The use of space through satellites is more and more important for nations, companies, and individuals. However, since the first satellite was sent up in 1957, mankind has been polluting space with debris (i.e., artificial objects with no function), especially in low orbits (between 100 and 2000 km). The current situation is such that: 1) space agencies send on average several collision risk alerts every day, and 2) satellites as well as the International Space Station regularly perform avoidance maneuvers to escape being damaged or simply destroyed. In addition, in the last few years, these problems have become more worrisome and may permanently change dimension with the advent of mega-constellations of satellites. Indeed, in order to develop telecommunications and high-speed Internet, several companies (e.g., Starlink, Kuiper, OneWeb, Hongyan, Hongyun, Leosat, Athena) are planning to send several tens of thousands of satellites into low orbits, which are already the most polluted. The purpose of this paper is to provide an economic analysis in terms of dynamic games of the trade-off between constellation size and cost of preserving the space environment. Our goal is to contribute to provide a framework for a sustainable development of a space economy.