Author Topic: SpaceX Falcon 9/Dragon CRS SpX-1 MISSION GENERAL DISCUSSION  (Read 629428 times)

Offline simonbp

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Re: SpaceX Falcon 9/Dragon CRS SpX-1 MISSION GENERAL DISCUSSION
« Reply #580 on: 10/08/2012 05:01 pm »
I guess that means Falcon 9 v1.0 is not quite reusable.

Finally, a sensible bit of armchair engineering! :D

Though, I really wish they had gotten the first stage recovery thing working, as it would have been cool to see the aftereffects.
« Last Edit: 10/08/2012 05:02 pm by simonbp »

Offline rubicondsrv

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Re: SpaceX Falcon 9/Dragon CRS SpX-1 MISSION GENERAL DISCUSSION
« Reply #581 on: 10/08/2012 05:06 pm »
[quote author=simonbp link=topic=29130.msg962967#msg962967
Though, I really wish they had gotten the first stage recovery thing working, as it would have been cool to see the aftereffects.
[/quote]

If they want to see the damage badly enough they can always go fishing.

The range tracking should give them a very good idea of where the first stage crashed, so it could be recovered for examination if there was a need.

That being said, i doubt there is much value in doing that.


Offline butters

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Re: SpaceX Falcon 9/Dragon CRS SpX-1 MISSION GENERAL DISCUSSION
« Reply #582 on: 10/08/2012 05:06 pm »
I hope this is something simple, like the engine faring came loose and hit the nozzle. As we saw with Columbia, things coming off near max-q and hitting other things can cause surprising amounts of damage. They'd have to figure out if it was a failure of a fastener or the faring itself. The woman on the SpaceX webcast who manages the dynamic testing group seemed to be very uncomfortable at the end of the webcast, FWIW.

Either way, there's not actually that much commonality between the M1C and the M1D. Different turbopumps, different nozzles, different engine installations. No engine farings on the F9 v1.1 of course. It's hard to imagine this failure having any impact on M1D development.

Online jabe

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Re: SpaceX Falcon 9/Dragon CRS SpX-1 MISSION GENERAL DISCUSSION
« Reply #583 on: 10/08/2012 05:07 pm »
while we are waiting for news..what are people's thoughts on this..
lets say the GNC door failed to open and can't be opened...  What will Spacex Do  with Dragon? fly it in orbit for as long as they can or get it down ASAP?
jb
« Last Edit: 10/08/2012 05:09 pm by jabe »

Offline Garrett

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Re: SpaceX Falcon 9/Dragon CRS SpX-1 MISSION GENERAL DISCUSSION
« Reply #584 on: 10/08/2012 05:08 pm »
Wrong, this is not a finest hour.  They just got lucky.  A performance critical mission would not have the same out come.
Of course this isn't the finest hour. A fine hour is one which goes unheard of, like a good referee/umpire at a football game.

But saying they got lucky is unsubstantiated, unless of course you have inside info (that quick!?), which is unfair on the rest of us :P

If indeed luck has played a part, then today was their unlucky day, and the previous 3 flights were their lucky days.
- "Nothing shocks me. I'm a scientist." - Indiana Jones

Offline IRobot

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Re: SpaceX Falcon 9/Dragon CRS SpX-1 MISSION GENERAL DISCUSSION
« Reply #585 on: 10/08/2012 05:13 pm »
The F9 shuts down two engines part way through the boost to keep Gs down, right? Does anybody know how an unplanned shutdown would affect the planned shutdowns?
That is simple. You have 9 engines. There are a few hundred of combinations of 1-2 engines out before shutdown and a couple more out after it. The number of engines out before normal shutdown delays the shutdown time (or even cancel it) and a new pattern of engines to be cut off is generated. No sense on cutting 2 engines of the same side.

Offline Go4TLI

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Re: SpaceX Falcon 9/Dragon CRS SpX-1 MISSION GENERAL DISCUSSION
« Reply #586 on: 10/08/2012 05:13 pm »
Wrong, this is not a finest hour.  They just got lucky.  A performance critical mission would not have the same out come.
Of course this isn't the finest hour. A fine hour is one which goes unheard of, like a good referee/umpire at a football game.

But saying they got lucky is unsubstantiated, unless of course you have inside info (that quick!?), which is unfair on the rest of us :P

If indeed luck has played a part, then today was their unlucky day, and the previous 3 flights were their lucky days.

The fact that the vehicle continued to orbit is indeed a good thing.  The appearance of a possible engine explosion is not a good thing and I concur with Jim they got "lucky".  There are likely a host of scenarios where it could have ended differently and performance relative to other potential payloads could be a factor in the future. 

Regardless of the outcome of this specific launch, it is imperative a root cause is determined.  There could be other engines with similar issues (if and when the problem is discovered) that need correcting.  It could be a process issue, which goes beyond that specific serial number or even engine design.

Spinning it as no big deal really devalues what must be done from an investigation data collection and evaluation standpoint. 

Offline ugordan

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Re: SpaceX Falcon 9/Dragon CRS SpX-1 MISSION GENERAL DISCUSSION
« Reply #587 on: 10/08/2012 05:14 pm »
But saying they got lucky is unsubstantiated, unless of course you have inside info (that quick!?), which is unfair on the rest of us :P

Luck as in the vehicle had enough performance left to complete the primary mission (Dragon). The fact the required performance "reserve" might have come from propellant actually allocated for the secondary (Orbcomm) I'm sure makes Orbcomm folks feel warm and fuzzy.

For example, it could have survived the engine failure and still put the payload in the drink .

Offline Jim

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Re: SpaceX Falcon 9/Dragon CRS SpX-1 MISSION GENERAL DISCUSSION
« Reply #588 on: 10/08/2012 05:16 pm »
Designing is a continuous process, and the reason this domain is in so much trouble is that people take a design and run with it ad infinitum, expecting it to work over and over again with little or no improvement. That may work for NASA and the Air Force, but it's not going to work with the new paradigm of commercial space flight if you expect progress in the timeframes of your lifetime.


That just shows that you don't know what you are talking about.

a. Launch vehicle designs are not static.  That is not a "new" paradigm of "commercial" space flight.  That is very old school spaceflight.  Look at the first Delta and the last Delta II.  Look at the first Atlas Centaur and look at the last Atlas III.  The current Delta IV's and Atlas V's are not even the same as the ones that first flew in 2003. 

b.  And NASA and the Air Force have been onboard with this and are big drivers
« Last Edit: 10/08/2012 05:18 pm by Jim »

Offline Garrett

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Re: SpaceX Falcon 9/Dragon CRS SpX-1 MISSION GENERAL DISCUSSION
« Reply #589 on: 10/08/2012 05:18 pm »
From the Update thread (trying to keep it free from general discussion)
The silence surrounding the GNC door is starting to worry me. It should have opened by now, and it's not like SpaceX to ignore facts surrounding successful milestones.
Wouldn't SpaceX public relations be hard at work now trying to word a new document (or Elon Musk tweet) about the engine failure? Maybe "boring" stuff like GNC door opening is way down on their list for the mo?
« Last Edit: 10/08/2012 05:30 pm by Garrett »
- "Nothing shocks me. I'm a scientist." - Indiana Jones

Offline Genuine

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Re: SpaceX Falcon 9/Dragon CRS SpX-1 MISSION GENERAL DISCUSSION
« Reply #590 on: 10/08/2012 05:18 pm »
I will continue to respond to your inanities until I am banned here.

Not a very nice way to introduce yourself with your first post.
Can we please be polite?

Sure, I can be polite. The question is, can Jim?
You're confusing "impoliteness" with "bluntness". If the latter offends you, then you need to consider avoiding internet forums in general, and scientific/engineering orientated forums in particular.

Oh, and welcome to the forum.

I assure you my skin is thick and I can outblunt Jim with finesse.

Bluntness does not change the content of my rebuttal. He makes these kinds of blunt 'not even wrong' absolute statements with impunity here because very few people here have the experience and knowledge to disqualify these kinds of obvious falsehoods and 'old wives tales'.

If you care to comment on the topics of proof and demonstration and the demonstrable decades' long standing problems of the lack of design innovation and progress within the NASA and Air Force launch vehicle procurement process, then I would love to hear about it.

Reusable launch and propulsion is going to be a huge industry in the very near future, with hoppers moving from pad to pad delivering upper and core stages to low Earth orbit and beyond with airline like efficiency, and I'll use any technique I have to knock down the barriers to progress. Statements like the one I commented here have thus far escaped even the most mildest of rebuttals, and that's something I just wanted to bring to the immediate attention of those interested in this industry.

Offline Jim

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Re: SpaceX Falcon 9/Dragon CRS SpX-1 MISSION GENERAL DISCUSSION
« Reply #591 on: 10/08/2012 05:20 pm »

If you care to comment on the topics of proof and demonstration and the demonstrable decades' long standing problems of the lack of design innovation and progress within the NASA and Air Force launch vehicle procurement process, then I would love to hear about it.

More proof of lack of basic understand of the industry.

Offline MP99

The F9 shuts down two engines part way through the boost to keep Gs down, right? Does anybody know how an unplanned shutdown would affect the planned shutdowns?

Under normal conditions, two engines shut down to avoid going over a G-limit.

Speculation:-

With only eight engines the thrust is lower, so the stage could in theory continue on all eight engines until 8/9ths of nominal thrust hits the same G-load (ie less thrust so later in the burn, as measured by prop load). Would help a bit to compensate for gravity losses earlier in the flight. Basically, what IRobot said.

OTOH, maybe the off-axis burn puts stress on the core that need to be relieved by an earlier MECO-1.

Depending on the payload, and if the engine failed early (ie navigation predicts it can't hit the target orbit even using all margin), I wonder if navigation might keep all eight engines firing - not do a MECO-1 at all and just hope everything survives the G overload (which could be up to 1.14 x nominal, ie 8/7ths).

Reminder: all speculation from first principles.



ISTR the voiceover on the SpaceX feed saying they'd hit the time of nominal MECO-1, but don't remember them saying a MECO-1 actually occured. Was there anything that said there was a MECO-1 that cutoff the eighth engine, or did anyone observe a MECO-1 shutdown?

cheers, Martin

Offline Herb Schaltegger

Reusable launch and propulsion is going to be a huge industry in the very near future, with hoppers moving from pad to pad delivering upper and core stages to low Earth orbit and beyond with airline like efficiency, and

Whatever you're drinking, send some this way.

In the meantime, please define "very near future" and "airline like efficiency," and correlate with the known rate of airline mergers and bankruptcies.

Thanks.
Ad astra per aspirin ...

Offline Jim

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Re: SpaceX Falcon 9/Dragon CRS SpX-1 MISSION GENERAL DISCUSSION
« Reply #594 on: 10/08/2012 05:23 pm »

But saying they got lucky is unsubstantiated, unless of course you have inside info (that quick!?), which is unfair on the rest of us :P


Lucky that they had performance margin on this flight

Offline Genuine

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Re: SpaceX Falcon 9/Dragon CRS SpX-1 MISSION GENERAL DISCUSSION
« Reply #595 on: 10/08/2012 05:23 pm »
Quote
[Impoliteness snipped]
Launch vehicle designs are not static.

The SRB joints were redesigned after the loss of seven lives and the addition of post launch inspection didn't occur until another seven lives were lost. The overall configuration of the vehicle didn't change for the entire life of the program. Ditto the EELV program. Compare to SpaceX.

Offline Garrett

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Re: SpaceX Falcon 9/Dragon CRS SpX-1 MISSION GENERAL DISCUSSION
« Reply #596 on: 10/08/2012 05:25 pm »
1. There are likely a host of scenarios where it could have ended differently and performance relative to other potential payloads could be a factor in the future. 

2. There could be other engines with similar issues (if and when the problem is discovered) that need correcting.  It could be a process issue, which goes beyond that specific serial number or even engine design.
1. says who? we still have no factual info on what happened.
2. a lot of ifs.

Today was a bad day for SpaceX. We'll know soon hopefully whether luck or good engineering saved their bacon today.
- "Nothing shocks me. I'm a scientist." - Indiana Jones

Offline Jim

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Re: SpaceX Falcon 9/Dragon CRS SpX-1 MISSION GENERAL DISCUSSION
« Reply #597 on: 10/08/2012 05:26 pm »

The SRB joints were redesigned after the loss of seven lives and the addition of post launch inspection didn't occur until another seven lives were lost. The overall configuration of the vehicle didn't change for the entire life of the program. Ditto the EELV program. Compare to SpaceX.

you still don't know what you are talking about.

The HSF industry is separate and different from the rest of the launch industry.  Their paradigms are not applicable.

Wrong about the EELV program
« Last Edit: 10/08/2012 05:28 pm by Jim »

Offline Garrett

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Re: SpaceX Falcon 9/Dragon CRS SpX-1 MISSION GENERAL DISCUSSION
« Reply #598 on: 10/08/2012 05:26 pm »
Quote
[Impoliteness snipped]
Launch vehicle designs are not static.

The SRB joints were redesigned after the loss of seven lives and the addition of post launch inspection didn't occur until another seven lives were lost. The overall configuration of the vehicle didn't change for the entire life of the program. Ditto the EELV program. Compare to SpaceX.
Tell that to passengers of a Boeing 747!
Sheesh!
- "Nothing shocks me. I'm a scientist." - Indiana Jones

Offline Go4TLI

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Re: SpaceX Falcon 9/Dragon CRS SpX-1 MISSION GENERAL DISCUSSION
« Reply #599 on: 10/08/2012 05:27 pm »
Quote
[Impoliteness snipped]
Launch vehicle designs are not static.

The SRB joints were redesigned after the loss of seven lives and the addition of post launch inspection didn't occur until another seven lives were lost. The overall configuration of the vehicle didn't change for the entire life of the program. Ditto the EELV program. Compare to SpaceX.

That is indeed a very wrong statement.  The configuration changed all the time, as has been suggested in previous statements. 

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