The Sol system, commonly called Earth system, includes one star and its various planets
Sol, a class G2 star and earth's home star, serves as an astronomical reference standard. It is accompanied by eight planets, with two asteroid belts, called the Inner System and the Outer system.
The Inner system has four planets. Mercury, Venus, Earth, and Mars. Mercury is a hot rockball located nearest the sun, tidally locked by the sun in 3-2 day-year ratio. Venus is a hot greenhouse world. Earth, the parent planet of humankind, has one large moon which was first visited in year 12 of the space age. Earth Station, in high orbit around the earth, is the center of space-related industriy. Mars, first colonined in the second century of the space age, is also considered. Mining operations in the main Asteroid belt, considered part of the Inner System, began after Mars was colonized.
The Outer system has four planets: Jupiter, Saturn, Uranus, and Neptune. all of which are gass giants. Jupiter is the largest planet of the system, and there is a thriving colony on its outermost Galilean satellite Callisto. Saturn with its famous ring system is next. Uranus and Neptune are considerably smaller, but still considered gas giants. The Kuiper Belt, the secondary asteroid belt, lies beyond the orbit of Neptune, and has a number of dwarf planets. Pluto, once considered a planet, was the first discovered.
Earth remained as the mother world. Colonies were planted at Alphacen (1.27 Parsec) and later at Barnard (1.83 parsec). These remained the only two immediate destinations for earth-based ships for decades: Wolf 359, 2.4 parsecs in a different direction, remained tantalizingly out of reach.
Year 0 of the Space Age calendar began with the launch of the first artificial satellite. Within half a century, the moon had been visited, three space stations had been build in low earth orbit., and myriad unmanned probes had explored the solar system. In the last half of the century, the first fully reusable suborbital craft were developed, and scaled up to reach the space station. A new permanent station was developed in higher orbit, this one intended as a way station for manned exploration of the Moon and Mars. An astronomical and research observatory was built on the Moon, and the first manned exploration to Mars occurred. Toward the end of the century, the first advances in gravitic technology began to make space travel more accessible than the old chemical rockets.
Early in the second century, as Earth Station continued to grow, the Lunar colony gained its first permanent inhabitants, and more missions to mars took place. A colony was finally planted about mid century, Later, manned explorations to Venus and the outermost moons of Jupiter were also made and toward the end of the century, a colony was planted on Callisto. At the same time, new advances in physics resulted in development of the Jump drive, which offered the promise of exploration of the stars.
Colonization of other systems proceeded very slowly at first, but proved a boon for the struggling off-earth colonies. All the first colonies in other systems required artifical life support in the form of power generators, intrasystem craft, habitat modules, and foodstuffs adapted to artificial illumination rather than earth's natural sunlight, to name a few examples. Each of the colonies had its own particular area of expertise, which was greatly demanded. Industries began to flourish, jobs and educational opportunities abounded, and the various Colonial agencies began to demand periods of off-earth residence for would-be colonists to go to other systems.