SpaceX Texas launch site Discussion and Updates - Thread 10

[TorenAltair]

[...]
Purchase price is only the start. You then have ongoing maintenance, crew training & certification and crane inspection and certification.

That's clear, but that is something a "crane rent company" charges as well. So if they are closing in now on a manufacturing and operations baseline that requires a large crane regularly, it might be cheaper to buy one. Of course I don't know it, it's just a guess from me. If they only need the crane for building the highbay, then renting will be cheaper of course.

[samgineer]

I'm curious about launch stand, there are two new rigs inside, one is from black painted steel tubes but another one on top is from stainless. Black one we saw some mozzles, this mean it is almost for sure water sound suppression/deluge. But stainless one is bit of mystery for me.
I'm speculating, but what if stainless one is for liquid nitrogen as system for displacing air/diluting methane in case of leak as we saw few weeks ago at SN4 last test? What do you think about this idea? I see no reason why is it too stupid, it makes some sort of sense. Nitrogen is inert and in big enough volume it should prevent methane from burning as vaporizing liquid fire extinguishers do (Liquid nitrogen is vaporizing liquid). They are for A, B and C class fire. B is flammable liquid (LCH4) and C flammable gas (GCH4). For example here is paper about feasibility of liquid nitrogen extinguishing system in nuclear power plant for metal fire (Uranium is flammable). https://inis.iaea.org/collection/NCLCollectionStore/_Public/08/293/8293457.pdf or in urban utility tunnels https://www.sciencedirect.com/science/article/pii/S2214157X20300654, but I'm not sure if it should work in such an open space like starship test stand. Also here is nice text about LNG carriers extinguishing, http://www.liquefiedgascarrier.com/tackling-fire-LNG-ships.html I found this interesting.

Although CO2 and nitrogen smothering systems are not suitable for use in exposed open air applications, they are otherwise the most efficient agent for fighting liquid and vapour fires. By diffusing in a burning mixture, they lower the oxygen content and render the mixture inert. If the flames can be separated from the liquid, the boil-off rate will also be reduced.

Nitrogen is more effective and less dangerous to personnel than CO2 but CO2 is more easily stored.

SpaceX have more than enough LN2 on site, what if they decided to do kind of "yolo" extinguishing system by spraying tons of liquid nitrogen on potential leak of methane?

Edit: I forgot image what I meant.

[zubenelgenubi: Attach image file to post.  Do not embed image files in post.]

[loekf]

Perhaps it might be cheaper to buy such a thing used than to rent it.
I found a few offers

1998 LIEBHERR LR1800
Hours 12723
Price without taxes: about $2.5 million

„like the blue one“
2012 MANITOWOC 18000
Hours 1800
Nettopreis: USD $3,399,000

„bigger brother to the blue one“
2001 MANITOWOC 21000
Nettopreis: USD $2,900,000

Purchase price is only the start. You then have ongoing maintenance, crew training & certification and crane inspection and certification.

It is not a ridiculous idea. I think for the Tottenham Hotspur stadium, they actually bought the cranes used during the built. There were six or seven tower cranes and two huge mobile cranes, also used for demolition of the old stadium. But.. it was a 3 years' project.

[Nomadd]

  The thing next to the flare tank is getting more involved.
 One thing I think was missing for the flare might have been a heater. The flame was usually not at maximum when the liquid came spilling out, so they might have needed something to warm it up when depositing large amounts of LCH4 in the tank.
 The flare went back in at the same level. I guess the occasional flooding doesn't concern them.

[zubenelgenubi]

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Attach files--this function is available in the mobile version of NSF as well. Scroll down past the text box. "I'm on my smart phone" is not an excuse.

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[Yazata]

If they do eventually plan to launch Starship test flights from the SH pad, what will that mean for the tank farm? How far can the tank farm be from the pad it services?

[Kansan52]

If they do eventually plan to launch Starship test flights from the SH pad, what will that mean for the tank farm? How far can the tank farm be from the pad it services?

I was wondering that myself and got thinking about 39-a and the distance there seem to my untrained eye farther than BC.

[the_other_Doug]

In case of pad fallback of a SH booster, you want the tank farm outside of the projected blast distance... 

[danw]

For Shuttle the tanks were about 700 feet from the pad. As long as the lies are adequately insulated the distance is not critical. However how do they detank if they have a shutdown after the fueling lines are disconnected? What happens if they take off and land with significant fuel remaining? Venting methane without a duct to a flare stack could create an explosive atmosphere, particularly if winds are calm.

[Vanspace]

In case of pad fallback of a SH booster, you want the tank farm outside of the projected blast distance... 

Wouldn't that be way on the other side of Padre Island?

[the_other_Doug]

In case of pad fallback of a SH booster, you want the tank farm outside of the projected blast distance... 

Wouldn't that be way on the other side of Padre Island?

Depends on which blast effects you're most anxious to avoid.  There's a difference between enduring a really loud bang, and being enveloped in a conflagration replete with flying shrapnel...

[beelsebob]

In case of pad fallback of a SH booster, you want the tank farm outside of the projected blast distance... 

Wouldn't that be way on the other side of Padre Island?

Depends on which blast effects you're most anxious to avoid.  There's a difference between enduring a really loud bang, and being enveloped in a conflagration replete with flying shrapnel...

There is - but a "really loud bang" is extremely dangerous, especially to things that are mostly water, like us.  At around 15psi your lungs are going to take a beating, and there's a non-zero chance you'll die.  At around 50psi there's a 50/50 chance you'll die.  A giant tank of methane and oxygen exploding near by is likely to cause a blast pressure around 60-80psi, which will kill 99% of people (without any debris, fire, etc).

[Nomadd]

Venting methane without a duct to a flare stack could create an explosive atmosphere, particularly if winds are calm.

I've heard that somewhere.

[OTV Booster]

For Shuttle the tanks were about 700 feet from the pad. As long as the lies are adequately insulated the distance is not critical. However how do they detank if they have a shutdown after the fueling lines are disconnected? What happens if they take off and land with significant fuel remaining? Venting methane without a duct to a flare stack could create an explosive atmosphere, particularly if winds are calm.

If they abort after GSE disconnect but before clamp release the GSE is supposed to be able to reconnect. It was a failure in testing this that made SN4 so 'interesting'.


If it aborts after liftoff it has the same dismal effect of any rocket in this situation with the bonus of maybe being able to land. Detanking is an issue that no other rocket, except maybe F9 would ever face because none of them can land.


O2 could probably vent ok. Maybe a motorized cart to drag a hose to the landing pad and dogbot does a hookup?  Maybe Nomadd's looking for part time work. Pays good but very irregular.

[Herb Schaltegger]

If they abort after GSE disconnect but before clamp release the GSE is supposed to be able to reconnect.

Historically, the umbilicals for most rockets don't disconnect until launch commit and the vehicle leaving the pad.

[Okie_Steve]

Venting methane without a duct to a flare stack could create an explosive atmosphere, particularly if winds are calm.

I've heard that somewhere.

The question now is can you *STILL* hear

[danneely]

Venting methane without a duct to a flare stack could create an explosive atmosphere, particularly if winds are calm.

How did Hoppy vent its leftover methane after its flights?

[Texsun]

Venting methane without a duct to a flare stack could create an explosive atmosphere, particularly if winds are calm.

How did Hoppy vent its leftover methane after its flights?

If Hoppy got the Tesla software update it probably had Fart Mode as a touch-screen option. 

[Nomadd]

Venting methane without a duct to a flare stack could create an explosive atmosphere, particularly if winds are calm.

How did Hoppy vent its leftover methane after its flights?

[Slothman]

Venting methane without a duct to a flare stack could create an explosive atmosphere, particularly if winds are calm.

How did Hoppy vent its leftover methane after its flights?

Though the fact that it's lit on fire on this one occasion was likely unintentional. Hoppy has always just vented it's remaining fuel to the air, both after his hops and after it's static fires (due to the fact that they disconnected the GSE before firing the engine and didn't automatically reconnect it afterwards)