Q&A with Michel Denis, ExoMars flight director

Humankind’s largest emissary to Mars in a generation is set for blastoff Monday, when Europe and Russia will dispatch a mission to unravel the mystery of Martian methane.

A European-built communications satellite, manufactured in secret for the Egyptian government, joined a European Space Agency exoplanet observatory aboard a Ukrainian Antonov An-124 cargo plane for a trans-Atlantic flight Wednesday to begin final launch preparations in French Guiana.

The European Space Agency has announced four candidate landing sites for the ExoMars rover, as a deadline looms to secure full funding for the mission in time for a scheduled launch to the red planet in 2018.