Micronations/Starting your own micronation/Extraterrestrial Territory
Where to claim?
Space is enormous, so you might ask, What should I claim? Well, there are a lot of places in space, and many of these are probably worth claiming, but a good place to start would be one of our own planets. These are certainly worth claiming; the inner, rocky planets and the many dwarf planets have vast mineral resources and incredible landscapes, the gas giants have dozens of moons with these and are also valuable sources of hydrogen and helium, and the ice giants have all of these plus their impressive appearance. But you can't claim all of the solar system; other nations are certain to go to war with you over that! A better idea might be to claim a portion of the Moon, or of Mars or Venus, or a single moon of one of the gas or ice giants.
Warning: Several micronations already have outer space claims
But when you're claiming outer space, be careful. Several micronations have already made claims on other planets. For instance, the Republic of Molossia has claimed a territory, called Vesperia Venus Territory, on Venus, and the Aerican Empire has made claims to two extraterrestrial territories, the Colony of Mars (720 acres of land on Mars), and Northern Plutopia (the northern hemisphere of Pluto). The Federated Republic of Xylvakye passed executive order #1 on October 24, 2012. This claims the planets Mercury, Northern Venus, all remaining land on Mars, Jupiter, Saturn, Neptune, and Southern Plutopia. The Kingdom of Zadonia has claimed the 4 moons of Jupiter, Callipsto, Io, Ganymede, and Europa.
If you claim any territory in these areas, it could lead to war. Beware!