starship-design: rtg

[Steve VanDevender <stevev@efn.org>]

Curtis Manges writes:
 > Pardon my ignorance, but what's an RTG?

A Radioisotope Thermal Generator.  It's basically a quantity of
radioactive material that generates heat, which is converted to
electrical energy by a thermocouple.  They're long-lasting and have no
moving parts, making them very useful as power sources for long-duration
outer-solar-system space probes.  They've also been somewhat
controversial, as generally the radioactive material used in RTGs is
plutonium (a fairly active radioisotope is needed so that it will
produce enough heat).  Despite substantial care being taken in building
RTG casings so that they will survive any likely launch accident, and
the plutonium contained in a durable ceramic material, there have been
protests surrounding the launches of the Galileo and Cassini spacecraft
due to them carrying RTGs with tens of kilograms of plutonium.