[meteorite-list] Landing Site Recommended for ExoMars 2018

From: Ron Baalke <baalke_at_meteoritecentral.com>
Date: Wed, 21 Oct 2015 17:29:58 -0700 (PDT)
Message-ID: <201510220029.t9M0Twrv008384_at_zagami.jpl.nasa.gov>


Landing Site Recommended for ExoMars 2018
European Space Agency
21 October 2015

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.

ExoMars 2018 landing site candidates

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).

The sites must also conform to strict engineering constraints to ensure
the safe entry, descent and landing of the entry module. These include
the need for a relatively low-lying site, in order that the module passes
through enough atmosphere for the completion of key events such as parachute
opening and deceleration.

The horizontal and vertical wind speeds expected during the descent must
also be also considered - it will land at the end of the planet's
global dust storm season in 2019.

Knowledge of how the terrain slopes over various scales is important,
because the lander uses radar to monitor its velocity and altitude. Slopes
can alter the degree of certainty in the measured distance to the ground,
with implications for fuel consumption and landing.

Steep slopes and boulders taller than 35 cm - the clearance beneath
the landing module - need to be avoided, although the rover will be
able navigate around local hazards after egress.

Taking into account these requirements and the individual science cases
put forward for each site, the Landing Site Selection Working Group today
recommended that Oxia Planum be the primary focus for further detailed
evaluation for the 2018 mission.

A further recommendation was made to also consider Oxia Planum as one
of the two candidate landing sites for the backup launch opportunity in
2020, with a second to be selected from Aram Dorsum and Mawrth Vallis.

"Our preliminary analysis shows that Oxia Planum appears to satisfy
the strict engineering constraints while also offering some very interesting
opportunities to study, in situ, places where biosignatures might best
be preserved," says Jorge Vago, ESA's project scientist.

Oxia Planum contains one of the largest exposures of rocks on Mars that
are around 3.9 billion years old and clay-rich, indicating that water
once played a role here.

The site sits in a wide catchment area of valley systems with the exposed
rocks exhibiting different compositions, indicating a variety of deposition
and wetting environments.

A period of volcanic activity may have covered early clays and other aqueous
deposits, offering preservation for biosignatures against the planet's
harsh radiation and oxidation environment, and have only been exposed
by erosion within the last few hundred million years.

"Compared with landing site selection for previous missions, which relied
primarily on the morphology of candidate sites alone, we are today in
a much better position to understand the mineralogy of the various sites,"
adds Jorge.

"This puts us in the best position to choose sites that offer access
to the most ancient, pristine material that not only preserves a record
of early Mars but which is globally representative of processes occurring
across the planet.

"It made for a challenging decision today, given the quality of the
cases for all sites, but we are looking forward to the next stage of analysis
as we move closer to the launch of our exciting mission: our rover will
search for molecular biosignatures in the subsurface for the very first

Selection of the final landing site by ESA and Roscosmos is planned to
occur six months before launch.

Notes for Editors

Detailed descriptions of all four candidates are available here:
Aram Dorsum
Hypanis Vallis
Mawrth Vallis
Oxia Planum

More information about the Landing Site Selection Working Group is available

For further information, please contact:
Markus Bauer
ESA Science and Robotic Exploration Communication Officer
Tel: +31 71 565 6799
Mob: +31 61 594 3 954
Email: markus.bauer at esa.int

Jorge Vago
ESA ExoMars 2018 project scientist
Scientific Support Office, Directorate of Science and Robotic Exploration
Tel: +31 71 565 5211 / +31 6 27 65 87 70
Email: jorge.vago at esa.int
Received on Wed 21 Oct 2015 08:29:58 PM PDT

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