NASA reports the Ulysses spacecraft, a joint NASA-ESA venture, recently passed beneath the south pole of the sun on it’s way up to the sun’s north pole. This is the third such pole-to-pole passage in the spacecraft’s 17 year history.
Ulysses is powered by an RTG built by Lockheed-Martin and provided to the mission by the US Department of Energy. The RTG uses a Pu238 heat source and SiGe (silicon-germanium) thermocouples operating at about Th=1000 oC and Tc=300 oC.
Gotta love those RTGs.