For most of its history, spaceflight has been done with military, scientific or commercial motives in mind. But lighter-hearted uses are possible too. Wealthy space cadets can already buy trips into orbit (the next such mission, run by a firm called Axiom Space, is due to take four astronauts to the International Space Station on May 21st). Now two groups are planning to use the heavens for art. One wants to build an artificial comet; the other to set up man-made meteor showers.