Sikorsky is a crater on the far side of the Moon. It is situated behind the southeastern limb of the Moon, just out of sight from the Earth. It lies to the northwest of the huge walled plain Schrödinger. To the northwest is the smaller crater Moulton. In 1967 the Lunar Orbiter 4 photographed this region in high resolution, discovering a 310-km-long gouge cutting through the middle of Sikorsky. This linear formation is radial to Schrödinger and has since been named the Vallis Schrödinger. The crater is named after Igor Sikorsky, a Russian-American aviation pioneer.