Ceres

Ceres, in astronomy, a dwarf planet, the first asteroid to be discovered. It was found on Jan. 1, 1801, by G. Piazzi. He took three distinct observations; on the basis of these the mathematician Gauss calculated Ceres' orbit with such accuracy that it was found one year later within 0.5° of the predicted position. Ceres is the largest and most massive of the asteroids; it has a diameter of c.590 mi (949 km) and a mass 1/100,000 that of the earth. Its orbit has a semimajor axis of 2.78 astronomical units and a period of 1,681 days. From its discovery until the 1850s, when many additional asteroids began to be identified, Ceres was regarded by many astronomers as a planet. In 2006 the reconsideration by astronomers of Pluto's status as a planet also led to the reclassification of Ceres as a dwarf planet.

Colonization
Ceres has been proposed as one possible target for human colonization in the inner solar system.

Physical Conditions
Ceres is a dwarf planet in the main asteroid belt, comprising about one third the mass of the whole belt and being the sixth largest body in the inner solar system by mass and volume. It has a round planet-like shape and a surface gravitational acceleration about 2.8% that of Earth. Observations indicate that it contains large amounts of water ice, about 1/10 of the total water in Earth's oceans. The solar flux of 150 W/m 2 (in aphelion), which is nine times smaller than that on Earth, is still high enough for solar power facilities. The upcoming Juno mission to Jupiter, for example, will be relying on solar power in a location further out from the sun than Ceres. Strategic location Being the largest body in the asteroid belt, Ceres could become the main base and transport hub for future asteroid mining infrastructure, allowing mineral resources to be transported further to Mars, the Moon and Earth. Its colonization also could become a step on the way to the colonization of the objects in the outer solar system, such as satellites of Jupiter. Because of its small escape velocity combined with large amounts of water ice, it also could serve as a source of water, fuel and oxygen supply for ships going through and beyond the main belt.

The establishment of a permanent colony on Ceres might be preceded by colonization of the Moon or Mars. As a consequence of Mars' greater semi-major axis Ceres has more frequent launch windows to/from cislunar space than to/from Mars, and the travel time is lower. It is more energy-efficient to transport resources from the Moon or Mars to Ceres, than from Earth. In fact, transportation from Mars or the Moon to Ceres is more energy-efficient than even transportation from Earth to the Moon.