On the 24th of January 2004, the Opportunity rover touched down on the surface of Mars.
Opportunity was one of two rovers tasked with finding ancient evidence of water on the Martian surface.
After travelling 45km over the incredible Martian landscape, it did exactly that.
Despite a life expectancy of just 90 days, Opportunity ended up working on Mars for an
incredible 14 years before succumbing to an enormous dust storm in 2018.
Although Opportunity’s time has come to an end, its incredible scientific discoveries
live on in NASA’s ‘Curiosity’ rover.
After a six-month journey through space, Curiosity finally made Mars its home when it touched
down on the 6th of August 2012.
Armed with an array of advanced tools, Curiosity looked to make new discoveries about the Martian
climate and the geological processes that shaped Mars over its lifetime.
Since arriving on Mars, Curiosity’s main focus has been on Gale crater, which had been
an area of high interest for scientists.
Almost right away, Curiosity found strong evidence that this crater was once filled with water.
In the past, rivers of liquid water would have flown into the crater carrying
sand, silt and gravel along with it.
Over time, these layers would build up and compress into rock - leaving a snapshot in
time for Curiosity to discover.
In order to further examine these ancient formations, Curiosity drilled into the lake
bed and discovered several types of organic compounds.
These are chemical compounds that contain carbon, one of the most common elements found
in life on Earth.
Although there is a lot of carbon in our solar system that doesn’t originate from life,
this was a good sign that microbial life could have existed on Mars billions of years ago.
Curiosity continues to travel around Gale crater, discovering interesting formations
and analyzing rock samples.
So far, Curiosity has travelled 22km across the Martian surface -
but it hasn’t all been smooth sailing.
Over the last 7 years, the rough Martian terrain has caused a significant amount of
damage to Curiosity’s wheels.
This is just one of the many problems that threaten Curiosity on the Martian surface.
In order to reduce tyre wear, the engineers that control the rover have started to re-route
Curiosity on its journey, to avoid the harshest of terrain.
Curiosity remains in close communication with Earth via the Deep Space Network, which consists
of antenna complexes at three locations around the world.
The rover uses a steerable high-gain antenna which can be pointed directly towards Earth.
The data rates when talking directly to Earth are slow, so Curiosity often sends its data
through the Mars Reconnaissance Orbiter.
This orbiter passes over the rover for around 8 minutes each day.
In that short period of time, Curiosity can send around 30 megabytes of data up to the
orbiter which can then pass it onto Earth.
If Curiosity was to send the same amount of data directly to Earth, it would take 20 hours.
Communicating directly with Earth also uses a lot of power from the spacecrafts batteries,
so sending information can only be done for a few hours per day.
Curiosity is powered by a radioactive thermoelectric generator.
This works by converting heat from radioactive isotopes into electricity.
This electricity charges two lithium-ion batteries, allowing Curiosity to carry out high power
tasks each day.
The RTG is expected to fully power Curiosity until at least 2026.
After that, the power will decrease and the amount of movement and science it can perform
Although Curiosity will continue to limp on, it’s entirely possible that mechanical failure
or the Martian weather might stop Curiosity’s exploration before its power runs out.
A Martian dust storm, much like the one which silenced Opportunity, may also be the end
of Curiosity's mission.
Dust storms on Mars form clouds which can reach up to 100km above the surface of the planet.
The dust particles which circulate during these storms are small and slightly electrostatic,
so they can often stick to the rovers surfaces and interfere with electrical components.
Curiosity is just one of many rovers which will, in time,
come to explore the endless bounds of space.
The Mars 2020 rover is set to launch later this year and is expected to land on Mars
in early 2021.
While Curiosity was sent to Mars to discover habitable conditions, the 2020 mission takes
things a step further – and hopes to find real proof of microbial life.
Mars rovers are becoming more complex, more intelligent and more useful.
And while Curiosity may have many years left to roam, it’s electrical power weakens each
day and the threat of dust storms could easily be the end for Curiosity.
Over time, engineers will slowly start shutting off instruments to preserve power, until Curiosity
sends its last bit of data and disappears silently into the Martian landscape.
Either way, we can appreciate the enormous amount of information that Curiosity has collected