Why does...?

[duke]

Why does the US space shuttle's main external tank have an orange or rust tone to it?

 

[toph99]

because they don't paint it

 

[Gatsby]

Like toph99 said its not painted..

But it was painted for the first 4 shuttle flights though.

Gatsby - 38

 

[duke]

Sure about that? Being that the external tank is made of an aluminum alloy, why would it be orange?

 

[ltk007]

oxidation, rust, combustion, burning, Al+O2---->AL2(O2)3

 

[Gatsby]

Duke-

Thats what I remmeber from my Space Academy thingy a while ago. I even bought the book about it.

Gatsby - 33

 

[duke]

Oxidation? Brand new external tanks are used for each launch and are orangish in color even as it leaves the hanger. Sure about that?

 

[SSP]

It's a giant Carrot!

 

[duke]

My guess is that the orange color is from the insulation used to keep ice from forming. Can anyone confirm?

 

[DadofOne]

DING!!!! you are correct, the orange color is the isulation for the cryonic fuel and oxidiser located inside. After the 4th shuttle flight, it was decided that the paint could stay behind, so more cargo could go up. A few years back, they had a problem with some woodpeckers who were determined to check out that huge tree at Launch complex 39....