Author Topic: SpaceX's Autonomous Spaceport Drone Ship Discussion Thread 3  (Read 601648 times)

Offline Kabloona

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Re: SpaceX's Autonomous Spaceport Drone Ship Discussion Thread 3
« Reply #260 on: 03/26/2016 01:30 AM »
Quote
I've never understood why people have been saying anything the shape or size of an octaweb could be under that white tarp near the 'X'.

Because the diameter of its circular end is roughly twice the height of the man in the photo, or about 12 feet, which is exactly the diameter of the rocket. So it's big enough in diameter to be the octaweb or the top end of the stage.

The object you circled in the previous post is only about half the height of the blast wall, ie nowhere near 12' diameter. It might be a fragment of tank cylinder lying on its side, but it's not big enough to be an octaweb lying on its side.

« Last Edit: 03/26/2016 01:39 AM by Kabloona »

Offline Kabloona

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Re: SpaceX's Autonomous Spaceport Drone Ship Discussion Thread 3
« Reply #261 on: 03/26/2016 02:03 AM »
And here's an even better closeup from MarekCyzio's awesome hi-res panorama. We can even see the concave shape under the tarp, with the black hole in the center of the concavity where the propellant feeds down into the engines.

Workman in foreground gives us convenient scale. IMHO, it's the bottom end of the stage, with the engine bells facing away from us. Red circle is the diameter of the stage aft end.

CyndyC, the object you circled upthread might be the object in the lower right corner of this photo. It looks like a section of tank flattened on one side.
« Last Edit: 03/26/2016 02:58 AM by Kabloona »

Offline OxCartMark

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Re: SpaceX's Autonomous Spaceport Drone Ship Discussion Thread 3
« Reply #262 on: 03/26/2016 02:47 AM »
I agree, it was in the pic of the ASDS coming in, I just didn't look close enough and it had been moved a bit.  But I have a hard time buying that the closeup(s) of it on deck are the bottom of the tank with the octaweb.  That octaweb is somewhere below the deck and its no longer shapely after bashing through the deck.  I think what we're looking at is the top end of the tank and the black center coloration is the area that houses the manhole / access hatch.  My visual theory for its being relatively unscathed is that the whole machine was coming down tail first at an impressive velocity (Vi) and when it hit the pressure vessel that is the tank went kaboom as we've seen and in doing so the top end of the tank and interstage were accelerated axially up relative to the stage at a speed relative to the stage of very roughly Vi while the sides of the tank departed radially (from pressure) and downward from pre-impact velocity.  This left the top of the stage somewhere above the deck with not much horizontal speed and a vertical speed much lower than it had prior to the impact, either + or -, and it fell from there.

Elon,

You'll have fools on the internet making silly speculations / assertions such as this until you release the video!

Offline dorkmo

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Re: SpaceX's Autonomous Spaceport Drone Ship Discussion Thread 3
« Reply #263 on: 03/26/2016 06:13 AM »
if i had to guess i think im going with kablooma's theory on it being the bottom of the tank/top of octo web.

the engines all probably got trash compacted but the octoweb is the beefiest part and wouldnt be moving very far.

i think its possible that under the tarp one of the legs is still attached to the octoweb

Offline Kabloona

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Re: SpaceX's Autonomous Spaceport Drone Ship Discussion Thread 3
« Reply #264 on: 03/26/2016 09:19 AM »
Quote
i think its possible that under the tarp one of the legs is still attached to the octoweb

That would make sense, as the crater looks like the stage may have been tilted WRT the barge when it hit. So the leg farthest from the deck when it hit would have a chance of staying attached to the base of the stage. Meanwhile, the engines on the oppositie side took the brunt of the impact.

Offline Kabloona

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Re: SpaceX's Autonomous Spaceport Drone Ship Discussion Thread 3
« Reply #265 on: 03/26/2016 09:40 AM »
Another reason I believe it's the aft end of the stage: i think we see one of the anti-vortex baffles at the center where the propellant exits the tank. Compare to the in-tank photo of the second stage LOX tank. Different tank, of course, but same design principle. Baffles highlighted in yellow.
« Last Edit: 03/26/2016 10:05 AM by Kabloona »

Offline Ohsin

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Re: SpaceX's Autonomous Spaceport Drone Ship Discussion Thread 3
« Reply #266 on: 03/26/2016 12:22 PM »
The piece is from top of stage it has grid fins attached and we are probably looking at the inside of LOX tank very top part of it that is still attached to interstage.
« Last Edit: 03/26/2016 12:23 PM by Ohsin »
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Offline CyndyC

Where are you seeing grid fins, Ohsin? Dorkmo's highlight of a leg looks like a leg:

« Last Edit: 03/26/2016 12:37 PM by CyndyC »
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Offline Kabloona

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Re: SpaceX's Autonomous Spaceport Drone Ship Discussion Thread 3
« Reply #268 on: 03/26/2016 12:58 PM »
Grid fins in yellow?

Offline Ohsin

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Re: SpaceX's Autonomous Spaceport Drone Ship Discussion Thread 3
« Reply #269 on: 03/26/2016 01:07 PM »
Grid fins, interstage seam and manhole highlighted.
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Online Johnnyhinbos

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Re: SpaceX's Autonomous Spaceport Drone Ship Discussion Thread 3
« Reply #270 on: 03/26/2016 01:27 PM »
Ohsin is correct - definitely a grid fin on lower right. However I'm not sure this is the same piece as being discussed under light tarp.
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Offline Ohsin

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Re: SpaceX's Autonomous Spaceport Drone Ship Discussion Thread 3
« Reply #271 on: 03/26/2016 02:17 PM »
Dirt and sunlight making it look different. At bottom both have wall peeling off slightly and bumps under tarp are similar on both. Too good in shape to be bottom of stage and the rim should have hint of those windows/holes.
« Last Edit: 03/26/2016 02:18 PM by Ohsin »
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Offline CyndyC

However I'm not sure this is the same piece as being discussed under light tarp.

Below is a detail from one of Marek's first photos that shows the gray tarp covering the top of the stage w/ grid fins, and behind the rolls of black sheets is the white tarp used (later - not as large) to cover the bottom of the stage with one leg.

 
« Last Edit: 03/26/2016 04:00 PM by CyndyC »
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Offline OxCartMark

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Re: SpaceX's Autonomous Spaceport Drone Ship Discussion Thread 3
« Reply #273 on: 03/26/2016 04:11 PM »
I'm not sure about the grid fins I'm seeing or not in these images.  But I'm still leaning toward thinking this is the top.  Because a) Kabloona's anti-swirl baffles don't convince my eyes that they are anything more than weld seams, b) Ohsin's closeup (and also kabloona's above) shows a high density circular bolt pattern which is indicative of an access hatch vs. the tank cam images of the bottom of the tank which show no such bolted joint.

Also, Kabloona's yellow lined image shows the bottom of the LOX tank which is a bit different from the bottom of the fuel tank in that the fuel tank has (at least when intact) the large diameter LOX feed tube going through it on the side we are potentially seeing.  We don't see remnants of that LOX tube in the image which may be due to tarp coverage or it may be due to that tube having been ripped cleanly off.  But the prevailing preponderance of my ponderance is that we would see something to indicate that that tube had been there if it was the bottom of the tank we are looking at and we don't.

And separately, notice in the foreground of Cindy's image (and others as well) we see a largish chunk of tank section.  Its completely black.  And certainly more blackened than any part of the exterior of the recovered O-2 booster.  That may be from post crash fire.  Or it may be a preview of how we expect to see our stages looking after a ripping hot re-entry.
« Last Edit: 03/26/2016 04:34 PM by OxCartMark »

Offline dorkmo

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Re: SpaceX's Autonomous Spaceport Drone Ship Discussion Thread 3
« Reply #274 on: 03/26/2016 05:20 PM »
boy im not sure. i want to agree with johnny that these are probably two different ends of the rocket. but its hard to piece much evidence together from the one low res image with what appears to be a lighter color tarp. could be lighting? or one side is a different color than the other? the way it looks like a leg could just be it pulled taught out to cover something else. theres a little bump that could be another gridfin on top. hard to image we wouldnt have a nice picture showing both ends at the same time.

the part that oshin highlighted are for sure gridfins.

i think there might also be a piece that is a little more than half of a leg sitting out there too.

edit: thinking about it more, its hard to imagine that the octoweb bulkhead would look that good after crushing throught the deck. and perhaps wildly unlikely that it and the interstage bulkhead would look appear in similar condition. perhaps it could have been one or the other but the chances of them being mistaken for each other seems impossible.
« Last Edit: 03/26/2016 07:49 PM by dorkmo »

Offline OxCartMark

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Re: SpaceX's Autonomous Spaceport Drone Ship Discussion Thread 3
« Reply #275 on: 03/26/2016 09:11 PM »
the part that oshin highlighted are for sure gridfins.
I had trouble seeing it in the images that Ohsin and Kabloona were pointing to but when I went back to the source image from Marek, I can't agree more, that's a grid fin for sure on the right at deck level and by logical extension what they point to on the left is a grid fin.

And they don't put grid fins on the bottom of the machine.

i think there might also be a piece that is a little more than half of a leg sitting out there too.
Yea, that was my kinda sorta thought as well.  Along with thinking that the perforated looking rectangular part near it must be for anti-slosh.

edit: thinking about it more, its hard to imagine that the octoweb bulkhead would look that good after crushing throught the deck. and perhaps wildly unlikely that it and the interstage bulkhead would look appear in similar condition. perhaps it could have been one or the other but the chances of them being mistaken for each other seems impossible.
Yep.  The octaweb area is smithereened.

Can you imagine being those upgraded leg lock collets all locked in place, proud and happy, ready to do their job right and then the surprise they must have had when they were hit with a barge at that speed?

Offline cambrianera

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Re: SpaceX's Autonomous Spaceport Drone Ship Discussion Thread 3
« Reply #276 on: 03/27/2016 11:03 AM »
What do you think the circled feature is?
if the part we see is the bottom of the tank, the feature is the attachment of leg's telescopic cylinder.
I cannot think to another feature passing "through" the wall of the tank this way.
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Online cscott

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Re: SpaceX's Autonomous Spaceport Drone Ship Discussion Thread 3
« Reply #277 on: 03/27/2016 02:23 PM »
LOX umbilical connection/vent?

The thing right under your circle is very very clearly a grid fin.

Offline cambrianera

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Re: SpaceX's Autonomous Spaceport Drone Ship Discussion Thread 3
« Reply #278 on: 03/27/2016 03:00 PM »
LOX umbilical connection/vent?

The thing right under your circle is very very clearly a grid fin.

Not a LOX umbilical, propellant feeding for first stage comes from bottom; seems too low for upper vent.

The grid fin is here and very clear; does not mean it is attached to something, specially after a "landing" so hard that punched a hole in barge deck.
I believe that grid fin is a detached, collected piece.
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Offline apirie98

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Re: SpaceX's Autonomous Spaceport Drone Ship Discussion Thread 3
« Reply #279 on: 03/27/2016 04:07 PM »
Looking back at some of Marek's photos I think that we've seen both the top and bottom of the stage. I'm fairly convinced by that leg shape under the white tarp as well as the (definitely at least two) grid fins under the black tarp. I checked up on the fin orientation in the picture and it seems like it could well be attached to that part of the stage.

Looking back at the black tarp pictures I think i see more than one section of the stage under there. There's clearly what looks to be the top of the stage - annotated red in the images below - complete with what looks like some buckling  of the stage as well. Although it's really pushing it I also see a rectangular-shaped mark on the stage. Going out on a whim I think this might be the bottom stripe of the flag at the top of the stage. But i'm really not too sure. Looks too square to just be dirt, and sort of looks a bit red as well.

What I also see is another stage sectiron highlighted yellow - it definitely looks like a cylindrical section of some sort. And it's situated on/in/near the hole in the barge. It looks to me like this may be the bottom end of the stage, or at least the octoweb. Considering that it's a pretty hefty lump of metal it seems unlikely that it woud've simply disappeared off the barge into the sea. What's more I see what I believe is the raceway (the inside side?) on that piece of skin by the yellow area (highlight green.) The tarp seems to go over part of this as if it was still attached to something. Could this still have been attached to the bottom of the stage at the time?

Assuming that all the above happens to be by some miracle correct, I think the bottom of the stage bedded into the barge deck and whole stage folded in and exploded, resulting in the rocket ending as it did with octoweb in the hole, top of stage close by and parts everywhere, but more or less logo side down(ish - some of the SPACEX logo was over the broken thruster.) When in the port the wreckage was removed - the top end of the stage being craned off and taken away (seems to just disappear in the photos) and the bottom end being temporarily dragged out of the hole (see drag/scrape marks on the deck) and then covered in the white tarp, which we see in the later images.

</speculation>
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