NASA's Robotic Lunar Lander - Smarter Every Day 252

hey it's me destin welcome back to smarter every day in a previous episode of smarter every day we started a deep dive series into how to land on the moon by going back in history to find out how we train the apollo astronauts to actually pilot the spacecraft down to the surface of the moon on the lunar landing mission we talked about the challenges of maneuvering a spacecraft in the 1 6g environment on the surface of the moon versus here on earth which is at 1g although it doesn't seem like a big deal this difference in the gravitational pull of earth versus moon creates all different kinds of strange control problems for the spacecraft to get used to this astronauts trained at several different facilities such as the lunar lander research facility and ultimately the pilots of the apollo program said their best training method they had at their disposal was the lltv or the lunar landing training vehicle so when neil armstrong was descending to land on the lunar surface he was running an algorithm in his head that he developed as a result of flying the lunar lander test vehicle that's interesting but think about this if you had to do the whole thing again today with today's technology would you do that would you put humans on a lander system like this and make them fly or let me propose something else what if you were to create a robotic test vehicle that you could load different software loads on there and you could practice landing that thing over and over if you had a way of simulating lunar gravity on earth i asked that because that's exactly what my buddy logan did he works at nasa what was this program called again it's called the mighty eagle program the mighty eagle okay and my understanding is it was just trying to get ready to land on the moon right yep this was a program in the early 2010s where we used small robotic landers like this to test out algorithms and sensors we would use on a lunar mission got it and there was a crawl walk run strategy to the mighty eagle as i recall right yes so what was the crawl phase so the very first part was a lander called the cold gas test article and that was designed and built in just nine months and it used compressed air to get about 10 seconds of flight time and we used that to got over 100 flights and we used that to test out and learn how to fly a vehicle and then it was very successful what was it like the first time seeing that thing fly loud did it freak you out a little bit uh yeah a little bit was it cool though very cool okay so once you start popping these thrusters and it's a blow down system right once you start hovering that thing you're starting to develop the control algorithm right okay so from there that was successful and awesome fast forward and you took me to the mighty eagle right this was the walk phase so what's different about mighty eagle so instead of compressed air mighty eagle used 90 hydrogen peroxide as fuel in these two tanks here and with peroxide you just flow that over a catalyst bed and you get thrust out of it okay the cool thing about peroxide is that it is a green fuel meaning it's good for the environment and safety officers don't freak out when you spill it everywhere right if you just dilute it with enough water you can just pour it in the ground it's not hydrazine or anything toxic or dangerous okay cool so the magic of youtube allows us to go back in time and the way we're going to do that is through this time machine otherwise known as a hard drive because in 2013 you actually invited me out to a mighty eagle test we've never published this footage um it sports you in a super sweet beard and mustache it was pretty amazing i'm gonna be honest amazing as one word yeah i'm sure your wife's gonna love this so the point here is you were doing the walk phase what is the purpose of the test that we're about to watch from way back in the day so whenever we change something on the vehicle or try to try something new we would always start with a tether test and so it was attached to the ground from below and it would be a very short test and if we were successful with that test we would remove the tethers and do a free flight after that okay so let's go back in time to 2013 and let's watch a mighty eagle test and i will let logan with the facial hair explain how exactly we take out five 6 of earth's gravity in order to actually simulate lunar gravity during this test all right this is it this is called the mighty eagle and this is basically a lander test bed you can load different types of software onto it and test your software before you're actually working with the real hardware but we're on earth's gravity so how do we how do we take that into account this test of the mighty eagle test vehicle is occurring at marshall space flight center located at redstone arsenal alabama okay they've got it out of the trailer now now we have to get it over to the pad that's where we're gonna actually launch the thing so we have to get over there safely without damaging anything which is another routine in itself so kevin you got three lifting points some of these red tags are this is where lift points are all the way around so how much does it weigh about 450 pounds empty 700 pounds when it's full that's a lot yeah so the propellant mass fraction that's pretty yeah that's crazy it's a third all right logan what are you doing hooking up the tethers yeah i want this thing to fly away so put a tether right there on the foot pad and we bolt it to the ground we got these really cool energy releasing things called soft stops if you like jump off a building it'll uh it has a bunch of stone uh nylon it's like a dampener it's like a dampener yeah so in case it does pull on it which it's never done before in case it does it'll take out a lot of energy and then it'll hit this uh steel cable at the end basically if if this if this cable ever gets tight then that's going to input information into the motion control that it's not expecting and it's just going to go haywire it's not good if you pull the tether it's not good so we don't want to go crazy and so we got these uh this really nice tether system to hold it down okay let me explain this this is a robotic test bed that's a lander basically and it's used to test software right logan that's correct all right so this is my understanding is this is a mono prop blow down system right that's correct that is correct all right so is this our i'm assuming this is our nitrogen up top here's our nitrogen so we got two basically scuba tanks up here they end up about about 3000 psi during flight okay and then that goes through a regulator that regulates it down to about 700 800 psi so this is just what we call our pressure rent pressure okay gotcha and our propellant is in here that's 90 hydrogen peroxide so what's the difference in this this hydrogen peroxide and what you have at home that you have at home is three percent pure this is 90 percent pure gotcha yeah this will blow you up right it'll melt your face anything organic okay gotcha so do we have a bladder in here no it's just a uh it's a metal liner and it's carbon fiber over wrapped and then carbon fiber and peroxide don't get along so that's why we have these wraps on top of them to prevent so we just have i think that the gas inside of a of a pressure tank like this is called uledge i believe yep and so that olage is that just on top of the liquid and there's no interface there there's no piston or anything no piston it's just it's just the nitrogen pushing on the peroxide gotcha okay simple real lightweight and so we got the peroxide in here today we're going to have about 42 kilograms in there our max max load is about 116 kilograms wow so it's a pretty uh not a full flight because we're only doing a short flight so it's a light load light load yeah and you push the peroxide out of the tanks it goes under the deck and it comes out the thrusters man i noticed you had some diy water over here is that what that was yeah now what was that for [Music] crackers for fleshing out our uh [Music] so you have to you have to use pure water to mess around with the h202 so you don't flash right got it all right show me what we got here so under here our big thruster here we call the egc the earth gravity canceling thruster when we originally designed this lander we wanted to simulate lunar gravity and the lunar gravity is one-sixth of the earth's gravity so we have this thruster that throttles and it continually offsets five six of the vehicle's weight so the vehicle weighs 600 pounds it's thrusting at 500 pounds so the vehicle thinks it only weighs 100. gotcha and so that's straight through the center of gravity of the vehicle as best as we can get it yep okay now that makes sense so if you wanted to swap up and instead of landing on the moon you wanted to land on mars you could just change how much thrust you've got through the egc or the earth gravity canceling thruster that makes sense we're just blowing hydrogen peroxide down through what so we have a catalyst bed it's not a nozzle it's not just pure nozzle it has a catalyst catalyst yeah peroxide doesn't get along with a lot of things and one of the things it really doesn't get along with is silver so inside each of our thrusters here's one right here this is a thruster this is a thruster here this is one of our descent thrusters we have a catalyst pack that's got silver and nickel screens overlapping it's about this much like up in there up in here yep okay and so when you blow hydrogen peroxide across that screen it reacts it reacts it decomposes rapidly and you get pressure and temperature and we put that out at the nozzle here and you get thrust okay so it's like steam it's basically steam it's it's water and oxygen yeah so basically the point of using this is it's a green propellant right yeah that's awesome if you dilute it enough you can just dump it in the ground so how do you like if that's if that's just holding it you know basically we're simulating lunar gravity by taking 5 6 of the earth's gravity away how do we translate and rotate now obviously you have to have thrusters away from the center of gravity right that's what these are yeah so we have three different classes of thrusters we have the earth gravity canceling thruster under the middle uh-huh we have three what we call descent thrusters that are here and they're responsible for the ascent and decent vehicle two there are three of them yep okay that's actually what does the lifting that's that's right that's right so the the egc throttles but these here are called pulse thrusters they're bang bang they're either on or off okay and so the vehicles they're hovering you'll see them pulsing on and off to go send or their pulse less to go down so it's like yeah they're a little bit slower they're like okay you go up and down got it all right and then with the other class of thrusters are these right here these are called the acs or attitude control system thrusters yep they're about 10 pounds of thrust and they're responsible for the orientation of the vehicle we have 12 of them we have four that makes sense that they're far away from the center of gravity right the more torque the more you control yeah and we have four that point down on the bottom deck yep one of them there's another one yep we got four that point up yeah on the top deck and we got four that point laterally for roll control gotcha the ones that point laterally so you got you got two pointing in this direction and you have two pointing in that direction right so we with that we can rotate and the other ones are responsible for pitching y'all gotcha so give me your coordinate system here so this is x right x is up yep plus y is we call the battery side so it's right there they're the batteries and then z would be coming to me this way through this leg right hand rule okay got it awesome so i understand the main ones on the bottom there's you said there's three or four of these there's three that's what's picking you up and letting you down this is what's spinning you and this is attitude control thruster here but what's the inner ear so like that that tells you you know that that's the ability to move but this has to have an inner ear to see where it's at right so that's our imu our inertial measurement unit and that's this right here it's got accelerometers and gyroscopes in it we got one for each axis x y and z so it can sense the acceleration and the movement of the vehicle so if we move like this it knows it and it sends a command to right our vehicle gotcha so this is the inner ear of the vehicle correct so this is the inner ear and these are the ways this this is the thresher that helps you go up and down this is the attitude control thruster so all these are controlled independently correct cool the uh the throttle for the edc is over here yeah now look at that and it's the only thruster that's variable right correct the rest of them are all bang bang they're all pulse thrusters you have the the fuel running through here it goes down the actual throttle is in there and then we actually use a smart motor here for like an animatronics like a dinosaur to control the throttle here what do you mean a dinosaur you know dinosaur those animatronic dinosaurs oh gotcha gotcha i see it's just a little smart motor from that and uh you can see the throttle would move from here to here these are our two limit switches here's all the way closed here's all the way open i see that's the only thing that moves on the vehicle and so so how much gravity you're taking away depends on where this this uh actuator is and that's the valve right there so the further back this way the more open the valve is and the more thrust you get the more thrust you get got it so the more gravity you're taking away and so further that way you go the more close the valve is so that's more more of earth's gravity that the vehicle will see and the vehicle knows how much fuel it's burning and so it adjusts the throttle based on that how does it know that does it have a flow meter in there or something it knows it has an approximation for how much fuel is used every time you turn a thruster on yeah and it knows how many times it's actually used the thruster oh so the vehicle has to because you're burning fuel the vehicle has to adjust its algorithm exactly during the flight yeah it can't be a constant thrust that has to start off more thrust and as we use more fuel you throttle less and less nice so let me run you through it let me see if you explained it to me well so i have the egc the earth cancel or the earth gravity canceling thruster straight in the middle and then i have these which are what lift me and lower me there's three of them what are they called descent thrusters descent thrusters okay and then i have up here this is how i control my roll around the x-axis i've got one here one here one there one there's a total of four and then i have these which are attitude control thrusters i have four there pointing up and i also have four pointing down which are right here correct is that right and the idea is to get those as far away from the center of gravity of the vehicle as possible so you can induce more roll and translation more torque well i guess not translation just the torque yeah like you say all right so what's the deal today we're gonna go how high off the ground point eight meters so it's not going to be super high it's not gonna be super high we got a new control system on here so we have it tethered to the ground which you can see here and uh we're gonna see what happens all right so we're not actually gonna we're not actually gonna jerk it like a leash though are we no we're those are there just in case something goes wrong if everything goes right they should just extend a little bit and they shouldn't pull on any of the tethers if you pull a tether that'd be a bad day because that that gives you more inputs into the the control algorithm what was it you're the guidance and control guy what'd you call it oh it introduced an attitude disturbance into the introducing an attitude disturbance i have to do that with my kids every once in a while introduce an attitude disturbance once the vehicle was positioned and ready for test we got ready by going to the block house which is a concrete area where everything would be controlled from the countdown to flight is a long structured coordination between different team members for example there are technicians out on the pad fueling up the vehicle and getting everything ready for flight but inside the block house you've got engineers who are carefully monitoring every aspect of the system getting everything ready to go this process is scripted down to every minute detail which is carefully choreographed such as the safe and arm keys which are put into the arm box also you have to make sure everyone around the facility knows what's about to take place this is nasa lunarlander we are getting the airspace with t-minus one hour for flight okay this is the final check before they do the launch all right go no goes dad daddy's good man go ls go red crew attention all personnel the wgta pet has been evacuated and the time is x minus three minutes after the test only the designated crew returned to the firing site all right install completion plug and enable has a ground system is 744. okay issue command psn requested state to preflight copy going to pre-play dsm paper stage is free flight the system is pressurizing very good i'm called about three times n2 tanks are at 2100 pop tanks are at 500 and rising pump tanks are at 760 and holding prop iso is open source of speed press reading 750 pressures and tips look good [Music] okay vehicle has landed yes vehicles okay cool so tethered test works that thing was just hovering but i mean that wasn't like incredibly impressive right we went up and we went down what did you learn in doing that so for that test we knew that the the new software load or the new hardware that we were on the vehicle was was safe and so we knew we could go on to the more complex hazard avoidance testing okay and i didn't actually go to that test but i heard about it and i saw the footage so what is this test that we're about to watch here so uh hazard avoidance is hard uh you know that neil armstrong had to avoid some some hazards and craters when he landed on apollo 11. but if you do that robotically you would need something very small and very lightweight to do that and so we had a low low swap sensor so size weight and power and we built a very uh specific custom terrain field we shipped a very specific volcanic ash from a crater from all the way from arizona all the way to marshall and we flew over that field which had craters and boulders in it and it used that that on board sensor to to avoid hazards um the sensor was just two cameras so just like with your eyes you can see three dimensions this camera could see three dimensions and it would fly over the field and find a safe place to land what was the maximum altitude you got with my eagle about 50 meters now for that for this test was about 30 meters but 50 meters is what we did for something that's hundreds of pounds that's pretty serious it was fun that's pretty legit okay sweet so this is the test of the hazard avoidance system is open showing 719 verb sequence we are still green and we have temperature increase on all three thrusters [Music] gtb is aligning or a countdown holding vehicles translating while descending vehicle should be exiting the lunar field vehicle should be landing vehicles declared landed set ground station limits free post test limits so the mighty eagle was awesome the question is was it successful absolutely why so we tested the algorithms and the sensors that we would use on a lunar mission and more importantly we developed that sub subject matter expertise that we just haven't had for a while we haven't soft flooded anything on the moon in since the 70s and since we're going back to the moon today uh all the same people that worked on the mighty eagle and on all the other landers that were going on at the time and since then all still work in the lunar business so it's like a scientific flywheel you have to spin up like everybody that did the landers to begin with they were tired but now you've got new engineers and scientists that have to understand all the physics involved with landing softly on a surface that's amazing and so that was the whole point yep but my understanding is that's not the only program like this there was also morpheus that was developed at johnson space center right tested where uh started at johnson and then did their big flights at kennedy so how was morpheus which was a different lander system different than mighty eagle um they they didn't have an earth gravity canceling thruster uh they had different propellant they had different uh sensors that they were testing same general concept but theirs was more applicable to a human lander and ours was more applicable to robotic landing got it but that flywheel is still getting spun up that's all lander expertise all lander people yep so are you guys all working together now or what's going on yeah so since 2013 when these tests were happening uh all the teams kind of congealed together and we've worked on a number of landers and lander technology since then up until today this is rolling into artemis in some way right right what is the new component of artemis that does this sort of stuff right so artemis is the program to go back to the moon and the lander part is called the human landing system or hls and you're actually a part of that team i am and we're not going to talk about that right now because that's a bridge too far for this video okay i got logan out of the room because i want to say something that has nothing to do with nasa this is destin talking not nasa nothing like that okay here's my question if we now have the ability to load software on a lander and test that software out and over and over we'll get to test it should we do that should that be how we quote train to land on the moon or should we do what happened in the 60s with a lunar lander test vehicle i can say this if you think about like flight test engineering if you have ever heard of cooper harper that's a measure of how difficult it is to perform a task back in the day when you had the apollo astronauts flying the lltv it was a pretty complicated thing to do they were task saturated at any moment right but now we have improved sas stability augmentation control systems i think it would be easier for us to do a lot of the landing with software however i don't think we should if you think about it at some point if you don't trust the software you need a human to be able to like say no we're not doing that we're gonna do what i'm doing because i'm making decisions real time i'm in the seat so when she's landing on the moon this artemis astronaut whoever she is as she's descending i think that that pilot needs to have experience in the seat they need to have stick time flying a lander down to the surface of the moon in 1 6 g 1.625 meters per second squared and i don't know i just feel pretty strongly about this i feel like this is something that needs to happen which is why i'm excited that i found something on the internet nasa put out an rfi a request for information about how to build a new lunar lander test vehicle we have different technology now maybe we could do something like this with drones and propellers instead of just a jet engine i i don't know but i know we need a way to simulate landing a vehicle in a 1 6g environment because the angles change everything changes the beauty of having a software test bed like the mighty eagle or morpheus is that you can prove out your control algorithms before you get the humans in the loop and yes it might be great to hopefully have a system that's cooper harper one it's so simple that you can just land by pushing a button but at the same time you do have to have the ability to human override if stuff goes sideways i love solving problems like this a software testbed that will ultimately augment a human decision in a very real-time up-tempo environment i think there's a place for software landers i also think there's a place for human-controlled landers i just wanted to create this video to open up the question about what the future ll tv should look like because we're going back to the moon and it's time to start building the thing would you like to see a sneak peek of an upcoming video of smarter every day i think i i'm really excited about it i'll tell you that much so here's the deal i'm going to tell you about the sponsor and then i'm going to show you what's behind you the camera here the sponsor for this episode of smarter every day is kiwi co and kiwi co is amazing in fact kiwi co did not advertise on youtube to my knowledge before i reached out and i was like can i please work with you on smarter every day because i love what you do and the first video i ever did that on way back in the day my kids were like little i love kiwico and you will too it's a subscription box they send kits to your house with everything needed to do a fascinating like brain journey for your children every single time it never fails to please at the sandlin house you will love it to show kiwico that you came from smarter every day please consider going to kiwico.com smarter50 that gets you 50 off the first month you can choose from a variety of different kits and it doesn't matter what country you live in they deliver now to over 40 different countries check it out these things are amazing the other day sat down two kiwico boxes and just waited within minutes my son started building the planetarium and my 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watching smarter every day i am grateful i'm extra special grateful to everyone who supports smarter every day on patreon it's a really big deal and i'm thankful so thank you to the sponsor cubico kiwico.com smarter50 thank you to the patrons and thank you for you for watching this whole thing thank you to you for watching this whole thing you know what i'm trying to say anyway i'm destin you're getting smarter every day have a good one [Music] bye

Channel: SmarterEveryDay

Views: 1,016,665

Rating: 4.9463305 out of 5

Keywords: Smarter, Every, Day, Science, Physics, Destin, Sandlin, Education, Math, Smarter Every Day, experiment, nature, demonstration, slow, motion, slow motion, education, math, science, science education, what is science, Physics of, projects, experiments, science projects, aerospace engineering, control systems, rockets

Id: aw8kRZEvh_s

Length: 27min 16sec (1636 seconds)

Published: Sun Mar 07 2021

Reddit Comments

[u/TheXypris]

I just saw that today and thought the exact same thing

[u/Ruscfox]

https://soundcloud.com/user-356605017-81519030/nasa-moon-lander

[u/justjoeisfine]

Both. Robotic or human testing gives a solution, but together, you have a redundant landing system. That reduces risk for a critical mission like a soft moon landing.

[u/N1N74]

It's a hype bgm which ensures that the lander is feeling pumped to get it done

[u/dagdrommer94]

Could be a dope Rammstein intro. :D