MARATHON VALLEY: This view from NASA’s MER Opportunity shows part of “Marathon Valley,” on the western rim of Endeavour Crater, as seen from an overlook north
of the valley. It combines four images taken by the rover’s panoramic camera (Pancam) on 13th March 2015. This location was chosen as a science destination for the
rover as evidence of clay minerals was found here by observations from MRO’s Compact Reconnaissance Imaging Spectrometer for Mars (CRISM). Such minerals may be
indicative of ancient, wet environments on the planet. Credit: NASA/JPL-Caltech/Cornell University/Arizona State University
The MER rovers also had the task of calibrating and validating sur-
face observations made by Mars Reconnaissance Orbiter instruments,
so as to help determine the accuracy and effectiveness of instruments
surveying Martian geology and surface composition from orbit.
Both rovers greatly exceeded their original primary 90-sol missions
(one sol = one Martian day, or the equivalent on Earth of 24 hours 39
minutes 35 seconds), surpassing their science mission objectives, and
capturing the public imagination on their slow but epic journeys across
the Martian surface. Spirit became stuck in sand in late 2009 and even-
tually fell silent on Sol 2210 (March 22, 2010), having covered a distance
of 7.73 km (4.8 miles), visiting a number of craters, climbing and explor-
ing the Columbia Hills and surviving dust storms.
Having completed its ‘marathon’, covering over 43 km (27 miles)
to date, Opportunity is still operational. Having visited Endurance Cra-
ter and the 800m-wide (half-mile) Victoria Crater (where it spent two
years), it is now located at ‘Spirit Mount’ on the rim of the 22 km (14
mile) diameter Endeavour Crater, the first science target of its 10th ex-
tended mission phase. Here it continues to analyse the type and com-
position of rock samples, and seeking to confirm the past importance
of water on Mars. Like Spirit, it has also made astronomical observations
and obtained atmospheric data.
Mars Science Laboratory – Curiosity
Few of us who followed the arrival of NASA’s Mars Science Labora-
tory (MSL) at the surface of Mars on the 6th August 2012 will forget the
so-called ‘seven minutes of terror’, as this 899 kilogram (1,982 pound)
car-sized wonder was delivered to the Martian surface by the new ‘sky-
crane’, in one of the most complicated spacecraft landings ever at-
tempted. Its target was Gale Crater, a suspected former lake location
with a 5 km-high (3 mile) mountain of layered materials – named Aeolis
Mons or ‘Mount Sharp’ - in its centre. Studies from orbit had revealed
different mineral compositions of these layers, depending on their
height, and the possibility that these might hold a record of two billion
years of Martian history. There are also flow channels in this target study
area.
With its rover named Curiosity, the MSL mission is part of NASA’s Mars
Exploration Programme, the goal of which is to determine the planet’s
habitability and to try and discover whether or not it has ever had an
environment able to support microbial life. Curiosity is designed to col-
lect data on all aspects of its surroundings - geological, chemical, at-
mospheric, water, radiation – and is also looking out for signs of organic
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