A true engineer stuck trying to survive on an earthlike world with uranium and solid ice lakes everywhere would/should know that a simple homemade Thermovoltaic is Copper-Copper Oxide-Copper unijunction... made "simply" by twisting two copper wires tightly together and burning them until their contacting surfaces Char/Burn/Oxidize, and being careful not to let the char flake off (thats the magic stuff, if copper is on either side of it amounts to conductors/heat pipes). then have one end of the twisted pair be "hotter" the other "colder", arranged in a soup can with a lump of radioactives int he center, and embed the can in an ice lake. Presto! a homemade RTD power generator that may (given 3 months of twisting and charring) barely generate the 5v, 300ma his arm mounted PipBo.... erm... arm PDA needs to signal for help. ...just saying. It may not be pretty, nor efficient. but will get you tons of groupies at a Maker Faire. Potato batteries are small time. So, in that light -if SE was realistic at all it should make a single rotor be able to make a small reactor, but the welder time to build should take months.