OT: Voyager watts - test-drb@ccmp.vtda.org

12 May 2003

...
 From: chris &lt;cb(a)mythtech.net&gt;

 From what I remember, those probes (and most
(all?) other deep space probes, I
think), use a radioisotope decay generator for power.  This is a
sub-critical-mass nuclear power plant; it uses the heat produced by a
near-critical lump of plutonium to generate electricity, rather then using
fission to produce heat to produce electricity. 
So is this the power supply all those whiney people were bitching about 
NASA trying to put into a Mars probe? They were all afraid the probe 
would explode during launch and be ground zero of a nuclear blast (or 
some other most likely vagely based on reality doomsday outcome activists 
are notorious for).

-chris
<http://www.mythtech.net>

Hi
 You can't even get a pile of plutonium of greater than critical
mass to blow up, by it self. It will just get hotter and hotter
until is melts or if contained long enough to vaporize. To
make a bomb you need to increase the neutrons quickly. In
a bomb, this is done with a thing called a trigger.
 What most where worried about was just the accidental
spread of radioactive material in the atmosphere. I don't know
about you but I don't like breathing that stuff if I don't
have to. The problem is that NASA doesn't have a good track
record for using common sense to avoid accidents.
 I'm still in favor of them using the radioactive power sources
for the probes, I just wish it was someone else determining
when and how it was safe to launch them.
Dwight