SpaceX Falcon Heavy : Arabsat 6A : LC-39A : April 11, 2019 - DISCUSSION

[meekGee]

It's what Ed always does: Use accurate statistics to paint an inaccurate picture.
….
The thing with Ed, he's utterly convinced that if he can look back and say "but my numbers are correct", then it somehow makes his analysis correct.

Shrug. People are entitled to their opinions...  But the caravan moves on.

These are not "statistics".  They are simple integers documenting facts.  How is that controversial?  Why on earth does it merit repeated bullying insult? 

 - Ed Kyle

Ed, statistics use whole numbers all the time.  Are you thinking about probabilities maybe?

I did not insult  and I did not bully. I only comment, occasionally, on your pattern of posts, and I'm not the only one who's protesting them.

Case in point: Counting how many cores were successfully recovered out of a total of launches that does not exclude those launches in the beginning that didn't even have recovery hardware on them. And bolding that number, no less, as if it has any significance whatsoever.

[lonestriker]

It's what Ed always does: Use accurate statistics to paint an inaccurate picture.
….
The thing with Ed, he's utterly convinced that if he can look back and say "but my numbers are correct", then it somehow makes his analysis correct.

Shrug. People are entitled to their opinions...  But the caravan moves on.

These are not "statistics".  They are simple integers documenting facts.  How is that controversial?  Why on earth does it merit repeated bullying insult? 

 - Ed Kyle

As a (mostly) impartial bystander, I can see both view-points here.  What I've noticed is that when presented with a "fact", particularly if it pertains to SpaceX, you (Ed) will often take the more negative view of it.  Perhaps that comes from being in the industry long enough to see so much hype and over-promising that it's the more prudent path to take to be more critical of anything presented.  I certainly don't see any malice or deception in your comments, many of which are very insightful.  There is definitely a bias though in your comments; we all have them, so you're not alone.

In this case, you've certainly presented numbers to show the number of flights and success/failure rates for launch and recovery.  Raw numbers by themselves don't have biases, but which numbers you choose to report and emphasize can show a bias.  SpaceX arguably has succeeded in the harder part of the recovery for Arabsat and that's the landing of the booster itself.  That it tipped over in rough seas is a much more tractable problem to solve than trying to land a hot GTO booster.

Also, in all of your figures, you never point out that no other current launch provider has even landed an orbital booster (Blue's NS hops don't count.)  So even if SpaceX is failing to recover at a higher-than-before rate, they are still infinitely higher than the 0% rate that the other providers have shown to date.

[Stan-1967]

It's what Ed always does: Use accurate statistics to paint an inaccurate picture.
….
The thing with Ed, he's utterly convinced that if he can look back and say "but my numbers are correct", then it somehow makes his analysis correct.

Shrug. People are entitled to their opinions...  But the caravan moves on.

These are not "statistics".  They are simple integers documenting facts.  How is that controversial?  Why on earth does it merit repeated bullying insult? 

 - Ed Kyle

I also have found Ed's numbers too sometimes provide a refreshing reality check to a big picture question, but then on a different issue be kind of maddening in the heuristics of data selection.  I think it boils down to biases, which as stated earlier up thread, we all have them, & that's normal. 

However when using numbers and statistics to make decisions, the heuristics of the number cruncher matter a great deal.  I think Many of the very vocal objections to Ed's methodology are pointing out very common pitfalls faced by people who rely on numbers for decision making, whether they be sports bookies or CEO's, or rocket insurers.  How one chooses to frame the question, weigh past data as equal to or different than new data, implementation of decay functions to past data, all need to be divorced from the traps of how our minds typically work when trying to interpret & predict future outcomes.   

Yes, Ed shows us simple numbers which are indisputable, and then he says they document facts, but the argument is what facts do they document?  That they are in fact integers, yes they do document that , but useful as a predictive tool for a the dynamic outcome of some event?  Maybe not. 

As this relates to F9 & FH, I can't think of a better example of something that should more rapidly discard old data points.  To my approximation, giving equal weight to all F9/FH data points shows a framing & status quo bias.  To my eyes, I also see this status quo bias displayed by SpaceX fans when projecting numbers for SS/SH future performance.  I never see anyone projecting absolute failure & bankruptcy of SpaceX, but I'd like to see real numbers on that, & may in fact be interested in placing a bet.  Nobody wants to be a black pill thread killer, so Im guessing those with doubts just keep quiet. ( a confirming evidence trap for the believers)

Ed, thanks for your posts.  Whether I love them or hate them, it doesn't really matter to the numbers, & they do make me think.

[Shanuson]

44186    ARABSAT-6A   2019-021A   2006.65min   16.92deg   90133km   2510km

Can we assume this is the orbit of injection? Or already after some perigee raising by the Satellite?

[Steven Pietrobon]

I've enhanced the Twitter images so that we can see the first stage more clearly. Looks like the LOX tank and interstage have gone walkabouts.

[Semmel]

I hope there is a video of that booster tip over. Such a no-no-no-nononoNONONO-aawwwww moment. Funny how it broke. The shape is almost intact, as if cut neatly in half. Hopefully the data recorders were either already read out or remain in the lower part of the booster so that they have all the telemetry recordings of the flight. I guess thats more valuable at this stage than the hardware.

[Steven Pietrobon]

More enhanced photos. Looks like two nozzles on the right are bent. Can't see if the two bottom nozzles are bent, but would not be surprised if they were. Surprised to see helium bottles in the RP-1 tank.

[woods170]

Well darn. That's four rather expensive titanium grid fins (and associated plumbing) that are now resting on the bottom of the ocean.

[frog]

Looks Like Spacex is testing ULAs smart re-use plan for them

[niwax]

Well darn. That's four rather expensive titanium grid fins (and associated plumbing) that are now resting on the bottom of the ocean.

Do we know that? It looks like the core has been cut to fit safely on the ship, they might have removed the fins as well. On the one that landed in the water, they recovered the fins, too.

[Alexphysics]

Surprised to see helium bottles in the RP-1 tank.

Why? 

[envy887]

Surprised to see helium bottles in the RP-1 tank.

Why? 

Because it's much less mass-efficient than putting them in the LOX tank. SpaceX must have some other reason for putting them in the RP-1 tank.

[Prettz]

Surprised to see helium bottles in the RP-1 tank.

Why? 

Cause they used to be in the LOX tank?

[speedevil]

Surprised to see helium bottles in the RP-1 tank.

Why? 

Cause they used to be in the LOX tank?

It's one way to entirely eliminate the 'solid oxygen combustion' thing, without requiring a liner, which might buy back a little of the gained weight and complexity.

[Alexphysics]

Surprised to see helium bottles in the RP-1 tank.

Why? 

Because it's much less mass-efficient than putting them in the LOX tank. SpaceX must have some other reason for putting them in the RP-1 tank.

Keep in mind that "not mass-efficient" doesn't mean it is not useful to put a few in there. There are very good reasons as to why there are COPV's on the RP-1 tank, keep thinking and you'll know why 

I think I've been saying that there are COPV's on the RP-1 tank for like a year and a half? Yeah, more or less. Glad that now people have first-hand proof of that.

[Rocket Science]

Well, that's two and a half out of three recovered stages for FH... Getting closer...

[envy887]

Surprised to see helium bottles in the RP-1 tank.

Why? 

Because it's much less mass-efficient than putting them in the LOX tank. SpaceX must have some other reason for putting them in the RP-1 tank.

Keep in mind that "not mass-efficient" doesn't mean it is not useful to put a few in there. There are very good reasons as to why there are COPV's on the RP-1 tank, keep thinking and you'll know why 

I think I've been saying that there are COPV's on the RP-1 tank for like a year and a half? Yeah, more or less. Glad that now people have first-hand proof of that.

There are plenty of possible reasons: RP-1 doesn't oxidize CFRP, it lowers the center of gravity, it probably simplifies the plumbing for the tank pressurization and leg deployment a little. I'm just surprised that they traded those for increased stage mass. Since they are still putting them in the LOX tank on the upper stage, they have to resolve the LOX compatibility issues anyway.

[apirie98]

Surprised to see helium bottles in the RP-1 tank.

Why? 

Because it's much less mass-efficient than putting them in the LOX tank. SpaceX must have some other reason for putting them in the RP-1 tank.

Keep in mind that "not mass-efficient" doesn't mean it is not useful to put a few in there. There are very good reasons as to why there are COPV's on the RP-1 tank, keep thinking and you'll know why 

I think I've been saying that there are COPV's on the RP-1 tank for like a year and a half? Yeah, more or less. Glad that now people have first-hand proof of that.

There are plenty of possible reasons: RP-1 doesn't oxidize CFRP, it lowers the center of gravity, it probably simplifies the plumbing for the tank pressurization and leg deployment a little. I'm just surprised that they traded those for increased stage mass. Since they are still putting them in the LOX tank on the upper stage, they have to resolve the LOX compatibility issues anyway.

I'm fairly sure that around the time of AMOS-6 it was stated in one of the discussion threads that the S1 COPVs were/are mounted in the RP1 tanks (IIRC this was being used as a reason why the F9 S1 couldn't suffer the same fate as AMOS-6's S2). I haven't had any luck finding a source for this sadly - but shall keep trying.
 
If this is the case it suggests that this has been the configuration of all F9 boosters for at least 2.5 years, and probably at least since the introduction of F9FT.

[deruch]

re: COPVs in the first stage RP-1 tank vs. LOX tank -- I don't think it's a matter of Either/Or, but rather one of both.

[pb2000]

Does it look like maybe the top 2/3d's was deliberately cut loose to avoid losing the whole thing?