SpaceX Texas launch site Discussion and Updates - Thread 12

[gongora]

Thread 12 for SpaceX's development of a Boca Chica launch site.

Previous threads.

   Thread 1 COVERAGE
   Thread 2 COVERAGE
   Thread 3 COVERAGE   
   Thread 4 COVERAGE
   Thread 5 COVERAGE
   Thread 6 COVERAGE
   Thread 7 COVERAGE
   Thread 8 COVERAGE
   Thread 9 COVERAGE
   Thread 10 COVERAGE
   Thread 11 COVERAGE


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[StuffOfInterest]

Based on Mary's photos from yesterday, it looks like the three short pieces of the OLIT are going to be lifted individually and then cross supports installed.  Guess they were not setup well for preassembly and lifting.  We'll get to see a lot of crane work with this bit.  Also interesting, if you look close at those pieces, the tops are capped with just a small hole for (presumably) concrete filling.  There are also some interesting flanges at different spots than usual so it looks like there will be some other structures mounted in the top of the tower.

[wannamoonbase]

Based on Mary's photos from yesterday, it looks like the three short pieces of the OLIT are going to be lifted individually and then cross supports installed.  Guess they were not setup well for preassembly and lifting.  We'll get to see a lot of crane work with this bit.  Also interesting, if you look close at those pieces, the tops are capped with just a small hole for (presumably) concrete filling.  There are also some interesting flanges at different spots than usual so it looks like there will be some other structures mounted in the top of the tower.

It doesn't surprise me that they are going to stick build this last section.  I was wondering if a single tier would have the rigidity for lifting and placing it. 

Stick building it won't take too long, the big pieces will go one at a time and then they may Christmas tree the smaller pieces so they can take multiple pieces at a time.

It's encouraging they are moving onto the detailing of the tower, it's visually gratifying, but the pace can pick up for sure as they can stack people at multiple levels.

[edzieba]

Based on Mary's photos from yesterday, it looks like the three short pieces of the OLIT are going to be lifted individually and then cross supports installed.

Per latest RGV flyover (photos/video not yet public) there is an assembly jig sitting right next to the tower with the Section 9 columns. Looks like it will be pre-assembled next to the tower before lift. Presumably just to clear up that area of the old gas-well site for other uses.

[awests]

Based on Mary's photos from yesterday, it looks like the three short pieces of the OLIT are going to be lifted individually and then cross supports installed.

Per latest RGV flyover (photos/video not yet public) there is an assembly jig sitting right next to the tower with the Section 9 columns. Looks like it will be pre-assembled next to the tower before lift. Presumably just to clear up that area of the old gas-well site for other uses.

Yes and in yesterday’s daily video the jig is still at the launch site.

[zubenelgenubi]

Moderator:
If it's off-topic, don't post it here.
It's been ONE DAY since the previous discussion thread was locked--partly because the thread was overrun by off-topic-ness.

[nameUnavailabl]

Where is this foundation is being laid down?

https://forum.nasaspaceflight.com/index.php?action=dlattach;topic=52398.0;attach=2047719;image

It can't be the Launch site, right? because the barrel section is visible on the left and is placed on the ground and on the Launch site we just have BN3, GSE1, and GSE2, all of them are on some kind of platform (as per their requirement).

[Seems BN2.1 to me]

[alugobi]

Why is the crane hooked up to the GSE tank again at the launch site tank farm?

[Barnalby]

Seriously though what's the lowdown on the yellow tubular structure that's taking shape on the landing pad vs the new black tubular structure that got trucked in yesterday?

Those are going to be some absolutely massive truss structures once they're finished.  Has there been any sign of parts that could be the external "carriage" that everyone (myself included) seems to think will be built on the outside of the OLIT to carry whatever grabber claw they'll use to lift/mount Starship and possibly catch SuperHeavy?  The more lightly built black lattice structure that RGV saw almost looks like it could be the beginnings of the claw itself.

[grndkntrl]

... Has there been any sign of parts that could be the external "carriage" that everyone (myself included) seems to think will be built on the outside of the OLIT to carry whatever grabber claw they'll use to lift/mount Starship and possibly catch SuperHeavy?  The more lightly built black lattice structure that RGV saw almost looks like it could be the beginnings of the claw itself.

Yes that's what I surmised: https://forum.nasaspaceflight.com/index.php?topic=54342.msg2266175#msg2266175

[baking]

Where is this foundation is being laid down?

https://forum.nasaspaceflight.com/index.php?action=dlattach;topic=52398.0;attach=2047719;image

It can't be the Launch site, right? because the barrel section is visible on the left and is placed on the ground and on the Launch site we just have BN3, GSE1, and GSE2, all of them are on some kind of platform (as per their requirement).

[Seems BN2.1 to me]

Between the two mystery structures near the gas plant.  See it at 5:16 into RGV's latest video:

[FutureSpaceTourist]

https://twitter.com/furqan263/status/1418351010117001218

#SpaceX Orbital Launch Tower Assembly Progress as of 22nd July 2021 6pm CST

Mon-Wed:
- Detached crane from 8th level.
- Removed 1 scaffolding from 6th and 7th level.

Thursday:
- Roof Segment started, 3 columns + 4 beams added.
- Removed 1 scaffolding from 3rd, 4th, 5th level.

[grndkntrl]

For sections 1 through 8 of the OLIT, between two adjacent vertical columns a series of horizonal beams are bolted.
Diagonal braces are then bolted from the middle of a beam *upwards* to a column.

Section 9 is different.
The diagonal braces are bolted from the middle of a beam *downwards* to a column.

I think this means something that will experience great downward force will be added on top of section 9.
What else could it be?
Or is this just how these towers are topped?
Or could it not matter structurally, but look better this way?

The very last thing to go up on the very top of the tower has to be the 10ft/3m lightning rod.

With section #9 (roof level) the tower will already be at an estimated 469ft/143m, so the addition of the lightning rod to the roof will bring the tower to the final height stated in the FAA Obstruction Evaluation Study Report which is 479ft/146m.

So there's no room left for anything else above roof level, other than the lightning rod.

Heavy equipment for the pulley system (for the lift/stacking & catch arms) will go in section 8 under the roof level, along with whatever other equipment they need up there, but there will be no "crane" on top if that's what you're suggesting.

[cdebuhr]

For sections 1 through 8 of the OLIT, between two adjacent vertical columns a series of horizonal beams are bolted.
Diagonal braces are then bolted from the middle of a beam *upwards* to a column.

Section 9 is different.
The diagonal braces are bolted from the middle of a beam *downwards* to a column.

I think this means something that will experience great downward force will be added on top of section 9.
What else could it be?
Or is this just how these towers are topped?
Or could it not matter structurally, but look better this way?

The "missing" corner (i.e., the one with the ledge built around it at the top of section 8 ) has plates for the same (more or less) diagonal beams as the other three corners.  Two of the horizontal beams have been installed, while the gusset plates on the columns suggest the other two horizontal beams are coming, but since the "missing column" doesn't go that high, these will need to be half-length.  It would be pretty hard to do this in a sensible way without reversing the slope of the diagonals.  See attached (very poor) sketch.  I'm expecting the black configuration.  If they were trying to keep the diagonals the same, they'd end up with something like the red sketch which (to my non-expert eye at least) seems structurally sub-optimal.

[DreamyPickle]

A lot of people are speculating that the tubular structures being assembled at the launch site will be part of the catching mechanism but so far there is no clear confirmation.

Any particular reason they would be welding tubes instead of the more traditional girder shapes making up the launch tower?

[baking]

A lot of people are speculating that the tubular structures being assembled at the launch site will be part of the catching mechanism but so far there is no clear confirmation.

Any particular reason they would be welding tubes instead of the more traditional girder shapes making up the launch tower?

Since Elon has said that they are still working on the design for the catcher, these are more likely for integration.  Something to hold the top of the booster and bottom of the Starship steady while they are attached together.  They need to be big and sturdy but have a certain amount of forgiveness.  They also need to be moved away before launch.  There also may be umbilicals for fueling the Starship, at least in the early versions.  Whether there will be an integrated crane or lifting mechanism is unclear at this point.

I would still like to have some confirmation on the technical reason for using round tubes.  Are they less likely to be damaged from rocket exhaust?  Are they aerodynamic and less likely to flex in the wind?  Is it because their bending resistance is the same in all planes and less likely to be damaged by a randomly swinging Starship?

I do think they would use girders though if this device was supporting much more than its own weight, so I think it is only for steadying.

[V42]

For sections 1 through 8 of the OLIT, between two adjacent vertical columns a series of horizonal beams are bolted.
Diagonal braces are then bolted from the middle of a beam *upwards* to a column.

Section 9 is different.
The diagonal braces are bolted from the middle of a beam *downwards* to a column.

I think this means something that will experience great downward force will be added on top of section 9.
What else could it be?
Or is this just how these towers are topped?
Or could it not matter structurally, but look better this way?

The "missing" corner (i.e., the one with the ledge built around it at the top of section 8 ) has plates for the same (more or less) diagonal beams as the other three corners.  Two of the horizontal beams have been installed, while the gusset plates on the columns suggest the other two horizontal beams are coming, but since the "missing column" doesn't go that high, these will need to be half-length.  It would be pretty hard to do this in a sensible way without reversing the slope of the diagonals.  See attached (very poor) sketch.  I'm expecting the black configuration.  If they were trying to keep the diagonals the same, they'd end up with something like the red sketch which (to my non-expert eye at least) seems structurally sub-optimal.

While I completely agree with you that the gusset plate details currently visible on the existing section 8 & 9 structure will (at a minimum) result in a design matching your sketch shown in black, adding the green member shown below would make the red sketch work as well.

[daavery]

more bad paint......

[AstroDave]

  Just got a chance to watch yesterday's NSF update video. Looks like they had a team tapping/cleaning the holes used for rails on the lower tower sections. Looking forward to seeing the catching/hoisting assembly that is put together for this.

[alugobi]

At what point, if ever, does this thing get filled with concrete?