Re: Strengths of materials

From: Spike Jones (
Date: Tue Aug 08 2000 - 14:05:11 MDT

Amara Graps wrote:

> Is that Al2O3 correct? I didn't know that sapphire whiskers and
> Aluminum oxide was the same material. Cool.

Same elements, but not the same molecular structure. Fortunately
we can make sapphire in bulk. The THAAD missile seeker window
is a single crystal sapphire. The recent order of 1100 of those
windows has caused the price of manufactured sapphire to drop

> Al2O3 is the material that is released from the solid rocket motor
> firings when pushing a satellite into higher orbits.

Right but the use of solid motors is being strongly discouraged for
use in orbital transfer maneuvers, for the resulting slag may damage
existing satellites. Perhaps Doug knows the last time such a thing
was used. I dont know of a solid being used recently. The notion
that solids deposit materials that could later be used for other
has never occurred to me. Amara! Run to the patent office and
claim all orbiting slag.

> This material
> is among the most common debris material in orbit around the earth.

So this material has a natural source? I guess I could see why that
would be, for whatever caused the asteroid belt (planetary
collision) would leave yottagrams of dust, which would likely be
aluminum oxide.

> Here is a picture of an aluminum oxide sphere attached to a
> micrometeroid (cosmic dust) particle:

Cool thanks! Im guessing the spherical one is the Al2O3,
resulting from a solid rocket motor burn in orbit. spike

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