Golden Shields

> But what if your golden shield were a metre or two thick? I'm
> guessing that the secondaries problem wouldn't be a problem in that case.

OK, that sounds like fun. Let's suppose a small habitat like Kalpana One, 250 m radius and 550 m long. Let's not worry about the endcaps but only consider covering the main cylinder. You said a meter or two; let's take a the middle and suppose a layer 1.5 m thick.

Gold masses 19300 kg/m^3, so this works out to 2.51*10^10 kg of solid gold. Let's call it 25 billion kg of gold. Gold in the U.S. currently costs about $650/oz, or about $23000/kg. So, your gold shield would cost about $575 trillion dollars.

Of course, that's assuming that you could actually get 25 billion kg of gold, and that doing so wouldn't change its price. Perhaps this is reasonable if you assume finding and retrieving some large, gold-rich asteroid.

But as for me, I think I'll just stick with a couple meters of lunar dirt. :)

Joe Strout -- joe@...