The European-Chinese MESSIER satellite: lifting the veil on galaxy formation

The European-Chinese MESSIER satellite project has been designed to explore the extremely low surface brightness universe at UV and optical wavelengths. The two driving science cases target the mildly- and highly non-linear regimes of structure formation to test two key predictions of the LCDM scenario: (1) the detection of the putative large number of galaxy satellites and (2) the identification of the filaments of the cosmic web. Many important secondary science cases will result as free by-products and will be discussed, along with the synergies with LAMOST, Gaia, and EUCLID.