[meteorite-list] Hayabusa Spots Its Asteroid Target

From: Sterling K. Webb <kelly_at_meteoritecentral.com>
Date: Thu Aug 18 14:52:19 2005
Message-ID: <4304D8BE.40DE4E6B_at_bhil.com>

Darren,

    Tantalum is the tenth most dense element,
with a density of 21.02 times that of water,
or three times that of iron. There are others
more dense, but they suffer from various
disadvantages: low melting point (osmium),
danger (plutonium), expense (gold).
    As you said, one of tantalum's advantages
is a clear signature to discount. It is hard
(6.5 on the mineral hardness scale). It has
a reflectivity of 0.78, and it looks a lot like
pewter.

Sterling Webb
--------------------------------------------------------------------------------
Darren Garrison wrote:

> On Thu, 18 Aug 2005 08:16:09 -0700 (PDT), Ron Baalke <baalke_at_zagami.jpl.nasa.gov> wrote:
>
> >the firing of a tantalum pellet into the asteroid at 300 metres per second.
>
> Why such an exotic material? So that you could find and discount it's signature in the returned
> sample?
Received on Thu 18 Aug 2005 02:51:42 PM PDT