totm nov 2023 SpaceX Discussion Thread

[Deddly]

Gaaah portrait video why?? 

[tater]

That high bay pic needs to be bigger...

[tater]

 

[JoeSchmuckatelli]

Given SX's capabilities - are we seeing an uptick in government / commercial launches unrelated to Starlink? 

(Just wondering how sustainable is the launch capacity, and whether we are seeing the start of deeper market for the exploitation of space - based economic growth, or if the launch frequency will peter out once Starlink has been deployed) 

Edited June 15, 2021 by JoeSchmuckatelli

[Beccab]

7 minutes ago, JoeSchmuckatelli said:

(Just wondering how sustainable is the launch capacity, and whether we are seeing the start of deeper market for the exploitation of space - based economic growth, or if the launch frequency will peter out once Starlink has been deployed) 

No idea od the answer to your first question, but remember that each starlink has a lifetime of ~5 years after which it reenters and will need replacing. So, SpaceX is going to continue launching starlink satellites for as long as the constellation is active

[tater]

You can see the thrust structure in the middle back. They are soon to be connected.

[mikegarrison]

1 hour ago, Beccab said:

No idea od the answer to your first question, but remember that each starlink has a lifetime of ~5 years after which it reenters and will need replacing. So, SpaceX is going to continue launching starlink satellites for as long as the constellation is active

Starlink is "the gift that keeps on giving" (into the SpaceX budget).

[JoeSchmuckatelli]

How far is the 'drive' from the bay to the launch site?

Any idea whether the increased height of the booster might make that trip a bit more fraught?  Hate to see the thing tip over between build and launch.  NASA's crawler-transporters have both a lot of weight and a wider base, so moving a vertically oriented rocket isn't really a problem - or do they drive it horizontal like that one JAXA rocket a while back and lift it vertical again once there?

[magnemoe]

17 minutes ago, JoeSchmuckatelli said:

How far is the 'drive' from the bay to the launch site?

Any idea whether the increased height of the booster might make that trip a bit more fraught?  Hate to see the thing tip over between build and launch.  NASA's crawler-transporters have both a lot of weight and a wider base, so moving a vertically oriented rocket isn't really a problem - or do they drive it horizontal like that one JAXA rocket a while back and lift it vertical again once there?

Strong wind might be an issue but lifting is much more restrictive in wind speed.  
Superheavy is not that much higher than starship and much heavier. 

[tater]

SH has about 44 tons of engines on the bottom vs SS with <5t.

SH has about 60-65t of 304 steel on the tube vs ~46t for SS.

So it's a little under 1.5 times the height of SS, but 8X heavier at the base.

Edited June 15, 2021 by tater

[JoeSchmuckatelli]

34 minutes ago, tater said:

SH has about 44 tons of engines on the bottom vs SS with <5t.

SH has about 60-65t of 304 steel on the tube vs ~46t for SS.

So it's a little under 1.5 times the height of SS, but 8X heavier at the base.

I thought they mounted the engines once the ship was on the platform at the launch site.

So - if I'm wrong about that - where are the outdoor pictures of them mounting / demounting the engines taken?

[tater]

Just now, JoeSchmuckatelli said:

I thought they mounted the engines once the ship was on the platform at the launch site.

Totally forgot about that!

Yeah, they will pressure test it sans engines.

So it's about as much heavier as it is taller.

 

[magnemoe]

38 minutes ago, tater said:

Totally forgot about that!

Yeah, they will pressure test it sans engines.

So it's about as much heavier as it is taller.

 

For superheavy its quite possible they take it back to the construction site because the number of engines but that is another question

[tater]

Just now, magnemoe said:

For superheavy its quite possible they take it back to the construction site because the number of engines but that is another question

True, it's one thing to put three engines on at the pad, but 29? Yikes.

Also, where? The suborbital pads might not have clearance, and it would be tricky to do way up on the orbital pad.

 

[RCgothic]

And they have rolled out previous SN's with engines pre-installed where it made sense. They do do a lot of engine installation and swap outs at the suborbital pads though.

 

As mentioned by others, Superheavy may be particularly challenging to install engines on at the pads. The outer engines would interfere with the pad interface, and the orbital launch platform is at substantial height.

[JoeSchmuckatelli]

As someone who has driven heavy stuff down roads...  I'm wondering what the ground pressure of their transport trailer is going to look like.  There's a reason NASA went with a crawler - and while I've seen lots of different ways of doing things since its inception - a vertical drive down the road looks risky.

 

This makes sense: 

...but this looks fraught: 

A configuration like the first image makes it unlikely to tip over and really spreads the load (preventing damage to the road, or getting the load tipping if the road partly collapses) - but the height over the base of the vertical alignment plus the greater ground pressure of having fewer wheels makes me hope someone has run the numbers on the road surface.

[RCgothic]

I believe they're currently resurfacing the road to take heavier loads and allow vehicles to turn more easily.

[RealKerbal3x]

26 minutes ago, JoeSchmuckatelli said:

 

A configuration like the first image makes it unlikely to tip over and really spreads the load (preventing damage to the road, or getting the load tipping if the road partly collapses) - but the height over the base of the vertical alignment plus the greater ground pressure of having fewer wheels makes me hope someone has run the numbers on the road surface.

They simply don't have the capability to rotate Superheavy from vertical to horizontal and back again. It would require a truly monstrous transporter erector.

[zolotiyeruki]

2 hours ago, JoeSchmuckatelli said:

As someone who has driven heavy stuff down roads...  I'm wondering what the ground pressure of their transport trailer is going to look like.  There's a reason NASA went with a crawler - and while I've seen lots of different ways of doing things since its inception - a vertical drive down the road looks risky.

This makes sense:

<snip>

...but this looks fraught:

<snip>

A configuration like the first image makes it unlikely to tip over and really spreads the load (preventing damage to the road, or getting the load tipping if the road partly collapses) - but the height over the base of the vertical alignment plus the greater ground pressure of having fewer wheels makes me hope someone has run the numbers on the road surface.

That's a good question, and I don't have any definitely-true answers, but a couple things come to mind:

1) the space shuttle was moved to the pad with two 300 Ton solid rocket boosters strapped to it.  That's a lot of mass SH/SS won't have
2) as I understand it, SS/SH will be integrated on the pad, so you're only moving half the launch stack at a time
3) SS/SH are each tail-heavy when unfuelled (less tip-over risk)
4) normal semi trucks are limited to 40 tons for a full-length trailer (roughly 10T per axle, 2.5T/wheel).  If SS is 100T dry, you'd only need 40 wheels to meet that same standard.  SuperHeavy may be somewhat heavier, but in a similar ballpark.

[mikegarrison]

4 hours ago, JoeSchmuckatelli said:

As someone who has driven heavy stuff down roads...  I'm wondering what the ground pressure of their transport trailer is going to look like.  There's a reason NASA went with a crawler - and while I've seen lots of different ways of doing things since its inception - a vertical drive down the road looks risky.

General rules of thumb are more wheels, bigger wheels, or tracks. I suppose any of those solutions could be used.

They tried all of them on the B-36. The one they ended up sticking with (and the one that was used on most large airplanes ever since) was "more wheels". https://en.wikipedia.org/wiki/Convair_B-36_Peacemaker#Landing_gear

Edited June 15, 2021 by mikegarrison

[StrandedonEarth]

4 hours ago, RealKerbal3x said:

They simply don't have the capability to rotate Superheavy from vertical to horizontal and back again. It would require a truly monstrous transporter erector.

And it may not be strong enough to support itself on its side, at least not unpressurized. 

Roads for superheavy loads are a carefully prepared bed topped with gravel, otherwise the surface would be pulverized when the rig tried to turn. NASA’s crawler turned the crawlerway gravel into sand as it passed, IIRC…

Edited June 16, 2021 by StrandedonEarth

[tater]

Not sure if they stacked the 5th section on the integration/catch tower yet, but that is at the site, and section 6 looks pretty complete, and they are building 7.

[CatastrophicFailure]

1 hour ago, mikegarrison said:

They tried all of them on the B-36. The one they ended up sticking with (and the one that was used on most large airplanes ever since) was "more wheels". https://en.wikipedia.org/wiki/Convair_B-36_Peacemaker#Landing_gear

Darn shame the whole “tracks” thing never got much, er, traction. Sigh... what could have been... 

And speaking of roads, right down this one comes the latest kerfuffle: 

 

[JoeSchmuckatelli]

12 minutes ago, CatastrophicFailure said:

Darn shame the whole “tracks” thing never got much, er, traction. Sigh... what could have been... 

And speaking of roads, right down this one comes the latest kerfuffle: 

 

Re: the tweet... Somebody feels they are not getting their cut.  Police Union, maybe?

[tater]

It’s still a road. 
 

Gotta keep it open.