Free Astronomy Magazine May-June 2019

agenda, as many other structures would have been fixed over time. It was not just a question of knowing the Moon. The lunar basins indi- cated that the young Solar System was a very dynamic environment. If the Moon had been bombarded, the Earth would have suffered as well. Studying the Moon would have provided an idea about the ancient history of our planet. On the Earth, recordings of this pe- riod are lacking, because the crust is recycled by plate tectonics. The Moon, for its part, is so quiescent that its face has remained virtually unchanged for billions of years. The task was to find, in the corrugated soil, a crater with a clear access line from the east, providing a landing point a few kilometers away and having a sharp rim. A cavity 400 meters in diameter was chosen, lo- cated 35 km north of Fra Mauro. Since this was exactly the type of terrain that was avoided during the search for safe sites, selectors ran the risk of certifying a site for which they had only four high-res- olution photographs taken by Lunar Orbiter 3 for scientific inter- est. However, as it was located on the east coast of Oceanus Procel- larum, the site was well lit during the Apollo 12 mission and it was possible to obtain new images. In December 1969, Fra Mauro was confirmed as the landing site for Apollo 13. Given its shape, the crater to be sampled was called Cone. The best terrain for a landing was the relatively flat plain about 1 A POLLO 14 − Shepard examin- ing a large rock. [NASA, Proj- ect Apollo Archive]