Scientists from the joint European/Russian ExoMars rover mission have narrowed their candidate landing sites to four.
Last week, 60 scientists met at ESA’s European Space Astronomy Centre near Madrid to discuss eight potential sites. On 27 March, they cast an informal vote, and four sites emerged as favourites: Mawrth Vallis, Oxia Planum, Hypanis Vallis and Oxia Palus. An expert working group tasked with recommending a final landing site will now consider the proposals, before announcing a formal shortlist of three or four sites in June. Following detailed studies of the shortlisted sites, the panel will make a single recommendation to ESA and Roscosmos in late 2016.
This is maybe the most risky mission to Mars in decades, as the landing design is coming from the Russians, who have not had a successful interplanetary mission since the era of the Soviet Union, and even then had a 100% failure rate for their missions to Mars. (On a more optimistic note, the European Mars Express mission used a Russian rocket to take off, making it the first Mars mission with Russians participation that actually succeeded.)
One of the factors that has made this mission more risky is the fact that the U.S. was once a participant and backed out very late in the game. The Russians are our replacement, and have had to scramble to catch up.