Umi

Umi (systematic designation: Mars I) is the larger and closer of the two moons of Mars, the other being Deimos. Both moons were discovered in 1877. With a mean radius of 11.1 km (6.9 mi), Umi is 7.24 times as massive as Deimos. A colony of the East Asian Federation, it is named for the Japanese word for "sea". It is a terraformed world, with its environment modified to support human life, a process began in 2012 and completed in 2017. Umi orbits about 9,377 km (5,827 mi) from the center of Mars, closer to its primary than any other known planetary moon. It is currently undergoing orbit correction, to prevent its impact with Mars in approximately seven million years.

Physical characteristics
Umi's shape is highly non-spherical, which leads to discrepancies in its natural gravity. Gravimetric engineering allows a constant gravity of 1G across the moon's surface. As a part of the terraforming process, Umi was completely covered in water brought from Earth over a period of five years. Impact craters from before terraforming now exist as depressions under the lunar sea. The Stickney depression, the largest depression, is a popular location for diving for tourists.

Human presence
Umi is a prefecture of the East Asian Federation, and has full representation in the Federation Board. There are two settlements on Umi, Bada-esi and Nuova Venezia. Bada-esi is the administrative center, and seat of prefectural government. Umi's primary function is as an international tourist resort, open to citizens of any and all nations, and its government is structured to support that primary function. Several engineering support functions necessary to sustain the artificial environment of Umi, including gravimetric stabilization and atmospheric regulation are controlled remotely from Bada-esi. The entire colony is powered by a twin-reactor fusion power station, located in Nuova Venezia.

Umi also plays host to the Federation Space Forces Umi Logistics and Resupply Station, in orbit around the moon, which doubles as the primary spaceport for passengers and equipment arriving to the moon.