1950s-70s USA and Russia philatelic covers that are related to the early satellites development, manned and unmanned spaceflights to the moon.
1964-01-30 USA Ranger 6
Ranger 6, launched on 30 January 1964, was designed to take a series of images as it approached the moon, right up to the point where it crashed into the lunar surface. Unfortunately, the spacecraft's cameras failed and no pictures were returned. Ranger 6 crashed into the Sea of Tranquility on 2 February 1964.