Colonization of the inner Solar System Colonization of the inner Solar System Bodies in the inner Solar System have been considered for terraforming and space colonization. The main candidates for colonization in the inner Solar System are Mars and Venus. Other possible candidates for colonization include the Moon and even Mercury. The short distance between the Earth and the Moon makes it a natural expansion after Earth. A number of government space agencies have periodically floated lunar plans such as Russia (2014), China (2012) and the US have made plans in constructing the first lunar outpost. The European Space Agency (ESA) head Jan Woerner has proposed
Timeline of discovery of Solar System planets and their moons Jupiter using numbers while the names suggested by his rival Simon Marius gradually gained universal acceptance. The International Astronomical Union (IAU) eventually started officially approving names in the late 1970s.</onlyinclude> In the following tables, planetary satellites are indicated in bold type (e.g. Moon) while planets and dwarf planets, which directly circle the Sun, are in italic type (e.g. "Earth"). The Sun itself is indicated in roman type. The tables are sorted by publication/announcement date. Dates are annotated with the following symbols: In a few cases, the date is uncertain and is then marked "(?)". "* Note: Moons marked by an