Sputnik

Sputnik¹

The Soviet Union didn't officially issue covers for Sputnik 1, and any Sputnik 1 covers found are anniversary covers or possibly some unofficial back-dated examples - and possibly even some fakes.

Ideally, any actual Sputnik 1 launch covers would be from the Soviet Union, such as Moscow or the area of the launch site, but since this was a world-wide event, in many collectors' opinions, any October 4, 1957-dated cover from anywhere in the world would suffice.

Below is a cover from the US Aircrafr Carrier the USS Lake Champlain of MR-3 fame.

Notes:
1) Cover from Bob McLeod on collectSPACE