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Centaur elemental composition? by Warren Platts on 19 Nov, 2013 21:58
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Does anyone know how much of each element (in kilograms) that goes into the construction of a Centaur 3rd stage? E.g., I understand there is some gold foil in there, but how much does it mass? The fuel tank is stainless steel: Does that mean there were also substantial quantities of chromium? Is aluminum a major component? Magnesium? Vanadium? Silver? Copper?
The reason I'm asking is because I'm trying to figure out the role of contamination of the Centaur stage itself in the LCROSS lunar results. The papers published in Science tend to discount contamination as having a significant effect on the published results; however, various internet pundits still dismiss certain surprising results as a consequence of contamination by the Centaur 3rd stage.
Any help will be much appreciated and will be duly acknowledged in the AIAA paper I'm helping to write for the January conference.
Cheers
Warren -
#1 by Warren Platts on 19 Nov, 2013 22:30
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Actually, just found this article by Jon Goff that suggests that the apparent "gold foil" in Centaurs are actually MLI ("Multi-Layered Insulation")--mylar basically, so, evidently, there are no parts containing significant amounts of gold?
http://selenianboondocks.com/2011/11/tooting-someone-elses-horn-quest-product-development-corps-advanced-mli-technologies/ -
#2 by Jim on 19 Nov, 2013 22:36
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Does anyone know how much of each element (in kilograms) that goes into the construction of a Centaur 3rd stage? E.g., I understand there is some gold foil in there, but how much does it mass? The fuel tank is stainless steel: Does that mean there were also substantial quantities of chromium? Is aluminum a major component? Magnesium? Vanadium? Silver? Copper?
The reason I'm asking is because I'm trying to figure out the role of contamination of the Centaur stage itself in the LCROSS lunar results. The papers published in Science tend to discount contamination as having a significant effect on the published results; however, various internet pundits still dismiss certain surprising results as a consequence of contamination by the Centaur 3rd stage.
Any help will be much appreciated and will be duly acknowledged in the AIAA paper I'm helping to write for the January conference.
Cheers
Warren
The LCROSS people and PI have this information -
#3 by Jim on 19 Nov, 2013 22:37
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E.g., I understand there is some gold foil in there, but how much does it mass? The fuel tank is stainless steel: Does that mean there were also substantial quantities of chromium? Is aluminum a major component? Magnesium? Vanadium? Silver? Copper?
Yes to all the questions. -
#4 by Warren Platts on 19 Nov, 2013 22:46
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The LCROSS people and PI have this information
OK fine. I'll bug Gladstone and see what he has to say...E.g., I understand there is some gold foil in there, but how much does it mass? The fuel tank is stainless steel: Does that mean there were also substantial quantities of chromium? Is aluminum a major component? Magnesium? Vanadium? Silver? Copper?
Yes to all the questions.
Which is interesting, since no chromium was reported, only tiny amounts of Al, and magnesium was at about the expected crustal abundance. Thanks. -
#5 by Warren Platts on 04 Dec, 2013 10:15
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Well, Tony Colaprete got back to me: ULA did provide an inventory of potential sources of volatiles (since the primary mission was to look for water), but did not provide a breakdown for anything else: things like battery electrolytes (13.25 kg), foam insulation (57 kg--chemical composition proprietary), and paint (19 kg--chemical composition proprietary.
As for metals, the vast majority of the mass would be concentrated in the stainless steel oxygen tank (chemical composition proprietary, I'm guessing, but I imagine it's probably some sort of nickel-based Inconel-type steel that can withstand cryogenic temperatures).
Dr. Colaprete did mention there might be some gold coating in the rocket nozzle(s)--I understand that gold plating prevents hydrogen embrittlement from the hydrogen rich steam exhaust. However, no gold foil was used, evidently--correct me if I'm wrong.
As for silver, "LO2 pumps where contact with the inducer or impeller could result in ignition are coated with silver". And there's probably a bit in the solder in the electronics.
But bottom line is that since silver and gold are used only for plating, the amounts have got to be measured in mere grams.
I assume there's a bit of silver in the soldering for the electronics, but this cannot be more than a few grams, can it? Also,
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#6 by JRB2 on 04 Dec, 2013 17:13
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For RL10, the LOX pump isn't silver coated and there's no gold coating in the nozzle
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#7 by Warren Platts on 05 Dec, 2013 02:26
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For RL10, the LOX pump isn't silver coated and there's no gold coating in the nozzle
Source? -
#8 by Warren Platts on 05 Dec, 2013 17:26
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Well, I emailed Bernard Kutter, and he was kind enough to reply. This is what he said:Quote
There are multiple sources of gold and silver on Centaur:
- MLI on forward bulkhead, aft bulkhead, and component shields
- Avionics includes some gold and silver
- Parts of the propulsion include silver
So that's interesting: MLI is a form of gold foil, evidently there is silver plating in the rocket engine, and if Colaprete, the PI whose based at NASA Ames, thinks there's some gold plating on the nozzle, I guess I have to take his word for it.
But it still seems like the amounts involved are relatively tiny, and measured in grams, rather than kilograms.
Feel free to correct me if I'm wrong!
