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

[JohnFornaro]

Second, when I was a kid, I was next to a pressure cooker doing exactly that. Let me tell you - it did not explode, not even close.  It made a hell of a mess on the hood, but did not even knock it away.

That's because it was designed to gracefully degrade.  It lets off steam before it blows its top.

[zodiacchris]

Guys, this is the Falcon Heavy thread, can you please take the CRS1 failure somewhere else? Heavy won't be flying with the Merlin1C, and whatever remedy SpaceX will find (if needed for the 1D) will be well established by the time Heavy flies. And yes, we have been over this rupture/explosion ground before, it is getting rather stale now. So please, discuss this in the CRS1 thread or somewhere else...

[Chris Bergin]

60 something posts from the FH thread - that are mainly about CRS-1 and the Engine 1 issue - split and merged into this related thread.

Do not take other threads off topic.

[kevin-rf]

That's because it was designed to gracefully degrade.  It lets off steam before it blows its top.

Actually pressure cookers have two valves. One, the little weight on the top is what lets the steam out slowly to keep the pressure below a safe level. The other is a blowout plug that lets loose if the first gets clogged  and is what sprays your contents all over the place. If both fail, you get shrapnel... But that is something really hard to do with a modern pressure cooker.

As far as Merlin's go they have shielding to protect the other engines if one or more parts produce shrapnel. With out visible inspection of the failed fuel dome we do not know if shrapnel was produced. All we know is the pressure suddenly dropped in the dome. The rest is recover and reaction to the event.

[Antares]

It's just terribly odd that non-pros question so rampantly the pros.  Part of the value of NSF is that there are industry people here.  Worse, especially that there are and will be more proprietary restrictions on commercial and SLS is hiding behind eyetar, there will continue to be more instances where the pros can't say why they know what they claim as truth.  The debates become tedious for all sides.  I recommend looking at a user's accuracy record on items that are public and using that to measure whether they are accurate on something where they can't share the background.

[Nomadd]

 Not that it matters, but the weight at the top of a pressure cooker is to keep the pressure up, at a desired level. You control pressure by rotating the weight to change the surface area of the pressurized area on the bottom. Smaller area means more pressure to lift the weight needed. The safety valve is in case the orifice on top gets plugged.
 It does sort of relate. If some sort of pressure event caused an overpressure of the combustion chamber. But, I take it the data would have showed that happening.

[QuantumG]

It's just terribly odd that non-pros question so rampantly the pros.

Don't question the experts?

Part of the value of NSF is that there are industry people here.  Worse, especially that there are and will be more proprietary restrictions on commercial and SLS is hiding behind eyetar, there will continue to be more instances where the pros can't say why they know what they claim as truth.

Then, in my opinion, they have no business saying anything at all. If they can't back up their comments with facts and evidence (which is public information), then they shouldn't say a word.

[padrat]

So we should say nothing while those who aren't experts make statements and spread false info or speculation, sometimes mistakenly, sometimes blantently, or just to push their own agenda? Isn't that one reason Space Policy is now only open to posting by L2 members?

Ought to be some nice lively conversations. I'll grab some popcorn....

[Lar]

So we should say nothing while those who aren't experts make statements and spread false info or speculation, sometimes mistakenly, sometimes blantently, or just to push their own agenda? Isn't that one reason Space Policy is now only open to posting by L2 members?

Ought to be some nice lively conversations. I'll grab some popcorn....

I don't want you to get fired for posting something that you were not supposed to.

I also hate it when people say "I can't tell you why I know that", as it just grates to hear it.

Those two things seem to work against posting. But I hope you and other experts find a balance and continue to provide information. (and debunk incorrect information) Sometimes it might be questioned when you do that.  That's life. Just do the best you can.

[edkyle99]

My definition of "explosion" comes from NFPA-921 "Guide for Fire and Explosion Investigations", which is a guide to the particular work I do these days. 

It says that an explosion is a "sudden conversion of potential energy (chemical or mechanical) into kinetic energy with the production and release of gases under pressure, or the release of gas under pressure. These high-pressure gases then do mechanical work such as moving, changing, or shattering nearby materials."

The "sudden" and the "release of gas under pressure" and the "mechanical work" all clearly apply to what happened to that Merlin 1C.  There was an explosion, though a relatively small one, emanating from the top of the engine.  If it had been in a building, it would have messed up a room or two or three, but it wouldn't have taken the entire building down.

That's how I see it.

 - Ed Kyle

[mlindner]

Some people are their own sources.

In academia a source isn't a source unless the source also explains how it derived the information or points to other sources for its information and even then the source can sometimes be wrong because it improperly derived the information.

Experts are free to state things, but they shouldn't be expected to be believed at face value without explanation or reasoning. I rank statements on here in the order of: Experts with correct explanation/reasoning > non-experts with correct explanation/reasoning > experts stating information > non-experts stating information. A key piece of information for believing an expert source is some kind of record that shows their area of expertise. Of note I rank padrat rather highly whenever he talks about whats going on with pad ops or integration or related because that is directly with what he is involved with.

It would be great if this forum had a way for people who work in industry be able to have a location in their profile to give a quick summary of their knowledge base (if they so wish to state it) for people who are new to the forums or for people who are new to seeing that expert's posts.

I know Jim has worked on many launches and worked on spacehab and works on various ULA launches, but beyond that and I have yet to see him state why he is an expert for SpaceX related launches. He may have stated it long before I came to these forums. He has a notably high rate of one-liner posts which are usually very bereft of of an kind of reasoning or background on why he is correct.

We are getting _very_ off topic right now though. This is a topic for the main general discussion forum.

[Carl G]

Agreed and trimmed. Thread title is what this is about. No more unless it's relevant.

[Jim]

I know Jim has worked on many launches and worked on spacehab and works on various ULA launches,

NASA uses other vehicles and not just ULA's.

[MP99]

It's just terribly odd that non-pros question so rampantly the pros.

Don't question the experts?

Part of the value of NSF is that there are industry people here.  Worse, especially that there are and will be more proprietary restrictions on commercial and SLS is hiding behind eyetar, there will continue to be more instances where the pros can't say why they know what they claim as truth.

Then, in my opinion, they have no business saying anything at all. If they can't back up their comments with facts and evidence (which is public information), then they shouldn't say a word.

Alternatives are no info, or info when understood why it can't be backed up. Happy to take the info in those circumstances, with allowance for the poster's previous history.

Cheers, Martin

[Jim]

Then, in my opinion, they have no business saying anything at all. If they can't back up their comments with facts and evidence (which is public information), then they shouldn't say a word.

Then continue to live in ignorance

[SF Doug]

Much thanks to Ed Kyle for the explosion definition and to all other expert contributors and reasoned debaters.  My on-topic questions are reduced to:   

Engineering: Was the fairing/panels detachment caused by 1) the fuel dome explosion or 2) an engine shutdown at MaxQ or 3) both.

Management: Were the statements by SpaceX  1) poorly-worded 2) intentionally misleading or 3) spin.

I am willing to wait for more investigation results to decide.

Doug

[Robotbeat]

Spacex is just putting things in a good light. And really, considering the primary mission was a big success and the (very small) secondary even acheived many of its objectives. This was in spite of an engine-out, which is impressive.

Meanwhile, you should be aware that Ed Kyle tends to put things in a bad light. If there's anything that goes off-nominal and leads to a little less performance or something (even if the primary mission is a success), he will label that a full failure. It borders on schadenfraude.

[cambrianera]

My take about panel detachement:
Broken fuel dome (or fuel line) creates a fuel mist inside the fairing; the resulting fireball blows out the lateral panel, the top fairing follows after few seconds due to air stream.

[oiorionsbelt]

Thanks cambrianera. What are the 'thingys' between the two lateral panels? Would it have been a less benign event if the number 2 engine had the same thing happen to it?

[cambrianera]

Still lateral panels.
Only corner engines have top fairing.
Here a pic without panels and top fairing.

About eng. n°2 I don't know, but probably not different, that panel blow out.