You may have heard recently that the Opportunity Rover has not been in contact with the Earth
since the 12th of June, 2018.
This is due to a global dust storm which has been covering the entirety of Mars for the
last couple of months, during which the sun has been blocked from reaching the solar panels
of the rover.
Opportunity is thought to have gone into safe mode to preserve its battery, and with any
luck it will reawaken now that the dust storm has passed and that its batteries can be recharged.
NASA has stated that they will give the rover 45 days from the 28th Aug to make contact
with Earth, otherwise they will assume that it is never going to recover.
If that is the case, it will be the end of a nearly 15 year mission, far surpassing the
original mission timescale of 92 days.
So what has it achieved during all that time on Mars?
Well unsurprisingly, it has contributed a huge amount to our knowledge of the red planet,
helping us understand the past of Mars, and whether or not there was ever a surface water
ocean on the planet.
It has travelled more than any other vehicle on an extra-terrestrial body.
And it has helped shape our understanding of the formation of the solar system.
I’m Alex McColgan, and you’re watching Astrum, and together we will take the journey
Opportunity has taken on Mars.
Let’s start right at the beginning.
Having launched on a Delta II Heavy spacecraft, Opportunity landed on the other side of Mars
from its sister rover, Spirit, about three weeks after Spirit had already landed.
Opportunity used a parachute to slow itself on its descent, and fired some rockets just
before it landed.
The effects of the rocket firing are evident from this lighter patch of ground, as seen
by the Mars Global Surveyor.
Opportunity first bounced, and then came to land inside a tiny 22m crater, now known as
Eagle crater, with the heatshield and parachute ending up a few hundred meters away.
NASA scientists were so excited by this that they called the landing a “hole-in-one”,
although they weren’t actually aiming for this crater.
They didn’t even know it existed until they got there, as Opportunity actually landed
about 25 kms away from its intended target.
As Opportunity emerged from its protective shell, the first thing it did was have a look
around.
Opportunity is equipped with a panoramic camera, which it can use to survey the area.
It saw some outcrops only a few centimetres tall, made up of extremely fine dust, each
grain far smaller than the grains typically found in Earth’s sandstone.
Opportunity and Spirit were primarily on Mars for its geology, the end goal being to see
if Mars was ever a place that was conducive to life.
The way they did that was by looking at rocks for evidence of water, thus giving scientists
an idea of what Mars might have been like millions of years ago, as rocks contain clues
about their history.
Opportunity explored the outcrop closely over the course of the next few weeks, already
discovering evidence that in the past some kind of moving current had made the bedrock
dip, although it wasn’t clear if it was water that had done this, or volcanic flow
or wind.
You can see this in this image as the thin rock layers are not parallel to each other.
On Sol 30, or Opportunity’s 30th Martian day on its surface, it got close to the outcrop
and used its Rock Abrasion Tool to drill into a section of the rock face.
As it did so, it found something known to geologists as “vugs” or voids in the rock,
the result of crystals having been eroded away.
The rock also contained hydroxide ions, meaning water was likely present when the rock formed.
Next up for Opportunity was to dig a trench in the soil for further analysis.
It did this by digging its front wheels into the soil while the back four wheels held it
in place.
After some shuffling about for 22 minutes, it had made a trench 50 cm long and 10 cm
deep.
Under the top layer of soil were some things it had not seen before, including shiny little
pebbles and grains so small this microscopic image can’t distinguish between them.
Over the course of the few Martian weeks, having discovered everything it needed to, Opportunity powered out of the crater at an
average speed of 1cm per second, and headed towards the next biggest crater in the vicinity,
Endurance Crater, which is about 200m wide.
On its way, it passed by this little tiny crater called Fram.
It took a photo, but didn’t stop for long.
On Sol 84, it reached the edge, and had a look inside.
Mission planners already knew that Endurance had many layers of rocks to be investigated,
and wanted to have a closer look at them.
Opportunity circled around the crater, looking for a good entry point, as getting in wouldn’t
be a problem, but getting out might.
By Sol 127, mission planners decided to drive Opportunity into the crater even if it couldn’t
get out, as the value of the science that could be garnered was too promising to pass
up.
So on Sol 131, it carefully edged its way over the ridge of the crater, and tried to
reverse back to see if it could.
Luckily, the angle of the rim was only 18 degrees, well within Opportunity’s known
safety margin, so the excursion into the crater began in earnest.
Opportunity went on to spend 180 Sols in the crater.
It explored an area called Karatepe where it saw various layers in the bedrock.
It went near to, but not into some sand dunes as mission planners didn’t want it to get
stuck.
It saw some wispy clouds similar to Earth’s cirrus clouds.
And lastly, it went to a cliff face called Burns cliff, an impressive looking cliff face
with various layers separated by broken up rocks and dust.
It finally left Endurance on Sol 315.
During the time there, the data collected by Opportunity meant that scientists were
able to confirm that water didn’t just cover this area once, but it was in fact episodic
in nature, with floods that would have washed across this landscape before drying up again.
At any rate, the water here would have never been that deep.
After that substantial discovery, the next stop on its adventure was to investigate out
its own heat shield.
On the way, it came across a rock that was later confirmed to be a meteorite, named Heat
Shield Rock.
It was the first meteorite to be identified on another planet.
Opportunity then set a course for Erebus crater,
It pressed ahead through a region called the “etched terrain” to search for more bedrock.
While traversing this area, on Sol 445, Opportunity got stuck in a 30cm sand dune.
Thing did not look good for the rover; all four of its corner wheels were dug in to the
dune by more than a wheel radius.
This dune came to be known as “Purgatory Dune”.
It stayed motionless for just short of 20 Martian days as mission planners frantically
tried to figure out how to get it out.
They simulated the scenario on Earth and tried various methods before they ordered Opportunity
to try anything.
On Sol 461, the rover advanced a few centimetres to see if it was doing what their tests had
predicted.
Over the course of the next 20 Martian days, Opportunity moved a few centimetres, took
a photo of the progress, and sent the results back to mission control.
By Sol 483, Opportunity had successfully escaped the dune and all six wheels were on firmer
ground.
It would have been disappointing if it had travelled for a year on Mars, just to get
stuck by a 30cm dune.
Opportunity studied Purgatory dune for another 12 Martian days, before setting off again
on its way to Erebus crater.
By the time Opportunity reached Erebus, it had received new software to prevent it from
getting stuck again, with software designed by learning what happened from the experience
at Purgatory.
With this new software update, it was ready to carry on its adventure at Erebus crater.
Which we will save for the next part!
Did you enjoy learning about Opportunity today?
The pictures that it took are awe inspiring, but as I mentioned before, the main reason
it was there was to perform experiments and gather valuable data to further our understanding
of Mars.
But what is the process of making scientific discoveries?
Brilliant.org has a great course on the fundamentals of science, and how we attain and organise
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This context is hugely valuable when learning about our universe.
So give Brilliant a go for free today!
By using the link brilliant.org/Astrum, you can have a sample of their courses, plus if
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If you want to support my channel and also expand on your own knowledge, I highly recommend
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