NASA Successfully Tests Ion Engine

On Sat, 29 Nov 2003 07:58:47 -0700
\(formerly\)" dlzc1.cox@net wrote:

I'd worry about "selectively ionizing" a molecule for propulsion. Since the number of electrons stripped off provides the handles for
accelerating the mass, the more electrons removed means the faster you
can accelerate the molecule. But the more electrons you remove the
weaker (or smaller) the molecule fractions become. So your C60
becomes just 60C, and you are back to accelerating a bunch of light
nucleii.

C_60 is pretty stable, though, and, like any molecule, will hold on tighter to its remaining electrons once it's already lost some. Some quick googling suggests C_60 can lose at least 3 electrons without breaking up, but will start shedding C_2 ions at some point after that. I don't know much about ion drives, but I'd think that'd be good enough.

What I'd be more worried about is carbon buildup on the grids. If even a small fraction of the molecules sticks to the charged surfaces (and those C_2 fragments are likely to be particularly sticky) the resulting soot buildup might well become a problem over time.

--
Ilmari Karonen
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