Geological Chronicle
Mare Moscoviense (Latin for 'Sea of Muscovy') is a lunar mare located within an impact basin on the far side of the Moon at 27.3° N, 147.9° E. The mare spans approximately 277 kilometers (172 miles) across, making it one of the few extensive volcanic plains on the lunar far hemisphere. Unlike the lunar near side, where volcanic plains cover wide regions, the far side has a thicker crust that generally prevented magma from reaching the surface. Mare Moscoviense formed where a deep basin penetrated an unusually thin crustal zone, allowing mantle material and basaltic lavas to emerge.
The underlying Moscoviense basin formed during the Nectarian epoch, while the subsequent volcanic basalt flows erupted during the Upper Imbrian epoch. Data from the Japanese SELENE (Kaguya) mission indicated that volcanic activity in the basin persisted for at least 1.5 billion years following its initial impact excavation. The basalt layer occupies the lower southwestern portion of the basin floor, surrounded by higher highland terrain. Doppler tracking by the Lunar Prospector spacecraft in 1998 detected a distinct mass concentration (mascon), marking a strong positive gravitational anomaly caused by dense basalt and mantle uplift.
Surrounding impact features include several named craters along the basin margin. The crater Titov lies within the northeastern section of the mare, while Tereshkova borders its northern rim. To the southeast lies the floor-fractured crater Komarov, alongside the larger Korolev basin. Just to the south sits the crater Leonov, named after Soviet cosmonaut Alexei Leonov. Farther east lies the ancient Freundlich-Sharonov Basin.
The mare was first discovered in October 1959 when the Soviet spacecraft Luna 3 returned the first photographs of the lunar far side. The Soviet Union proposed naming the feature after Moscow. In 1961, the International Astronomical Union (IAU) officially approved the designation after French astronomer Audouin Dollfus noted that Moscow was a state of mind, reconciling the choice with lunar naming conventions that typically use weather or abstract terms.