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BFR Developments

Yazata Offline
Mary reports that liquid nitrogen tankers are arriving and unloading at the launch area, and there are road closures scheduled for Saturday Jan 25.

https://twitter.com/BocaChicaGal/status/...4507403269

So presumably, they are either going to be mating two of their new domes with rings to make a new tank-like pressure vessel similar to Bopper, or else they are going to be pressurizing the LOX header tank ball. And not just with water this time, but with cryogenic liquid nitrogen.

Elon said at Cape Canaveral that they are finding the fuel tank domes challenging. So I'm guessing it won't be the LOX header ball.

There's speculation that pressurization might be inflating and expanding the cylinder differently than the domes, causing the welds along the circumference of the domes to fail. Lots of very technical engineering discussion of that, well above my pay grade.

Welds respond differently at cryogenic cold temperatures. And it's possible to strengthen welds by pressurizing them and then releasing the pressure, and cycling that a few times, so there might be several things that the SpaceX engineers might want to look at. They may be able to improve on their 7.1 bar achieved with the Bopper with some tweaks. Or maybe not. (I'm not an engineer, I don't know.)

But they are going to experimenting again on Saturday.

Elon in Boca, looking at a fuel tank dome (from Lab Padre's stream):


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[Image: index.php?action=dlattach;topic=48895.0;...8334;image]

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Yazata Offline
Elon's being crazy again!!

If you are going to be a visionary, don't hold back.

Expanding on his vision of what he ultimately wants to do.

Starship design goal is 3 flights/day avg rate, so ~1000 flights/year at >100 tons/flight, so every 10 ships yield 1 megaton per year to orbit.

https://twitter.com/elonmusk/status/1217989066181898240

Building 100 Starships/year gets to 1000 in 10 years or 100 megatons/year or maybe around 100k people per Earth-Mars orbital sync

https://twitter.com/elonmusk/status/1217990326867988480

Loading the Mars fleet into Earth orbit, then 1000 ships depart over ~30 days every 26 months. Battlestar Galactica ...

https://twitter.com/elonmusk/status/1217993568482025472

If Elon ever accomplishes even a small fraction of this, it will be more than NASA ever envisioned.

This is what happens when you have science-fiction nuts in charge of a space program and not government bureaucrats. (I love it.)
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Yazata Offline
And Elon's posted a new photo on twitter of the inside of the first Giant Tent (still rather empty) with a new Bopper 2.0 under construction. (The first burst one has already been cut up for scrap.)

One of the new fuel tank bulkheads/domes has been joined to a steel ring. I expect another to be joined to another ring, one to be flipped over and the two rings to be welded together around their circumferences. Then various plumbing fixtures will have to be attached. They still seem to be shooting for something to happen on Saturday. Elon's currently there and he probably wants to watch what happens. More liquid nitrogen deliveries today.

This dome looks cleaner and better constructed than the dome that Elon's examining in the photo above. Mary has a photo of another new dome that seems to be constructed of larger shaped pieces of steel and fewer welds. That might be what they will be going to next. And in other news, the LOX header ball has been partially disassembled and it looks like the top of it has been junked.

They are a lot pickier than they were when they were producing the mk.1 Popper.


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[Image: EO3O2kHWkAE-Izr?format=jpg&name=4096x4096]

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Yazata Offline
The flipping-over part has happened. Here's a bulkhead dome (the same one in the photo above?) and attached ring being lowered atop a support stand.

https://twitter.com/BocaChicaGal/status/...8399800323

In other news, construction of the second Giant Tent seems to have stopped for some reason. Nobody is sure why. Perhaps it's being built by SpaceX employees instead of Sprung Structures contractors, and Elon has drafted them for a different task. Maybe completing the pressure test tank for Saturday. Not sure about that one, since I'd guess that different skills are involved. Of maybe they are all working on the new vertical frame structure. I'd guess that's more likely.

But whatever the reason, nothing much has happened with the new Giant Tent since the first arches went up.

Mystery detective stuff: First, the nose cone was trucked off to the launch area today. Question is why they would need the nose there. They are going to be conducting tank pressure tests and what does the nose have to do with pressure tanks?

Elon has long said that he eventually wants to go to integral header tanks, where the structure of the vehicle doubles as the wall of the tanks. Add in what was done to the LOX header ball, with its top cut off and junked.

Well, speculation is that the LOX ball, minus its cut-off top, has been welded inside the nose cone to form a tank with the tip of the cone replacing the removed hemisphere and serving as the new top of the tank. (The ball and the cone might have been alongside each other in Elon's photo because they were always intended to be combined into one.)

There are photos of the bottom of the nose at the launch area that appear to show the bottom of the ball inside the base of the cone (complete with what may or may not be plumbing fittings), thus appearing to confirm the speculation. There are also pictures of the intact ball with yellow lines around it above the center 'equater' line, seeming to show where they planned to slice it.

So, perhaps the pressure test coming up is for the nose and not Bopper 2.0. Or maybe there will be more than one pressure test.

Like the drawing below, with the circle a sphere and the angle a cone, and with the portion of the sphere on the right, the dish between D and E removed. (It would be a nice little math problem to figure out the volume of the resulting teardrop tank. I assume somebody at SpaceX already has.)


[Image: circthe6.gif]
[Image: circthe6.gif]




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[Image: 065-sphere-inscribed-in-cone.jpg]



Part of the cut off portion of the LOX header may or may not have been rescued from the scrap heap and has appeared at a collection of airstream trailers near the Village where some workers may be living. They seem to be using it as a barbeque fire pit. Looks like a do-it-yourself version of this commercial one, but a lot bigger. (It's Texas.)


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[Image: 1452645712832.jpeg]

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Yazata Offline
Something is happening at the launch site with the nose cone right now. Mary is out there with her camera, so news should be coming shortly. There's some kind of road closure announced for late tonight, 10 or 11ish their time.

https://www.youtube.com/watch?v=2d8l_0w2VKM

https://youtu.be/dvaop9sazvU

It looks like a small amount of vapor might be coming out of the top of the nose cone.

Edit: Chris Bergin is in touch with Mary and she's apparently telling him that it's definitely venting and that it looks all frosty. So there's apparently liquid nitrogen in it.

In Lab Padre's live feed, the nosecone is starting to look like a little volcano, with white frost on the top and abundant vapor coming out the tip. Hopefully it doesn't erupt like Poppy did.
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C C Offline
(Jan 25, 2020 03:43 AM)Yazata Wrote: Something is happening at the launch site with the nose cone right now. Mary is out there with her camera, so news should be coming shortly. There's some kind of road closure announced for late tonight, 10 or 11ish their time.

https://www.youtube.com/watch?v=2d8l_0w2VKM

https://youtu.be/dvaop9sazvU

It looks like a small amount of vapor might be coming out of the top of the nose cone.

Edit: Chris Bergin is in touch with Mary and she's apparently telling him that it's definitely venting and that it looks all frosty. So there's apparently liquid nitrogen in it.

Hot dog. The long cemetery status if finally over.
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Yazata Offline
The vnting was pretty violent for a while, but it's reduced now to almost nothing. The SpaceX drone was hovering overhead like a UFO (don't tell MR) but it's flown away. So the nosecone seems to have withstood everything they threw at it and it wasn't a test-to-destruction.
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Yazata Offline
Here's Mary's video of last night's nosecone pressure test. It's filmed in time lapse and took longer than this. (Don't tell MR about the little object buzzing around overhead.) It's not a UFO if it's identified, it's the SpaceX camera drone.

https://www.youtube.com/watch?time_conti...e=emb_logo

More pressure tests upcoming. The top and bottom halves of Bopper 2.0 have been joined to create a single pressure vessel.

https://twitter.com/NASASpaceflight/stat...0252006400

https://twitter.com/BocaChicaGal/status/...7128110081

Edit: I wasn't watching, but they pressurized the nosecone again this evening, with water instead of liquid nitrogen this time, all the way to destruction. So the nosecone is no more. Video here (the nosecone is beneath the left side of the launch mount in this video):

https://twitter.com/nextspaceflight/stat...4272381952

Still no word on pressures, but given that it withstood yesterday's liquid nitrogen test, which I expect was to operational pressures, I'm guessing that test succeeded. Today's test to destruction was probably to determine what its upper limit was (and how much safety margin they have between operational pressure and the header tank's failure point).
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Yazata Offline
Bopper 2.0 disappeared last night. Then it was spotted inside the Giant Tent.

People who watch the livestreams around the clock (some of them are in other parts of the world like Europe or Australia, so it isn't as crazy as it sounds) report that three Teslas pulled up in front of the Giant Tent last night and a group of people emerged, two of whom appeared to be Elon and Gwynne.

This morning, having gotten the VIP treatment, Bopper 2.0 is on the move atop a crawler on its way to the launch area. There is a road closure scheduled for tonight. Speculation is that they will treat it like they treated the nosecone, a liquid nitrogen cryo test to operational pressures tonight, then perhaps a test to destruction using water (safer, because water isn't as likely to BLEVE) tomorrow night to determine what its upper limits are.

Screenshot from LabPadre's stream this morning showing Bopper 2.0 emerging from the Giant Tent atop a blue RollLift crawler:


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[Image: EPTO2WcXsAI-2fZ?format=jpg&name=large]



Here's Bopper 2.0 on its launch mount after its arrival at the launch site:

https://twitter.com/SpacePadreIsle/statu...0501705731
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Yazata Offline
(Jan 23, 2020 06:06 PM)Yazata Wrote: In other news, construction of the second Giant Tent seems to have stopped for some reason.

OK, I lied.

As soon as I wrote that, construction on the second Giant Tent resumed and it's more than half completed.

https://forum.nasaspaceflight.com/assets...609540.jpg
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