Thanks to Blinkist for sponsoring today’s video.
The Opportunity Rover was a marvel of engineering.
Why?
Well, not only did it have impressive science equipment to help us understand the history
of Mars, but it’s more the fact that this was initially going to be a 90 Martian day
mission, or 90 sols, yet it has so far in this series clocked up around 3,800 sols.
To give you some context, it landed in 2004 and we are now in 2014 in this series, and
we still have a way to go.
Unsurprisingly however, simple wear and tear and the variable environment of Mars had taken
its toll on Opportunity.
It had experienced mechanical failures in its arms.
Its flash drives were malfunctioning.
Some of the science experiments didn’t operate at anywhere near the same efficiency as when
it had landed.
However, cold winters and treacherous sand dunes had not stopped Opportunity so far,
and we join it heading towards the Cape Tribulation summit.
I’m Alex McColgan, and you’re watching Astrum, and in this last episode of the Opportunity
series, we will follow Opportunity’s tracks until the very end of its impressive mission,
and recap all the discoveries it made during this time.
On the top of Cape Tribulation, on sol 3894, Opportunity looked out over the huge 22km
wide Endeavour Crater.
Endeavour is an old crater, and sand dunes have covered the crater floor.
The only indication from this angle that it is a crater at all is the crater rim, still
raised in contrast to the flat Meridiani Plains.
Just a bit further beyond Cape Tribulation was Opportunity’s next destination, Marathon
Valley.
This valley got its name from the fact that as Opportunity was to enter this valley, it
would have travelled the whole length of a marathon.
Completing a marathon in 11 years?
That’s a pretty impressive finishing time.
In celebration of this milestone, mission controllers took part in a relay marathon
with a replica of Opportunity as they crossed the 42km, or the 26.2 mile mark.
But there was more to Marathon Valley than just a waypoint, there were interesting rocks
here that mission controllers wanted to investigate.
To get down into Marathon Valley, Opportunity had to go down the steepest slope it had faced
yet, 32 degrees.
Such was the steepness of this slope, that dust that had built up on the solar panels
began to flow off.
After successfully descending down the slope, Opportunity first investigated a region known
as the Spirit of St. Louis.
It’s actually a small crater, yet it has some outcrops exposed.
Unfortunately, it was around here that the flash memory caused the onboard computer to
reset again.
Although mission controllers had narrowed down the problem to a specific cell bank on
the flash drive, quarantining this section apparently hadn’t completely solved the
problem.
The solution had helped somewhat though, a reset once a month is a lot better than the
few times a day they were getting before the reformatting and quarantining.
Eventually though, engineers decided to bypass the flash memory altogether, and operate the
rover in RAM-only mode.
The danger there though was that RAM gets wiped if the computer switches off, meaning
any scientific data not transmitted back to Earth is at risk of being lost forever should
the onboard computer turn off.
The northern edge of Marathon Valley was a ridge named Hinners Point, to the south was
a ridge named Knudsen Ridge.
In these regions, Opportunity was again looking for clays, evidence of past liquid water oceans
on Mars.
Mission controllers detected clays on these ridges from orbit with the MRO, which correspond
to these reddish areas seen in the enhanced colour versions of these photos.
Opportunity found these rocks to be brittle and to disintegrate a lot easier than other
rocks it had previously observed, as well as having unusual compositions.
They were unlike a lot of other rocks in the area.
Although data collection was constant here, it was also extremely slow going.
The alpha spectrometer on Opportunity’s arm was losing its potency, meaning sample
anaylsis that would have taken minutes at the beginning of the mission were now taking
days or weeks.
This was also combined with Opportunity’s temperamental onboard computer, which was
really starting to struggle.
As a result, it took Opportunity well over a year to get through Marathon valley.
It began to head deeper into Endeavour, and it was greeted with quite a spectacular sight.
A dust devil was spotted on the crater floor.
Spirit, Opportunity’s sister rover, had seen dust devils in the past, but they were
a lot rarer for Opportunity.
It is believed that dust devils passing over the rovers had been responsible for the occasional
cleaning events that removed dust off the rovers’ solar panels.
Opportunity’s next goal was again found further south, a gully that scientists believe
might have been carved out by water.
A gully had never been closely examined by any Mars mission in the past, so scientists
were excited by what they might find.
But getting there was tricky.
On its way down the crater rim, it passed through a gap in this ridge named the Lewis
and Clark Gap, down Bitterroot Valley, to Spirit Mound.
On its way down, it took some spectacular panoramas of various ridges overlooking the
sand dunes stretching across the crater floor.
Upon reaching Spirit Mound, Opportunity had been on Mars for well over 4500 sols, roughly
12 Earth years.
All things considered, Opportunity was in reasonable health, and generating a very comfortable
450 watts of power from its solar panels.
On its way to the gully, it would stop periodically to perform some science operations, like imaging
select rocks and measuring argon in the atmosphere.
Opportunity finally reached the gully in September 2017.
The gully was named Perseverance Valley.
Scientists wanted to know whether it was water, ice or wind that had carved this gully.
From the shape of the gully, it certainly looks to have had something flowed down it.
Opportunity also spotted rocks lining the channels.
Could these have been deposited by water currents?
As it turned out, Opportunity wasn’t able to find anything conclusive.
After several months of examining the area, Opportunity passed through 5000 sols on Mars.
And what better way to celebrate than by taking its first full selfie.
You’ll notice this image is very blurry, that’s because it was taken with the fixed
focus microscopic imager on its arm.
It was only designed for very close targets.
In June of 2018, the MRO detected the formation of a dust storm.
This isn’t unusual, Mars has seen its fair share of dust storms coming and going on a
fairly regular basis.
Opportunity had even lived through some itself.
However, within days of its first formation, it was clear that this was going to be a big
one.
It very quickly spread across the entire planet, and mission controllers began preparations
for a period of low power.
On the 3rd June, Opportunity was producing 468 watts of power, by the next day, this
had dropped to 345 watts.
By the 6th June, it had plummeted to 133 watts.
Dust caught up by this storm filled the atmosphere, obscuring the precious light from the Sun
to the point where it would have barely even been visible.
The worst storm Opportunity had experienced up until this point was in 2007, where the
atmospheric opacity, known as a tau value, was at 5.5.
This is almost enough for Opportunity to not make it through.
This storm, on the other hand, had a tau value of 10.8, almost twice as bad as the previous
storm.
Although operations were kept very basic, only sending back health reports every morning
and evening, by the 12th June, Opportunity fell into a continuous hibernation mode.
The storm dragged on for months, and with each passing day mission controllers lost
more hope that Opportunity would wake up on the other side.
Three months later, the storm finally subsided enough for Opportunity to wake up from its
hibernation mode, and efforts were made to re-establish contact with Opportunity.
By October, the storm had cleared completely, but no contact had been made with the rover,
even after 350 attempts.
From November on, mission controllers hoped that if the rover simply had a lot of dust
on its panels, that wind would blow a lot of it off, however 1000 communication attempts
later all the way through to February, mission controllers gave up hope and declared the
mission dead.
The 15-year, or 5352 sol Mars mission had finally ended.
And what a mission it was.
Opportunity measured temperatures, atmospheric readings, the rotation of Mars and more, however
the real prize was the definitive proof that Mars was once a world similar to our own in
that it held stable bodies of liquid water oceans on its surface in the distant past.
While we may take that for granted now, when it was first confirmed it was truly ground-breaking.
Shortly before communication was cut off, Opportunity was in the process of sending
back one last panorama of its final resting place.
Its famous last communication was poetically translated to be “My battery is low and
it's getting dark”, and its final image was of the Sun obscured by the dust.
And there we have it!
A recap of the entire Opportunity mission.
If you missed any of the previous episodes, be sure to take a look at the playlist here.
Now here’s a sponsor you may enjoy.
Some of you have mentioned that you watch Astrum because I try to be as concise as possible,
providing as much information as I can in a short space of time.
Perhaps you don’t have a lot of time, so getting information quickly is important to
you.
This is where Blinkist comes in handy, it’s an app that condenses non-fiction books into
text or audio podcast style insights that can be ingested in roughly 15 minutes.
They have over 3k books in their library so far, with more being added all the time, and
all these titles are even available offline.
I recently came across a book called “The Order of Time”, and how time fits in with
our universe.
It’s pretty mind blowing, but nicely written and condensed for a quick read.
If you download Blinkist using the link in the description, you can and try it out for
free for 7 days, and that link will also get you 25% off a full membership.
So, if you want some quick, compact learning, why not give it a go.
Thanks for watching!
And a big thanks to my patrons and members for continuing to make videos like these possible.
If you want to support Astrum too, find the link in the description.
Subscribing and liking also goes a long way if you want to support in other ways.
All the best!
And see you next time.