solve.

I'm skeptical. They've tested the heck out of this engine design, and I've got to believe they've characterized its stability with known and robust stability margins. But hopefully they've got high-frequency Pc telemetry and will know right away whether or not combustion stability was an issue.

[Jason1701]

Statement out:

The Falcon 9 rocket, powered by nine Merlin engines, performed nominally today during every phase of its approach to orbit

Aw

They should have said

The Falcon 9 rocket, powered by nine then eight Merlin engines

[meekGee]

yeah, just like the announcer on NASA TV, at about 2:30:
"All nine Merlin engines are performing nominally"

9 +/- 11%, that is.

[BobCarver]

I'm thinking there's no way to actually test a fully-rocking and rolling 9-engine rocket at Max-Q other than by flying it and seeing what kind of failures occur. They may have to institute a throttle back like Shuttle to avoid a repeat of this problem. Or, it may have been a one-off. But, I'm thinking those turbopumps may be prone to failure under this condition (if it was the turbopump, that is).

[cordor]

I have made a slow motion video of the anomaly. Please tell me if I this is not fair use and I will remove it immediately.


Of course we will have to wait for an official assessment but I would say that something has definitely happened and it is not just some clouds.


Sorry for the slowed down audio, I could not find the exact mencoder option to kill it.

(P.S. Moved from the other thread due to moderator indications).

looks to me was just ice falling off the rocket while passing max-q.

Elon said it was an engine problem.

where? link please.

[Kabloona]

yeah, just like the announcer on NASA TV, at about 2:30:
"All nine Merlin engines are performing nominally"

9 +/- 11%, that is.

I'm pretty sure they kept George Diller out of the vehicle systems comm loop 

[Jason1701]

I have made a slow motion video of the anomaly. Please tell me if I this is not fair use and I will remove it immediately.


Of course we will have to wait for an official assessment but I would say that something has definitely happened and it is not just some clouds.


Sorry for the slowed down audio, I could not find the exact mencoder option to kill it.

(P.S. Moved from the other thread due to moderator indications).

looks to me was just ice falling off the rocket while passing max-q.

Elon said it was an engine problem.

where? link please.

http://spaceflightnow.com/falcon9/004/status.html
http://nasawatch.com/archives/2012/10/spacex-crs-1-st.html
http://www.parabolicarc.com/2012/10/07/falcon-9-suffers-engine-anomoly/
As well as Gwynne's statement in the presser.

[Jason1701]

I'm thinking there's no way to actually test a fully-rocking and rolling 9-engine rocket at Max-Q other than by flying it and seeing what kind of failures occur. They may have to institute a throttle back like Shuttle to avoid a repeat of this problem. Or, it may have been a one-off. But, I'm thinking those turbopumps may be prone to failure under this condition (if it was the turbopump, that is).

F9 1.1 will throttle its M1Ds back at max-q.

[marsman2020]

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?

[Lars_J]

I don't think it is coincidence that this event occurred at Max-Q... Therefore I don't think the "combustion instability" theory floated a few posts above mine is very likely. It seems more likely that some external event impacted the engine.

All 100% armchair Internet speculation of course.

[rickl]

When I watched it live, the 'anomaly' startled me at first, but since the rocket had just passed Mach 1 (and kept on flying), I assumed it was either the shock wave or a big chunk of ice falling off.

But after watching the replays, both at normal speed and in slow motion, it sure looks like an explosion of some kind occurred.

And I did notice that the first stage burned longer than expected.  I wasn't just imagining things.  (At the time I thought the audio and video were out of sync.)

It looks like they have a very robust design there.  They may have proven that they really do have engine-out capability, just as they claimed.

It's probably lucky that Dragon was not carrying its maximum payload weight, though.

[simonbp]

Oh, I'm pretty sure I saw a gremlin at T+1:18.256...

Seriously guys, enough "interpreting" a blurry, badly-lit video.

[cordor]

I have made a slow motion video of the anomaly. Please tell me if I this is not fair use and I will remove it immediately.


Of course we will have to wait for an official assessment but I would say that something has definitely happened and it is not just some clouds.


Sorry for the slowed down audio, I could not find the exact mencoder option to kill it.

(P.S. Moved from the other thread due to moderator indications).

looks to me was just ice falling off the rocket while passing max-q.

Elon said it was an engine problem.

where? link please.

http://spaceflightnow.com/falcon9/004/status.html
http://nasawatch.com/archives/2012/10/spacex-crs-1-st.html
http://www.parabolicarc.com/2012/10/07/falcon-9-suffers-engine-anomoly/
As well as Gwynne's statement in the presser.

thanks, i watched nasatv earlier,  Gwynne didn't say anything about that. Don't think it's on spacex frontpage, twitter neither.

[CapitalistOppressor]

I'm thinking there's no way to actually test a fully-rocking and rolling 9-engine rocket at Max-Q other than by flying it and seeing what kind of failures occur. They may have to institute a throttle back like Shuttle to avoid a repeat of this problem. Or, it may have been a one-off. But, I'm thinking those turbopumps may be prone to failure under this condition (if it was the turbopump, that is).

The only thing that (probably) isn't speculation at this point is that an energetic event occurred which caused large pieces of the rocket to separate and led to the shutdown of engine 1.

Speculation about the cause at this point is just speculation.  Folks at SpaceX have a ton of actual data to look at while the rest of us have a few frames of blurry video.

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.

[starsilk]

Oh, I'm pretty sure I saw a gremlin at T+1:18.256...

Seriously guys, enough "interpreting" a blurry, badly-lit video.

isn't that what the people on the airliner said? 

[Lars_J]

*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?

[guckyfan]

The Orbcomm satellite was deployed. But was it deployed in the intended orbit? Meaning, did the second stage fire for a second time as planned? There was the option to deploy it on lower orbit if the second burn of the second stage does not occur.

I did not hear about that.