totm nov 2023 SpaceX Discussion Thread

[tater]

35 minutes ago, Mad Rocket Scientist said:

Thanks. I actually messed up, I meant to say that it this was confirmation that it was being built at the port, not that it will be built. Although we already knew about the tool, this sounds like something more:

"She says that prototype production has already begun at a factory at the Port of Los Angeles."

The factory right now is that huge tent (somewhere up thread there are pictures), since the Southwest Marine building area (which they own) hasn't been demolished and replaced yet. There is a thread at NSF I think.

[tater]

https://forum.nasaspaceflight.com/index.php?topic=45633.0

 

The total facility will be 200,000 ft² (18,580 m²), with a single part being 80,000 ft² (~7400 m²) that is 80 ft tall (24 m), with no columns---that's a big hanger (200'x400').

[mikegarrison]

7 minutes ago, tater said:

The total facility will be 200,000 ft² (18,580 m²), with a single part being 80,000 ft² (~7400 m²) that is 80 ft tall (24 m), with no columns---that's a big hanger (200'x400').

I guess that's "big". Unless you are used to something like https://en.wikipedia.org/wiki/Boeing_Everett_Factory

[tater]

6 minutes ago, mikegarrison said:

I guess that's "big". Unless you are used to something like https://en.wikipedia.org/wiki/Boeing_Everett_Factory

Yeah, even subdivided the Boeing facility has far bigger clear spans. But SpaceX doesn't need to make hundreds or thousands of BFRs any time in our lifetimes, lol.

Edited July 26, 2018 by tater

[mikegarrison]

Just now, tater said:

Yeah, even subdivided the Boeing facility has far bigger clear spans. But SpaceX doesn't need to make hundreds or thousands of BFRs any time in our lifetimes, lol.

True. I just couldn't resist a little bit of "mine's bigger than yours"....

[tater]

1 minute ago, mikegarrison said:

True. I just couldn't resist a little bit of "mine's bigger than yours"....

Looking at interior shots of that facility, it makes me think of the way I see mountains. I've spent about 4.5 months in Nepal in my life... the Himalayas ruin mountains elsewhere, they all look like foothills to me now.

So yeah, anyone who has been in that space must see other "large" buildings and think, "That's cute."

 

[CatastrophicFailure]

46 minutes ago, tater said:

Yeah, even subdivided the Boeing facility has far bigger clear spans. But SpaceX doesn't need to make hundreds or thousands of BFRs any time in our lifetimes, lol.

Well in all fairness, if when they do need to, they’ll just make something bigger. I can just see it now, a high level meeting at SpaceX HQ, Elon sees a picture of the Sea Dragon... pauses a moment... then gets that look in his eyes....

 

...and across the table Gwynne just slowly raises a hand to her face. 

Edited July 27, 2018 by CatastrophicFailure

[mikegarrison]

18 minutes ago, tater said:

Looking at interior shots of that facility, it makes me think of the way I see mountains. I've spent about 4.5 months in Nepal in my life... the Himalayas ruin mountains elsewhere, they all look like foothills to me now.

So yeah, anyone who has been in that space must see other "large" buildings and think, "That's cute."

I used to feel that way about mountains in New England, having grown up playing in the Cascades. Nepal though ... yeah. Maybe someday I'll go there.

Do we know what the BFR production model is intended to be like? Boeing makes 747s in an assembly line process where the airplane moves to different stations for different jobs, but Airbus makes A380s by leaving them in one spot in the factory and moving teams from one plane to another as that part of the assembly is sequenced.

[tater]

Not that I know of. It sounds like the tent will be for making the "grasshopper" at the very least for hover testing.

[Wjolcz]

Not exactly sure how the assembly line of F9 looks like but I'd assume that since they have experience with that then BFR's production process will share a lot of similarities.

[Xd the great]

1 hour ago, tater said:

https://forum.nasaspaceflight.com/index.php?topic=45633.0

 

The total facility will be 200,000 ft² (18,580 m²), with a single part being 80,000 ft² (~7400 m²) that is 80 ft tall (24 m), with no columns---that's a big hanger (200'x400').

Considering that the bfr is almost as large as a saturn five, the hangar isnt too big...

[Xd the great]

Assuming bfr is a complete success, will they build an ITS or somdthing even bigger?

[Ultimate Steve]

3 minutes ago, Xd the great said:

Assuming bfr is a complete success, will they build an ITS or somdthing even bigger?

Presumably, although that's a decade or two off.

[cubinator]

2 minutes ago, Ultimate Steve said:

6 minutes ago, Xd the great said:

Assuming bfr is a complete success, will they build an ITS or somdthing even bigger?

Presumably, although that's a decade or two off.

They might even consider building giant nuclear or electric space tugs at that point. Its hard to say. 

[mikegarrison]

It looks like they do move the rockets from station to station during the build process (ie. assembly line).

 

 

[Xd the great]

4 hours ago, cubinator said:

They might even consider building giant nuclear or electric space tugs at that point. Its hard to say. 

I widh they build a big falcon heavy like they build a falcon heavy. Aka 3 bfr boosters tied together.

[Rakaydos]

52 minutes ago, Xd the great said:

I widh they build a big falcon heavy like they build a falcon heavy. Aka 3 bfr boosters tied together.

Elon has said, basically, never again. Falcon heavy would have been canceled if Gwynn hadnt REMINDED Elon that the air force had already bought a ride. Plus, apparently, two other near-cancelations.

[Xd the great]

35 minutes ago, Rakaydos said:

Elon has said, basically, never again. Falcon heavy would have been canceled if Gwynn hadnt REMINDED Elon that the air force had already bought a ride. Plus, apparently, two other near-cancelations.

Yeah sad, considering 3 bfs booster is just 93 engines firing together...

Anyway, how do they plan to use laubch clamps to catch the booster?

And the bfs reentry profile looks dangerous to me...

[Wjolcz]

50 minutes ago, Xd the great said:

Yeah sad, considering 3 bfs booster is just 93 engines firing together...

Just. I don't even want to know what kind of stresses this would induce on the boosters. We've talked about this some time ago.

50 minutes ago, Xd the great said:

Anyway, how do they plan to use laubch clamps to catch the booster?

It won't have launch clamps like the ones you see in KSP. AFAIK it will just stand on them. The rocket needs to withstand more than one gee of acceleration so I don't think it will have any problems supporting its own weight while standing on the pad. Besides, it's been done already with a comparable rocket and that's Saturn V.

50 minutes ago, Xd the great said:

And the bfs reentry profile looks dangerous to me...

Why?

Edited July 27, 2018 by Wjolcz

[magnemoe]

1 hour ago, Rakaydos said:

Elon has said, basically, never again. Falcon heavy would have been canceled if Gwynn hadnt REMINDED Elon that the air force had already bought a ride. Plus, apparently, two other near-cancelations.

The heavy configuration work very well with disposable rockets. not so well with reuse as core will go very fast 

[AVaughan]

The outer boosters produce thrust that needs to be transferred to the central booster.  That means that for a light weight core booster design that is already designed and is approaching its maximum materials design limits, you need to redesign the central booster, so that it is capable of supporting those higher loads.  Not impossible, but a lot of work.  You also need to consider the aerodynamics of the core plus boosters, especially near max Q and separation.  (Also how the strap on booster will transfer that thrust to the central core).  None of this is a problem if you are designing the rocket from scratch and know that it will use strap on boosters, and design the rocket accordingly.  But it is a lot more work than designing a newer version of the existing rocket using improved higher thrust versions of the existing engines.  Plus the new 3 core version will have new potential failure modes, and increased risk of failure on every launch.

[CatastrophicFailure]

What everyone else said, plus there's simply no need. There's no payload even on the drawing boards right now that would max out what the BFR can do. Need to send something lighter farther? Send up multiple tankers to refill the BFS. That's the point of the entire architecture. Rapid, reliable re-use.

Need something bigger? Scale up the original ITS concept, much easier, at that point, than BFR Heavy, given all the trouble FH had.

Still have a real, pressing need for something even bigger? We're getting silly now Refer to my Sea Dragon comment above... 

[Xd the great]

1 hour ago, Wjolcz said:

 

It won't have launch clamps like the ones you see in KSP. AFAIK it will just stand on them. The rocket needs to withstand more than one gee of acceleration so I don't think it will have any problems supporting its own weight while standing on the pad. Besides, it's been done already with a comparable rocket and that's Saturn V.

Why?

I thought engine bells are fragile amd will require launch clamps.

Also, stalling a bfs at supersonic speed during gliding to have engines first sounds wrong.

[magnemoe]

4 minutes ago, Xd the great said:

I thought engine bells are fragile amd will require launch clamps.

Also, stalling a bfs at supersonic speed during gliding to have engines first sounds wrong.

Clamps are rarely on the sides outside of on Soyuz who uses the booster top mount as hardpoint. 
Shuttle had the clamps on the SRB who was majority of the weight. 
Falcon 9 have them on the octaweb who is the structure who hold the engines. 
Assumes BFR will do the same, it would also need an structure to hold engines and also lift the rocket during burn. 

Now I question the accuracy of the landings a bit here, also landing on the launch pad as if you crash you will loose the pad 

Upper stage will have landing legs, the flip from falling sideway to upright is not that hard, DC-X did it in tests, both it and BFS is flying bricks, not sure if the flip will be supersonic on earth, it will be on Mars as air resistance is so low. 

[Brotoro]

I would think they could build a set of clamps on a separate landing pad to practice landing the BFR away from the launch pad.

I would do that, anyway.