Castelion's Series A funding round raised $100 million, led by Lightspeed Venture Partners and including several other firms.

The RPS uses two Stirling engines to convert the heat generated by the decay of Plutonium-238 (Pu-238) into electricity.

The pecking order at the top of the league has been set for a while (as evidenced by very little movement at the top of this week's Power Rankings), but the deadline provides a quick shot of ...