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Insight is dying.
The planet it was sent to study is killing it.
The contest between Insight and Mars has been going on for four years.
The Insight lander has attempted to pierce the heart of the planet with metal and hammer,
and day after day has pried out its deepest secrets with clever instruments.
But from day one, Mars fought back with an unending assault; using an innocuous tool
that never stopped mounting, a pressure that claimed inch by desperate inch, choking the
light from Insight’s components and rendering it powerless.
But not before Insight uncovered what it set out to find.
It has learned things that expanded our understanding of Mars and the Solar System.
I’m Alex McColgan, and you’re watching Astrum.
And so, for what might be the final time, let’s look over the Insight mission and
its discoveries, even as it begins to power down forever.
But as if this were a good crime drama, there is one more twist to this tale.
Insight’s final, dying messages to us might just turn out to be the most important of
them all.
Those who are frequent watchers on my channel will know that Insight landed on Mars back
on 26th November 2018.
Its mission was to study Mars’ interior, thus helping us gain a deeper, more accurate
understanding of the planet’s structure, and how it might have been formed 4 billion
years ago.
As Mars is one of the 4 rocky planets in our solar system, this would give us insight into
the other 3 – Mercury, Venus, and even our own Earth.
However, Insight’s opponent was Mars, and Mars would not give up its secrets easily.
Before Insight won the war, it would lose battles.
And the first defeat came through its sensors.
Insight carries two primary sensors for collecting data.
The first is a Seismograph known as SEIS, designed for detecting the slightest vibrations
in the crust that might indicate Martian quakes or meteorite impacts.
The second was a heat flow and radiometer sensor package attached to a hammering digging
device known as the mole.
Unfortunately, due to differences in the Martian soil from what was tested for back on Earth,
Insight’s mole quickly found itself struggling to achieve the 3-5 metres depth that was necessary
to get good readings.
In fact, it barely managed to get beneath the surface.
Scientists tried to find ways to coax the mole to dig for over two years, but in January
2021 decided to give up on that element of the mission.
This left the SEIS as the principle means by which scientists could look beneath the
planet’s surface.
This was done by listening to the P waves and S waves of marsquakes.
When a quake happens, ripples travel in all directions through the planet’s crust, core
and mantle.
When these ripples come up against the transition points between these three sections, some
of the waves can bounce back towards the surface.
This means that when SEIS hears the rumblings of a quake, it will often hear many secondary
echoes from that same quake.
By detecting the time taken and magnitude of these secondary echoes, vital insights
can be gained into the shape, structure and density of Mars’ inner workings.
But Insight was facing a race against time.
NASA’s arch nemesis reared its ugly head.
A seemingly innocent, and yet insidious tool of destruction: You’ve guessed it, dust!
As a stationary lander, Insight was made with two large solar panels that were designed
to give it the energy it needed over a two-year mission.
When that mission was extended into a 4-year mission, however, scientists knew that one
of the problems they’d come up against would be dust.
Although it seems innocuous, if it fell on the solar panels, dust had the potential to
completely disrupt Insight’s ability to collect power.
Over the course of the 4 years, more and more dust did just that.
At the start of the mission, these panels were capable of producing 5000 watt-hours
each Martian day.
Now, at the time of this video’s release, they’re only producing 500 watt-hours – about
enough to power an electric oven for 10 minutes.
Without this power, Insight would not be able to keep its heaters on, subjecting its components
to the -70°C temperatures of Martian nights – enough to quickly break them.
Scientists had not built Insight with onboard cleaners or fans.
Instead, they had relied on the arrival of little whirlwinds or dust devils native to
Mars to come along and remove excess dust in “cleaning events”.
Sadly, although these windy phenomena were observed, they did not come close enough often
enough to clear Insight’s panels well enough.
And so, in 2021, Insight started powering down.
However, scientists were not willing to let this slide, and in early June 2021 came up
with an admittedly counterintuitive way of removing dust from the panels – adding more
dust!
Although Insight does not have cleaning tools, it does come equipped with a small robotic
arm with a scoop attached, which it can use to scoop up the sand from the floor around
it.
The idea was to slowly trickle sand down onto the panels from the scoop while the Martian
wind was blowing.
Hopefully, the wind would bounce the falling sand off the panels’ edges, and as the sand
hit the panel it would knock dust loose, thus removing it.
This plan might sound crazy in theory, but it worked in practice; gaining the lander
an additional 30-watt-hours of energy a day.
This extended Insight’s mission through the Summer of 2021 and into the following
year, which turned out to be a game-changer.
It was only in the final year of Insight’s life, past the point where it should have
died, that it detected its largest quakes.
Over the course of Insight’s mission, the lander detected over 1300 Martian quakes.
Most of these quakes were relatively small.
Due to Mars’s smaller size, Mars’ crust is not split into different plates, so it
does not have plate tectonics – the process which causes some of the more powerful quakes
on Earth as one plate rubs up against or goes underneath another.
Mars’ quakes are almost always under a magnitude 4 on the Richter scale, which means that unless
you were right on top of their epicentre, you likely wouldn’t notice them.
Thankfully, while detecting such small quakes is very difficult on Earth, on Mars it’s
much more possible, and Insight’s SEIS instrument is capable of detecting mag 4 quakes from
almost 1000km away.
Mars is less noisy than Earth.
On Earth, there are oceans constantly beatings back and forth, which create vibrations that
can completely mask smaller quakes.
But obviously, Mars doesn’t have this problem.
Still, scientists hoped to hear some larger than Mag 4 quakes on Mars.
These would provide the clearest pictures of what was going on beneath Mars’ crust.
For most of Insight’s mission, this hope was not realised.
However, in May 2022 the ground rumbled.
Data streamed in.
Insight’s SEIS sensor detected a Mag 5 quake, the largest yet.
If Insight had already powered down, it would never have heard this clear data point.
And so, NASA has proclaimed Insight’s mission a fantastic success.
It has provided data that will pave the way for many future missions to come.
But what did we learn from that last message, and the ones that came before?
What does the provided data tell us about Mars?
To begin with, thanks to Insight’s data, we now know that Mars does indeed have a crust,
a mantle and a core, just like on Earth.
However, that crust is much thinner than we expected.
It contains 2 to 3 sublayers and descends 20-37km deep, compared to the Earth’s which
can have a thickness of 70km.
Its mantle is not as hot as scientists previously believed and descends a further 1,560km.
Finally, its core is larger than scientists thought, with a radius of 1,830km.
Surprisingly, it is also less dense than expected.
This has led scientists to predict that it is not simply made of Nickel and Iron, like
the Earth’s core, but that it must contain lighter elements like Carbon, Oxygen, Sulphur
and Hydrogen.
This is a fascinating insight.
It explains why the core of Mars is still molten.
Much like salt’s ability to reduce the freezing point of ice – which is why you see grit
thrown on roads in cold weather – these lighter elements reduce the freezing point
of Mars’ core.
It also points to the origin of the planet.
These light elements must have been collected into Mars in the very earliest periods of
the solar system’s history, as by the time Earth was formed these elements were not around
in as great a quantity, explaining why Mars’ core has them and ours doesn’t.
They were also found further out, indicating that Mars may have been brought closer into
the Sun’s gravity as time progressed, before finding the stable orbit it navigates along
today.
It confirms that during the early formation of Mars, all the cosmic dust that came together
must have heated each other up and become molten, thus allowing the heavier core metals
to easily sink to the planet’s centre.
During this period, or soon after it, Mars began to experience its dynamo effect.
Mars today has only a weak magnetic field compared to Earth’s.
Most of this field is left over as residual traces of magnetism, locked into many of Mars’
surface rocks.
However, back in its early formation 4 billion years ago, Mars’ moving metals in its core
created a massive dynamo, imbuing these rocks with their magnetism.
When the planet cooled, hot materials were not able to move about as quickly as they
needed to keep the dynamo going.
In time, Mars’ dynamo ceased to be.
Thanks to the data provided by Insight, scientists will have a much better idea of the timescales
involved in this dynamo.
This is relevant because when we talk about magnetic fields and dynamos, those can affect
what the atmosphere was like.
And once we understand that, we will have a clearer picture of Mars’ early habitability.
Insight might give us an idea of the time period when life was most likely to form on
Mars.
Insight has given us an incredible amount of raw data, including a fascinating comprehension
of Martian weather patterns.
Yet, there are still many mysteries.
Even though we now know the rough dimensions of Mars’ inner structure, Insight’s findings
have actually disproved some previously existing theories.
For instance, under a particularly volcanic region on Mars’ surface known as Tharsis
– home of Olympus Mons, a volcano two and a half times as tall as Mt.
Everest – there exists a hotspot of magma that feeds the volcanic processes we see in
this region.
Due to the absence of plate tectonics, it was unclear what exactly was causing this
hotspot, which seemed to have been present, unmoving, for billions of years of Mars’
history.
Scientists originally thought that this hotspot was being fed by a lower mantle, but it turns
out that Mars does not have a lower mantle.
As such, it is back to the drawing board to explain what is causing this phenomenon.
Still, these are the sorts of questions and discoveries that drive scientific endeavour.
And the discoveries that Insight has given us will inform future missions for decades
to come.
Scientists will pour over the data, analysing P waves and S waves, attempting to find patterns
and meaning in the sounds of Mars’ rumbling heartbeat.
And who knows how much more we will discover as a result of this successful mission!
If more comes in, I will keep you posted.
But as Insight powers down, as it closes its eyes on the scattered clouds and dusty plains
of Mars, it can rest easy.
It did what it came there to do.
Mars’ inner workings have finally been brought to light.
Worried that our world may end up looking like Mars?
Climate change is something that’s been on my mind a lot of late, especially as I’m
someone who looks through a lot of NASA data.
While a lot of CO2 responsibility goes to big corporations, each of us contributes to
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One important step is to know how you are contributing, and how you can improve on that.
This is where Wren is extremely valuable.
The website will ask you a variety of questions to help you understand your carbon footprint,
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For instance, one that resonated with me was a tree planting program in East Africa, and
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Thanks for watching!
Be sure to check out the InSight playlist here if you want to learn more about this
pioneering probe.
A big thanks to my patrons and members for your support too.
If you want to have your name added to this list, check the links in the description below.
All the best and see you next time.