Scientific Objectives

     Mars Express is a mission of comparative planetology.  It will make observations of the surface, atmosphere,  and surface-atmosphere and atmosphere-interplanetary medium interactions.  The studies of Martian ENAs resulting from the solar wind-atmosphere interaction addresses the fundamental question: How strongly do the interplanetary plasma and electromagnetic fields affect the Martian atmosphere?  This question is directly related to the problem of Martian dehydration.  The task of answering this question can be broken down into specific scientific objectives:     

	Determine the instantaneous global distributions of plasma and neutral gas near the planet.
	Study plasma induced atmospheric escape.
	Investigate the modification of the atmosphere through ion bombardment.
	Investigate the energy deposition from the solar wind to the ionosphere.
	Search for the solar wind-Phobos interactions.
	Define the local characteristics of the main plasma regions.