“...Palladium, platinum, rhodium, ruthenium, iridium and osmium form a group of elements referred to as the platinum group metals (PGMs). These have similar chemical properties, but palladium has the lowest melting point and is the least dense of them.”
Per Wikipedia.
Asteroids are rich in PGMs. If cold fusion becomes common, we will need a steady supply, and that is off-planet.
Outer space, here we come!
They're even richer in nickel (they call'em "nickel-iron" asteroids for a reason).
I often think wistfully what the world would be like had we pursued Kennedy's Space Initiative rather than LBJ's Great Society.