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Discussion of Storage Tanks at LC-39A
- Thread starter ecarfan
- Start date
Telephoto lens perspective distortion?
Or maybe it's for all those hydrogen-fueled trucks that haul rockets cross-continent.
Naah - I'll go with #1.
nwdiver
Well-Known Member
swaltner
Active Member
For scale and relative location to the launch pad, here's a picture I took on a KSC (Kennedy Space Center) tour back in 2012 on the LC-39A tour stop, which was actually not anywhere near the pad. I made trip down to KSC at this time, because it was after the Shuttle program, so there was a brief time that the VAB (Vehicle Assembly Building) was open to public tours. You can see the liquid hydrogen tank along the horizon in the left half of this image, far away from LC-39A.
You can also see the relative size and location of the tanks out on Google Maps
You can also see the relative size and location of the tanks out on Google Maps
I need to correct my error, and apologize: Helium gas (He) is used for ullage, not Hydrogen gas (H2). This article mentions that: Falcon 9 rocket explosion traced to upper stage helium system – Spaceflight Now
Quote: “The Falcon 9 rocket’s upper stage liquid oxygen tank contains several composite helium vessels, each pressurized to about 5,500 pounds per square inch in flight. The helium is routed through the second stage’s Merlin engine, where the helium warms up and is injected into the rocket’s propellant tanks to pressurize the stage as the launcher burns fuel, keeping the tanks structurally sound.”
So...what is the liquid Hydrogen in that storage tank used for?
I imagine they're left over from the Apollo and shuttle eras. There's no hydrogen in the Falcon 9 that I'm aware of.
Good point. I may well have made a fundamental error in assuming that the tank pictured contained something. Perhaps it is simply empty.
Unrecognized assumptions often lead to errors in reasoning...
That quote explains pressurization of LOX tank. Ullage means some trust to settle propellants in the tanks so that pumps can be turned on.
I also assume that LH2 tank was build for Shuttle or for some older rocket. Main engines of the Shuttle burned LH2. I don't know if SpaceX could use it to store methane. LH2 is very light, perhaps methane is too heavy.
This seems like a very sensible approach to handling these launchers. Building them vertically no doubt has some advantages, but when you actually have to work on the thing, lying it down must make everything a heck of a lot easier.
Shuttle used hydrogen fuel cells for electrical power.
NeverFollow
Active Member
I don't know if there is any 'liquid Hydrogen' but I remember reading that there are three tanks.
Two are used for the propulsion, and
the third tank is used to send pressure in the two other tanks to keep a constant pressure
allowing for a constant flow of delivery especially when the tanks start to be empty.
I will try to verify this information, but I might be completely wrong...
There are many tanks holding different stuff.
The main body of the first stage booster doesn't have "tanks"; rather the skin of the booster itself is the tank. It's divided into two pieces, with the smaller bottom section holding cooled kerosene (RP1), and the larger upper section holding supercooled liquid Oxygen. The internal pressure and cylindrical wall keeps the structure very rigid. Immersed in the LOX tank is a (one or maybe more for the first stage, not sure) Carbon Overwrapped Pressure Vessel holding extremely high pressure helium, which is used to maintain pressure in the other two tanks as fuel and oxygen are used up. (This COPV in the second stage is what blew up the second failed F9. As I understand it some Oxygen actually got into the Carbon layers, froze and ignited.) Somewhere in there is at least one tank holding liquid Nitrogen for the thrusters; it can't be in the LOX tank 'cause that would be too cold. They used to use hydraulic fluid for the landing gear and grid fins, but I'm not sure if they went away from that; maybe Nitrogen is used now.
Gentleman, this discussion of a tank of H2 (hydrogen) is in reference to the photo I posted upthread (post #392, photo credit is not mine) which showns the FH vertical on the pad and in the foreground a large ground-based storage tank labeled “Liquified Hydrogen”. The discussion then evolved into what that gas might be used for in the Falcon rocket. But the Falcon does not use H2. It was pointed out that the hydrogen storage tank was left over from the Apollo/Shuttle era. Not related to SpaceX. It just happened to show prominently in that photo of the FH due to where the photographer was located.
You appear to be talking about the tanks inside the rocket.
You appear to be talking about the tanks inside the rocket.
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