At apoapsis (the highest point in Argosy's elliptical orbit), MEM 1 undocks from its mothership, and starts a series of systems checks. At periapsis (the lowest point of the orbit) the MEMs deorbit motors will fire, to initiate the descent to the Martian surface.
Mars, here, is pictured more as we understand it to be today. Specifically, the atmosphere is still dusty from the dust storms that rage at times of Mars' nearest approach to the sun (perihelion). The Argosy mission was designed to get to Mars at this near point, to minimize transit time. The ability to get to Mars and wait the storms out in orbit is a major advantage to the direct entry model, which leaves the landers to the vagaries of the Martian storms. The Soviet Union, in particular, lost several probes in just such a way.
Modeled and rendered in Lightwave 10 and Photoshop.
Thanks for looking!