Any nuclear thermal rocket engine would have to be developed and tested in Russia because the enviro-whackos would not permit it in the U.S.
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You may have a point, IF the technology ends up being nuclear. Some have suggested the Ion-engine may be the real answer to long-term space rides...
Actually, the ideal engine would be a nuclear power plant driving an ion engine. The advantage of the nuclear powerplant is in the excess power available for instruments. Instead of relying on solar power the scientists would have huge amounts of power to use on more powerful radar and communication arrays. The real benefit of nuclear power is more apparent in outer solar system missions where solar power is very limited.