Oxia Planum has been recommended as the primary candidate for the landing site of the ExoMars 2018 mission.
ExoMars 2018, comprising a rover and surface platform, is the second of two missions making up the ExoMars programme, a joint endeavour between ESA and Russia’s Roscosmos. Launch is planned for May 2018, with touchdown on the Red Planet in January 2019.
Meanwhile, the Trace Gas Orbiter and the Schiaparelli entry, descent and landing demonstrator module will be launched in March 2016, arriving at Mars around this time next year.
Schiaparelli will land in Meridiani Planum. The orbiter will study the atmosphere and act as a relay for the second mission.
The search for a suitable landing site for the second mission began in December 2013, when the science community was asked to propose candidates. In October 2014, the Landing Site Selection Working Group chose four sites. The last year has been spent evaluating these sites, taking into account the engineering constraints of descent and landing, and the best possible scientific return of the mission
The main goal for the rover is to search for evidence of martian life, past or present, in an area with ancient rocks where liquid water was once abundant. A drill is capable of extracting samples from up to 2 m below the surface. This is crucial, because the present surface of Mars is a hostile place for living organisms owing to the harsh solar and cosmic radiation. By searching underground, the rover has more chance of finding preserved evidence.
Scientists believe that primitive life could have gained a foothold when the surface environment was wetter, more than 3.6 billion years ago. Buried or recently exhumed layered sedimentary deposits thus offer the best window into this important period of Mars history.
All four sites under study Aram Dorsum, Hypanis Vallis, Mawrth Vallis and Oxia Planum show evidence of having been influenced by water in the past, and are likely representative of global processes operating in the Red Planet’s early history.
All locations offer the opportunity of landing at a scientifically interesting site or finding one within a 1 km drive from the touchdown point, with numerous targets accessible along a typical 2 km traverse planned for the mission of 218 martian days (each 24 hours 37 minutes).
