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BFR Developments

Yazata Offline
Here's something interesting, an application to the FCC (Federal Communications Commission) for radio links between Boca Chica and Starship. (People are starting to call the Starship prototype Orby, Hoppy's slightly more mature cousin.)

https://fcc.report/ELS/Space-Exploration...EX-ST-2019

Highlighting by me.

Explanation:

This STA is necessary to authorize Starship suborbital test vehicle communications for SpaceX Mission 1569 from the Boca Chica launch pad, and the experimental recovery following the suborbital launch. Recovery is limited to 2 functions: (1) prelaunch checkout test of the TC uplink from the ground station at Boca Chica (less than five minutes in duration) and (2) experimental uplink testing from the ground station at Boca Chica during descent. Trajectory data will be provided directly to NTIA, USAF, and NASA. All downrange Earth stations are receive-only. Launch licensing authority is FAA Office of Commercial Space Transportation.

Purpose of Operation:

Experimental launch, landing, and recovery of the Starship suborbital test vehicle from Boca Chica TX.

Operation Start Date:10/13/2019

Operation End Date: 04/13/2020


Station location:

The transmitter/antenna is affixed to a suborbital test vehicle which will fly to an altitude of 20km.


So it looks like the tanking tests and static fires aren't anticipated to take very long, if the 20km flight is expected to have been completed by mid-April at the latest. We all know about "Elon-time", but when they are making applications to the government, I'd expect their time estimates to be more conservative/realistic.
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Yazata Offline
They have just installed the top oxidizer tank bulkhead on the Boca Chica Starship tank section. They have been busily welding away at it for the last few days in an impromptu enclosure made out of shipping containers. (Wind and welding don't mix.)

So they may be getting closer to mating the cylindrical tank section with the pointier nose fairing section. Still no sign of fins or control surfaces being installed.

Strange how they let people watch what they are doing in Boca Chica from close by, while security guards chase away anyone who tries to get close in Cocoa. Don't know why policies are so different. Maybe just a different security company with different ideas how to do their job.

Photos of it all fitted here. There were at least three (rocket)shipyard workers inside the tank guiding the new ring into place and presumably welding it in place and people wondered how the workers got out afterwards. The twitter photos below show the tank access hatch that they probably escaped to freedom through. (Don't know what kind of girth-welding machine they used, how large it was, and how it fit through.)

https://twitter.com/austinbarnard45/stat...2339898369

Screenshot from Labpadre's stream:


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C C Offline
(Sep 14, 2019 08:31 PM)Yazata Wrote: They have just installed the top oxidizer tank bulkhead on the Boca Chica Starship tank section. They have been busily welding away at it for the last few days in an impromptu enclosure made out of shipping containers. (Wind and welding don't mix.)


Didn't consider that, especially with stainless steel. MIG and TIG welding uses bottled gas to shield the arc, that maybe blows away easier than the flux-coating vapors of regular stick welding (or not?). I guess there actually are stainless steel rods available for the latter, but I can't recollect Hubby using them in his Frankenstein workshop.
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Yazata Offline
I didn't know this until now, but I'm informed that the American Welding Society's D1.1 Structural Steel Welding Code says (p.165) 

http://gost-snip.su/download/aws_d1_1_d1...code_steel

5.11.1 Maximum Wind Velocity. GMAW, GTAW, EGW, or FCAW-G shall not be done in a draft or wind unless the weld is protected by a shelter. Such shelter shall be of material and shape appropriate to reduce wind velocity in the vicinity of the weld to a maximum of five miles per hour [eight kilometers per hour].

GMAW and GTAW are just different acronyms for MIG and TIG. And yeah, I think that the concern is that the wind blows away the inert shielding gas.

Apparently these are voluntary standards of good practice and are ignored as often as not. Many welders work on offshore wind turbines and stuff, where this particular rule wouldn't be practical. So they just turn up the gas or something like that. But SpaceX seems to want to be good and do its welds by the book.

The top tank bulkhead for the Mk2 Prototype in Cocoa FL has been spotted inside their low building, looking ready to be installed there too. So both prototypes look like they are proceeding almost simultaneously.

BTW, the rumor machine (unverified as yet) is saying that Elon Musk's private jet just landed at Brownsville. His big Boca Chica presentation is still 2 weeks off. I'm guessing that he wants the Mk1 Boca Chica prototype to look cool for that big media event, so it needs to have the top and bottom joined and (maybe) some wings, so that he can show it off. (Even if they pull it apart again after he's gone, so they can continue to work on it.)

Edit: Elon's more than a rumor. He was just seen visiting Hoppy and the launch pad at sunset, local time. He arrived in a black Suburban with tinted windows (accompanied by aides/security in a second identical Suburban) was dressed all in black, and seemed to have a couple of kids with him and a dog. Took some selfies with Hoppy as the sun went down.
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Yazata Offline
Video of Elon visiting Hoppy last night.

https://twitter.com/spaceXcentric/status...7680878592

Short video of him under Hoppy high-fiveing his Boca Chica hardhats.

https://twitter.com/flcnhvy/status/1173271152061558784

Photo of the upper tank bulkhead ready for installation in the Mk2 prototype in Cocoa FL.

https://twitter.com/julia_bergeron/statu...5965372418

Meanwhile back at the Boca Chica launch site, lots of digging. Speculation is that they are building a flame-duct, so that Orby's rocket-blast isn't reflected off the ground back upwards like Hoppy's was. With three engines instead of one, that might be pretty intense. The idea is to deflect it sideways, like we see at Cape Canaveral, Wallops and Vandenberg. Here's a photo of the excavations, by local resident Austin Bernard.


[Image: EEYZPp4XUAACb5u?format=jpg&name=360x360]
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Yazata Offline
Even Elon sees the peculiar aesthetics of the amazing Boca Chica rocket-ship-yard.

He posted this rather interesting (to both the artists and the engineers) photo to Tim Dodd's twitter page, apparently taken during his recent evening visit, with the caption

"Droid Junkyard, Tatooine"

https://twitter.com/Erdayastronaut/statu...2604616704


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[Image: EEpue3XUcAETd0U?format=jpg&name=small]



Then Tim got Elon to tell everyone that the cryptic hunk of metal in the foreground is a mounting bracket for the control surfaces soon to be installed. You can see the slight curvature of the right side, where it will presumably be welded to the Starship cylinder. There will be more of these, but unclear how many.

Here's Czech SpaceX watcher Mirek Pospisil's speculation about where it will go -- the nose canards. (It doesn't look stout enough to bear the vehicle's weight.) He might be right. The tail configuration is more of a mystery. Apparently it's a work in progress and part of the purpose of Elon's big unveil on Sept 28 in Boca Chica is to explain their latest thinking on that.


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Somebody else noticed this little guy in the bottom center of the bigger picture: "Is this the droid you've been looking for?"

Somebody else quickly identified it as a baby Hoppy! That's how they're born!


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[Image: EErLj0uXkAAp-Mt?format=jpg&name=360x360]

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C C Offline
(Sep 17, 2019 10:18 PM)Yazata Wrote: . . . Somebody else noticed this little guy in the bottom center of the bigger picture: "Is this the droid you've been looking for?"

Somebody else quickly identified it as a baby Hoppy! That's how they're born!


[Image: EErLj0uXkAAp-Mt?format=jpg&name=360x360]
[Image: EErLj0uXkAAp-Mt?format=jpg&name=360x360]


Definite family resemblance. Wouldn't want to hear the birds and the bees story underlying the conception of Hoppies. Scary just to ponder about it.

(A welding helmet with a flip-up lens? No way!)
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Yazata Offline
The twitter post below contains a rather mind-boggling render of how the completely assembled Boca Chica Starship might look. It's a C&P of photos of the cylinder, nose fairing and pointy nose cone all stacked, with canards and a speculative tail. The artist suggests it may look like this in 10 days when Elon makes his big presentation and it's well known that Elon wanted it finished by then. But that looks increasingly unlikely at this point. Just too much left to do.

But there should be two of these gargantuan things flying inside of six months! One at Boca Chica, the other at Cape Canaveral.

The render gives an idea of just how big this thing will be. The manlifts give comparative scale. And remember: this is just the second stage of what will ultimately be a much bigger vehicle. (The Mother of all Rockets.)

https://twitter.com/Alex_ADEdge/status/1...2309661697

In Boca Chica news, they seemed to be working on a ring that wasn't attached to the cylinder or fairing. The ring's circumference looks smaller at the top than at the bottom, so it might fit somewhere up near the pointy top. They looked to be lowering structural components into it where I assume they will be welded in place. Dunno what that's about, but it might speculatively be where the canards, hinges and actuators attach. A larger crane repositioned itself this afternoon above it, perhaps in preparation to lift it atop the nose fairing section when the iron-work is complete. From Labpadre's livestream


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[Image: 1583080.jpg]

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Yazata Offline
Lot of activity at Boca Chica this Saturday.

The pointy nose was been installed atop the new ring with the structural components in the post above. Thinking still seems to be that nose canards will attach here. They were still welding away at it after dark Saturday night. From Lab Padre's stream


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And in fin-news, they are attaching fins to the tail end! These may or may not be the aerodynamic surfaces that were observed arriving on flatbed trucks in last few weeks.

Views of today's nose and tail work in Austin Bernard's twitter post:

https://twitter.com/austinbarnard45/stat...7915741184

Are these real-life fins that are actually being installed or just props to make Orby look cool for photos for Elon's big 9-28 presentation? (Like Hoppy's long forgotten nose.) Whatever they are, they do show us the latest thinking on the tail. These things certainly look a lot different than the landing leg fins that we've seen in previous renders. These look like they will just be aerodynamic surfaces and that the rocket will rest on separate Falcon9 style landing legs that will presumably unfold.

This photo from Lab Padre shows what can only be a temporary mounting. It's conceivable that it's just to hold top of the fin while the attachment bracket/hinge (like the foreground metal-hunk thing in the Droid Junkyard?) is welded in place.


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[Image: EE_1RXyXYAU0_m5?format=jpg&name=small]



The difference between this and a science fiction movie seems to be that they can't just design rocket fins to look cool (much as Elon probably wants to). The things have to be functional in hypersonic, supersonic and subsonic airflow. So they do all kinds of computational fluid dynamics modeling and what works best isn't necessarily the sci-fi version. So Orby's fins may end up looking like fins on earlier rockets, because the engineers who designed those rockets ran the calculations themselves and knew what they were doing.

In the photo below (from Lab Padre again) the grey area on the left is what people have started calling Ironhenge, the big Boca Chica weather protection shelter that the tall iron framework has turned into. (Boca Chica's answer to that big white cathedral like structure in Cocoa FL.) The white area on the lower right is the top of a lower building.


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Yazata Offline
Elon's tweeting again!

He posted a photo of the new fins in the process of installation

https://twitter.com/elonmusk/status/1175812366019244032


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[Image: EFFTHEkX4AAGwxp?format=jpg&name=900x900]



He writes:

https://twitter.com/elonmusk/status/1175814780323545093

"Adding the rear moving fins to Starship Mk1 in Boca Chica, Texas"

Somebody asked if the fairing will be stacked by 9-28 (the date of Elon's big presentation) and Elon says,

"Yes. There's a huge amount of hardware in the tip of the faring that being integrated on the ground, which is why we haven't closed it out.

Nose tip has forward movable fins, cold gas attitude control thrusters, header tanks for landing, composite pressure vessels, several large batteries, etc. Placed up there to balance high mass of Raptors & rear fins at the bottom."


More tweets:

https://twitter.com/elonmusk/status/1175820322597232640

Tim Dodd says

"So it appears as two's the magic number on this beast! Makes sense. Will they tuck in on ascent when attached to super heavy? 3 landing legs was super aerodynamically unstable on ascent (full stack) and also unstable on descent when landing."

Elon doesn't buy it:

"Stability is not an issue with 3"

Tim is incredulous

"When doing the final landing tail first with three huge landing legs/fins in the front of the airstream wouldn't have been unstable? IS KERBAL LYING TO ME?!?!?!"

Elon says, casting some light on the recent 'work-in-progress' nature of the tail fins:

"Stability is controlled by (very) rapid movement of rear & fwd fins during entry & landing, as well as ACS thrusters. The smaller leeward "fin" would simply be used as a leg.

Current analysis, which I'm not fully bought into, suggests that 2 rear fins with separate airframe-mounted legs will be lighter, so this is the plan for Mk1/Mk2."


So Elon doesn't sound 100% sold on separate fins and Falcon9-style landing legs, but he's going with it for the time being. You can kind of hear the echoes of arguments among SpaceX engineers in those comments.

In more news, the Raptor Van pulled into Boca Chica late last night and dropped off this:

https://twitter.com/BocaChicaGal/status/...3616823299

There's some discussion about whether it's a flyable engine, or another prop for Elon's presentation, a visual aid for him to contrast with the early-model Merlin that arrived the other day.

If it's a flyable engine meant for the Mark1 prototype, Orby's going to need THREE of these babies.

Edit: Subsequent photos of the Raptor in Boca Chica may or may not show two different engines. (There's only one in each scene, but there are differences between them.) So the Raptor Van may have dropped off two or even all three. Or not.


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