Deference between NASA’s Perseverance Mars Rover and Curiosity

Curiosity rover on left, On right Perseverance Mars Rover(aka Mars2020)

Remember that time when NASA sent an SUV sized Rover to the surface of Mars. Yeah. You might remember the curiosity Rover and perhaps you recall its daring touchdown sequence, which utilized rocket powered sky crane, whether or not you remember the curiosity Rover. I do have some great news. NASA’s about to do it again, only as you would hope they’ve made some awesome improvements, including a part of the mission that I’m super excited for because they’re going to be flying a drone around in the atmosphere of Mars. So in today’s video, let’s do an overview of this new Mars Rover named Perseverance, also known as the Mars 2020 mission.

The rocket that’ll take it to Mars, the timeline, the landing sequence, and then we’ll compare it alongside the Curiosity Rover to see what’s actually changed and what stayed the same, including the instrumentation and the missions.

NASA is curiosity. Rover has been a home run flagship NASA mission, and its produced an incredible amount of data since it landed on Mars all the way back on August six, 2012, and those eight years since doing science on the surface of Mars, it found evidence of previous liquid water. It discovered Mars has had the right chemistry to support living microbes, having discovered sulfur nitrogen,oxygen, phosphorus, and carbon, all the key ingredients that make life to further that note of potential life. It found organic carbon molecules,active methane in the atmosphere, and even found out that Mars once had a thicker atmosphere and more water. It’s also helped lay the foundation for future human missions to Mars by precisely measuring the radiation, finding that Mars is radiation environment is too high for human presence, if not shielded. So with all this awesome stuff, being tested and measured and discovered it raises the question, what else is there to do? I mean, what’s Perseverance going to do that curiosity. Didn’t do. They kind of look the same don’t they? Well, as you can probably guess there’s still a ton of science to be done and perseverance is really going to be kicking it up a notch. So let’s start off by doing an overview of the mission timeline. Then we’ll go into the details of the hardware and compare those to curiosity. And since this is a pretty long video,we’ve got timestamps here on the screen. The play bar on YouTube is actually divided into the sections. And we have an article version with sources in the description.

Perseverance is scheduled to liftoff during the 2020 launch window, which is from the middle of July to the middle of August. If you’re watching this about August 15th, 2020, and it hasn’t taken off, it means the next opportunity to launch isn’t until August, 2022. Although as of the making of this video, NASA is looking into potentially launching a little bit after August 15th as a contingency option, but regardless of when they actually end up launching they’ll land on Mars at the exact same time and date, February 18th, 2021 at 3:30 PM Eastern, thanks to orbital mechanics. Now just like the curiosity Rover Perseverance will be heading to Mars, riding the Atlas five rocket in almost its most powerful configuration, which is the five, four, one, meaning it’s going to have a five meter fairing. You’ll have four solid rocket motor sand a single RL-10 centaur upper stage engine. It’s going to take all that power of United launch Alliance’s workhorse rocket to get the heavy Perseverance, the 105 million kilometres to Mars. Well actually to be pedantic, the distance the Rover will actually travel to get to Mars is more like 497 million kilometres. Because as those of you who have played Kerbal space program might know to get to Mars, you don’t travel in a straight line when the two planets are closest to each other, you actually raise your orbit around the sun. So it intersects with Mars is orbit and you need to intercept Mars when it gets to that exact point at that exact time after its long seven month journey, perseverance will touch down on the Martian surface in February, 2021 it’ll land at the Jezero crater location chosen for its possibility of harboring life. In the past, it’s believed that the crater was at one point flooded with water, which would have allowed for the presence of life in ancient times, the EDLs or the entry descent and landing system will contain a new technology called terrain relative navigation. This will allow a computer to scan the terrain during descent and then compare it to an orbital map, and it will be able to divert to a safer landing zone if necessary. Another feature known as the range trigger will determine when the parachute should be open, allowing the Rover to land much closer to points of scientific interest, which ends up saving valuable time that otherwise be spent just slowly driving around on Mars. So here’s how that sequence of events will actually occur. This might all sound pretty familiar if you’ve seen curiosity’s landing sequence that also features the rocket powered sky-crane. [Inaudible]. At entry minus 10 minutes, the cruise stage separates and burns upon the Martian atmosphere at entry plus zero minutes, that’s of course, when the craft will begin to enter the Martian atmosphere. Entry plus 80 seconds, the heat shield experiences, the maximum amount of heating roughly 2100 degrees Celsius. At entry plus 90 seconds, the craft experiences, the maximum deceleration slowing down from 21,200 kilometres an hour to just 1600 kilometres an hour and only two and a half minutes at Eplus 240 seconds at an altitude of around nine to 13 kilometres,the parachute deploys. At E plus 260 seconds shortly after the heat shield separates and falls to the Marshall surface, the radar ground system will activate and begin scanning the Martian surface for a suitable touchdown zone at around E plus 350 seconds. The back shell separates and the Rover begins a brief free fall before the landing motors ignite. This is definitely the maximum pucker moment at an altitude of just 21 meters. The Rover separates from the landing stage and is gently lowered to the ground on three nylon ropes. At this point,the craft has slowed down too, just 2.7 kilometres an hour.

Finally, the Rover touches down on the surface and the landing stage that sky crane will fly away before it crashes into the surface. And this will officially begin perseverance his mission on the surface of Mars. Now, if you’re anything like me, maybe you’ve always wondered how can that sky crane make he sends? It seems like there’s a lot of factors, extra parts, extra systems dangling from this rope and all this stuff. It seems like a lot more trouble than it’s worth. Why don’t they just put the Rover on top of the sky-crane and just land it like normal and drive off the top. Wouldn’t that be a lot it’s easier and lighter? Well, to answer that there’s really two main reasons. And the first one is, when you have something as heavy as perseverance, which is about a metric ton landing propulsive you can’t have the rocket engines firing too close to the ground. You’ll basically make a crater, which is the same reason why we’re seeing the lunar Lander version of Starship have auxiliary landing engines up really high. So if you did put the Rover on top ofit and you wanted to make sure those rockets weren’t too close to the ground, you’d have to put it on like giant stilts or a giant landing legs and those weigh a lot. And then now your rover’s on top of a giant thing with landing legs and stilts, and to drive it off, you’d have to have this ramp or some kind of system then to get it off of that. And now you just added even more weight and complexity and made it pretty, pretty risky, honestly. And the other reason is actually for control. It’s a lot easier to let the crane just kind of hover roughly above the surface and then use a tether that has some Slack in it. So there’s a lot of wiggle room there. You basically to start lowering the Rover until it touches the ground.

Once it touches the ground, they cut those tethers and the sky crane just flies away. So it doesn’t need to get down perfectly and just land very, very, very gently. So again, this all sounds like deja VU with Curiosity having done quite literally all of this stuff, proving out this entire system and all the wacky landing sequences. So let’s actually compare these two rovers side-by-side and then we’ll see what’s new and note-worthy. Well, to begin, both rovers are virtually identical designs with perseverance actually using some of curiosity’s backup parts. Each Rover is 2.9 meters wide, 2.7 meters long, and 2.2 meters tall. It’s easy to forget just how big these rovers are. I mean, they’re almost the size of a small SUV, although they’re nearly identical in size, perseverance will be heavier weighing in at 1050 kilograms versus Curiosity’s 899 kilograms. So let’s take a look at the changes that make perseverance heavier. Both rovers utilize the same body, which is called the WEB or the warm electronics box. It’s this strong outer layer that protects the computers and the electronics and keeps them temperature controlled on top of the web or the deck is the large mast that houses the main cameras, which are the supercam and the Mast Cam Z. Then there’s the Mars environmental dynamic analyzer or known as MEDA, which is basicallya little weather station. And on the bottom of perseverance is a sample collecting system. Now this is one of the biggest upgrades for perseverance. Perseverance will collect rock cores for future study. Now this is a little confusing to me because the samples will just be stored, ready for someone or something else to pick them up and return them for further analysis. But if something else comes along to grab these samples, why can’t that thing just drill its own core samples?! Isn’t that kind of trivial compared to getting to Mars? I mean, isn’t it actually kind of hard to have to retrace Perseverance’s steps and grab all of its cores instead of just drilling its own samples itself? Well, first off storing samples before anymore human interference or future Mars missions land on the planet ensures clean samples before any potential combination.So that’s a good thing, but second, it also saves the weight of the heavy drill and containment system from being required on a future Rover perseverance, will collect at least 20 samples. It has 43 sample collecting containers and five witness tubes.

So what they’re going to do is they’ll open up these witness tubes during drilling sessions that are preloaded with materials that can capture molecular and particle contaminants. In other words, these witness tubes will capture gases that may be released or out gas from the Rover itself, chemical remanence from the landing system or any other earthly organic or inorganic material that may have somehow made its way to Mars. This ensures that there’s a control to observe later on. So when they’re looking at samples, they can cross reference the witnesstubes and that’ll let them know whether or not the materials actually from the sample or from the Rover, or potentially even from Earth, the Rover stores, the tubes under its belly on a carousel. And there’s a small robot arm that hands,the sample tubes off to the main arm, it’s kind of like a lab assistant to the big arm, which is kind of cool. Then depending on what NASA ends up wanting to do, it’ll do a deposit of the samples all at once or in a few strategic places for future sample collection and return. There’s even already plans in the works with ESA and NASA to send another Rover down that will have a mini rocket on it, and basically be a small launch pad. And that’s of course possible because Mars has a lot lower gravity. As my shirt will tell me and a lower atmosphere, which shirt will also tell me. So it takes a lot smaller rocket to get something from Mars into Mars orbit, and then back to earth than it would to get something from Earth to Mars. Okay. So they’ll take this new Rover, drive it over to a sample. They’ll stick that sample on this little rocket they’ll launch that rocket into Mars orbit, and then it will likely rendezvous with another probe that will end up pushing it all the way to earth. Now these plans change and they won’t happen until at least 2028. So we won’t be getting any sense sample returns until the 2030s at best. And this feels like a pretty hail Mary stretch of events to have to work perfectly. It almost makes me wonder if humans will just end up collecting those samples themselves or just bringing their own drills and observing Mars right there on a Martian base or something, or bringing them back to earth with them. But although it’s definitely a cool way and an important thing to preserve samples before any human presence.

Okay. So back to perseverance and that big arm on the front, it’s been massively upgraded compared to curiosity, it has a new hand or a turret full of new science tools. It also has an updated coring drill and two science instruments alongside a color camera for closeups surface inspections and those awesome selfies like curiosity has taken.Learning from the issues with curiosity, the teams at NASA have made some significant changes that should extend the Rover’s lifespan and allow it to conduct even more science. The biggest change is probably the wheels which have been redesigned to have a larger diameter and a smaller tread width than Curiosity’s wheels. These new wheels should prevent Perseverance from getting stuck in the Martian sand, as curiosity did in 2014, perseverance also has a new cutting edge instrument suite using its x-ray spectrometer and UV laser it’ll scan the Martian surface at an even finer scale than ever before, to search for evidence of Martian life. Perhaps one of the upgrades that I’m most excited for is its huge upgrade to cameras. Perseverance will carry a remarkable 23 cameras to the surface, including some that will film the final into the Martian atmosphere, capturing all inspiring footage. As the craft drifts down towards the Martian surface. The new cameras will also be higher resolution. Curiosity’s best. Camera was only about two megapixels. The camera on board will capture 20 megapixel full color images. Now I know that this might not seem like the most scientifically valuable thing, but I think it’s one of the most important pieces of the mission that help raise the public’s interest and help all of us get a sense of actually being there. After all, Public interest is a big part of these flagship NASA missions. And this has a few fun elements that you may have actually been a part of. Perseverance will be carrying 10.9 million names on board, three thumbnail sized Silicon chips, maybe your name’s on it.

There’s also a tribute plate to the medical community and another with an image of earth Mars and the sun and the Rover was named perseverance by Alex Mather who won a K through 12 public naming contest with 28,000 entries. I love seeing the public gets so involved in these missions, but to expand on the public experience, perseverance will also carry two microphones, which will capture the sound of Mars during the landing as well as on the surface, I can’t wait for all the footage to roll in. Beautiful descent footage with real sound awesome high resolution images. I mean, perseverance would be bringing Mars to us better than ever before. Perseverance is power system will basically be the same thing as Curiosity, which has proven to be incredibly reliable. It’s a 45 kilogram radioisotope electric generator or an RTG that converts the heat of radioactive decay of plutonium into electricity.Along with the RTG, there’s also pair of lithium ion batteries to help handle peak demands or times when the Rover is using more energy than the RTG produces. The RTG is designed to last 14 years, which is fine beyond the plan mission duration of 1.5 Mars years or three earth years. This is a pretty typical JPL thing to over-engineer and we’re definitely thankful when it comes to rovers like curiosity and perseverance, I guess, opportunity also who have exceeded all expectations of life duration. I mean they just keep on going! Fun side note here about the RTG. This will be the first mission to launch from the U S utilizing an RTG that won’t require the president to directly approve the launch. The permissions have changed allowing NASA administrators to approve the launch.

So our good friend, Jim Bridenstine will give his thumbs up and it’ll be launch time. Another thing that’s just like curiosity, perseverance, will use three forms of communications, an ultra high frequency antenna with data transmission of up to two megabits per second, from the Rover to the relay link. Then there’s the X-band high gain antenna, which has a steerable beam that can transmit data directly to earth at 160 to 500 bits per second. And lastly, there’s an X band, low gain antenna, which is primarily for receiving signals and can only transfer 10 bits per second. So you really don’t want to use this for any images or anything like that. Another fun upgrade and experiment that’s going to be on perseverance. And something that’s going to be really useful for future crewed missions to Mars will be the first attempts at producing oxygen on the surface of Mars using in-situresource utilization with an awesome experiment called MOXIE. Although Mars has an atmosphere it’s very thin as you can read on my shirt, only about 1% as dense as birth and of that 1% density carbon dioxide makeup around 96% of the gas in Mars’ is atmosphere. Oxygen is only 0.174% compared to the 21% in Earth’s much thicker atmosphere getting really pedantic here. If you factor in the partial pressures of earth and Mars, take the average temperature into consideration and convert to moles, taking a breath on Mars,you’d only inhale about 0.071% as much oxygen as you would at sea level on earth. Or in other words, there’s about 14,000 times more oxygen per liter on earth than on the surface of Mars. So if humans are going to live on Mars, we’ve got to make oxygen. And maybe just as importantly, if these humans are to return home, they’ll need oxygen for their rocket. So figuring out how to make oxygen out of the carbon dioxide in the atmosphere of Mars is vital. And as if all of this wasn’t just enough, awesome upgrades, Perseverance has one more incredible trick up its sleeve, or should I say under its belly, Perseverance will not be flying alone. It’ll be joined by a small drone helicopter named ingenuity. Ingenuity will demonstrate the possibility of flight on Mars and will provide engineers on Earth with aerial images to better plan routes for Perseverance because of its proximity to the surface, Ingenuity will capture images with approximately 10 times the resolution of orbital images. Ingenuity is pretty lightweight though. It only weighs 1.8 kilograms and has two counter-rotating rotors that are 120 centimetres in diameter. It’s pretty awesome that they can just use to counter rotating blades to be able to do all the control dynamics of this vehicle. The little helicopter drone is expected to fly at least five times in its 30 day test campaign with each flight lasting no more than just three minutes. While that’snot that long of times, of course the blades have to do quite a bit of work in that really thin atmosphere. The idea of there being a drone, that’s just flying around on another planet though,millions of kilometres away, honestly, absolutely incredible to me. Okay. Okay. Okay. I might just be a little bit biased perhaps.

I just think it’s extra cool because I’ve seen it with my own eyes from only a few meters away while it was going through its final testing at JPL. Now this will just be the first of hopefully many drones to fly around on other worlds. Because of course, I’m also looking forward to the dragon fly mission, but I’ll be a quad copter that’ll be flying around on Saturn’s largest moon Titan, but that won’t happen until the mid 2030s. So Perseverance is a pretty massive overhaul of Curiosity and has a ton of cool things to look forward to. So all this said, I asked my friend and JPL engineer Bobak Ferdowsi what he was most excited for. Hey Tim, it’s Bobak, you know, as one of the people who got to work on curiosity and help get it to Mars with perseverance kind of being like a 2.0 version of that. It feels a little bit like a proud grandparent now, and I’m really excited for the mission and what it’s going to accomplish and all the improvements that were made from curiosity. I think two that stand out to me in particular: Terrain relative navigation, that’s basically where the Rover can avoid major obstacles during the landing that really increases the chance of landing safely. And I would say the MOXIE instrument where it’s creating oxygen on the atmosphere of Mars, not only does that mean incredible things for generating fuel on Mars, but as somebody who kind of hopes one day maybe to visit their baby on Mars, I would love to have lost the oxygen. When I get there, I’m really excited for the team. I wish them all a super safe and successful journey. I can’t wait to see what this mission shows us. Personally, I think I’m in between ingenuity the drone and just seeing better images in general, but then again,In-Situ resource utilization. That’s going to be amazing.I mean, think about it. SpaceX’s Starship will require In-Situresource utilization in order to get back from Mars, it has to make its own fuel. It has to make methane and oxygen. So I mean, it’s a vital thing that needs to be tested out. There’s just so many awesome things to look forward to on Perseverance. I don’t know if I can pick a favorite, but what about you?

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