In sci.space.policy Robert Clark wrote:
Also, as I said it is *very* likely that a reactor design can be
created for the Am-242m fuel that produces an Isp of 6000s since such
designs already exist for uranium and plutonium and Am-242m is 100
times more efficient. An Isp of 6000s would result in a mass ratio less
than 8.

It is utterly unimportant how effective Am-242 using nuclear reactors
would be becuase the fact is that you aren't going to get the Am-242.
Because teh total worldwide production of Americum is in kilograms,
only about 5% of that is Am-242 *and* it has a half-life of 150 years.

There are experimental methods now used that can efficiently separate
isotopes in small amounts. These methods very likely would scale up to
larger amounts. The cost of this scaling I estimate would be a small
fraction of the cost of the mission.

You can't extract what isn't there. Am-242 is a short half-life element
that does not occour naturaly at all.


Bob Clark


--
Sander

+++ Out of cheese error +++