NASA Successfully Tests Ion Engine

Henry Spencer opined

In article ,
Ilmari Karonen wrote:
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...

Unfortunately, preliminary experiments with it for ion propulsion were not
favorable -- in the sort of environment needed to quickly ionize significant
flows of material, it's not stable *enough*. The more determined folks have
not entirely given up, but it's not going to be easy.

Given all the symmetries with the C60 molecule, could a tuned laser do the
ionization?

-ash
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"Ash Wyllie" writes:

Henry Spencer opined

In article ,
Ilmari Karonen wrote:
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...

Unfortunately, preliminary experiments with it for ion propulsion were not
favorable -- in the sort of environment needed to quickly ionize significant
flows of material, it's not stable *enough*. The more determined folks have
not entirely given up, but it's not going to be easy.

Given all the symmetries with the C60 molecule, could a tuned laser do the
ionization?


Yes, but it would almost certainly have to be a tuned ultraviolet laser,
and those are pretty hard to come by. Harder still if you demand even
five percent efficiency, which you need to be competitive with the more
conventional propellant ionization systems.

Two-photon processes could theoretically get you ionization using only
tuned visible lasers, but such processes are inherently inefficient,
demand very high laser intensities, and are generally not worth the
bother unless the universe obliges you with a metastable state halfway
between ground and first ionization.


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