"Bruce Farquhar" wrote in message
news
On Sun, 09 Dec 2018 21:40:03 -0000, Rod Speed
wrote:

Bruce Farquhar wrote

A thermocouple produces enough to power a spacecraft?!?

It isnt a single thermocouple, it's a thermopile.
https://en.wikipedia.org/wiki/Thermopile
https://en.wikipedia.org/wiki/Nuclear_power_in_space

Or just for some small electronics?

Not small at all.

Why are these not used on earth?

A few were, mostly by the russians for powering remote places like
lighthouses.

Its more viable to use a solar panel and batterys for most situations
on earth. The long range probes don't always have enough sunlight
to go that route with probes so use small nukes instead. Very reliable,
no moving parts to fail.

On Sat, 08 Dec 2018 21:04:59 -0000, Brian Gaff

wrote:

I'm sure you know this but the Voyager spacecraft are using
thermocouples
using the heat from decaying plutonium for power all the way out in the
cosmos. it may be reducing now but its been one heck of a long time.