Mare Cognitum ("
The Sea that has Become Known") is a
lunar mare located in a basin or large
crater which sits in the second ring of
Oceanus Procellarum. To the northwest of the mare is the
Montes Riphaeus mountain range, part of the rim of the buried crater or basin containing the mare. Previously unnamed, the mare received its name in 1964 in reference to its selection as the target for the successful impact probe
Ranger 7, the first American spacecraft to return close up images of the Moon's surface.