Mars Exploration: Curiosity and Beyond - with Anita Sengupta

[Music] thank you for the introduction thank you for coming tonight it's a real pleasure to be here I want to talk to you about some of the fascinating engineering challenges that we've faced in the development of the curiosity mission so here by a show of hands who knows what the curiosity mission is okay good good studying ahead of time and the picture that you see here on the initial slide is actually a selfie that curiosity took of itself on the surface of Mars and people ask what how can it do that it has many different cameras and also has a arm which can go around and piece together the pictures and take a 360 degree of view just like we could do here by taking a picture of you the other thing which is of interest is that you can see the surface of Mars right here and you can see several different craters on the surface of Mars and we landed curiosity in one of those craters a crater known as Gale Crater so I'll talk a little bit about the challenges of landing on Mars and the challenge is specific to the element that I worked on which was the supersonic parachute we have some demos and materials to show you as well in terms of giving you a little bit of background about myself I've actually originally found the United Kingdom I was born in Glasgow I have no accent now because I've moved to New York when I was a small child but I spent I guess the first two to three years of my life here in the United Kingdom and then moved to the United States which is where I did all my education on my schooling and whirring out currently work in terms of my story another British aspect is that when I was growing up as a child in New York I watched an amazing science-fiction program on public television known as Doctor Who and ever since a small child since the age of six I watched these reruns and my doctor was Tom Baker actually and I was so fascinated by this alien who actually had the ability to solve all problems by using his brain right using his willpower his brain his compassion and his humanity even though he wasn't human and so growing up I felt as though that was a wonderful influence for me and I actually expired to be able to be something like him which was a scientist a engineer a brilliant person being able to solve the challenges and that's kind of what motivated my instruments in engineering and in space exploration so that's kind of an interesting aside and I'm still a huge dr. fan Doctor Who fan today and I attend conventions in the United States on the topic but I always knew I wanted to be involved in the space program and so what I selected was to be an aerospace engineer and so I studied aerospace engineering for my undergraduate degree and then I continued to do aerospace engineering for my masters and my PhD and I did that out in California and over the course of my career so far I've worked for NASA for around 15 years I've been able to work on a variety of different projects the very first one was developing something called ion engine technology or plasma propulsion so my background actually is rocket science that was also something I wanted to do growing up and so we developed engines which are now powering the dawn spacecraft so if any of you are familiar with dawn there's three very high precision low thrust but high efficiency engines which have taken our spacecraft from Earth to the main asteroid belt I'm looking at two very unique asteroid elects one Vesta one series after I worked on the development of ion engines for several years I decided to do something completely different I was asked if I wanted to work on the next mission to Mars which was the Mars Science Laboratory Curiosity mission and I thought wanted to develop the supersonic parachute and to me that was an opportunity I couldn't refuse how could you not want to work on a mission to another planet so I did that for about five years and that was successful and then I decided to move on to a different challenge which is my current challenge which is developing a scientific facility for the International Space Station which is gonna launch in just under one year actually and so that's my career path and what's so amazing about engineering for the students in the audience or for the parents with students is that with engineering you can kind of do whatever you want you take the tools of math and science and create new technologies to solve the world's problems and in most cases advanced humanity so that's the reason why I think engineering is a wonderful profession it's a wonderful degree for anyone to obtain even if you choose to do something different beyond that so that's a big plug for the field of engineering whichever one that may be but what I wanted to start off tonight is to talk about how it was so difficult for us to be able to land a rover basically the size of a small car on the surface of Mars which is billions of miles away and so obviously I'm a little bit biased since I worked on it but it was probably one of the most fascinating engineering feats the past couple of decades and so we've been successfully driving the rover around on the surface for the past almost four years now collecting science data I'll talk a little bit more about the rover mission in terms of what its science is and what it's collected to date but I wanted to focus a little bit more about the entry descent landing second and also why is it that we explore Mars and so the obvious question to ask is why are we interested in Mars and the picture that you can see behind you is obviously earth is on the left and Mars is on the right and they look incredibly different from each other but what's fascinating is that when the solar system first formed planetary scientists actually believe that Earth and Mars were very similar to each other both in terms of having a thick atmosphere and also having water on the surface but over time the two planets have evolved very differently from each other where earth still has a very thick atmosphere the you know it's almost three-quarters covered in ocean whereas Mars it's very dry dusty a very thin atmosphere and no appreciable water on the surface so why is it that these two planets evolved so differently from each other and also by comparison venus which is one planet in from us which also has a very similar initial composition in size to earth is completely different venus on the other hand is around four hundred and seventy degrees C on the surface and has 100 atmospheres of pressure on the surface so on one hand one planet in you have you know essentially what is like the inside of a self-cleaning oven and one planet out you have something we couldn't survive on and so the way we can understand how the planets evolved is actually by sending spacecraft their spacecraft to orbit around the planet and then also spacecraft that deposit Landers and Rovers to explore and make scientific measurements of the surface and so that's the reason why we explore Mars from a scientific purpose but the second reason of course is that at some point in humanity's future we're going to want to live on somewhere other than Earth and Mars is actually a relatively nice place so we want to be able to learn as much as we can relative to other places in the solar system but we want to be able to learn as much as we can about the planet from a scientific perspective so we can understand what the properties are in the surface what the composition is like can we possibly access water what the radiation environment is like but we also have to develop the engineering technologies to be able to lend a human-sized payload on the surface of the planet as well as technologies to be able to survive on the surface of the planet so those are the two reasons why we explore Mars but first I'll test some of your knowledge of as would we one day live on Mars so who thinks that the day on Mars is shorter than the Dan earth by show hands longer slightly longer yes you're right so it's a little bit longer it's 24 point 6 hours which means from a human circadian rhythms perspective it wouldn't be that challenging to be able to acclimate yourself to a slightly longer day and actually our engineers at the Jet Propulsion Laboratory who operated the rover do just that they're always shifting their time in terms of going from 24 to 24 point 6 hours in terms of what their operational shift is on the ground now in terms of gravity who thinks the gravity on Mars is higher than on earth if I show hands lower it is lower it's about 1/3 the gravity of Earth and the reason for that is that the planetary body itself is much smaller therefore the gravitational force the gravitational attraction acceleration is much lighter so even though 1/3 G isn't good for a human body to be able to deal with it's still much better than zero-g that for example we have on the International Space Station so from a human physiology perspective it's also relatively more sustainable for us to be on Mars versus on our moon which is even smaller with 1/8 G or in basically essentially in freefall it from the International Space Station in the vacuum of space now from a temperature perspective the temperature on Mars although it is cold especially in the night time in the you know polar latitude regions in the wintertime it actually does get relatively warm 5 degrees C is actually a very common California winter for example so from a temperature perspective it's also much better to be on Mars than in the vacuum of space or on our moon so for these reasons actually it's not a bad planetary body to think of for future colonization of human beings for example now the big problem with Mars of course is that the atmosphere is very thin it's only about 1% of what the atmosphere is here on the surface of the earth which means that if we do live there one day we would have to be in a pressurized environment or pressurized suits for the surface of a planet and then of course the atmosphere is not made out of air which is primarily a mixture of nitrogen and oxygen but it's made out of co2 and we can't breathe co2 so if we do in the future go to Mars we would have to either come up with a way to turn co2 into oxygen by spitting it up or bringing our own oxygen supply with us but in terms of a future destination for these reasons Mara is feasible it is practical and it's also the closest planet to us so then the challenge becomes being able to land something on the surface and be able to survive on the surface for extended periods of time I think they wanted me to take questions at the end but I'll take your one question now so go ahead it's a really good idea and that is like a terraforming approach so if you're able to bring bacteria with your plants which hook in the co2 and created Oh - that would be a way to actually self create your own atmosphere so that's a great idea and so that's something which would be a type of terraforming that you could do but that's actually a fantastic idea so if I go to the next slide however is thinking back to the geological history on Mars Mars actually had a very very ancient geological past and the picture that you see on the upper right Olympus Mons is an extinct volcano it's actually the largest volcano in the solar system so who thinks it's um twice as high as Mount Everest three times as high it's actually yes three times as high as Mount Everest and the reason for that is because at some point in the planet's past it did have a lot of volcanism but now that volcanism appears to have stopped or doesn't appear to be present and we don't really understand why perhaps that's correlated to the reason why the magnetic field was lost why the atmosphere is lost we don't know and so we send spacecraft to make measurements to be able to answer that question and that's actually one of the primary reasons for the insight mission which is launching in 2018 which is actually going to carry onboard a seismometer to make measurements of Mars quakes if there are any still portent another fascinating feature is the picture that you see on the lower left which is Valles Marineris it's actually a scar that goes across the center of the planet and we like to talk to it as being Mars's version of the Grand Canyon and it's an impressive impressive feature it's actually roughly six times as deep as the Grand Canyon so what this means that at some point in the past there were appreciable water flows on the surface but now they're gone and we don't know why was the water completely lost was it stripped away and taken off into space or is it still frozen in the subsurface or in the polar regions of the planet and the way we can answer those questions is once again by making measurements on the surface of the planet which we have been doing so who thinks that Mars has moons by our show hands Mars actually has two moons it has fobos and damos and the reason why they look so strange and sort of potato-shaped is because they're relatively small and they haven't compressed into a spherical basically structure under their own gravitational force so they're probably captured asteroid embodies that currently orbits the planet Mars but one potential architecture or use of these moons is to use them as a telecommunications relay point right where you actually set up satellite dish you could think of on the surface of these moons so that people or Rovers on the surface would communicate to a constant telecommunication source on these moons which then communicates back to earth that's another way of doing it that's a potential architecture that you could use and we also think there may be materials that we could mine from these moons whether it be minerals that are useful tool to us for construction or even water for future surface missions but another important scientific finding is related to water on Mars so I kind of gave it away but we have found water on Mars here's an example of some of the water that we found this is actually a picture taken underneath the Phoenix lander which was landed in the mid 2000s and that white region that you see there which was exposed as the Phoenix lander was coming in to land its engines were pluming towards the ground kicking up all the dust in the soil and exposing this white region beneath and what this actually is as salt water ice so it's like a brine so we know that closer to the polar regions there actually is a lot of frozen subsurface water and this is another picture that you can see that's been taken from orbit with our Mars Reconnaissance orbiters so we do know that there is actually water there which is important because that means future human colonies could use it for drinking washing growing plants that type of thing so now who thinks that there's actually water flowing on the surface of Mars today you're right so this picture that you see here are pictures of water which is actually seeping out of the cliff faces on Mars because Mars is rotated on its axis as the planet goes around the Sun it heats up and it cools down so if there are frozen subsurface aquifers they can melt and then seep out and that's we see here is seasonal flows coming off the sides of these cliff faces and we've seen them again and again and again using high-resolution imaging from the Mars Reconnaissance Orbiter which is a spacecraft which is in constant orbit around Mars and takes high-resolution images so this once again is a really important finding because it means that there is water it means that there is water accessible if we were to need it for you know future human needs and it means that there could be stuff in that water but until we actually are able to go sample it and take a look at it we won't know so that's another potential future mission where we would take a rover and have it access one of these sites so we could make compositional measurements of what's actually in that water so the big challenge however for almost any mission that wants to land on another planet with an atmosphere is developing the technologies to be able to get yourself safely from exo-atmospheric all the way down to the ground and so landing on Mars actually has been a huge challenge it's only been done seven times successfully to date the very first one was the Viking landers in the late 1970s and you can imagine what an amazing engineering feat that was right we didn't really have sophisticated computers at that point in time we also had very little knowledge of the Martian atmosphere it was done again in the late 1990s with the Pathfinder Rover which was kind of a resurrection of the Mars program between the seventies and the 90s it was done again in the early 2000s for the Spirit and Opportunity rover Opportunity rover is still driving actually to this very day so that was an amazing engineering feat to have something that could last for so long and the Phoenix lander which was a landed platform as opposed to a rover Curiosity in August of 2012 and then we have two missions coming up there's the European ExoMars mission which is actually launching in October of this year so I hope you guys are all familiar with that landed technology and then the insight mission which is going to lend to make measurements of Mars quakes in 2018 and then of course an interesting aside is that the Beagle mission although it was lost what initially came in for its landing in the early 2000s we later found it so we did find evidence of where it landed on the surface it means that their entry descent and landing technology suite did actually work just unfortunately I think the solar panels weren't able to deploy I wasn't able to communicate so if they weren't able to do science with it but that was an important finding for the European Space Agency that that was successful and these are some of the images taken this was of the Viking landers on the surface of Mars this is Sojourner and this is the spirit an opportunity Mars exploration Rovers and I think what I like to say about these images is how eerily similar they actually are to earth so even though it's another planet it's another world away there are so many similarities between what we have here on earth and what we have here on Mars of course however Mars doesn't have an atmosphere so if I don't think it should motivate is to take better care of our own planet so we don't go out of the path that particular planet has gone but in terms of how do we do it so in all engineering feats we tend to build on our prior experiences which are called our lessons learned and we turn to improve our technologies from mission to the next mission to the next mission and so what you can see here is the very first Rover which was the Sojourner Rover which was about the size of a Tonka truck which is a child's toy and then we moved to a slightly larger version which I would say was the size of a lawnmower which was the Spirit and Opportunity rover and then most recently we moved to the size of something the size of a golf cart or a small car and the reason why we've increased the size of the roads as simple if you were going to move your house from one house to the next house would you do it on the back of your bicycle or would you do it on the back of a truck you would do it on the back of a truck because a truck allows you to have a bigger wheelbase you can carry more equipment and you can also traverse more complicated terrain so as we increase the size of the Rover we increase the capability in the size of the scientific payload and we increase our ability to drive over more typical terrain which may be more interesting from a science perspective as that's the reason why we've increased the rover size again and again not just because Americans like to drive big cars it's not it but but then I always like to give people a reference example of how big the Curiosity rover is for scale so you can see here relative to the police box so it is actually quite large but unfortunately it probably can't fit in sideways so it's not going to go in the TARDIS any time soon disappointments but but it is pretty amazing how we can increase these technologies and each time we do it we get better at landing the system at driving the system at communicating with it and then getting even more and more science data so what is the purpose of the Mars Science Laboratory mission what is the purpose of the Curiosity rover so it's actually to assess prior past present habitability of the surface so it doesn't actually look for life but does it it looks for weather the building blocks of life the environment for life either existed in the past or currently exists on the surface of Mars and we do that by making several scientific measurements but I'll talk about a little bit more but we're trying to assess the biological potential we're trying to assess sort of the geochemistry of the planet how did things form today all from volcanic Li or do they also form in the presence of water and then we're also trying to assess what the surface radiation environment is because one of the most difficult things for organics as far as we understand organics is their susceptibility to radiation and so we know that radiation in space is quite bad we know their radiation in deep space is very very bad so what is the radiation like on the surface of Mars so we've never actually made that measurement until this particular Rover and so that's really important to understanding you know is it so harsh that everything should have been destroyed based off of our current knowledge of organics DNA and radiation interaction or is it not so bad that number one maybe things can survive there and also how much shielding do we have to bring with us to be able to support people living on the surface of the planet so probably the two biggest challenging things to send people to Mars is one developing the technologies to learn something so large and to being able to survive in whatever the radiation environment has to be so those are both technology challenges but you need to have the data to understand what your requirements are to derive the technology to be able to facilitate it so those are the reasons why we've put the specific suite of instruments that we have on the back of the Curiosity rover which is essentially a robotic geologist so then the next question becomes you're gonna send this Rover where are you gonna send it you have to actually pick a landing site and the way you pick a landing site is a combination of can I actually land there and where do I want to land and so what we do is we work with the science community the Mars atmospheric science community and the Mars geological science community and they hash it around they've argued for probably about two to three years as to the best site to go to and they finally down selected on Gale Crater and the reason why they selected Gale Crater is because they believe these from orbital images of it that it probably was the site of an ancient water body whether it be a dried-up lakebed dried-up you know riverbed but they actually thought that and we're better to look for evidence of past life than in the base of a water body where sedimentary rock layers would form and you could see the history over time so that's the reason why we selected Gale crater from a science perspective our challenge then was to ensure that the engineering system could land there accurately and from a scale perspective this crater geometry we would have to land somewhere between this mountain in the middle and between the crater edge on the side because if you didn't you would either smack into the crater wall or smack into the mountain and then there would be no mission moving forward but also for reference this is kind of like a Mercator projection of Mars so MSL landed in Gale Crater Mars Exploration Rover B is currently over here in Meridiani it's a very large difference between these two things so unfortunately they'll never be able to drive to meet each other I have been asked that question before so they'll forever be a part but if you've seen the Martian people have seen the Martian here I seem the movie you can utilize those parts for a future human mission so I was able to guess within two pages of that book that that was what they were going to do but well we can have a discussion about that later if you're interested so this is Gale Crater so this is the home of curiosity now and this is the landing site that we selected what you see here is sort of a black ellipse and what this black ellipses is something called our landing ellipse this basically we've designed a system that we could land in a area which was 20 kilometers long by 7 kilometers wide and that happens to be very tricky when you're trying to learn into space which is basically so this is what I'm using for reference so this is the distance between London Heathrow and central London is roughly around 20 kilometers so we have to have the ability to have a precision so that we knew we could land in that area all the way from Earth going out to Mars and so that drive the design of our engineering systems because if you didn't you have Mount sharp here which would be game over and you have the edge of the crater wall here which would also be gained over and that we also knew that we wanted to be able to drive to the lower reaches of Mount sharp because we could see from orbit that's where we had some interesting rock layers that we wanted to be able to interrogate it but because of the uncertainties in the atmosphere because of the uncertainties in a whole variety of engineering parameters you can only get yourself you can't get yourself to a pinpoint location you can only get yourself to this kind of ellipsoid location so we did our best effort to be able to drive down or drive up the accuracy of that so another way of viewing that is a bull's-eye and so what you can see on this outer ring here is the landing ellipse size for the 1976 Viking mission 174 miles we had to go from 174 miles all the way down to 12 miles apologies for going between English and metric units so that's where the challenge was was improving the accuracy of our landing system to be able to land in that very small space thereby facilitating having access to Gale Crater because if you had a landing ellipse the size of Viking you wouldn't know whether you would land here or over here on landing day so that wouldn't work for you so that was essentially the challenge associated with it so I wanted to talk through through a little bit of this video so this is the entry descent landing sequence landing up through a planetary atmosphere utilizes the atmosphere to produce aerodynamic drag so you come in at 13,000 miles an hour you decelerate roughly from 13,000 miles an hour to around 1,000 miles an hour on a heat shield you then decelerate from 1,000 miles an hour to around 250 miles an hour on a parachute then you actually can't go any slower on the parachute you've hit terminal velocity and so at that point you actually cut the parachute away and you just send the rest of the way slowing yourself down using retro rockets firing towards the ground that's the way you dissipate the energy and we have a total of eight retro rockets actually going towards the ground when we were around sixty feet above the surface we started to lower the rover on a tether this is called the sky crane maneuver and we can talk about the might be good for question answer session if you want to know why we chose to do certain things that we did but we primarily do it to increase the distance between those retro rockets and the surface of Mars because they end up kicking up a lot of dust and sand you'll see that in a moment it also allows the rover to be the landed platform so instead of carrying an air bag which you have to carry all the way down to the surface you just touch down your wheels and you're ready to go so what makes Mars actually nice more landing perspective is that you don't have to carry as much propellant with you because you can actually use the atmosphere to slow you down so anyone has put their arm out that side of the car when you're going down a motorway and you feel the force on your arm that's aerodynamic drag so we use that principle to slow ourselves down to take out roughly 99% of the energy coming in the rest does have to be taken out using retro rockets but the atmosphere does help you in that sense the problem however is that you know when you rub your hands together they get very warm you may get warm because of friction we also experience friction with the atmosphere and that for the atmosphere would make anything burn up so we used a technology called a heat shield to absorb that energy so the rover inside of it doesn't heat up and doesn't get damaged so that's the traditional architecture between how you land in a planetary atmosphere so this is a two dimensional view of that entry descent and landing sequence and so it does start out here at hypersonic speeds 13,000 miles an hour roughly gets you down to supersonic speeds which is Mach 2 you then deploy the parachute going from Mach 2 which is around a thousand miles an hour down to around two hundred and fifty miles an hour and then we switch over to the power descent sequence and and through all this we have to manage our speed manage our location manage our altitude and we have to know that and we don't fly this back from Earth because the time delay between Earth and Mars is roughly 14 minutes in the worst case scenario so this is all done autonomously by the spacecraft by having knowledge of what the atmospheric properties are and then making measurements using an accelerometer to tell us tell them tell it basically what it's velocity is and then going through a sequence associated with that so this is the overall architecture and it's broken up into different phases and so I'll talk a little bit more about the parachute phase just because you know that's what I worked on for several years so what is a parachute and why do we parachute use parachutes on Mars so what a parachute is is basically a textile device and if I could have is there are there any kids in the audience could the kids come down I just need two or three people he could help me hold it so you can show everybody what it's like so what a parachute is is it's incredibly lightweight but it's very very strong see if we can go out front here so you can kind of show it for everybody so you can hold this end and then you can hold this end and then I'll pull it and you can hold the end in the middle here and then we can kind of open it up together and so what you can see here is it weighs almost nothing it occupies almost no space it generates a lot of aerodynamic drag and so the parachute that we used for MSL was 21 and a half meters in diameter so that's 60 feet in diameter it's huge as you can see from the picture there the size of the people the size of the parachute and the reason why the parachute has to be so big if the atmosphere is so thin which means a bigger drag area so you can slow yourself down and the reason why we like a lightweight device is because when you go into space you usually don't have a lot of mass available to you right you're otherwise we're more mass more propellant so you want something which is as light as possible and so you can see you should touch it here and see how thin it is right it weighs almost nothing and least to the touch and the same thing with these lines which are called the suspension lines they're also very thin and they don't weigh that much and so that's the primary reason why we use it because it's basically using the atmosphere for free and and we use modern materials which allow things to be incredibly strong versus you know more ancient materials like if you had a middle parachute or something you wouldn't get much benefit from it so that's what it is and then also because it's so thin you can pack it into really tiny spaces and so when we pack these parachutes they actually approach the density of wood so that gives you an idea of how tightly we can tack them how little space they actually occupying the vehicle yeah when they open up they open up to fill a room probably about six times the size of this so this is a scaled version of a parachute this isn't the full-sized version for MSL but it does have a very similar design and the way you also note here is that there's an opening here so this is called a gap this region at the top here is called the disc and this is called the band and so the reason why we have a very specific parachute design is because of the aerodynamic environment that we found ourself in it's actually a supersonic aerodynamic environment and it gets really unstable and the way you control sort of the stability and the flow is by having this gap here which kind of allows the the atmosphere to flow through it so it doesn't collapse too much but I'll show you the discs on fire so I think that I think I put this back and then I'll let you touch to this other thing since you're down here so the other thing that is important is by having really strong materials and so one of the strongest materials in terms of lightweight materials that we know about is Kevlar so you can touch this one too so Kevlar is a very special material it's a poly aramid fiber and it has an incredibly strong strength to weight ratio so this kevlar cord that you see here you can basically hold thousands of pounds off of the end of it and it won't break because they're engineered materials so one of the neatest things about engineering is that you're able to develop these amazing lightweight incredibly strong materials and of course kevlar is the same material which is used in bulletproof vests so that gives you an idea at how strong it is but this is more in a textile sense so that you can sew it and you can work with it but I think we can we can play pass it around to the audience that's I think that's kind of what it wants you thank you for coming down and I'll give you stickers later for coming out [Laughter] south pass it around so you guys can see what it feels like thank you and so that's essentially why we use a parachute and so the scale of the MSL Parrish you can see here it's incredibly large I took sort of an international regulation football field and you basically fit a total six of these MSL Parrish unit that's how big it actually is so then the question becomes well how do I design the parachute and test the parachute to make sure that it survives on Mars before I get there and we actually do a lot of testing that was one of the reasons why I took the job because I love testing out in the field and this was our very first successful test of the MSL parachute we actually put it on a helicopter we take it up to around 3,000 feet altitude and then we deploy it and this allows you to match the same load that the parachute sees in an earth-based test then it would see in a Mars environment the difference however is that the atmospheric pressure and density on earth is much higher which means that you don't have to take it up to as high in altitude on Mars the atmospheric density is much lower so you end up having to have it go faster match the insane aerodynamic load but the real challenge is that parachutes on Mars behave very differently and the reason for that is that they deploy in a supersonic low density environment so this is actually what it looks like when a parachute on Mars deploys it's very very different so you see how it collapses and inflates and collapses and inflates it actually starts to get a tear in it so this is an example of a test that was done probably in the 1970s I think it was and they were able to take this parachute up to around 150,000 feet altitude on earth attach a rocket to it to get it up to Mach 2 and then deploy it to be able to experience the exact same conditions that it would see on earth as on Mars it happens to be very expensive to do these kinds of tests so we weren't able to do that for MSL so the space program budgets have gone down over the years so what that means is that we can't just test everything how we would like to test it we end up having to come up with much smarter more cost-efficient ways of doing it so what we decided to do was use our knowledge of fundamental physics aerodynamics and computer simulations to be able to understand how's this parachute going to perform on Mars how are we gonna make sure that it's strong enough and so we first started off with a computer simulation and so this is something called computational fluid dynamics where we represent the flow field around the vehicle so the MSL vehicle is basically here and it's sort of trailing behind it as the parachute and so what you see in front of this is a bow shock this is because we're in supersonic flow and so we generated a simulation to understand how the flow field of this entry vehicle would affect the parachute and then what would the pressure distribution be like how much load would experience but when you do a computer simulation the simulation is only as good as if it's correct right and so just by doing a simulation isn't enough you have to validate your simulation so what we did to validate the simulation is by building little subscale parachutes and so we've got one demo coming up but I'll show you an example of a subscale parachute so this is actually something we developed for the human space program but you can get an idea that this is roughly this size parachute is roughly 3% of the size of the full-scale parachute so if you build an identical model in terms of geometric shape you should get similar aerodynamic performance you can then put this model parachute in a wind tunnel at the appropriate condition see there's actually wind tunnels where you control the density we can control that pressure we control the atmosphere you control the speed and so what we did was we built little subscale parachutes put them in the correct aerodynamic environment see how they behaved made measurements of them in terms of the total load on them and then compare it to simulations to validate the simulations and so we do have one as Andy my colleague is up there he's actually Annie Cowley is I would say Britain's foremost parachute expert and he has come to help me with a demo so this is an example of what the parachute looks like when it's deflating yeah well done Andy and so what you can see here is a sub scale D GB so this is very similar to the one that we tested for the Mars Science Laboratory mission so it's a little bit smaller than this one this is roughly three percent scale of the full parachute and what we did was we put this in a wind tunnel and so we in the wind tunnel you have the vehicle this is kind of like the MSL vehicle rigidly mounted and then you're basically flowing air through the wind tunnel and so it's flying as it would in actual flight and then you're also making measurements of how much load does it experience is it collapsing inflating like we had seen before and I'll show you some of those measurements but it's amazing how much you can figure out by doing sophisticated computer simulations and then validating them by excellent experimentation and that's kind of what this institution is about right like experimentalist Michael Faraday that's what he did we did experiments and then you figured out how things worked based off of those experiments and that continues to the present day and just about every field of science and engineering that you can find and so this is an example of the wind tunnel measurement that we did this little parachute flying B's video that you can see actually has been slowed down so you can see it so this whole cycle that you see looping actually happened in the order of milliseconds so it happens incredibly fast the eye can't see it but we can use high-speed imaging so we can see what's going on and you see the little dots on the outside of the parachute this is basically a motion capture technique so we're taking many many images of this video we're capturing them on sub millisecond intervals and then were reconstructing the motion of the parachute using image processing basically after the fact to determine what the parachute shape is like as well as making a measurement of what the parachute load is and so this is how we can provide that same data set but that's super expensive high altitude test provided but at a much lower cost in a much shorter time scale so you can actually repeat measurements like change the speed change a whole variety of parameters you can learn even more and in terms of the fundamental physics of what's going on we also used a technique called Liron to take a look at what's going on in the supersonic flow field and so the computer simulation I showed you before you could see the bow shock moving back and forth this technique allows you to see density contours in the air in the wind tunnel and so you can see the bow shop is moving forward it's collapsing it's moving forward and it's collapsing so this is the physics behind what happens to parachutes in supersonic flow and so we validated the physics of what was happening we validated our simulations and then we were able to design our parachute to be strong enough perform well enough so we could send it to Mars and so even though we did full-scale tests to do scratched role testing we also did little sub scale tests to verify how it would actually perform that difficult dangerous supersonic environment and we were successful and of course we didn't land on Mars so it did work and I do like to show this picture because sadly and one of the reasons why I do a lot of these lectures you know basically around the world and oftentimes mainly to students is because we do need diversity and the engineering science fields and this is an example of where there is insufficient diversity and sadly aerospace engineering Electrical Engineering is pretty underrepresented from a female perspective so I would encourage you to talk to your daughters your sisters to get involved in engineering because it's a great job the STEM fields are kind of amazing they pay you really well they're intellectually stimulating and I would like to work with more women although I love my male colleagues as well but but it is important because and I do like to say this is that you know if if all you had was a carbon copy of everybody like everybody was a you know I guess clones of each other you would come up with one idea right so you have to have diversity in the workplace to have a diversity of solutions you can come up with a better product at the end of the day so it's really important whether it's ethnic diversity you know religious diversity men versus women different countries those different backgrounds that you come from allow you to come up with a different way of solving problems which is and we work together actually a very diverse team in that sense for the overall entry descent landing sequence and I think that's really important so just to drive that point home so I wanted to talk a little bit about curiosity in terms of the Rovers you can see here curiosity is the size of a small car curiosity does also have a difference between the prior Rovers the prior Rovers used solar panels for power curiosity uses an RTG it said radioisotope thermoelectric generators it uses the decay of plutonium 238 the heat associated with that and converts it into electrical energy and so what that means is that you have constant power not just power when the Sun is pointing on you that allows you to operate over longer period the day it allows you to operate in places you know further away from the equator it allows you to do more science basically that's the reason why we selected that particular technology so that was different from this Rover to the next Rover and the curiosity of course had a very sophisticated mobility system that you can see down here which allows it to traverse over rocks up to 1/2 meter in size without tipping over or without having any problems whatsoever so once again that big wheel base is that big capability to take you to really interesting places so the rover is a robotic geologist and any geologist wants to be able to see as well as touch things and so the rover does have eyes it actually has a whole series of cameras some of those cameras are actually used for navigation for hazard avoidance so we do not drive the rover or the joystick we give it a set of commands and tell it we want you to go there today it has to do that safely and it does that by collecting images with its cameras and doing you know sophisticated algorithms to make sure that it isn't gonna have a problem in terms of you know going into a dangerous location or or driving to an area that it couldn't drive so that's what some of the cameras are for and then others of the cameras are used to collect panoramic image of its surrounding as well as microscopic images of the rocks that it's analyzing for scientific purposes so one very important instrument is the Sam instrument sample analysis on Mars it's actually a mass spectrometer so mass spectrometer allows you to determine both elemental and molecular composition so this is how we're able to look for organics and organics of course are the building blocks of life and this is probably the most it's a very heavy instrument it's a very sophisticated instrument and it does allow you to make the determination of whether or not organics are present and then one of the ways that it does that and this may be only Americans will appreciate this but an easy-bake oven so it has a little oven that heats up samples and when the sample is heated up they release a certain spectroscopic signature which then you can associate with molecular composition elemental compositions and so this is probably our most sophisticated instrument on Mars and so we have another instrument which has a laser and that laser also it's called libs laser and do spectroscopy so what does a laser on Mars look like not quite I'll show you what it actually looks like but everybody loves that but this is a high-power laser right so if you were you know a astronaut on Mars you probably would not want to stand on the way because it burnt a whole spacesuit for example because you have to use this laser to vaporize rocks and when you vaporize the rocks they then generate this spectroscopic signature is basically a plasma which allows you to determine what the rock is made out of so we have two ways of doing it mass spectroscopy as well as laser-induced breakdown spectroscopy so if you were on Mars can you imagine not being able to touch anything that'd be terrible somebody wrapped her arms around your back so curiosity does have an arm the arm has many different purposes but it allows it to go and touch rocks because if I was if I put a tablecloth on top of this table would you know that it was made out of wood you wouldn't right you have to be able to remove the tablecloth to figure out what the table is actually made of so what the arm has at the end of it ISM thrush a brush a drill so it can actually interrogate the subsurface to determine what the composition is not just the surface layer which could be quite different because it could be deposited by winds and things like that so the arm is very important for making measurements of soil composition of things not just the surface but the subsurface material so moving forward we built the entry descent landing system we built the rover we package them inside of the aeroshell which is the vehicle which contains the rover which has the heat shield which allows it to withstand and the parachute packed inside there so who thinks it takes more than a year to get Mars less than a year yes it takes roughly nine months so it's the gestation period of a human baby or it's a school year for at least American kids maybe a little bit less than a school year for a British kids but it's not that long actually if you think about it right of course maybe for you the kids it seems like a long time but for adults it's not a long time and so we had and so we basically launched in November of 2011 got there about eight months later so in August of 2012 I was landing night and it was nighttime at Pacific time in Pasadena which is where we operate the rover from where the majority lot of the work was done we had a very unique opportunity this mission where we attached a camera to the underside of the rover so that during the landing event all the way from you know entry heatshield separation down to the ground we could actually see what was going on so that is the next video I will show you and this is kind of amazing it's the bird's eye view so what you're seeing is the heat shield falling away in the distance and the reason why we remove the heat shield when we can is because it reduces mass so then reduces the amount of fuel that you need to slow yourself down it also allows our radar to look down towards the ground so the radar is basically it sends an RF pulse out it gets back there's five beams it allows you to determine what your altitude is what your vertical velocity is much a horizontal velocity is and that information goes into a closed-loop algorithm to help fly the vehicle safely towards the ground so the other thing to notice is that you can see it's kind of rocking back and forth and the reason why it's rocking back and forth is because this is a rover hanging underneath the parachute so if anyone has skydive tier you know that you don't just fall straight down you kind of move around a little bit so that that actually shows you what the dynamics under the parachute is and you can see here these darken regions are probably ancient volcanic deposits user some impact craters on the ground these are all craters within the Gale Crater so at this point we're just looking at Gale Crater coming down and then what you'll see in a few moments is that the rocking has stopped now it seems to be moving to the side that's because it has been from the parachute has been cut off it's now under those retro rockets and the retro rockets can actually be fired differently from each other to vary your thrust and vary your trajectory so what you're seeing here is you're getting closer and closer to the ground we're starting to get this interaction with the soil you can see it's actually getting kicked up and that's because those rocket engines are so strong this is the wheel falling into the view this is the start of skycrane maneuver and it's getting closer and closer to the ground now you can't really see the ground because there's so much interaction with the soil but at this point essentially we've landed so this data set got downlinked you know a couple of days after landing so we didn't get it right on land a night but when the rover had successfully land on the surface its primary job was to send to send us telemetry saying everything's good and an image of where it landed on the surface and you know we're all anchors here waiting for this image to come down and so this is the first image that we saw so this is the shadow of the Curiosity rover it looks like a transformer for anybody who likes transformers out there and then what you can see here in the distance is Mount sharp and so it's pretty amazing right so it's hurtled its way all the way from Earth to Mars and safely landed on the surface of Atlantis you can imagine we were all ecstatic that this happened and it went off as planned and here's another more colorful image of Mount sharp and this is also a better shot of sort of the striations that exist on the site of Mount sharp and what I'd like to show here is if anyone has been to you know the American desert near Nevada or you know anywhere like that and Arizona it looks just like Earth and I think that it's kind of mazing of course there's some error there so you wouldn't last long once you stuck your head out but but it does look like Earth and I think that's kind of an amazing thing that even though these are worlds apart from each other they have so much similarity to our own home and I would say our greatest fear of course was that everything would have won we would land safely on the surface but those tethers wouldn't get cut and then the rover would be like dragged across the surface of the planet that didn't happen obviously everything went as planned so we were rather ecstatic and so if you are an engineer you are most likely a nerd and you'll want to know how good your calculations were this red ellipse you see here it was our calculated landing ellipse like I mentioned before in this white box is basically where we landed so that means number one our calculations are great and it also means that we were on a so that means our our calculations of drag coefficient of that miss very properties were pretty much spot-on so that means to be Patterson also that could be a good job in addition to other things so now other thing to point out here is this is where we landed but this is where we wanted to go so we have several kilometers that we would have to drive in order to reach that eventual location which is our target location so and just so you know the rover moves about you know this is its top speed basically and that however doesn't compare anything to when the science community says nope stop there stop there stop there stop there so they make measurements so it takes a long time to be able to drive from point A to point B in this particular case and you can if you want to ask me questions why we drive so slow there's actually a reason for it but nevertheless we landed where we wanted to land and then we started our traverse towards the final location making science measurements along the way but as you can imagine after learning that we had a wonderful party I think we were all out until 6 o'clock the next morning and we're dancing and singing and stuff like that and then we got this picture on our smartphones and what this picture is is a picture taken by the Mars Reconnaissance Orbiter it was actually positioned into place to capture the parachute and the rover descending on Mars and of course this made me incredibly happy so this is basically a picture of the descent on Mars what you can see here is the parachute is nicely inflated there's no apparent holes in it and of course this is the backshell which has the rover underneath it so we've never been able to take an image like this before so it was pretty awesome right that we have enough assets around Mars that we can take pictures of our landings so for PR purposes just kidding it's got engineering purposes too so now if you were to buy a car what's the first thing you're gonna do before you actually buy you're gonna go to test-drive right so the very first thing we did with the rover after landing wasn't start the science mission but you have to do a test drive make sure all the systems are working well so you can see we drove it around rover back and forth and I always like to point this out you see this tread on the tires here this actually says JPL and Morse code so it was our way of getting our signature there because when there's an alien race in the future who goes to Mars we go look JPL was there they may not know what it is might be long gone by then but anyway that was our way of and it actually has a secondary purpose which is a solution so by knowing the exact geometry and when you take images you can use that as a calibration target basically but it also said learning I love this picture and so this picture is what a dried-up riverbed on earth looks like the one on the left is where we landed on Mars and so I'm not a geologist but when geologists do look at these images by looking at how the rocks are formed together and how they're sort of worn on one side they're able to confirm that they were actually formed in the presence of water we have several other scientific measurements that cooperated but what we do know is that that Curiosity rover landed in the base of an ancient water body which was about knee-deep so in the past in the ancient past obviously the water is not knee-deep now but just put yourself into that mindset about where curiosity is driving around that there actually was sort of lake on Mars there which is which is pretty exciting I think now we have had some very important findings over the course of the past several years of driving around this is another example of what the surface features look like we found the presence of phyllosilicates which can only form in the presence of water and we've also confirmed that the soil is actually neutral in terms of its alkalinity which means it's not basic it's not acidic and that's very important from a formation of organics perspective life forms perspective because our existing experience on Earth suggests that neutral soil is much better for supporting life than acidic soil which makes sense right but that's an important finding because other places that we visited on Mars have been acidic so this is a location because of its water body nature where it was not acidic so that was a pretty important finding so some more things that the rover did it scoop the soil so what you can see here is it uses the scoop to collect samples that it then puts inside the instrument into the Eva bake oven and gets it to work and then we did a lot of using of our laser our libs instrument and as you know that's obvious right curiosity go figure now I am a cat person so I don't mean to be heartless but it is very funny and it had to happen ok so but so now what does the laser really do it's not as impressive as that as killing a cat that's not impressive so this is what it does so if you ever if you were on Twitter after Lana you heard people with a hashtag pew pew pew and a few saw they're not that was the libs instrument going so when it does it burns a hole in a rock so this is the before after before after Luke and when it burns the hole in the rock it vaporizes the rock it generates a spectroscopic signature that you can see here and so each one of these lines is associated with a particular wavelength and we know that that's actually a fingerprint for iron magnesium silicon so this is sort of a elemental fingerprint for what the composition is of the soil on Mars that we analyzed so it's a very sophisticated but very robust way of determining what the composition is and of course you have to have a weather station curiosity also has a weather station and so it has the ability to measure winds pressure and temperature and so the interesting theory here of course is this is you know the diurnal variation right so it gets colder at night warmer during the day colder night Warner during the day so you can see the correlation between temperature changes solar changes as well as pressure changes and that's also a very pretty looking picture I think so this is another important measurement you won't make much of this hash but now we do have Mars surface radiation measurement it's not as bad as we thought it was going to be it's still obviously is good for human beings but now we have an ability to know what we have to attenuate if we are to send people on the surface it also gives us a better idea of what earth-based analog life-forms could survive with that kind of surface radiation level and the other thing to note is that having an atmosphere actually serves to attenuate radiation so we can they see variations in this radiation signal which actually correlate with the surface temperature because the pressure or the density the atmosphere is changing during the psych course of the day so this gives us a ton of information which we have never had before and then another really important measurement is of organics and so we did have confirmation of methane on Mars and so methane is really important that's an organic it can only come from one of two sources either geological or biological so geological coming out of the rocks volcanic processes and biological would be you know cows produce methane in their gut which is bacteria so that's why we don't know until you have to make a more sophisticated measurement to get you an idea of whether or not it's biological or geological nature so that we don't know but having found it there is really important because methane has a very short lifetime which means it had to have been produced relatively recently meaning in the in the past less than million years so that's actually a pretty significant finding so now of course there is no car wash on Mars so what that means is poor Curiosity has dust everywhere underneath its belly pan and then on its wheels and another interesting aside from this though is that just like you would you want to change the your tires for your car unfortunately we can't so our wheels have one shot at it and they are experiencing some wear as a result of going over these big rocks which is to be expected over time but there is no tire changing station no triple-a out there so is there intelligent on Mars I would argue that there is right so we have curiosity who's quite intelligent and then we're behind curiosity in terms of telling it what to study next and I think that's kind of exciting so I've got one video I wanted to show you which is a compilation of all of the images that curiosity took over the course of the first year so that's the very first image and so you can see how busy it is right every day all it does is work collecting scientific information and there you can see it using its arm and it's just kind of amazing because it really is a geologist but it's a robot ecology biologist and of course we're driving it as opposed to you know a person actually being there but from our perspective it actually is very similar to us actually being there so it's super exciting and I own every go over the fact that looks like a transformer so just sharing that with you so what is in the future to the future is actually bright we want to send human beings to Mars hopefully within our lifetimes and we need to enable the exploration of other worlds and going to Mars will do debts that would be the first stepping stone sort of for Humanity out into the stars beyond low-earth orbit so in terms of the future we would need to be able to live on the surface we have to develop the technologies to land on the surface we have to develop a rocket which will launch off at the surface we have to develop habitation modules where we can survive the radiation environment have the ability to maintain a pressurized environment for many many years so what I would like to point out though is Freddie the young people in the audience the future is basically what you would be doing as engineers and scientists and mathematicians if you want to go into the aerospace fields because this really is the push right so up into this point in time it has been sending robots to Mars and we're going to continue to do that continue to collect more scientific data but what is going to happen in the future is sending people there and then all of the technology that gets developed is all done by engineers whether it's aerospace engineers electrical engineers chemical engineers computer scientists those are the people who do the work to make this happen so that's why it's super exciting so that's my plug to you so would you want to live on Mars these are some you know artist conceptions of what it might look like and and I think it is a thing a real thing of the future and it's really just a matter of time in a matter of money and ingenuity for us to get there and I think the last thing I want to say is who's the future of space exploration you really are and so what I like to do is go and talk to students so I have my students that I teach at USC and then I talk to students in the local community I talk to students everywhere to kind of motivate you do the same because this is a super fun job it's incredibly exciting really nothing does compare to it there isn't a day you go to work where you're not challenged excited sometimes it's scary is some things things go wrong but you're the person who's there to fix it right so that's kind of important so that's my motivation and to help you study and so in terms of what's over the next horizon we don't really know but we do know that there's several more Mars missions plans so that's for sure and also to point out and of course this is not a u.s. audience but curiosity took over 3,000 people scientists and engineers to design it to build it to test it to operate it 12 countries were involved that either contributed instruments or science investigations all of the images that we take are returned to earth almost immediately available for everyone to look at in a really interesting because people know about is that that finding of water flowing on Mars was in October of 2015 he was actually discovered by his and Georgia Tech so these images which we make available any scientist any student can analyze and make it a part of the research program so and yeah because it's our Rover that's kind of how we like to say it so I am happy to take questions for the remainder of the talk I think we have 30 minutes thanks [Applause]

Channel: The Royal Institution

Views: 52,068

Keywords: Ri, Royal Institution, curiosity rover, mars exploration, space exploration, lecture, science lecture, anita sengupta

Id: KvFKo2ifuVU

Length: 55min 40sec (3340 seconds)

Published: Wed Nov 08 2017