In this episode, Curiosity explores a giant dune field, takes some stunning images
and approaches the entrance to Murray Buttes.
Still squarely within the Pahrump Hills region, Curiosity pictures
more evidence of cross-bedding. Due to the angles of these layers,
it s more likely they were created by wind, rather than water.
On Sol 1099, the rover looks towards its main objective, Mount Sharp. The lighter coloured rocks
in the distance are the oldest in this image, and have been heavily eroded by the wind. A large
proportion of the other rock variations present are thought to have been formed by water.
Whilst looking for the best way to get up the mountain, the mars reconnaissance orbiter
spots a huge dune field. The team at NASA decides to send the rover to investigate.
From it s current position, Curiosity can see part of this dune field
the dark band in the mid-ground. The team at NASA give it the informal nickname The Bagnold Dunes,
named after Ralph Bagnold, who crossed the Libyan Desert and was one of the first explorers
to acquire a deep understanding of the physics behind sand dunes.
In this map, we can see the true scale of the Bagnold Dunes. Curiosity will explore
only a small portion of it. As the rover moves closer,
it captures this stunning image, with Mount Sharp looming in the distance.
But first, Curiosity has some drilling to do at a site named Big Sky.
The rover takes a selfie in celebration of a successful drill.
On Sol 1176, Curiosity reaches the edge of the dune field.
This is the first active dune system studied up close on another planet. Scientists observing the
dune estimate they are migrating by about 1 metre per year, due to action from the Martian wind.
The rover carefully dips a wheel into the sand.
This close up image of the dune portion disturbed by the wheel
shows finer grains of sand below the surface.
This close up shows an undisturbed portion of the dune. We can see that only coarse surface
material remains - after wind action has removed smaller particles.
On Sol 1197, Curiosity comes across a very steep dune which the team name Namib Dune .
The thing which differentiates dunes from the usual sand deposits,
such as those the rover was nearly stuck in at Hidden Valley, is that dunes are steep enough
on their downwind face that material can actually fall down the dune.
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Curiosity takes a sample of sand from near the Namib Dune site,
and takes a selfie to celebrate. The coarse material from the sample,
which was too large to fit through the rover s filter - is dumped on the ground.
The team wait until nightfall to take an image of the dumped material with artificial lighting. This
lighting makes it easier to differentiate between darker and lighter grains.
Curiosity continues the journey up the base of Mount Sharp,
reaching a site known as Naukluft Plateau .
On Sol 1276, Curiosity comes across some knobbly textured sandstone within Naukluft
Plateau. These nodules seem to be more resistant to wind exposure than the surrounding host rock.
It s the first time Curiosity has come across this type of pattern in Gale Crater,
but it has been spotted by previous rovers on Mars. It s likely these are what the team at
NASA refer to as Blueberries , and are made up of a mineral known as hematite,
which suggests the presence of water in the ancient past.
From it s position within Naukluft Plateau, the rover takes a long
distance image of the northern rim of Gale Crater. The image is taken during sunrise,
when dust in the atmosphere is relatively low. On the lower portion of the crater rim we can see
valleys, channels and debris fans, much like what we currently see at the base of Mount
Sharp. This leads scientists to expect that the entire crater was once filled with water.
Curiosity takes a full circle panorama at Naukluft Plateau.
The rocks present here are dominated by thick layers of wind-blown sand,
suggesting that these deposits formed during a dryer time on Mars.
On Sol 1315, NASA orders to rover to complete a wheel health check.
Since the last wheel check nearly 300 Sols ago, little further damage is observed,
meaning that the rover planners are doing a great job of selecting easier terrain for Curiosity.
As Curiosity comes close to completing 4 Earth years on Mars, it hits a milestone
of 2 Martian years studying the planet. During this time, Curiosity has been studying
Martian seasonal patterns. As you can see from the graph, Mars is much colder than Los Angeles.
The height of the bars represents the temperature difference between night and day. During the
summertime in Gale Crater, daytime temperatures can reach a survivable -10 degrees Celcius, or
14 degrees Fahrenheit. However, on the very same night temperatures could drop all the way to - 70
degrees Celcius, or -94 degrees Fahrenheit. Curiosity also takes measurements of atmospheric
pressure. This data will prove to be extremely useful if NASA ever wanted to
send a helicopter to accompany a future rover. The rover takes a drill sample at Naukluft Plateau
and looks towards Mount sharp. We can also see some left over rock powder; the grey
substance on the surface - dumped by the rover after it did not pass through the filter.
After a big drive, Curiosity arrives at the gates of a site known as Murray
Buttes. Curiosity will pass through here to access higher areas of mount sharp.
In the next episode, Curiosity gets up close and personal with Murray Buttes, finds a Martian
meteorite, uncovers evidence of fossilised Martian mud and witnesses multiple dust devils.
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