Deployment of the MARSIS Radar Antennas On-board Mars Express

On the first European planetary mission, the deployment of the two 20-meter long MARSIS antennas onboard the ESA Mars Express spacecraft has represented an unprecedented technological challenge, in the mi ddle of a successful science mission. While Mars Express was already performing regular observations at Mars, a complex process has been performed on Earth, involving the ESA Project, coordination between ESA, NASA and ASI, the Mars Science community, the spacecraft manufacturer EADS Astrium and the Mission Control Centre at ESOC. This paper des cribes the steps that led from an initial no- go in 2004 to deployment one year later, as well as the conditions and difficulties encountered during the actual deployment. It provides insights in the technical and managerial processes that made it a success, and analyses the rationale behind the decisions.