Koppai

Koppai is the planet Alph, Brittany, and Charlie are from. The story of Pikmin 3 revolves around the fact that the food supplies have begun to run out on their

planet due to extreme population growth, and the brave astronauts leave in search of the needed food supplies. Not much is known about the planet Koppai other than it having a single moon and that it's about 279,000 Lightyears away from PNF-404. This kind of distance suggests that Koppai is located outside of the Milky Way Galaxy, as it is only 100,000 light years long. This suggests Koppai (and maybe Hocotate) could be situated in one of the many "Mini Galaxies" clustered around the outside rim of the Milky Way Galaxy. Its surface is never seen or described in-game, but the opening cutscene seems to imply that the planet has a very thick atmosphere, covered in large masses of clouds.

Koppai, just like Earth, appears to rotate on a tilted axis. However, its moon appears to revolve around it vertically, revolving from North to South counterclockwise. This type of orbital pattern has never been observed in any real life celestial bodies.

According to Brittany, the gravity on Koppai is roughly ten times stronger than on PNF-404, and the oxygen levels are about three times higher on PNF-404. The stronger gravity suggest from an astronomical standpoint that Koppai is about ten times larger in mass than PNF-404.

In Pikmin 3, if the Data Glutton in the Tropical Wilds is reached and not returned before the end of the day, Alph will state that something has been found beyond the jungle, in the desert that is said to look similar to the terrain of Koppai. Nothing is known about life on Koppai other than that it's inhabited by sentient life forms known as Koppaites, which are very similar to Hocotatians. Hocotatians and Koppaites seem to speak the same, or very a similar language, as in the ending of Pikmin 3, they communicate effortlessly. They also seem to have a very limited diet, seeing as how vegetables aren't favoured, as seen in a conversation between Brittany and Alph on the Drake.