How long to the moon?

Permanent human habitation on a planetary body other than the Earth is a central theme in science fiction and conspiracy theories. As technology has advanced and concerns about the future of humanity on Earth increase, some argue that space colonization is an achievable and worthwhile goal. Because of its proximity to Earth and the early telescopic observation of familiar land forms, such as mountains and plains, the Moon has long been seen as a candidate for a possible human colony in space. Before any colonies are started, resources of some value are usually identified, and extraction of these resources often dominates the development of the colony. The Apollo program rock and dirt samples brought back by astronauts indicate that several valuable substances should be found in quantity on the Moon. First of these is oxygen, which represents approximately 42 percent of lunar regolith samples. Silicon, a valuable industrial resource, constitutes around 20 percent of the regolith samples, and iron, the primary ingredient in steel, makes up about 13 percent. One of the most widely used metals in modern technology is aluminium, which requires large amounts of energy to be refined from bauxite ore. This valuable metal makes up about 7 percent of the Moon's mass. Titanium is an even more valuable metal, being very light, but extremely strong. Titanium appears to be more plentiful on the Moon that it is on Earth, comprising approximately 1 percent of the mass of samples returned. However, the Apollo program, while demonstrating the feasibility of travel to the Moon (albeit at a high cost), dampened enthusiasm for such a lunar colony because rock and dirt samples brought back by astronauts proved extremely low in the lighter elements required as a condition for life.