Author Topic: LIVE: SpaceX - Falcon I (Mk.II) NET March 20 (Attempt 2) (Read 265157 times)

Jeff Bingham · « **Reply #280 on:** 03/21/2007 12:24 am »

Looked to me like nozzle was possibly overheating...saw some precessing movement but no spinning then lost feed here.

LaunchOps · « **Reply #281 on:** 03/21/2007 12:24 am »

I doubt it hit the kestral engine nozzle. It's made from niobium and from expericence with similar nozzles they are somewhat flimsy, if the first stage had hit it there would have been a nice dent.

just-nick · « **Reply #282 on:** 03/21/2007 12:25 am »

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Zachstar - 20/3/2007 6:19 PM

I saw the nozzle starting to act weird and then it started spinning wildly

It looked like the stage was starting to oscilate more and more dramatically and the nozzle gimballing more and more to try and compensate. My first thought was some sort of ugly coupling where the guidance system was actually inducing or exacerbating the oscilation. That can't last long until you run out to gimbal limits or overload the stage...

Jim · « **Reply #283 on:** 03/21/2007 12:26 am »

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wannamoonbase - 20/3/2007 9:21 PM

I noticed that too and was expecting immediate problems but it kept on going. I also noticed what looked like a ring come off the bottom of the nozzle, but its possible it was something from the fairing jettison. The steady increasing glow had me wondering how long that could last, hopefully that wasn't it.

Glowing is normal for radiation cooled nozzles (see Delta II second stage)

simonbp · « **Reply #284 on:** 03/21/2007 12:26 am »

Remember that this is a very thin niobium nozzle; I'd be surprised if it didn't glow...

Simon

Lee Jay · « **Reply #285 on:** 03/21/2007 12:26 am »

It had the *appearance* of a control system oscillation.

braddock · « **Reply #286 on:** 03/21/2007 12:27 am »

We are awaiting further information from the press call. They are attempting to contact Kwaj (in between sips of champagne).

Please don't hit refresh more than once every minute. The load makes it difficult to get updates posted.

WHAP · « **Reply #287 on:** 03/21/2007 12:27 am »

RL-10 nozzle glows during flight - I think this was visible during the Delta IV DMSP launch last year.

Flometrics · « **Reply #288 on:** 03/21/2007 12:27 am »

Looks like propellant slosh coupling to the second stage attitude control system, hopefully the propellants will drain out faster than it amplifies.
Steve
Flometrics

just-nick · « **Reply #289 on:** 03/21/2007 12:28 am »

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wannamoonbase - 20/3/2007 6:21 PM
I also noticed what looked like a ring come off the bottom of the nozzle, but its possible it was something from the fairing jettison.

Looked like a stiffener ring or some sort to me -- doesn't the Delta IV jetteson some similar bit just after 2nd stage ignition?

ilia25 · « **Reply #290 on:** 03/21/2007 12:29 am »

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LaunchOps - 20/3/2007 8:24 PM

I doubt it hit the kestral engine nozzle. It's made from niobium and from expericence with similar nozzles they are somewhat flimsy, if the first stage had hit it there would have been a nice dent.

And I doubt the glowing was an issue. I saw rl-10 glowing pretty much the same.

NotGncDude · « **Reply #291 on:** 03/21/2007 12:30 am »

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jimvela - 20/3/2007 9:23 PM

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ianmga - 20/3/2007 7:17 PM
Staging was a bit off alright. It bumped the engine. And now it's oscillating a little. So coooool.

Definately NOT cool. You never want to see ANYTHING bump the engine during flight, in particular the lower stage!

Regardless of what else happens, SpaceX just got a vehicle exoatomoshperic, and no doubt they've added a few lessons learned to make the next one better...

Hahaha. LOL!

Of course the bump is NOT cool. It's cool to WATCH it in real time. Damn, I lost the feed before the ending. Looking forward to watch it from L2 or wherever.

JWag · « **Reply #292 on:** 03/21/2007 12:30 am »

My hat's off to SpaceX for a great flight through staging.

My hat's also off to the folks who designed that second-stage guidance. The whack from staging required an aggressive course-correction which the stage managed without rolling or oscillation. Whatever the oscillation was that came on later, I hope it's not serious (maybe a feedback loop modification?).

Great job, SpaceX!

charlieb · « **Reply #293 on:** 03/21/2007 12:31 am »

me and another engineer clearly saw the 1st stage skirt rub against the nozzle. Didn't note any damages to the nozzle - and did note the radiation of the combustion turning the nozzle red (common - nbd). The nozzle did move a bit during the first moments after ignition - but it became stable. Then - yes - one sees the 'coning' effect which is not a great thing. I'm betting the control loops got saturated trying to control things and the vehicle would go out of control and spin out of control and forces would break it apart. Maybe the impact caused a hydraulic leak?

Nick L. · « **Reply #294 on:** 03/21/2007 12:31 am »

Yes, the RL10 extending nozzle glows, but it glows from the bottom of the bell up, not throughout the bell itself. I hope there wasn't a burnthrough of the nozzle!

ilia25 · « **Reply #295 on:** 03/21/2007 12:32 am »

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Flometrics - 20/3/2007 8:27 PM

Looks like propellant slosh coupling to the second stage attitude control system, hopefully the propellants will drain out faster than it amplifies.
Steve
Flometrics

Yes, I would imagine the slosh would look exactly like that.

rsnellenberger · « **Reply #296 on:** 03/21/2007 12:33 am »

If the control system actuators were damaged when the 1st stage contacted the 2nd stage engine bell, they might not have bee able to respond properly to control inputs -- it'd look like a control system problem (controls would lag), but only because the control model was based on control authority X but only had some fraction of X...

otisbow · « **Reply #297 on:** 03/21/2007 12:33 am »

I watch the launch video, the 1st stage hit the 2nd stage engine bell hard!!!

Avron · « **Reply #298 on:** 03/21/2007 12:34 am »

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Lee Jay - 20/3/2007 9:26 PM

It had the *appearance* of a control system oscillation.

Agreed

Great job Spacex... very well done...

ONe man and a dream... wow

ringshot · « **Reply #299 on:** 03/21/2007 12:34 am »

Delta IV US engines ablate, and occasionally various support rings fall away (though I don't know if they plan that).

...I don't know if the nozzle was supposed to ablate like that.

But I DO know the first stage was not supposed to impact the nozzle!

I agree that it looked like it didn't affect it, but if it input an initial tip rate and they set their autopilot filters tight, it could have been the cause of the oscillation (and eventual loss of control?) we saw.

I don't think the glow is something to be concerned about.

...just my 2 bits

G'Day...Ron