Ina

Ina is a peculiar small depression ("crater" in IAU nomenclature) on the Moon, in Lacus Felicitatis. It is , wide and 64 m deep (from the deepest point of the bottom to the highest point of the rim). Ina is remarkable for several dozens low hills with flat or rounded tops and very sharp rounded boundaries, looking like drops of mercury. Their surface looks like the usual surface of the Moon while the space between them is very different. Ina is the most prominent of several dozen similar features on the Moon. Their origin is unclear. Discovery, exploration and naming Ina was discovered on photographs taken in 1971 by the crew of Apollo 15 from lunar orbit. It could have been found 5 years earlier on images taken by Lunar Orbiter 4 had a photographic flaw not prevented this. At the end of 1972 Ina was observed and photographed by the crew of Apollo 17. After Apollo it was reconnoitred by several orbiting spacecraft beginning in 2009 when the Lunar Reconnaissance Orbiter obtained photos of Ina with resolution of about 0.5 m/pixel and with varying illumination angles. On a topophotomap published in 1974 by NASA this feature was given the Latin female name Ina, in accordance with the convention to give small lunar craters human first names. In 1979 this name was adopted by the International Astronomical Union. In Apollo-era publications the feature is called D-caldera due to its shape, and at the time it was believed to be a unique feature on the moon.