Transcript
20vUNgRdB4o • How this helicopter survived 1004 days on Mars, then disappeared...
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Kind: captions Language: en 427 days into what should have been a 30-day Mission and it's turned into a nightmare on the surface of Mars 297 million km away is ingenuity a tiny 680 G helicopter it's made from off-the-shelf Parts you'd find at home it's got bits from an Android smartphone batteries from a cordless drill and to everyone's surprise it's been performing well so far but something is wrong see the Martian winter is coming at night temperatures plummet to a frigid 85° c as Mars gets further away from the Sun the temperature keeps dropping and it kicks up more and more violent dust the Sun is blotted from the sky on her 427th day on Mars they try to reach her just like the day before but they get no response they try again nothing back on Earth the team gathers at the jet propulsion laboratory in Southern California all the signs point to Ingenuity being dead but there is still one thing one final trick they can try to reestablish a connection the first drone that's going to fly on another planet 6 years ago I visited JPL and saw Ingenuity before she left for Mars at the time NASA didn't really believe much in her Mission as Kenneth Farley the project scientist to the Mars 2020 perseverance Mission said I've personally been opposed to it spending 30 days working on a technology demonstration does not further the goals directly from the science point of view in short they thought it was a waste of time most projects to Mars get billions of dollars Ingenuity got only 80 million Which is less than the budget of the movie The Martian but this Scrappy team of scientists were working to prove a crazy concept and against the odds they made it to Mars on February 18th 2021 the perseverance Rover survives entry and lands on the Martian surface attached underneath is ingenuity this marks Saul zero her first day on Mars they sever the umbilical cord and Ingenuity affectionately known as jinny by some on the team prepares herself her mission is simple prove that flight on the red planet is possible but with an atmosphere just 1% that of Earth flying is really difficult she must be ultra light and her blades must spin at over 2,400 rotations per minute to generate enough lift it's a design that no one is really sure about for 2 months they rigorously check her systems running up the engine testing navigation and her control computer then on Saul 58 they finally think they're ready the blades spin up and she takes off only 120 years after the Wright brothers on Earth Humanity flies on another planet within days they fly again and then again and again in just one month they complete five flights so the mission has been accomplished we were a tick demo right meaning a specified narrow 30A Mission um get in get out we're done right we go to a bar and party and that should be the end of it but with success comes new expectations NASA tells them to keep going Ingenuity new mission is to assist perseverance in the search for evidence of ancient Life on Mars so she will Scout ahead Gathering data in areas too risky or costly for the Rover to explore for the team this is great news but it's also a problem there was no guarantee at you know after flight 5 we may be dead by flight 7 right we may be dead by flight 10 we were kind of thrown into the deep end of the pool we had no processes or no plans developed for such a thing until now every flight had been carefully planned they've all started from an area selected and analyzed by both satellites and the perseverance Rover itself these flights were tested hundreds of times in jpl's wind tunnel and tens of thousands of times in simulation but now now that they have to keep up with the Rover they're flying into the unknown now flying the helicopter isn't easy at its closest Mars is 56 million km from Earth which means there's at least a 6-minute roundtrip Communications time delay which is way longer than Ingenuity 2minute maximum flight time so she has to fly autonomously so what happens is the pilot programs in a route and jinny does the rest but to start JPL first needs to know exactly where she's located you might think that they would use GPS but for GPS to work on Earth you need at least 24 satellites for full coverage and around Mars there are only seven satellites total so Ingenuity can't use this method so instead what she does is far simpler we have two cameras a forward facing 13 megapixel camera and then the one pointing down is the one that we used to navigate the navigation camera takes 30 black and white images per second inu's computer analyzes the image and identifies features on the surface you can think of it sort of like an optical Mouse like your Optical Mouse is on the mouse pad it doesn't know where on the mouse pad it is but when you move to the right it knows you move to the right because what it's doing is it's looking at features on the surface of the mouse pad and watching them move under its field of Pew so Ingenuity is essentially doing the same thing it's looking at the surface it's picking out features like rocks and other things and between camera images is it says oh this rock moved this way this thing over here moved this way and from that you can compute a transform to say my helicopter was here and now it's here relative to the image now this sounds good but the method isn't 100% reliable on flight six the first time she leaves her testing area Ingenuity detects an error 54 seconds into the flight she starts wobbling wildly tilting 20° at a time her emergency alarms blare [Applause] we had black and white image black and white image black and white image and we had a color image come very closely to where that black and white image occurred in time this color camera was added late in development leaving little time for testing and during this flight one of the images arrives at the exact same moment as a black and white image the system doesn't know what to do so it drops the black and white image this makes every following image one step behind this means Ingenuity cameras are giving her outdated information so even when she's in the right spot the computer thinks she's lagging behind and pushes her forward so she overshoots tilts too far and then has to overcorrect in the other direction this cycle repeats making her wobble worse in a positive feedback loop now that is a problem but it isn't fatal the desyncing issue was like one camera frame off if it had been more than that I I think you could imagine that it might have death spiral instead Jenny detects the problem and is able to emergency land before it gets too ugly while safely on the ground JPL discovers the error and quickly corrects it with a software patch it's a close call but they recover over the next dozen flights they keep up with the Rover and support the mission that is until Flight [Music] 19 we were about to fly that 19th flight and I got a phone call the afternoon before basically saying there's a a dust storm brewing uh near Jero crater so we quickly cancel the flight and so well we're just going to hunker down and and see what happens they brace for impact it lasts 6 days with winds gusting up to 20 m/ second that first dust storm in the middle of fall in the first first Martian year that we're on the surface it clobbered us but they make it through nervously they try to make contact and she survived she hasn't died or toppled over but now they have a new problem dust dust on Mars is no joke I mean for jinny there are two big problems first dust is covering her solar panels reducing Power by 18% and second it's clogging her mechanical components we went to go fly and when we went to wiggle the servos they were actually stuck they were kind of jammed from the dust so that aborted the first attempt at Flight 19 now GPL had anticipated both of these problems but they hadn't had the time or budget to fix them so for the first they just have to accept that they have reduced solar power and they adjust their flight durations accordingly for the second they find a workaround by repeatedly wiggling the servos until the joints clear so she's able to keep flying albe it wounded and survival isn't getting any easier see every Martian night the temperature drops precipitously my friend Alex from the channel astram describes it well with less atmosphere M became far worse at retaining heat when the Surface starts to cool there is no air to catch the escaping warmth it is at the point where if you were to stand on the planet's equator during its warmest time of the day your feet might feel 23 de C while at your head it would be 0° C this means between day and night Ma has some intense temperature swings temperatures there now range from highs of around 27° C down to a freezing - 133° c at night if you want to learn more more about how this leads to entire planet covering dust storms astram has a whole video on the Martian climate so these massive shifts in temperature are happening all the time but as jinny's Mission progresses Mars gets farther away from the Sun and enters the Martian winter so it gets even colder at night which is a problem many of inu's key electrical components are hands soldered and big temperature swings cause expansion and contraction of this metal and so that can eventually break these connections also inside the batteries a liquid electrolyte solution allows lithium ions to move between the cathode and anode during charging and discharging but if this solution freezes JPL fears that the whole thing will stop working entirely so what they do is keep all the components sensitive to the cold inside a warm box which has resistance heaters that run during the night you might spend 25 or 30% of your battery flying and the other you know 60 to 75% is all just staying warm at night the problem is the colder it gets the harder the heaters have to work and if they can't keep up and the batteries cool too much they become less efficient so they Supply even less power to the heaters performance can continue to degrade in a vicious death spiral on the morning of May 3rd the team at JPL goes about a normal day they check the data from the previous downlink nothing they try pinging Ingenuity still nothing have they finally lost her did we just lose our our $70 million helicopter on Mars is this the end of the mission we thought this was it so let's just make sure before we close the door on Ingenuity we've thought of everything we just keep working through it they run through all the possible problems until they narrow it down to just one the way she was designed jinny has an alarm clock that wakes her up it stays awake for 15 minutes if it doesn't hear anything after 15 minutes it goes back to sleep and it doesn't wake up until the next alarm their hypothesis is this if the lack of sunlight forced Jenny to fully deplete her batteries then during the night her heaters would have stopped and she would have powered off completely when the Sun rises as long as her essential components still function she may recharge enough to wake up only now now her clock will have reset so they run the calculations if she's still alive based on when the sun comes up she should be waking up at 11:45 a.m. Martian time that is not the time they had been trying so they change their search window and start calling out to Jenny around when they expect her to power up they send out ping after ping until finally she's alive [Music] they check to see whether everything is still working and despite the components in her warm box only being rated to 45° they survived being completely Frozen well all except for one the inclinometer is dead the inclinometer is what lets Ingenuity know her physical orientation in 3D space before flight and that is pretty essential for getting the right heading you could imagine if you're off and heading by 10° you could fly into a mountain without the inclinometer there is no way for her to fly so at first the whole team is stumped but then they have an idea because Ingenuity is made of phone parts literally parts from phones people carry around every day her processor is from a Samsung Galaxy S5 and some of her sensors are from a Google pixel 3 and these phones can do a lot of the things that an inclinometer can do inside every smartphone are at least three little Micro electromechanical Systems aligned perpendicular to each other like x y z at their core is a small Mass suspended by flexible arms they work like Springs and follow hooks law FAL minus KX where force is proportional to displacement the mass also follows Newton's Second Law FAL ma a if you combine these equations you get a = - KX over M which links acceleration and displacement surrounding the mass are fixed arms when a voltage is applied to the mass and arms they form a capacitor where Epsilon and a stay constant but as the mass moves the distance between them changes with X this Alters the capacitance which becomes more noticeable with multiple plates hence why they have so many little Arms by measuring capacitance you can determine displacement and since displacement is proportional to acceleration changes in capacitance allow us to measure acceleration that's why these devices are called accelerometers and by integrating acceleration over time you can work out velocity and then position this is how motion tracking works for screen rotation gaming controls and step counting if you add gyroscopes you get an inertial measurement unit or IMU and Ingenuity has the same IMU as the Google pixel 3 so the team at JPL had an idea they could reprogram the computer to use the IMU to replace the inclinometer the in ometer is really just accelerometers that allows us to tell the initial attitude of the vehicle in Rolling pitch and the IMU also has accelerometers so in principle it gives you some information so from the clutches of failure they get her running again we got lucky in that like the one instrument we could afford to lose was the one that died but the IMU isn't space grade in fact none of these off-the-shelf parts are which means they're vulnerable to cosmic rays on Mars the thin atmosphere doesn't just make it harder to fly it also means cosmic rays reach the surface more easily and a single cosmic ray can strike a computer register and flip a bit inside the computer which can lead to some strange Behavior it even happens here on Earth it once added 4,096 unaccounted votes to a candidate in a Belgian election now on a martian helicopter flipping the wrong bit at the wrong time could mean losing control and crashing so why doesn't that happen if you asked somebody 10 years ago can you fly the latest cell phone processor they' be like no it'll last like 2 days and you'll be dead right it turns out that cosmic ray bit flips are not as big a deal as NASA thought the off-the-shelf components hold up way better than they expected and this is an important finding rather than going through all of the development cost of building up a processor from scratch to be radiation in tolerant or finding is you get a lot better bang for your buck by just going and basically buying batches of different processors and just quing them that means throw them through a radiation test campaign look at the failure rates you know and figuring out you hey this guy we don't know why but for whatever reason this processor over here is great it holds up so we'll fly that now using these surprisingly robust off-the-shelf Parts they survive the rest of the winter but they're only barely able to stay within the communication range of the Rover spring time came birds were chirping on Mars talk about spring optimism right like coming out of winter with the increased sunlight they can now fully recharge and return to their scientific Mission over the next 41 flights they image craters perseverance can't make it to they capture stunning images of the Martian Horizon from above they conduct daring aerodynamic tests and they begin to push the limits they want to fly faster but the faster they go the quicker features move across the camera's field of view and the vision navigation system just can't keep up with that so JPL comes up with a solution they fly higher then they can expand the field of view which means features will move more slowly through frame so from an initial goal of a 10 m altitude they go up to 24 M and as a result they're able to go from flying at 2 m/ second all the way up to 10 m/ second we set speed records distance records altitude records just everything we could think of to push that flight envelope on Ingenuity really make the most of this once in a-lifetime Opportunity of having a helicopter on Mars everything is going swimmingly jinny and perseverance have made it all the way to netv valis a river Delta in jezero Crater but on flight 71 there's a new problem and it's worse than any of the ones that came before now inu's only scientific payload is a camera so so she's taking hundreds of photos a day and sending them to JPL and she's not alone perseverance does the same including this selfie with Ingenuity honestly they're the most chronically online Duo on Mars we always know exactly where they are what they're up to and they're constantly sharing photos but really how different is that from us I mean we spend most of our Lives online constantly sharing data except in our case that data doesn't just sit in a NASA archive it gets bought sold and used in ways we're not always aware of that's why I've been using today's sponsor incog I created my account a year ago and since then they filed over 300 requests on my behalf resulting in my data being removed from over a 100 marketing and spam databases if I tried to do that myself it would have taken around 230 hours literally weeks of work that is time I can better spend making videos which I'm sure you appreciate so to try incognate visit incog docomo I'll put that link down in the description or you can scan this QR code and when you do make sure to use code veritasium to get 60% off your annual subscription so head over to incognit docomo and protect your online data today I want to thank incog for sponsoring this part of the video and now back to Ingenuity so we just had this one final thing to do we needed to cross this Sand Dune and make it to bright angel that RAB with the Rover so on 71 we basically went up we were flying and then after about 10 seconds of flying with degraded navigation we went into an emergency landing mode and sort of came down hard they hail Jenny and luckily she's still alive in the eror code they discover the problem as she was flying over the dunes there just weren't enough rocks or landmarks for her camera to identify and without those references she quick lost track of her position and had to make an emergency landing it's similar to the camera issue from flight 6 but this time there's no software fix they check for structural damage but surprisingly everything is still intact so they attempt another flight this time going straight up to scan the surroundings and then coming straight back down simple we popped up took pictures and then on the way back down we hit the same problems we did on W only this time it's fatal perseverance drives over and captures this image of her crash site when we saw the blades broken when we saw that first image after flight 72 that was heart-wrenching it was like no there's there's no way this mission is going to continue that was very depressing so why because 71 was also a crash landing for the same reason it was you know the nav system was confused and drove us into the ground but we came out of that apparently unscathed and yet on 72 we self-destructed this is the first air crash investigation on another planet right yeah that's right first aircraft on another planet and then the first uh air crash investigation on planet yeah they kind of go hand in hand at the crash site they find ingenuities blades scattered but not in the way they expect we noticed something interesting which is there was no blade strike spot blades spinning this fast when they hit the ground right they're going to create a spray there's going to be a pattern probably even visible from orbit and we didn't see anything like that so if the blades didn't strike the ground then what happened so this is an actual prototype blade from the development phase this is essentially identical to the blades on engineuity it's a carbon fiber composite with a foam core it's incredibly light if you want to feel it yeah whoa that's CRA that's like at least a quarter of what I expected just looking at it it doesn't feel physical so why did they break well as the blades spin the tips of the blades Trace out a circle which you can think of like a hula hoop if there's a force up on the near side you might expect the rotor to tilt immediately in this direction but that is not actually what happens see the blade isn't stationary it's moving really fast so when you apply this force it actually only moves after that point so the maximum displacement occurs 90° later so even though we push up on the near side the blades tilt up on the right and down on the left this effect is called procession and it's the same principle that explains this spinning bike wheel demonstration now Ingenuity has a second set of blades that are moving in the opposite direction which means that when a force is applied each set of blades experiences procession in the opposite direction for the helicopter overall these torqus cancel out but each individual blade still flexes because of that procession torque that results in a stress concentration right about here where that final reinforcement tapers off and so if you had a procession based failure you'd expect it to fail right here and sure enough that's exactly where you see it in the pictures you can see sort of this jaggy place where the blade tip just got ripped off so that is what happened on flight 72 as J came down hard she hit a dune at an angle the force was transmitted up through the body of the helicopter and this created A procession torque that bent the rotors and they snapped right where the reinforcement tapers down this thing came down hard it didn't it didn't destroy the landing gear it didn't break the avionics it didn't kill the servos the swash plates are all fine they're all intact it's the rotors that's the we link so that is the first thing they're changing on the next generation of Mars helicopter which is called Chopper you had a chance to hold the Ingenuity blade this is the is the next gen baby blade it looks fairly similar with a couple of key differences they reinforce the blades to withstand the torqus caused by hard Landings now they also have six rotors instead of two which means Chopper can hold a lot even carrying a scientific payload of its own we've developed now a very lightweight radio that can communicate directly to orbit W so we're a free bird when it comes to exploring that's huge you were sort of trying to Trail perseverance right and now you can go anywhere yep we're our own spacecraft in this blue box you can shove about 5 kg of science payload and bring it anywhere on the planet on Mars you can fly 3 km per sole in a matter of minutes that's really generated a lot of excitement in the science community so this is a fifth scale model of Chopper it's really two systems so this is our Chopper platform right this is what's going to go on and explore the the entire surface of Mars one day uh that's the point of the concept but underneath is a midair helicopter delivery platform see Mars rovers all need complex Sky cranes to land but a helicopter is different it just needs a platform to take off from so the idea is we come down uh through the atmosphere we have this jetp pack uh that we need to slow us down to get us down to a regime that is controllable so that we can take off from that platform midair and land under our own power for this it needs Rockets 3 2 one awesome you're envisioning like a future of Aviation all over Mars as a primary explorative capacity in my mind it's absolutely going to happen just a matter of time there there will be fleets flying you know throughout Mars there will be Airport on Mars one day uh and we'll have aircraft the size of Chopper more aircraft the size of Ingenuity and even bigger than Chopper NASA is thinking big thanks to Ingenuity a project they once doubted because jinny showed what is possible in 1890 you had said I'm going to fly it's like okay that kooky guy in his garage he thinks he can fly he's going to he's going to kill himself right after the right Brothers it's like oh okay yeah this is a thing that we're going to do and so that's the change in mentality that's occurred because of Ingenuity that's why still sitting there on the surface of Mars attached to the underside of Ingenuity is a tiny scrap 1 square cm of muslin fabric it was taken from the lower left wing of the first airplane the right flyer from the first flight on Earth to the first flight on another planet from inu's grave on Mars her spirit lives on [Music] except she isn't quite dead yet she's acting as a weather station now capturing photos every day capturing temperature measurements every day something no one would have ever predicted before flight 72 that if things don't go well we just still have a functioning spacecraft so she's a tank the team couldn't be more proud of what ingenuities accomplished