The European Space Agency has given the green light for the MARSIS radar on board its Mars Express spacecraft to be deployed during the first week of May. Assuming that this operation is successful, the radar will finally start the search for subsurface water reservoirs and studies of the Martian ionosphere. ESA’s decision to deploy MARSIS follows eight months of intensive computer simulations and technical investigations on both sides of the Atlantic. These were to assess possible harmful boom configurations during deployment and to determine any effects on the spacecraft and its scientific instruments.