Luna 13 was an unmanned module which landed on the moon on 24 December 1966; it was the third craft to land on the moon after Luna 9 and the US’ Surveyor 1. Luna 13 sent back holiday snaps until 28 December, when its batteries ran out and contact was lost.
I love the artwork on this stamp; it has that wonderful 50s/60s sci-fi vibe when. You can find a really nice (if more prosaic) montage of designs, cross-sections and the pictures sent back by Luna 13 at:
https://www.youtube.com/watch?v=VYykE_-Xe_8
https://en.wikipedia.org/wiki/Luna_13
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