Regardless of the turnout at a protest event, it does seem there will always be a degree of concern about harnessing and working with nuclear power (whether from radioactive decay or nuclear fission). But both the US and the former Soviet Union have been sending RTG's into space for decades, and a whole new nuclear propulsion ballgame is in the works with Project Prometheus. SLP is not a rocket blog (unfortunately), nor am I a physicist like Clark Lindsey. (In my dreams, yes.) I wanted to throw some law into the mix, since advocating non-nuclear power sources for space travel because nuclear power poses a degree of danger is one thing -- and vigilant attention to safety issues is fine -- but some NPS opponents (including Karl Grossman, whose activity in this arena, as Jeff points out, goes back to before Cassini) claim NASA's use of RTG's violates law. I hope their science is better.
I am not aware of details of the opposition's pre-launch litigation activity, if any, (but isn't there always litigation?) however I do recall the attempt to enjoin launch of the RTG-powered Cassini mission to Saturn (whose probe Huygens landed on Titan one year ago tomorrow, as a matter of fact) -- Hawaii County Green Party v Clinton, 980 F Supp 1160 (D Hawaii 1997). Apparently, the mission lifted off.
(To say nothing of other vehicles powered with RTGs like Apollo, Pioneer, Viking, Voyager, Galileo and Ulysses as well as lots of civil and military satellites.)
For a comprehensive analysis of the law of NPS, now would be a good time to look again at Steve Mirmina's recent Chicago Journal of International Law Journal article, Nuclear Power Sources and Future Space Exploration, which I posted in September. (Steve is a senior attorney, International Law Practice Team at NASA's Office of the General Counsel.)
Steve overviews the history of NPS, then discusses the legal regimes covering the use. His thorough analysis includes the relevant international space law, nuclear energy law and international environmental law; he then takes an indepth look at the US regulatory processes applicable to NPS.
And, as Steve reminds us, there are always the non-binding, but enlightening: Principles Relevant to the Use of Nuclear Power Sources In Outer Space (General Assembly Resolution No. 47/68, 1993).
I also found instructive this GAO report to Congress, Space Exploration: Power Sources for Deep Space Probe, prepared with Cassini in mind (May 29, 1998), but which outlines the regulatory hoops NASA goes thorough in preparing for an NPS mission.
For now, heads up. SLP wishes NASA a safe and successful launch and a long, fruitful voyage to the planet Pluto.
[Or, rather, the celestial body formerly known as a planet, Pluto?
Either Pluto is not a planet, or many other things are planets. Which is a better choice? I want my planets to be more special, not less special, so I favor Pluto not being a planet. Emotionally, though, I have to admit that I have grown up thinking Pluto this special odd-ball planet at the edge of the solar system. While I now know scientifically that Pluto is less special, it's still hard to let go. -- Mike Brown, Caltech astronomer who helped find Sedna]