Extract from ABC News
NASA's latest rover is now just days away from a daring landing on Mars.
Hurtling towards the planet at supersonic speeds, Perseverance will attempt to land about 8:55am (AEDT) on Friday morning.
If it succeeds, it will become the fifth rover NASA has landed since Sojourner, the first robot to trundle across the surface of another planet in 1997.
The size of a SUV and weighing around a tonne, Perseverance is the biggest, heaviest and fastest rover NASA has sent to Mars.
If you think it looks very similar to Curiosity, the last rover NASA landed on Mars in 2012, you would be right.
Much of the design — and the spare parts that make up the new rover — come from Curiosity.
And like Curiosity, Perseverance will descend towards the Red Planet in a nail-biting series of carefully choreographed steps dubbed the "seven minutes of terror".
But that is where the similarities between Perseverance and any mission before it end, says David Flannery, astrobiologist and Mars 2020 mission planner based at the Queensland University of Technology.
With a completely new suite of seven instruments on board, it could not only help answer one of the most fundamental questions about life in the universe, it could also change the face of space exploration for decades to come.
This is what sets this mission apart.
It will search for evidence of ancient life
Perseverance is the first rover with tools that can specifically hunt for signs of microbial life that may have inhabited Mars when it was covered in lakes and oceans billions of years ago.
"No mission has ever been given the mandate to look for evidence of past life," said Abigail Allwood, an Australian geologist at NASA who is charge of PIXL, one of the key instruments onboard.
Early rovers such as Spirit and Opportunity were tasked with "following the water", while Curiosity has been exploring the chemistry of the atmosphere and the soil.
While spacecraft circling above and trundling across Mars have detected organic material and taken some impressive photos of what appears to be a water-carved landscape, the information is not detailed enough to prove whether or not life ever existed on another planet other than Earth.
So the plan is to land Perseverance in Jezero Crater, which scientists think was a large lake around three and a half billion years ago.
It will use powerful instruments such as SuperCAM and Mastcam-Z to identify interesting rocks for the robotic geologist to explore in detail.
They will be specifically looking for telltale wobbly lines that resemble fossilised stromatolites — created by layers of microbes — like those found in rocks of the same age in the Pilbara.
Then it will use tools such as PIXL and SHERLOC to look for chemical and molecular signs at the nanoscale to confirm whether or not the structures were made by microbes.
Finding undisputed evidence of the earliest life forms on Earth is tricky; searching for them on Mars is next level.
If Perseverance finds stromatolites, that will be BIG news; but even if it doesn't, it would profoundly change our understanding of life, Mars 2020 project scientist Ken Farley said.
"If we find no evidence of life, we will have shown that at least in one place there is a habitable environment that is not inhabited," he said.
"It would tell us … that habitability alone is not sufficient, that something else has to be present [for life to exist]."
It will help bring Mars rocks back to Earth
Perseverance is the first of a series of missions planned over the next decade that will bring Mars rocks back.
"It may seem easy, you go there, you drill a rock and you bring it back. But every part of that process is really challenging," Professor Flannery said.
Perseverance will use a drill on its arm to take up to 40 intact cores of rock from different locations in Jezero crater.
"Drilling the rocks and handling the samples in a really clean way is a monumental engineering challenge."
Once the rover drills the cores, it will put them into a small tube and stash them on the surface of Mars to be picked up in the future.
The challenge then will be how to get them safely back to Earth.
Bringing those samples to Earth "is the biggest challenge in planetary science or space exploration of the next few decades ... and it can't be done in one mission," Professor Flannery said.
A series of future missions — still on the drawing board — could fetch the tubes off the surface around 2026 and take them into orbit. From there they would be picked up by another spacecraft and brought back to Earth in the 2030s.
Getting the cores back to Earth will be critical to settle the question of whether or not life existed on Mars, said Ken Williford, the mission's deputy project scientist.
"The stakes are so high, the question is so profound," Dr Williford said.
"We will need to get those samples back … to give them the further detailed study that is only possible on Earth in order to obtain some sort of scientific consensus for or against any potential biosignatures."
Not only will the cores give scientists more information about Mars than meteors, the process of getting them back will test critical technology such as the ability to take off from the surface, and rendezvous in orbit.
A drone will attempt to fly on another planet for the first time
Going along for the ride is Ingenuity, a small helicopter strapped to Perseverance's belly.
If it takes off, it will be the first time a powered craft will buzz around on a planet other than Earth.
"This will be a true extra-terrestrial Wright Brothers moment," said Thomas Zurbuchen, head of NASA's science mission.
Ingenuity has been tweaked to deal with the different conditions on Mars such as weaker air pressure, Dr Williford said.
"Ingenuity's blades need to be very long and spin very fast, and the whole thing needs to be very light to get airborne," he said.
If it succeeds, Ingenuity could revolutionise exploration on Mars.
Just as the first rover Sojourner set the path for future robots (it was part of the Pathfinder mission in 1997), Ingenuity could turn Mars into the planet of the drones.
"If I were going to Mars, I would love to have a drone with me," Dr Williford said.
"I could stay in my safe radiation-protected area and fly the drones out to explore possible places to look at, rather than put myself at risk."
It will attempt to extract oxygen from Mars' atmosphere
The atmosphere of Mars is mostly made up of carbon dioxide.
Scientists will test a small chemical plant onboard Perseverance called MOXIE, which can split carbon dioxide and generate oxygen.
The oxygen will be very handy for future human explorers — not just to breathe, but to make rocket fuel.
"We call it primary in situ resource utilisation; that is, going to a new place and living off the land," Dr Williford said.
"You wouldn't have to bring all the materials you would need to run your rocket engines from Earth if you have a scaled-up version of Moxie pumping away on the surface for months prior to landing."
It will test spacesuit material to see if it can handle Mars
Scientists want to know what happens when spacesuit materials, such as those currently used by astronauts on the International Space Station, are exposed to Martian conditions.
They will analyse what happens to five different types of materials using SHERLOC, when it is not analysing rocks for evidence of past life.
This tool analyses the molecular signatures of organic materials, including those used in synthetic and plastic fabrics.
"The primary concern for human safety is radiation," Dr Williford said.
"That is not just radiation effects on the human body directly, but radiation effects on any organic materials including plastic type or synthetic types of materials that space suits might be made of."
The scientists will compare the results from Mars to lab experiments on Earth.
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