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

12 May 2003

...
 From: "Kapteyn, Rob"
&lt;kapteynr(a)cboe.com&gt;

I think RTG stands for "Radioactive Thermal Generation" or something like that.

It is a hunk of plutonium that, on its own, glows at a high temperature.
Since the temperature of space is near absolute zero, there is a large  temperature
difference.
...
 A relatively simple, dependable thermocouple generates
electrical power from  this temperature difference,
...
 making a really long-lasting, dependable battery -- but
not of the sort you  want in your kid's toys :-)

Hi
 At least I know for sure that the Cassini uses a linear Stirling
engine and not thermocouples. These are much more efficient at producing
electricity with a thermal source. The linear ones can use magnetic
bearings and don't have wear factors to worry about. They can
also be controlled to give a more constant power output by changing
the efficiency as the radioactive source runs down.
Dwight