What is the purpose of a space station?

Space stations are not important for scientific research. They are important for space exploration, that is in order to put humans on Mars. However, instruments like the Hubble space telescope are much more important for scientific research as they enable us to look into unknown regions of space. As such they improve our understanding of the universe. Of similar importance are particle accelerators like the LHC at CERN in Switzerland which probe matter at the smallest scale and thus help us understand fundamental questions of particle physics for example the origin of mass.