Aluminum on S/C and Satellite

[PK69]

Hi guys,

Good morning to everybody!
I hope you can help me.
I wonder if it is possible to use Aluminum or Aluminum alloys on the spacecrafts or is it mandatory to anodize (alodyne or others) the AL parts? Could you indicate me a NASA std or ECSS to find something?
Thanks in advance,

Emilio

 

[PK69]

nobody?

 

[CoryPad]

Your question is worded poorly.

The first part "I wonder if it is possible to use Aluminum or Aluminum alloys on the spacecrafts", the answer of course is yes, you can use aluminium and its alloys.

Regarding anodizing, that is used for some, but not all, applications.

I am not sure what document would apply, so you may need to contact someone at NASA directly. If you are a current or future supplier, don't you have a liaison?

Regards,

Cory

Please see FAQ731-376 for tips on how to make the best use of Eng-Tips Fora.

 

[PK69]

Thanks Cory.
Yuo're right, it was written in a bad way.
The question is if it is possible to use aluminum and aluminum alloy without anodizing or passivating os S/C parts or on payload.
Bye,

Emilio

 

[btrueblood]

Did you read Cory's post, and what did your liason say?

In general, anodizing and passivating of s/c is done to eliminate the possibility of corrosion developing during storage, shipping, and vehicle assembly/launch pad waits. Consider that if your launch vehicle is US or French, you will be designing for a vehicle that may sit for months in a very humid climate, near a salty sea coast.

 

[PK69]

btrueblood,

thanks for your answer. I would like to contact prime and/or agency only after the internal review (we are still in a development phase...so we have time) and now your answer clarify a bit my doubt. I knew that the question was too generic but this was because we could use aluminum in different place of our payload and the doubt was mainly on a component that should be under argon (or nitrogen) environment (so teoretically protected, if o-ring or gasket has low permeation) along all phases (storage, shipping, and vehicle assembly/launch pad waits).
Thanks again,

emilio

 

[monkeydog]

PK69,
It is just good practice to do what you can for corrosion protection. The part may be installed in a location that is in an inert blanket gas, but concider the times from when it leaves the machine shop to final assembly and installation in the s/c.

 

[kenvlach]

My experience is only at the sub-subcontractor level, so I've had nothing to do with the specifying. That being said, my understanding is that internal aluminum surfaces are usually left bare, and external surfaces are anodized for thermal reasons (absorptivity & emissivity) and to reduce erosion (from the tiny, high-speed particles in space & ions in low orbits). Both clear & black anodizing are used.
I believe that chemfilm (Iridite, Alodine, etc.) isn't used used due to outgassing & because it doesn't serve much purpose in space.

For anodizing of spacecraft parts, the following is helpful:
NASA-TM-104622 "Preventing Cracking of Anodized Coatings" (1995)

http://ntrs.nasa.gov/archive/nasa/casi.ntrs.nasa.gov/19950025269_1995125269.pdf

Its reference 1, NASA TM-104335, "Evaluation of thermal coatings for use on solar dynamic radiators in low Earth orbits," may be helpful in deciding whether an anodize coating is required, but I don't have a copy & can't find on NASA sites. Link, anyone?

 

[PK69]

Thanks guys for your help!!