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The "catching" infrastructure is just as high risk as the SH itself, and technically the rest of the entire infrastructure itself. Starship is slightly lower risk, at least in terms of the parts already tested, such as belly flopping and landing. 

Due to that high risk, creating the actual "catching" infrastructure should be done now to remove as much risk, and give as much time for iteration later. Something as simple as fit checks, manufacturing techniques can be ironed out and iterated upon without trying to actually catch anything... yet.

I'd put a catching attempt down the line to make sure the booster even gets off the pad in one piece. 

Getting it off the pad will certainly be a landmark achievement, and a sight to behold. 

 

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Also keep in mind that the catching infrastructure is double-duty. The chopsticks provide a landing mechanism for Superheavy, but they are also used to stack Starship. So they need to be operational in order to have an actual launch at all, even though B4 is destined for a watery grave.

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9 minutes ago, sevenperforce said:

Also keep in mind that the catching infrastructure is double-duty. The chopsticks provide a landing mechanism for Superheavy, but they are also used to stack Starship. So they need to be operational in order to have an actual launch at all, even though B4 is destined for a watery grave.

With good enough wind conditions they can stack with the LR13500 as well as the previous stack proved, but that's 1: very restricting and 2: relying on a crane that has just been rented.

The QD arm, instead, is very necessary for finalizing the stack and the launch

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1 hour ago, Beccab said:

With good enough wind conditions they can stack with the LR13500 as well as the previous stack proved, but that's 1: very restricting and 2: relying on a crane that has just been rented.

I believe the only reason that worked was because they were doing a fit check.  They had no way of detaching the LR13500 from the top of Starship.  None of the worker lift baskets go that high.

Once they are actually ready to launch, they will want to use the chopstick arms to lift and place Starship.  That way, they can finish tiling the nose cone while it is still close to the ground. Current rumor is that there are lift points in the sides of Starship 20 which will not need any independent thermal protection because they are recessed.

1 hour ago, Beccab said:

The QD arm, instead, is very necessary for finalizing the stack and the launch

Agreed. Although I would’ve expected them to do booster fit checks with the QD arm and B4 right away, before adding the chopsticks. 

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14 minutes ago, sevenperforce said:

Although I would’ve expected them to do booster fit checks with the QD arm and B4 right away, before adding the chopsticks. 

One would think so, but may as well check it all at once in case adding one thing perturbs another just a bit 

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18 minutes ago, JoeSchmuckatelli said:

I'm a little torn watching SX's progress these last few months since SN-15s landing. 

On the one hand SX has proven the ability to to vertically land heavy class rockets - but on the other, BFR has never flown. 

My conservative side suggests they'd be better off testing its flight characteristics and their ability to to control the rocket in a landing situation with either a wet landing or another pad landing - despite the certainty that it will be a crash at the end. 

Yet everything I see suggests they're full speed ahead on the 'catch a rocket' plan. 

So while they have demonstrated the ability to do amazing things - they're set up to try two firsts at the same time. 

I worry about the prudence of this - because if BFR goes sideways during the final moments - there's a lot of expensive stuff nearby that is at risk. 

Wonder what the bookies are saying about the odds of success in the first BFR flight and catch scenario... 

The first superheavy will do an burn back but splash down, If the telemetry from that looks good as in it came down at the coordinates and slowed down correctly they plan to catch the second. 
If not they will splash the next to, if they have problems with accuracy they might add legs to the booster but this changes the flight characteristic. 

Starship will probably get back its test jump legs, as I understand they plan to land some of them on islands in the pacific, the US has some missile test sights who probably works well for this. Purpose here is to review the condition after landing and might reuse the raptors and some other hardware. Well and the first who lands intact probably end up as an memorial down the line. 
They want to catch starship to, but this require high accuracy out of the flip manoeuvre who is harder than superheavy pretty ballistic trajectory. 

Another problem for starship is that it has to overfly all of Texas to land back at site and you might even have to overfly Mexico. One solution here is to land offshore, 

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Why is the launch pad and tower so close to everything?

booster4starship20photoshop-scaled.jpeg (2560×1586) (nextbigfuture.s3.amazonaws.com)

 

The way Kennedy is laid out - if something bad happens out at the pad, there's not much else going to go boom.  geoeye-1-kennedy-space-center.jpg

but with SX... everything is at risk.

Edited by JoeSchmuckatelli
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3 minutes ago, Beccab said:

...no? It is pretty far from the rest

If the BFR pulls an "Astra" and flies off in the 'wrong' sideways orientation... a whole lot of stuff can go buh-bye in a hurry.

 

The top photo (the one that did not load) makes it look like the tank farm is only one BFR+SS length away from the launch table.

Edited by JoeSchmuckatelli
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Just now, JoeSchmuckatelli said:

If the BFR pulls an "Astra" and flies off in the 'wrong' sideways orientation... a whole lot of stuff can go buh-bye in a hurry.

No, if it does it will be terminated in flight. Again, the only thing that is at the launch site is the launch site

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Just now, Beccab said:

No, if it does it will be terminated in flight. Again, the only thing that is at the launch site is the launch site

Sorry - we are cross-posting:   The top photo (the one that did not load) makes it look like the tank farm is only one BFR+SS length away from the launch table.

 

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1 minute ago, JoeSchmuckatelli said:

Sorry - we are cross-posting:   The top photo (the one that did not load) makes it look like the tank farm is only one BFR+SS length away from the launch table.

 

This gives a good idea of how far the tank farm is from the pad. Telephoto images can be deceptive.

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12 minutes ago, RealKerbal3x said:

This gives a good idea of how far the tank farm is from the pad. Telephoto images can be deceptive.

That's the same photo (pretty sure) that I linked in the above post - judging by the shadows, it's literally one combined ship length away.  

https://nextbigfuture.s3.amazonaws.com/uploads/2021/07/booster4starship20photoshop-scaled.jpeg

You can also judge by pickup truck lengths... it's not that far away.

Edited by JoeSchmuckatelli
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54 minutes ago, JoeSchmuckatelli said:

the BFR pulls an "Astra" and flies off in the 'wrong' sideways orientation... a whole lot of stuff can go buh-bye in a hurry.

 

BFR is much more tolerant of losing a single engine than Astra is. :D

Also, SpaceX has to work with that they've got, they don't have nearly the real estate down there that KSC does. Hopefully they've already had enough on the pad Oopsies to retire that risk as much as possible. 

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2 hours ago, JoeSchmuckatelli said:

Why is the launch pad and tower so close to everything?

booster4starship20photoshop-scaled.jpeg (2560×1586) (nextbigfuture.s3.amazonaws.com)

 

The way Kennedy is laid out - if something bad happens out at the pad, there's not much else going to go boom.  geoeye-1-kennedy-space-center.jpg

but with SX... everything is at risk.

Someone is saying this finally. If SS blows it's gonna leave an N1 size explosions, blah blah cryogenics are safer or something but it's still much larger than the N1. SS needs to be launched extremely far from everything. 

I seriously doubt that crew will ever fly on starship but if they do it definitely will need an abort to pull something away from ~350 feet of tanks holding volatile gases.

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19 minutes ago, SpaceFace545 said:

Someone is saying this finally. If SS blows it's gonna leave an N1 size explosions, blah blah cryogenics are safer or something but it's still much larger than the N1. SS needs to be launched extremely far from everything. 

I seriously doubt that crew will ever fly on starship but if they do it definitely will need an abort to pull something away from ~350 feet of tanks holding volatile gases.

Note that your typical ICE car's gas tank  contains the chemical energy of about 40 kilograms of TNT, and people are allowed to just fill them up at the pump, whenever. Even fill spare gascans.

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8 minutes ago, Rakaydos said:

Note that your typical ICE car's gas tank  contains the chemical energy of about 40 kilograms of TNT, and people are allowed to just fill them up at the pump, whenever. Even fill spare gascans.

Note that cars aren't rockets and that rockets have a notorious habit for exploding especially in the least expected moments

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3 hours ago, RealKerbal3x said:
 Telephoto images can be deceptive.

Quoted for truth, since it seems people missed this comment. Here is a similar image, but from a different vantage point that makes BN4 and the launch tower look kinda tiny. Pic is also from RGV Aerial Photography.

https://ibb.co/6sGCvcS
 

(Apologies for the link, I can't get it to embed)

Edited by Meecrob
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1 hour ago, Rakaydos said:

Note that your typical ICE car's gas tank  contains the chemical energy of about 40 kilograms of TNT, and people are allowed to just fill them up at the pump, whenever. Even fill spare gascans.

While they aren't "allowed" to fill any old plastic bag with gasoline, it seems every shortage many people try it.   

 

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Looks like 1 gallon of gasoline is 114000 BTU, and 1 kg of TNT is 4000 BTU, so 28.5 kg of TNT per gallon of gas.

My car holds about 12.5 gallons of gas, so that's more like 356 kg TNT.

Looks like either you or I am off by an order of magnitude.

Note, energy != danger, per se. TNT releases its energy at a much faster rate than gasoline does (in normal circumstances).

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5 hours ago, JoeSchmuckatelli said:

Why is the launch pad and tower so close to everything?

booster4starship20photoshop-scaled.jpeg (2560×1586) (nextbigfuture.s3.amazonaws.com)

 

The way Kennedy is laid out - if something bad happens out at the pad, there's not much else going to go boom.  geoeye-1-kennedy-space-center.jpg

but with SX... everything is at risk.

The area inside the ring road around 39A, combined with the area of the crawlerway road to the turn off on the lower left—is the size of the ENTIRE Boca Chica facility, including the production site.

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