It is only possible to bring the large ExoMars payload mass to the surface of Mars by using a heavy launcher such as the Ariane 5 (nominal choice) or the Proton launcher (fallback solution). Launch is planned in January 2016 from Kourou.
The Exomars spacecraft is designed and qualified for both launchers, thus allowing for a late decision.
The mission profile employs a direct injection into fast interplanetary trajectory (T2 type) to Mars resulting in a cruise phase duration of about 10 months.
The spacecraft composite, assembly of the Descent Module and the Carrier Module, is injected into orbit around Mars when it arrives by the end of 2016. This has the advantage of providing a smaller landing ellipse for a more precise landing on Mars. It also allows the ExoMars project to decide when the entry is undertaken to avoid the global Dust Storm season on Mars, which could otherwise create difficulties during descent and surface operation. Thus, the possibility that ground control can time atmospheric entry is highly favourable.