Rockets that smoke

[Eric Vaxxine]

Can anyone tell me why the Shuttle boosters generates smoke pollution, but footage I have seen of Apollo launches are relatively smoke pollution free?

[Nicolas]

I think in the first moments after liftoff, the flame kind of blows away the smoke immediately behind it so far that you don't see it. Also, I think SRB's tend to smoke more than liquid rockets?

The Apollo's did smoke, check this video of further in the flight:

launch clip

And obviously, around the tower itself there's plenty of smoke as well, which to a large extent is steam from the tunnels I suppose.

I think the liquid/solid fuel explains a lot of the smoke. But I'm not sure.

[Eric Vaxxine]

Thanks Nicolas.

[Spherical]

American launch vehicles use large solid rocket boosters nowadays. These produce large clouds of particulates because the fuel is made from a mixture of rubber, finely divided aluminum, and an oxidizer. The Saturn V first stage burned kerosene (paraffin) and used liquid oxygen as an oxidizer so those engines would produce some relative small quantities of carbon soot. Most of our second stage engines burn liquid hydrogen and liquid oxygen which produce only water in their exhaust. The third stages use hypergolic fuels which also produce quite a bit of soot, but they are ordinarily only used outside the atmosphere.

[Nicolas]

Rocket launches aren't the cleanest things anyway

[Eric Vaxxine]

....the fuel is made from a mixture of rubber.....

Really? Like, used car tyres?

[Spherical]

Really? Like, used car tyres?

NASA doesn't use used tyres, but yes, it is essentially the same material. I do suspect that the North Koreans are using used tyres for some of their missiles.

[Wolverine]

This would likely be more at home in Space Exploration. Moved.