Mission: ExoMars
Targeted launch date: 2028
Target landing site: Oxia Planum
Aim: Search for signs of life
Estimated cost: $1.3bn (£0.98bn)
Weight: 310 kg
Size: 3.5m x 2m x 2 m
Key feature: Drill box capable of sampling 2m beneath the surface
Scientific instruments:
* CLUPI: Close–UP Imager
* Enfys: Infrared Spectrometer for ExoMars
* Ma_MISS: Mars Multispectral Imager for Subsurface Studies
* MicrOmega: visible plus infrared imaging spectrometer
+ MOMA: Mars Organic Molecule Analyser
* PanCam: Panoramic Camera
* RLS: Raman Spectrometer
* WISDOM: Water Ice and Subsurface Deposit Observation On Mar
Every day for the last three weeks, scientists have been carting Charlie out into the middle of the Tabernas Desert to put it through its paces.
With its deep valleys, wind–carved cliffs, and barren ground, this desert once served as the backdrop for countless Spaghetti Westerns, scenes in Indiana Jones, and even parts of Game of Thrones.
But as we bounce over a winding dirt road further and further from civilisation, it seems that those film studios missed a trick by not shooting a few science fiction films instead.
If you learn to ignore the odd power pylon in the background, and the small horde of journalists getting in the way, it's easy to forget you're actually on Earth and not on Mars' Oxia Planum.
Professor Susanne Schwenzer, a planetary mineralogist from the Open University and the field geologist for the ExoMars field tests in Spain, told the Daily Mail: 'We know quite a lot about Oxia Planum from orbital investigations and mapping, so we know it is a layered terrain where you have older layers on the bottom and younger layers on the top.
'We have a similar situation here if you look all around you, and so it is visually very, very similar to Mars.'
In fact, that strikingly alien quality is why it's worth lugging all this expensive equipment out into the blazing heat of the Tabernas Desert.
While it's important to check that all the equipment works as intended, these tests are really about giving the team a taste of what it will be like to drive a rover on Mars.
'You have three factors,' Professor Schwenzer explains.
'You have the science, that the scientists take care of; you have the engineering, which the engineers take care of, and you have the link between what the scientists want to do and what the machine can actually do.
'And they all need to work to get the best science return, and that's what we're doing here; testing and training people to actually use this to the best effect before we get to Mars.'
The Tabernas Desert is the perfect place to test a rover because it looks very similar to the Martian surface
It is extremely important that the test area actually looks like Mars, so that the scientists controlling the rover can practice navigating Martian terrain
Because of that, it matters that the landscape really does look like Mars, and the team go to great lengths to ensure it stays that way.
As Charlie gets ready to undertake the day's procedures, Professor Schwenzer follows along with a broom, sweeping away the footprints that would ruin the illusion for the control team peering out through the rover's cameras.
While a footprint might seem inconsequential, it provides the operators with an all–too–easy–to–use reference point that they would never have on Mars.
We've joined the team for a test of one of Charlie's critical instruments, the WISDOM ground–penetrating rover.
Dr Wolf–Stefan Benedix, an engineer from TU Dresden who co–developed WISDOM's antenna, says: 'It's a radar that is looking into the soil. We transmit some EM waves, and we receive some EM waves, and from that we see what is beneath the surface.'
In particular, WISDOM is tuned to look for layers in the Martian soil that might contain certain minerals created by water, or even layers of ice trapped beneath the ground.
That's absolutely critical, because the real Rosalind Franklin isn't just concerned with searching the Martian surface, but rather, what lies deep below.
Just like the Tabernas Desert, the part of Mars where the rover is scheduled to land, the Oxia Planum, is made up of layers upon layers of clay sediments.
Scientists know that these clays are an extremely good sign that water was once present.
In fact, research suggests that the entire area may have once been covered by an enormous ocean several miles deep, which dried up about four billion years ago.
To ensure the images that the crew see (pictured) are as close to the real thing as possible, scientists sweep the desert to remove any footprints or car tracks before testing
Rosalind Franklin's key piece of equipment is the drill, which will be able to collect samples from two metres beneath the surface. That is deep enough to retrieve material undamaged by radiation
However, since Mars has such a thin atmosphere, intense radiation from the sun has long since destroyed any signs of life in the top half a metre or so of soil.
That is why the Rosalind Franklin has been equipped with a newly designed drill, capable of taking pristine soil samples from up to two metres below the surface.
Since Mars doesn't have tectonic activity or erosion from water, these deep soil layers might have been undisturbed for billions of years, preserving a record of a time when Mars was warm, wet, and potentially habitable.
Unlike previous rovers, Rosalind Franklin is also equipped with an onboard suite of analytic instruments that can test that soil for the chemical signs of life – known as biosignatures.
Everything else, from the WISDOM radar to the specialised geological cameras, is designed to ensure the rover finds the perfect place to drill, and has the best chance of finding signs of life.
That means, if there are signs of alien lifeforms hiding beneath the barren surface, Rosalind Franklin stands a good chance of finding them.
Dr Nicolas Oudart, an astrophysicist at the University of Versailles and part of the WISDOM team, explains that one key biomarker the rover is looking for is called 'chirality'.
Like your hands, molecules often come in one of two mirror arrangements – a left and right–handed version.
While you'd expect the left and right versions to be fairly equally abundant, Dr Oudart says 'life is known to favour one over the other'.
So, if the rover finds a lot more left–handed molecules than right–handed ones, or vice versa, it could be a good sign that biological processes have been at play.
Rosalind Franklin will also be equipped with a set of cameras developed by British scientists at Aberystwyth University
The rover is equipped with a ground–penetrating radar to search for the perfect place to drill, and give scientists the best chance of finding signs of life
That would be just one piece of evidence that would form a wider picture in the search for signs of life, and scientists won't be eager to call the discovery too soon.
It will take a lot of tests, and a lot of potential biomarkers together to show that life really might have thrived on the Red Planet.
But, by doing practice tests like these out in the desert, the researchers are doing everything they can to give Rosalind Franklin the best chance possible.
And, if they do find signs of ancient life, it would change everything about the way we look at the universe.
Dr Oudert says: 'Right now, the only example of life we know is the one on Earth, so we don't actually know how likely it is for life to appear on a planet when you have the right conditions.
'If we find that there was life on Mars, it would mean that in the solar system you have two planets with the right conditions and on those two planets, you have life.
'That would mean that the Earth is not that unique, and it's more likely that we have many planets in the galaxy with life.
'So we don't know for sure what we will find, but if we find life, the implications are very interesting.'