50 Dollars - Elizabeth II E5 Hayabusa

The Hayabusa2 mission, operated by JAXA, successfully retrieved samples from the asteroid Ryugu in December 2020 after a six-year round trip covering roughly 5.2 billion kilometers — the first mission to deliberately blast a crater into an asteroid's surface to collect subsurface material. Cook Islands has no connection to the mission whatsoever; the issuing authority here is purely nominal, as the territory's numismatic program is administered through commercial licensing arrangements that place its name on bullion and commemorative issues globally.

The .9999 fineness corresponds to a precise troy half-ounce — 7.78 g being a standard fractional bullion increment rather than a figure tied to the subject matter.