Explained: NASA's Mars 2020 Mission
Millions of excitable nerds huddled around their devices earlier this month to watch NASA’s perseverance rover successfully touched down on the frigid surface of Mars captured in never before seen levels of details and at multiple camera angles. This astonishing technical feat was a landmark of human ingenuity and a moving tribute to the audacity of 21st century engineers. So what’s the rover actually going to be doing now it’s up there?
Perseverance was christened by Alexander Mather, a bright 7th grader from Springfield Virginia who won a NASA essay competition with his lofty name idea back in march 2020. The rover which engineers apparently nicknamed “Percy” for short has three broad aims. The first is to scour Mar’s landscape for clues that might hopefully shed light on whether or not life existed there before the planet became uninhabitable. Its second aim is to prepare the ground so to speak for future manned missions and Percy’s third aim is . . . . . . .
Let’s look at all three aims in turn.
First and foremost perseverance is hoping to spot traces of the microbial life, scientists reckon may have been present or even hyper abundant some three billions year ago, back then it’s believed conditions on Mars were probably strikingly similar to those on earth, to this end the mission plunged down in a region as the Jezero Crater. Scientists chose this 28 mile wide geographical feature situated on the western edge of the vast flat plane north of the Martian equator because Jezero once contained a lake. Orbital reconnaissance from existing satellites suggest the crater contains clays which only ever occur in the presence of water, back on earth similar clays have been identified in the Mississippi river delta and in those clays signs of life are relatively easy to spot. The colossal historic impact which formed the deep jezreel crater also exposed rocks that could be as old as 3.6 billion years. A prime candidate for the bio signatures so hoped for by scientist’s backup NASA mission control. But location aside how is perseverance actually going to search for life. A suite of cutting edge instruments bolted onto the 10 feet long rover will analyze rocks in situ and send back detailed data and images to salivating researchers on earth via three communicating antennae. These powerful instruments include the adorably named dynamic duo of Sherlock and Watson which together use ultraviolet imaging and high resolution cameras to make sense of diverse textures and fine scale mineralogy of the Martian terrain. Together Sherlock and Watson should provide tantalizing clues about the presence of life even billions of years after it perished however elementary it was.
There is more the so called pixel is a compact lunch boxed sized x-ray spectrometer on perseverance that’s seeking evidence of past biological activity especially bio films like the tartar on your teeth on carefully selected rock and samples but without a doubt the coolest piece of kit mounted on perseverance is its super cam. Super cam identifies a target rock that’s ripe for investigation it then fires a tiny pinpoint laser accurate from up to 7 meters away. When that powerful beam hits the rock the laser impact sends up a lightning quick superheated cloud of plasma free floating ions and electrons. Percy’s onboard accurate spectrograph and camera read this plasma signature and can from this alone identify the chemical composition of rock. The right chemicals could prove definitively that life once existed on Mars. Remember all this happens at a range of 20 feet from the rover itself. Supercam has an even cooler trick than that up its sleeve. The device is also fitted with a microphone one of the two mounted on perseverance that records the fast staccato pop generated by the supercam laser as it hits the target. Based on quality of that pop perseverance can ascertain how hard the rock is and by the extension whether it was first formed on a lake bed or windy exposed environment. All this live processing happens thanks to the rover’s two identical brains, it keeps one as a backup. The radiation hardened CPU has a Power PC 750 architecture works at 200 MHz speed and is capable of compressing and processing image and video in situ before them to mission control and its unaccountably popular twitter account. As well as analyzing rocks in the fields perseverance is also setting out to physically drill for samples seal them up and leaves them in witness tubes on the Martian surface ready to be collected and carried back to earth by an as yet unscheduled follow-up mission.
The second big aim of NASA’s perseverance mission is to smooth the pathway for future potential manned mission to the red planet. In one respect this mission has already been a success, its smooth touchdown occurred thank to an elaborate ballet of new technologies working in concert to refine landing techniques. A perennial problem for Mars mission for instance perseverance’s all new terrain relative navigation uses detailed onboard mapping cleverly cross referenced with input from the craft’s onboard cameras to refine its landing zone within a few meters, finding such a sweet spot is critical in such a rugged and potentially hazardous landscape, a sophisticated range trigger system also helps to autonomously deploy the mission’s parachute. In order to better refine the landing and avoid overshoot. After all if touchdown were to happen even a mile or so outside the designated area that could add months or even years to the mission duration. Four cameras and a dedicated onboard microphone were also deployed during the landing to generate and send home as much data as possible to help engineers plan future missions. Now safely on the surface way perseverance is helping pave the way for manned missions is with a little thing called Moxie. Moxie stands for Mars Oxygen in Situ resource utilization experimenting is investigating the possibility of generating life giving oxygen directly from the 96 % carbon dioxide atmosphere of Mars. Roughly the size of a car battery moxie works by diffusing carbon dioxide through a non porous disk of yttrium stabilized zirconium or YSZ sandwiched between two porous electrodes using a smart dual process of thermal dissociation and electro catalysis an atom of oxygen is liberated from the abundant atmospheric carbon dioxide picking up two electrons through those porous electrodes then combining its mate to make good as old oxygen. If it works NASA would hope soon to send a Moxie unit 100 times larger to generate and store oxygen that’s pure enough to breathe and may be even provide the basis of a fuel source, to help bring future Martian astronauts back safely to earth. Perseverance is also holding a smart device called “MEDA” or Mars environmental dynamics analyzer designed to provide precise measurements of temperature, wind and direction, pressure, relative humidity and the specific size and shape of passing dust particles and in case you thought this mission was only concerned with the planet’s surface the so called RIMFAX or radar imager for Mars subsurface experiment is a metaphorically groundbreaking device that’s designed to unobtrusively probe as 10 meters under the ground hunting for evidence of ice and even briny water which would help those potential future settlers out no end as you can imagine. So what’s the third aim of the mission?
Tucked away under the perseverance rover is one the most audacious certainly James Bond. Ingenuity as its known is a helicopter and it hopes to set a one of a kind record for the first powered flight on another world. The plan is for Percy to identify a suitable helipad location when it does ingenuity will be carefully released from the bottom of the rover to carry out a few pioneering test flights, for its first foray the plan is to just take off a few feet and hover up to for 30 seconds. Ingenuity has onboard solar panels that charge lithium ion batteries which provide enough juice for a 90 second delight a day. Weighing in at a trim 1.9 Kg, ingenuity is a potential game changer and its descendants will provide significantly more agile probes than the familiar rovers and maybe even one day carry payloads or passengers.
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