Earth as background and an astronaut.
Space (宇宙, Uchū) is an area located in Tapir-San's Place after you chainsaw Tapir-San's back and go inside with Spacesuit effect equipped.
Space is a fairly limited area with some planets and astronauts roaming around. There's no portal to go back, using any effect will make Urotsuki fall and wake up on her room's floor.
If you head right from the entry point, you will eventually come to a single, small, golden moon. Standing over this moon and interacting with it will take you to its surface, upon which is what appears to be a playground. Heading to either side of the screen will take you back to space, and there currently seems to be nothing to interact with in this area. However, unequipping the Spacesuit effect here will result in a unique falling sequence not seen in the larger Space area, and instead of waking up, Urotsuki will end up in a somewhat glitched Urban Street Area with the Fairy effect equipped.
In recent versions, there is a new area accessible via entering mars. The new area depicts the moon during a partial lunar eclipse.