Talk:July 27, 2021
I've always thought that Mare Crisium has to be pretty young, given the paucity of craters across such a wide area. Luna 15 attempted a sample return mission there in July 1969 when Apollo 11 was on the Sea of Tranquility, but it crashed somewhere near the centre of the Mare Crisium and the Soviets did not explain its true purpose until decades later.
These sources say it crashed into a mountain:
But this cannot be true if the best estimates of its crash site, in the middle of the huge plain, are correct.
For Luna 15, the Sea of Crises was appropriately named...