Thank you! It's more like a student internship than a job ;)

Yes, you're right that bluish tone to the sky is false colour. The true Martian sky is a dusty beige but turns blueish-white at sunset.

I'm not OP but it's probably just short of impossible it could chance upon a fossil of any sort of multicellular organism. Based on Earth history, we have evidence of microbial life from approximately 3.7 billion years ago.

The first evidence of multicellular organisms don't appear until circa 600 million years ago, so evolution took 3 billion years to advance from single to multicellular life.

From our observations of Mars, it is believed the last water would have dried up around 3.7 billion years ago. Its approximate age is 4.6 billion years, or around the same age as Earth.

Taking what we know about our own planet it is fair to say that any single celled organisms on Mars didn't have long enough to evolve to become multicellular, assuming there ever were any single celled lifeforms there in the first place.

So something like a fish is definitely out the question, because the period when Mars was habitable was only like 500-1000 million years after the solar system formed. Complex life like simple animals (jellyfish,sponges) didn't evolve until 3700 million years into Earth's history and fish didn't evolve until 4100 million years into Earth's history. Mars never had the time to evolve something so complex as a fish.

So instead of fish we're looking for much simpler microbial life. An individual fossil microbe is far too small for the rover to spot. Fortunately though, even simple microbes can group into larger colonies leaving behind rock structures called stromatolites which are really distinctive and are known from rocks of similar age on Earth. So that's the kind of thing we're hoping the rover just stumbles on.

It's worth adding though that Curiosity has been exploring lake-bottom sediments for 10 years now and nothing remotely like a stromatolite has yet been found. Perhaps that's telling us something. Maybe there were microbes but they didn't form into colonies for some reason, maybe the water conditions were wrong. Maybe there was life on Mars but it never reached this lake. Or maybe there was no life at all. OOOOor maybe there are stromatolites in Gale Crater and we just landed in the wrong place ;)

They are sedimentary, yes. In a lake bed setting, imagine clay particles settling out of suspension and forming a thin layer of mud ontop of the original rock. Now imagine that the lake persists for a million years, that deposit of mud on the lake floor has now grown hundreds of metres thick.

Billions of years later, the rover visits the site. The lake water is long dried up and that mud has turned into stone, which has been heavily eroded. The rover landed at the lowest point in the crater, where you can see where that very first layer of mud sitting ontop of the original rock. Therefore, we first encountered mud formed at the very beginning of the lake's history. In the years since, the rover has driven steadily uphill, climbing through sequentially higher mud layers and so 'further in time'. So, as the rover ascends upwards, we see progressively younger layers. We are now at the time when the lake dried up.

Sedimentary layers are laid down sequentially, and so document the passage of time. In archeology, this is what makes stratigraphy useful as dating evidence.

Thank you!

TBH I wouldn't know because i'm not involved with the engineering side of the mission at all (i'm on the science side). But probably yes. The place to check is the JPL website, and if that fails then you could ask the lead engineers of the mission.

Excellent question! This is one of the biggest debates in Mars science - we really don't know to be honest! All we know is that the atmosphere must have been far thicker than today and must have contained a lot of greenhouse gases to explain how a planet much further than the sun was able to sustain liquid water on its surface without it freezing.

Candidates include: CO2 NH3 CH4 SO2 H2O

Technically the rovers are only supposed to last for about a martian year (3 Earth yrs) but in actuality the engineers design the components to last much longer. Why? Well NASA virtually always gives funding to extend the lifetime of the mission. Opportunity, for example, was supposed to last 90 days but ended up surviving 14 years until a dust storm killed it off.

Curiosity and Perseverance's lifetime is limited by its power source, which is fueled by the decay of radioactive elements. This is only going to last 10-15 years before the rover runs out of power - for reference Curiosity is 10 years old and Perseverance is 1 year old. Once they run out of power, their instruments become irreperably damaged by the cold winter temperature.

So people definitely won't make it in time to save Curiosity, but perhaps we could greet Perseverance :)