SpaceX And/Or Rocketry In General

Mike Hewson
Mike Hewson
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That Ariane launched a

That Ariane launched a satellite for our nation's broadband effort. My daughter works for the company that paid for it, she does 'wholesale provisioning' I think it's called. Which is a fancy title for working out how/when/where to rollout the connections across several substrates, validating assets, and especially planning of activities per district. 

{ ..... yeah, so it's really weird that NBN Co decided to place an entire commercial grade satellite downlink facility in my backyard. I can tap into that straight off the main feed. Amazing bit rate & what a beautiful dish it is. A mere 32 metres across. You can toss a pie into the dish focus and it warms up snappy-like, so I have thrown out the kitchen microwave. I have some pork going slow on a sideband receiver right now, that Ku band really hits the sweet spot with the pigs. I have absolutely no idea why they chose my property to do that. Just dumb luck I guess .... :-):-) }

Cheers, Mike.

I have made this letter longer than usual because I lack the time to make it shorter ...

... and my other CPU is a Ryzen 5950X :-) Blaise Pascal

David S
David S
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I don't know if anything was

I don't know if anything was planned anyway, but don't expect to see any launches from Florida in the next few days. They do be havin' a wee bit of a blow 'n' rain there.

David

Miserable old git
Patiently waiting for the asteroid with my name on it.

Mike Hewson
Mike Hewson
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Aha ! "Shock diamonds" is the

Aha ! "Shock diamonds" is the name of the pattern that often forms in an established rocket exhaust plume. Elon referred to something about the Raptor test, I couldn't quite hear what he said about it.

shock_diamonds.jpg

I'd presume these at least imply some stability of combustion behaviour.

Cheers, Mike.

I have made this letter longer than usual because I lack the time to make it shorter ...

... and my other CPU is a Ryzen 5950X :-) Blaise Pascal

archae86
archae86
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There has been quite a lot of

There has been quite a lot of new material in the AMOS-6 pad failure discussion thread at NASASpaceflight.com.  The thread grows rapidly when there is news.  The pointer I've provided is in a section of thread triggered by comments reportedly made by Elon Musk to an NRO audience (yes, that NRO, the National Reconnaisance Office).

If you are interested an have time you'll do better reading dozens of posts in the thread than my poor ability to understand and summarize can give you here, but apparently they currently think that conditions during the loading sequence got them to a condition in which solid oxygen crystals were present in the overwrap of the helium bottles at time of rapid pressure increase.  At sufficient pressure even at that temperature LOX plus carbon fiber gives spontaneous combustion, which in this case rather rapidly gives BOOM.

The triggering material for this series of posts is at reply number 692, which quotes this material from a subsequently deleted reddit thread.  While represented as quotations from Elon, the post suggests this may have been somewhat informal transcription from memory by an attendee.

Quote:

“We are close to figuring it out. It might have been formation of solid oxygen in the carbon over-wrap of one of the bottles in the upper stage tanks. If it was liquid it would have been squeezed out but under pressure it could have ignited with the carbon. This is the leading theory right now, but it is subject to confirmation.  The other thing we discovered is that we can exactly replicate what happened on the launch pad if someone shoots the rocket. We don’t think that is likely this time around, but we are definitely going to have to take precautions against that in the future. We looked at who would want to blow up a SpaceX rocket. That turned out to be a long list. I think it is unlikely this time, but it is something we need to recognize as a real possibility in the future.”

Addressing return to flight:

“The plan is to get back to launch in early December and that will be from pad 39A at the Cape and we will be launching around the same time from Vandenberg as well. Pad 40 will probably be back in action around March or April next year. Probably around May or so is when we will launch Falcon Heavy. We are going to re-fly the first returned core December or January.  We have test fired one of the returned cores 8 times and it looks good.  That is promising for testing re-flight.”

Anonymous

archae86 wrote: Quote:“We

archae86 wrote:

Quote:

“We are close to figuring it out. It might have been formation of solid oxygen in the carbon over-wrap of one of the bottles in the upper stage tanks. If it was liquid it would have been squeezed out but under pressure it could have ignited with the carbon. This is the leading theory right now, but it is subject to confirmation.  The other thing we discovered is that we can exactly replicate what happened on the launch pad if someone shoots the rocket. We don’t think that is likely this time around, but we are definitely going to have to take precautions against that in the future. We looked at who would want to blow up a SpaceX rocket. That turned out to be a long list. I think it is unlikely this time, but it is something we need to recognize as a real possibility in the future.”

I believe that Elon and company need to spend more time on the technical side of cause and effect and not on some conspiracy theory.  

Mike Hewson
Mike Hewson
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Epic LOL. I'll wait for an

I'll wait for an improved source over : represented as quotations from Elon to the NRO quoted from a subsequently deleted reddit thread ! :-)

Cheers, Mike.

I have made this letter longer than usual because I lack the time to make it shorter ...

... and my other CPU is a Ryzen 5950X :-) Blaise Pascal

Gary Charpentier
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Maybe there is a reason no

Maybe there is a reason no one else uses super chilled LOX?

 

AgentB
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Gary Charpentier wrote:Maybe

Gary Charpentier wrote:
Maybe there is a reason no one else uses super chilled LOX?

Hmm, i don't think that is true (some other examples)

http://space.stackexchange.com/questions/13127/is-the-supercooled-lox-used-in-falcon-9-full-thrust-a-first

Mike Hewson
Mike Hewson
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I think the issue is still

I think the issue is still very much the mechanism of ignition ie. the hot thingy. It is agreed that there is alot of inflammable ( or flammable, I never know which to say ) stuff about under pressure which may leak etc. Rapid passage of gas through a restriction can cause heat eg. the bicycle pump nozzle. There the conversion is from pressure energies distributed throughout a volume into ( focal ) heat energy of some escaping fraction.

Cheers, Mike.

 

I have made this letter longer than usual because I lack the time to make it shorter ...

... and my other CPU is a Ryzen 5950X :-) Blaise Pascal

archae86
archae86
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This recent post at

This recent post at spacenews.com extends considerably from the same leak of Elon Musk's NRO presentation mentioned below.

The editor there clearly believes the leak is credible.  There is considerable extra material represented as the judgment of a nameless expert.  He discusses the ignition problem

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