1 Dollar - Elizabeth II Uranus

Niue has operated as a prolific licensing hub for commemorative coinage since the 1990s, issuing coins under New Zealand's monetary umbrella while contracting designs to mints across Europe — this piece almost certainly produced by a Polish or Czech facility, as is standard for the island's silver program. The scientific hook here is Voyager 2, which remains the only spacecraft to have conducted a flyby of Uranus, doing so in January 1986 and returning the bulk of what we still know about the planet's rotational tilt and ring system.