Humans On MARS - NASA Science Lecture

good morning welcome and welcome back to those of you who've been here throughout the series if you have been here throughout the series you have seen NASA's plans for the next 30 years or so and the question is do we have to kill you now the answer's no this is the civilian space program and and we work for you so so you've seen the plan and for the last two weeks you've actually seen the program that's underway today to build the transportation system to take people into deep space today and next week we're going to concentrate on two major problems that that are between us and being able to execute that plan you saw the first week of going to Mars with people and and Jeff Harith is here this morning to tell you about the problem of landing people on the surface of Mars and how we go from interplanetary speeds down to zero miles per hour safely and last week we talked about the rocket and how the rocket accelerates the people the astronauts and their cargo out of the gravity well that we live in this deep energy well that we live at the bottom of now that once the astronauts are in space it's very easy to move around okay only the only force you have to overcome there is inertia and but the problem is when you get to the next destination you've got to take all that energy the rocket put into you so now you're speeding along at 25,000 miles per hour and you got to slow down so now you're going down the well and you've got to do go down that slope that energy slopes safely and that's what you're going to hear about today as you know at this point in time we have ideas about how to do that but we we can't say we've got the solution in hand with that I'm going to turn it over to Jeff Aerith who is the product line lead at Langley for entry descent and landing good morning yes oh good morning everybody i'm jeff Harith I work here locally at NASA Langley Research Center and today I get to talk with you about Mars and the challenges of safely and affordably getting humans to the surface of Mars so first I want to start with an image does anybody see anything there that you recognize yell it out alright so you got the moon and if you can see a little bit further down there's this tiny little red dot that is what Mars looks like in our night sky from here at Earth and in fact you know from the earliest days when humans could first look at the skies they noticed this strange red light that moved a little differently than the other stars and so we've been looking at Mars and wondering about Mars for an awful long time and as we move forward we develop new technologies such as telescopes and we're able to look at and see Mars in a lot more detail and in fact over time if you look at the history of observing Mars you have people in the 1600s able to determine that Mars had polar icecaps you had also there's early observations they were able to determine the inclination of Mars or the tilt of its rotation and then you get into the 1800s and the late 1800s they could see more surface features and they determined that these were canals that were built by an intelligent species on a dying world and that was in 1894 this was this was the thinking at the time now of course now we know that that's not actually the case but Mars really is a very interesting place to study so Mars is the fourth rock from our Sun and is named after the Roman god of war Mars is half the diameter of Earth but twice the diameter of Earth's moon and in fact if you look at the land mass of Earth you know took out all the oceans it's about the same size as Mars and like Earth Mars has seasons it has polar ice caps as volcanoes has canyons as deserts and weather and some of the things on this start like I mentioned the inclination in that last slide Mars is inclination on its rotational axis is 25 degrees very similar to Earth's at 23 degrees its day the speed that it rotates at Earth were 24 hours at Mars it's only 240 minutes longer at 24 hours and 40 minutes now the gravity on Mars a lot less it's a smaller planet so if you weigh a hundred pounds here on earth you're gonna weigh 38 pounds on Mars which sounds really good to people like me yes so and the other thing as Mars is further away from from the Sun and so only about 44 percent of this of the energy that Sun energy solar energy that reaches earth reaches the surface of Mars and then next big thing would be its atmosphere it's got very little atmosphere compared to earth about one percent and the composition of that atmosphere is quite different about 95 percent of its atmosphere as carbon dioxide we're here on earth that's a very small percentage on earth we have a much higher percentage of nitrogen and oxygen that makes a far air now the average temperature of Mars is minus 64 degrees Fahrenheit so it's kind of chilly and but the ranges are if you go from night at negative 200 degrees Fahrenheit but then in the hottest days at the equator it can actually get up to 80 degrees Fahrenheit on the surface and as I mentioned Mars atmosphere is really thin in fact it's too thin for liquid water to survive on the surface it sublimates directly to a gas so but however several Mars missions have found evidence of past water in the Mars icy soil and in its thin clouds and we'll talk a little bit more about that so why Mars well Mars is the most earth-like of the planets in our solar system and so by studying these different areas we're looking at the history of the climate looking at its geology we're looking at whether life could have or ever did arise on Mars and then also evaluating it for the potential for human exploration so these are some of the key areas that were really interested in looking at Mars for there's one thing that ties all those together and that's water understanding the water on Mars and that is why when we and the Mars exploration program where we when we reinvigorated that in 1996 with the Mars Pathfinder mission the strategy has been to follow the water and understand the role of water and we've sent several missions there and in fact I'll show you a couple highlights of those here in just a minute and so the Mars exploration program is moving from follow the water in to looking for the signs of life and looking for the possibility of human exploration of Mars so a few highlights of our relatively recent explorations of Mars so if we go back to the Mars exploration Rovers these were the rover's Spirit and Opportunity they were sent there one of their main questions was the answer was there water on Mars and they definitely answered that Mars was once soaked in water in fact in this this slide when I'm showing here these are perchlorate salts that it found that can only form in the presence of liquid water and in fact these particular type were nicknamed blueberries just because of their shapes but the Mars exploration Rovers found seven different types of formations types of minerals that could only form in the presence of significant liquid water so then we move on to our Mars Reconnaissance Orbiter mission this particular mission had a ground-penetrating radar as well as a very high-resolution camera on it so what we're able to do with that ground-penetrating radar if you look at this is a global map of Mars and we're looking at the concentrations of h2o or water within the relative about one meter up to two meters within the surface of Mars and as you get as you go from the yellows into the blues and Indigo's it's more it's higher in higher water concentration and so what we prove with the Mars Reconnaissance Orbiter is that there is significant water on Mars particularly toward the polar regions but there is significant water what we didn't know is how that exists on Mars is it large chunks of ice under the surface is it actually could be lakes under the surface or is it just loosely distributed all through the soil or in different types of minerals so from our remote sensing we couldn't tell that we just knew that there was a significant amount of the out of the element h2o on underneath the surface and in fact the estimates are if you brought all of that water to the surface it would cover the surface of Mars about six feet deep the entire surface so it's a significant amount of water so what we did then as we took the Phoenix lander so now we knew there was water there but we didn't know as I mentioned what form it was in so we launched Phoenix and set that to Mars and landed it in the polar region and one of the things we noticed right away from one of the first images back right after landing this is underneath the lander you'll see that the landing rocket sort of cleared away an area and there's this nice shiny smooth surface there sorry for is that ice what is that you know so we took the the arm which has a shovel on the end of it out right beside the lander and dug just a couple inches in and so what you see here this white area is actually frozen carbon dioxide or dry ice now remember Mars has a lot of carbon dioxide so there is an awful lot of dry ice on Mars but what we also found which is hard to see in this bottom left corner it's blowing up there are these other little chunks and then within a few hours of that they actually disappeared so the water sublimated all right so we dug later brought those up into our ovens and our sensors and were able to prove that that was water ice rick very easy to get to within the surface of Mars so they're they're significant water of Mars it's it exists as ice within the soil as well potentially deeper down it could be liquid water we don't know that yet but there is significant water on Mars as I mentioned what's the next decade so we're moving from follow the water to looking for the signs of life and that's what our latest mission that you may have heard of our Science Laboratory is part of that transition with the Mars Science Laboratory we landed the Curiosity rover there about two years ago and it's beginning this work of looking for the signs of life now the most important discovery by curiosity so far is that ancient Mars did have environments that could have supported life if life had arisen on Mars their environments there as light light that life as we know it here on earth could have survived so it looked at the concentrations of carbon hydrogen nitrogen oxygen phosphorus and sulfur they're all there in the right concentrations they also found looked at the mineralogy and the Clay's that were formed in that area and found that there was significant freshwater actually not very salty water at all and in fact they believed if we had been there we could have dipped a cup in the water and drink it without any issue so Mars did have Hobart habitable environments we do not know to be clear we do not know if life ever arose or currently may exist on Mars but we do know that there used to be environments where it could have all right so curiosity is really the monster-truck of Rovers if you look here these are the other Rovers that we've sent to Mars our very first one here with Pathfinder and then the Mars exploration Rovers and then the Mars Science Laboratory at about one metric ton and that one metric ton represents the limits of our current entry descent and landing capability so this Rover is the biggest thing that we know currently how to put down on the surface of Mars and that's based on significant technology investments that were made in the 60s and the 70s leading up to the Viking missions in the Viking program there have been we humans have sent 40 missions to the surface of Mars from Earth many of those have failed it's a very hard place to go and in fact if you're keeping score we've had 16 successful missions versus 24 failures from Earth but since we're talking about landers today we've had seven successful Landers and we've had eight that have failed so let's start talking about what it takes first - how do we get to Mars now you all had a presentation on the Space Launch System I believe it was last week and so the first thing you need and we won't go into detail because you worry about that is a big rocket right and this is the SLS and it begins with a 70 metric ton capability and will grow to a hundred and thirty metric ton launch capability and so let's talk about a little bit about how to launch effects entry descent and landing so with your big rocket that leaves you have to package your payload up on the top of this rocket inside of a fairing now that fairing size is limited by what the rocket can launch and the aerodynamic loads that are going to be on it and its purpose is to protect your payload whatever we're wanting to send to Mars from the atmosphere of Earth as we're trying to push through it really quickly but the size of that fairing limits the size or the diameter of the vehicle that we can send to Mars and so why is that important entry descent and landing well the larger diameter vehicle that we can get to Mars the more drag we can create as we're trying to enter that atmosphere and slow down and therefore more mass we can get to the surface of Mars but right now with our current limitations as I mentioned before we're limited to about one metric ton to the surface of Mars so with that fairing up there we have our vehicle packaged in it we launch we accelerate after we get out of Earth's atmosphere we drop the fairing we now get up into orbit we check our orbit and then we ignite the engine again to accelerate ourselves to escape velocity and get us on the right trajectory headed to Mars and that's when we move from leaving Earth into what we call the cruise phase so we go from launch and departure to the cruise phase and cruise is where we are traveling from the earth vicinity to the Mars vicinity and now I have a short video here that describes how we do that how do you get to Mars if you want to send a spacecraft all the way to Mars first you'll need a fast rocket to escape the pull of Earth's gravity the heavier your spacecraft the more powerful your rocket needs to be to liftoff next make sure you launched at the right time Mars and Earth orbit the Sun at different speeds and distances sometimes they're really far apart and other times they come closer together about every two years the two planets are in perfect positions to get to Mars with the least amount of rocket fuel that's important the total trip is over 300 million miles finally make sure your aim is right you can't shoot for where Mars is at launch time you have to aim for where it will be when you get there it's a lot like how a quarterback passes a football also you may need a few frust to correct your direction along the way so you don't miss Mars if all goes well you'll get to the red planet in about seven or eight months so here we are we've we've gone from Earth to Mars we've arrived at Mars and this is what planet looks like as we get there and we're getting ready for entry descent and landing now one thing I mentioned from the cruise a lot of people the analogy for that is to getting as accurately as we need to to Mars is like making a basketball shot from New York to Los Angeles now as it said in that video we're able to cheat a little bit because we can make small corrections on the way there but we have to get we have to get a very accurate departure from Earth and we've been able to do that very well the last several missions and so that that is working really well so here we've arrived at Mars this is what it looks like as we're starting to get pulled in to Mars gravity well it's accelerating the vehicle toward Mars and so we're ready to start introducing and landing but what really is entry descent landing and so it is introduced in landing is about the controlled flight of the vehicle system through all appreciable atmospheres including the city including the safe landing where that's applicable and so we have to get from here where in this case relative to Mars we're going about 13,000 miles an hour down to the surface and in this case I'll show you what the the target was the Gale Crater this was our landing site for MSL and what it looked like from as we arrived at Mars and we have to get from that 13,000 miles an hour down through the atmosphere to the surface to roughly 0 miles an hour for a nice soft touchdown that's what you want once you've committed the EDL you're going to touchdown now hopefully we don't make another crater but we want to touch down nice and softly so let's talk about what the key challenges are for doing that the first is at Mars there's too much atmosphere to land like we do in the moon so what that means is we're traveling so fast and as we start interacting with this atmosphere that's there there is an awful lot of force on the vehicle there's an awful lot of heating on the vehicle and the the atmosphere itself has different winds has density variations and so all of these things conspire so that we can't just do a propulsive descent like we do at the moon you actually have to use the atmosphere the next is that there's too little atmosphere to do it the same way we do at Earth there's only about 1% of Earth's atmosphere at Mars and so that would be kind of like landing the the Space Shuttle at a hundred thousand feet here at earth it was just not enough atmosphere to do it that same way some of the other challenges are there is a wide variety of terrain elevations as well as the types of train to deal with when we get to the surface and then we have this issue of we design an EDL system or an entry descent landing system here at Earth but we don't have good ways to test that end to end here at Earth to test the entire system and it has to be done at Mars and so that's a huge challenge for getting a system that will be reliable and actually work when we get to Mars so first let's talk about the atmosphere like I said it's a very dynamic atmosphere and it's poorly characterized to date now there are no large storm systems like we have here at Earth but the seasonal and the diurnal variations are actually larger than what we see on earth and there are large sometimes global dust storms and that has huge changes on the density of the atmosphere and changes how we fly through it and actually on Mars they're even dust devils so in this case you know the Sun can heat the Martian surface and create winds and sometimes those winds create dust devils this particular one was captured by the hi-rise camera on the Mars Reconnaissance Orbiter and then we we created a three-dimensional model of it so that we can kind of you know fly around up kinda like you're in a helicopter and what you can see here this dark line on the surface is actually the shadow of the dust devil which allowed us to recreate its height and so what you're able to see from MRO we'll go back to the original image is that the dust devil is about a hundred feet wide on the surface and about a half a mile tall so it's quite a large one but one of the things we didn't know before sending the mars exploration rovers is how prevalent how common dust devils are on the surface I don't know if you'll remember but the those exploration Rovers when we sent them were only designed for a 90 day life because one of the main reasons is we thought that dust would collect on the solar cells and they wouldn't be getting enough energy to keep themselves warm and their electronics would fail turns out dust devils are pretty common so you can watch their battery life going down down down and then it gets hit by a dust devil and cleans off the solar cells pops back up so now we've had we've had these exploration Rovers up there for many many years back they had their ten-year anniversary it'll be good one of them is no longer operating but the opportunity is actually still operating on the surface so the point is that the vehicle system that we're trying to get to the surface of Mars has to contend with a lot of atmospheric variability so now let's talk about the terrain elevations this is a global map of Mars again and what we're showing here the black areas are the parts of Mars that are above two and a half kilometers in altitude and so this is the type of access that we'd like to have to Mars we'd like to be able to land anywhere the colors are on this map and what you see here the red X's are where we have landed and so if we now look where those actually are those have actually been all very low altitudes with our current technologies and our current entry descent landing techniques we have to land very low at a very low altitude so we have as much atmosphere as possible to work with to slow the vehicle down and get it safely to the surface and so this is one of our big challenges so they're also different types of terrain hazards Lister you got mountains craters canyons rocks right but the point is we do know a lot more now than we used to so if you look here in the viking era at the same scale we really couldn't tell anything about the surface and then the Mars Global Surveyor camera hey we could see there's actually a crater there but can't tell much more in these days now with our high-resolution camera on Mars Reconnaissance Orbiter we start being able to pick out features in terrain types and understand better where we're actually sending these vehicle systems and can better prepare them for where they have to land I mentioned the EDL system verification problem so it's really because of the complexity and the environments that we're sending it to the EDL systems for Mars generally can't be tested as flown here at Earth as we intend to fly them here at earth so we do component tests here at earth to build models of how the different pieces of the entry descent landing system work and then we assemble those models into an end-to-end simulation and so all of the models of the EDL component subsystems are brought together into this in the end system simulation so you have models of the the vehicle mass properties you have models of the atmosphere that we've been talking about you have models of the parachute understand the dynamics when that when that deploys even get into the the physics based modeling of the radar system to understand what kind of signals you're going to get back from when and how and how much dust and material is going to be kicked up as you get close and how the radar will react to that so there are a lot of different models that get pulled into this and the simulation exercises both the flight vehicle and the algorithms that autonomously fly the vehicle in the virtual environment and that's one of the things that actually these simulations are very good at we can push the system beyond even what were intending it to fly through we can find its sensitivity so we we dispersed different variables such as how well we know the vehicle center of gravity or how much wind it might encounter and that way we can understand better how this system will perform when it actually gets there now we run literally hundreds of millions of these entry descent landing runs in computer simulations in the development and the verification of these systems and actually now these systems are so complex that the only complete system performance verification are these Indian simulations so let's take a quick look at what the entry descent and landing sequence at Mars looks like alright so we arrive at Mars and we've had a crew stage which is that little thing up on the top there attached to us and helping us get from Earth to Mars accurately well we we jettison that and then we turn the vehicle to face the Mars atmosphere at the angle that we wanted to to hit the atmosphere and then in this case I'm showing the the Mars Science Laboratory sequence we jettison a balanced mass this is important because we now have changed the balance of the vehicle and we do that on purpose so that when we start flying through the atmosphere the vehicle won't just fly straight in like a bullet it'll it'll fly at an angle of attack it will fly at a slight angle and that gives us a lift vector and so we can use that lift vector to then control and steer the vehicle and help us slow down or I'll talk about that some more in a little bit so we've just in that balanced mass then we come slamming into the atmosphere at about 13,000 miles an hour it starts heating so that heat shield the rigid heat shield upfront is protecting us from that it gets up to about 3800 degrees and then we continue going through that peak heating and then we reach peak deceleration which for MSL was about 10 G's so now think about that in regards to humans right we can't we can't subject our humans particularly after being in space for a long time - 10 G's so we're gonna have to for humans slow down a lot earlier and slower right but for our current state of the art it's experiencing 10 G's and then we start maneuvering essentially doing s turns in the atmosphere to help us slow down and as we get down closer to Mach 2 we can deploy the supersonic parachute which helps us slow down a lot more we drop the heat shield the radar system then is looking for the surface to find out exactly how high we are and how fast we're moving and once it finds that it drops the and that our payload in this case for this mission it was the rover on with a rocket pack actually called the powered descent vehicle and it continues slowing down relative to the surface and touches down so that is the current state of the art for entry descent landing at Mars and I'll show you a little bit more about that in a few minutes but while flying through the EDL sequence the vehicle system needs to be able to land within a defined area now I showed you what Gale Crater looked like from orbit before here's a close-up of it so this was the the landing area for that Mars Science Laboratory mission and we targeted Gale Crater but that was impossible just a few years ago because like with when we did the Pathfinder mission its landing uncertainty was larger than the crater itself right but we've gotten a lot better since then and so here's the landing ellipse or the landing uncertainty they call it for the Mars Science Laboratory mission so after all the calculations we do in understanding how this EDL system will perform we're very confident it'll land somewhere in that ellipse the target of course is the center and in this case for MSL we actually did pretty well we were only about two kilometers away from the very center of that ellipse but the point is for humans we need to delete be able to land in an area that's ten times smaller than that even so within about 0.1 kilometers of our targeted landing area so let's take a quick look at how the sort of the history of entry descent landing at Mars I mentioned the Viking mission so Viking sent two probes to Mars they were Landers they entered with a rigid 70 degrees fear cone era shell and went and had a supersonic parachute to a propulsive descent on the surface now this was all possible this was the first landings at Mars right so this is all possible because of the significant technology development activities we had in the 60s and 70s the whose activities made it possible for us to understand the 70 degrees fear cone air shell on how that was going to fly it qualified this disc gap band supersonic parachute so that we would be able to use that as well as the autonomous propulsive landing so if we look at some of the more recent missions Mars Pathfinder it landed a small Rover there used airbags and I'll show you that in just a second Mars Polar Lander was another Lander sort of like the Viking air but we lost that one we don't know exactly why but through the mishap investigation the most likely scenario was that it's it's computer was listening to it's touchdown sensor too early so it's this touchdown sensor is looking for a shock it touches down on the surface to turn off its landing engines and so what most likely happened is it's listening to that too early and then it deployed its landing legs and shocked the system and the little sensor thought it had touched down it turned off the engines and most likely fill the last 60 meters to the surface so we then did the Mars exploration Rovers and so let's let's take a look at their ETL architecture so again we have a 70 degrees fear cone era shell separate from the crew stage and we're coming straight in to over ballistically into the Mars atmosphere so that heat shield protecting us from the era heating when going through peak heating and now peak deceleration and as we get down closer to Mach 2 because an employee that's supersonic parachute you know this we're still flying relatively horizontally let's play put the parachute the parachute is actually working on slowing us down and sort of tipping us over and then we can draw the heat shield right and then here is where it's different than what we saw before it has the payload when this tetrahedron hanging down below and that tetrahedron has airbags all around it which will inflate as we get a little closer to the surface and so those are just like crash the airbags for your your crashing right so and as we get within about thirty meters of the surface these retro rockets fire bring the entire system closer to zero miles per hour ropes up to the surface and then drops it and that that system that airbag system hits the surface at about 54 miles an hour and then bounces along until it stops now the actual emissions this is a simulation than the actual missions they bounced about 30 times before they stopped and then it deflates the airbags and then opens the tetrahedron and you have your payload safely on the surface of Mars in that case it was one of the exploration Rovers yes so similar even it's a rigid heat shield the material the actual thermal protection system on the latest ones is called pica and that's different for the Apollo ones it was called avcoat so it's a different material but the same type of idea with that rigid aeroshell and creating the shock in front of the vehicle to carry a lot yeah it bleats it's an ablative as what's called you burn off part of the heat shield material exactly yes the question was how do you avoid landing on a steep hill or incline and so one is we characterize how well the system can do that like what type of incline could it withstand right and then we've used our current orbital assets there to create what are called digital elevation maps of the area that we're going to lay on a wide area and so we understand where these these keep-out zones are and so we define our landing ellipse away from all of those bad areas yes so yes so the balloons were a composite material its ability was based on a Kevlar based and then it had a essentially a gas a gas barrier and inside to allow it to inflate but they had a very tough exterior that I believe was Kevlar based yeah and so we did an awful lot of testing of those dropping them on sharp rocks and throwing them sideways at things to make sure that they wouldn't rupture within the parameters of what we were playing or how we were landing exactly for humans to Mars we need to be within about a hundred meter ellipse or 0.1 kilometers right now we've got about a 4 depending on depending on lots of things that's between a 5 & 10 kilometer ellipse what that we can land in so we're over an order of magnitude away from where we need to be and our landing accuracy so then we had mentioned the Phoenix mission before and so this is now a more a modern Lander but still in the same type of architecture that we did for Viking so 70 degrees fear cone getting through the heating same type of supersonic parachute going to a propulsive descent and landing which was which was successful and so now the most recent one we have is the Mars Science Laboratory which was landing the Curiosity rover on the surface of Mars so this represents the state of the art so we'll watch how we got to the surface with MSL so again same type but much larger same type of rigid aeroshell drop the crew stage we now reorient this entry vehicle toward the atmosphere of Mars we drop that balance mass member slowly offset so we'll fly at an angle of attack and so now we start to get into the sensible atmosphere alright so the vehicle starts to feel deceleration it uses rockets call it a reaction control system to keep itself oriented correctly and then here you can see we've done through peak heating and it's starting to steer back and forth and these s terms continuing to slow down gets through peak deceleration which again for MSL was about 10 G's and so now we're continuing to slow down and as we get close to 2 we kick off board mass to recenter ourselves we don't want to be offset any more silly can safely deploy the parachute which there's that supersonic parachute again the same style this gap band that we providing but much larger so now we dropped the heat shield and the radars looking for the surface and once it finds the surface and a solution it's going to drop the rover and the powered descent vehicle which is the rover's rocket pack they fire and continued accellerating the rover relative to the surface one of the first things it does though is a big left turn to get away from the parachute so it's the parachute avoidance maneuver and so it's moved away from the parachute now there's radar system up front there it's continuing to look at the surface and understand how we our altitude and our velocity relative to the surface and as we get closer there's an instrument called the Marty instruments a camera right here that's also looking at the surface and comparing features to understand how much we're moving side-to-side that's what it's doing there and so now as we get closer to the surface we lower the rover on the tether system below this rocket pack and it continues decelerating very slowly toward the surface now and the rover has set its wheels into a landing configuration and right now the everything is just waiting for this touchdown sensor and once it since it's touchdown it cuts those tethers and the car doesn't vehicle flies away to a safe distance and crashes by the safe distance away from the rover and one of the big benefits of landing this way is you've now got your Rover system on the surface essentially ready to go all it has to do is stand up it's remote sensing mast and it's essentially ready to go as opposed so the relating that to is the Mars exploration Rovers that were packed in that airbag tetrahedron they were folded up like origami and it actually was I think it was almost three weeks of operations to unfold everything and get them set up and actually ready to ready to operate and so here we've landed within our landing ellipse and there in the back is that it's called Mount sharp it's the center of that Gale Crater that we we talked about and it has been it's been operating for just over two years and has just now gotten over to the base of Mount sharp now it's done an awful lot of science on the way there we've we've learned that there were small rivers that even at least knee-deep you know in that particular area and I'm again I mentioned the the big discovery for MSL is the existence of ancient habitats that could have supported life so it's done a lot so the point is that this is the limit of what we can currently do with our current entry descent landing technologies and so we have a significant technology gap look just along the bottom here this is too much too many words on the slide but where we are currently is able to put one metric ton within about a 10 kilometer ellipse and access about 40% of Mars surface and so where we need to be potentially for human missions is able to land 40 metric tons within a tenth of a kilometer of our target and have nearly global access and so it is a huge challenge it's why ADL at Mars is considered one of the two biggest challenges for human exploration of Mars the other one being radiation protection which you'll hear more about next week I believe but nASA has set the goal of having humans Mars and the in the 2030s and to accomplish that we're gonna have to leverage activities all around it's a very success or even a goal to be able to do that within 20 years most entry descent landing capability roadmaps so you have to have a consistent effort over 20 years for us to be able to get there and so we're going to be leveraging our international partners and commercial partners to get their other missions within within NASA that aren't just the human exploration portion of things like our science Mission Directorate and the missions that they send the various planets all of these things are going to need to combine to help move us stepwise closer to humans on Mars yes okay yeah so the question the question is during the entry when when the the very high heating portion of entry does Mission Control lose the radio contact with the vehicle in control what you think so first of all we're about communication time wise we're about 14 minutes away so the vehicle is actually working autonomously that whole time there's not any active control so from the time we've started entry at Mars right so when we get that signal 14 minutes has gone by from the time and it actually started entering and so it's either safely on the surface or crashed by the point we get that signal that it started okay so but but what does happen during that entry we there is some radio blackout and there there are special radios we use that are very small data pipes that send us some very small amounts of data all during that time and so it's all about the health of the vehicle and if we have a bad day helping us understand what happened so that has that well there's sorry yes the the question was what causes the radio blackout it's the ionized flow so we're slamming into this atmosphere and we're hitting it so hard that we're disassociating the species and creating ions heavy ions and a plasma flow and so that then surrounds the vehicle the radio leaves can't get through right yes so the quick yeah so the question is is the United States the only nation that has actually put Landers on the surface of Mars we're the only ones that have done it successfully so there have been Russian Landers the closest one they believe they got a signal that had landed but they lost contact immediately so we're not quite sure most of the others failed during launch or failed during during EDL and there have been European smart Landers that also failed during the attempt so the u.s. so far is the only one that has successfully landed on Mars the mission so are the missions coordinated with other countries yes in that even on like MSL here is an example there are contributed instruments on the mission from other countries like France and the European Union yep absolutely thank you so landing at Mars is not easy as we just said we've landed a total of seven times successfully on the surface of Mars the point is all of these successful landing systems have landed at low elevations at minus one kilometer or lower we've landed less than one metric ton and there's been relatively large uncertainties on our landing location and this the EDL system so critical to the overall mission that it generally drives the mission architecture and as I've mentioned all of the current Mars missions have relied on the technology investments in the 60s and 70s and we've essentially gotten to the end of where we can stretch those technologies where we can go so there's going to need to be systemic new investments in new atmospheric flight systems that are the basis for these entry descent and landing systems because that really is the core of EDL is being able to fly these vehicles through an atmosphere so the agency has started working on some technologies remember we mentioned in the beginning that we don't have the answer right now I'll talk about some of the things that we're working on so we've developed new thermal protection systems these are the materials on the front of the vehicle that protect you from all that high heating we've got some new deployable Aero shell concepts that we're working on in developing there are mechanical deployables and there are inflatable aeroshells now remember the inflatable aeroshells I'll talk about those in more detail here in just a few minutes and then we have what are called the mid l / D where that's mid lift / drag vehicles these are more like flying cylinders into the atmosphere and then we're also developed new parachutes new supersonic deceleration systems these systems actually inflate inside the atmosphere and create more drag and we're also working on supersonic retropropulsion and this is essentially you're in a supersonic flow and you're gonna fire a rocket into that and help yourself slow down and so that is another key one and then of course the the landing systems from propulsive systems to airbags to crushable structures being able to actually safely set down on the surface so how do we put these technologies together for humans to actually get to and explore the surface of Mars so nASA has done a lot of studies this I'm not expecting to go through in detail but this is looking at different combinations of these technologies and we're running simulations to understand how those might work and which ones are more effective and one of the key figures of Merit is the arrival mass at Mars how much stuff do you have to get from Earth to Mars for this type of system to work in this study was done around getting a 40 metric ton payload to the surface and so in comparing this we end up actually with architecture number two winning out it had a very low mass at Mars so around 84 metric tons but you'll notice that there is one over there number eight that's a little bit less in mass but it's EDL sequence has many more critical events and it's a little more risky and so we ended up saying that architecture 2 is a better way to go and so that's the thing if we were to pick today how we were gonna get humans to the surface of Mars this is the architecture we would take which is using an inflatable aeroshell I'll talk about those in just a minute using a narrow capture approach again this is using the Martian atmosphere to help yourself get into orbit I'll talk about that as well and then transitioning to supersonic retropropulsion and final touched on autonomous propulsive touchdown as well so looking at this architecture we don't see any cliffs we see that it can scale to the human class missions now there's a lot of work to get there but there's nothing that says that it can't be done so let's talk about some of those technologies I mentioned the error capture so this is when the vehicle system uses active control to autonomously guide itself into in this case the Martian atmosphere flying through that and if you're taking a lot of energy out and slowing down but then fly back out of the atmosphere into orbit so you haven't you didn't have to carry a bunch of rocket fuel to slow yourself down to use the atmosphere and this allows you to use a smaller more affordable launch vehicles to get the system there it also allows you to have a higher payload fraction meaning since you don't have all that propulsion or propulsive capability that you brought with you you can have more payload and the example here if you're really using air capture you can have 80% of your vehicle system your payload as opposed to if you're doing propulsive it's about 20% so it makes a big difference in the architecture studies so we need to slow down more mass at higher altitudes we've talked about right so the limit of that fairing size for the size of the aeroshell that we can bring to mars and help us slow down is a big limit and I just have a small image here on that but this is supposed to represent the rocket fairing and then that was the MSL shape and it was as big as we could make it but if we used an inflatable approach which here it is stored and here it is deployed we could carry with us and I mean we stow it and launch it in an everything and then we're able to deploy it or inflate it as we get to Mars and it's a much larger drag area so the anatomy of this you have an inflatable structure there's two main things there's an inflatable structure and there's a flexible thermal protection system the inflatable structure and both of those by the way in this case are packed very tightly and forward of this so you have this nice narrow vehicle alright so when it inflates it creates the it uses an inflatable torus approach or stacked torus approach and they're straps that halls together and carry all the loads and I don't want you to think when I say inflate I don't you to think balloon right so how people think of these balloons and they're squishy and stuff like that this is actually quite a rigid structure once it's inflated even with just a few psi differential and the material is very durable it's a Cylon base material kind of like kind of like Kevlar it has a gas barrier on the inside and all of these are made to be high temperature material systems and so so we have that as the structure but then you know when we when we come slamming into that atmosphere we're at 13,000 miles an hour it's going to get really hot so we need this flexible because it's gonna be folded up this flexible thermal protection system to go on the outside of it and that's what I guess here so that's a pinkish material along the outside and that's a material system that can stand up to those really high temperatures and so if we're able to do this it allows us to land if you remember these images those are that's our current access it allows us to be able to land either more mass to the same areas or the same mass to a much much higher altitudes and have much more access to the surface of Mars so what I want to show you now is a video of a technology demonstration of this of this technology and it's that's from a mission called Erb III or the inflatable reentry vehicle 3 and it shows the vehicle system you have the actual video from the test here this was on the vehicle and this is an animation showing kind of what it's doing at the time so we got to about 291 miles high that's higher than the International Space Station we then release the heat shield and start inflating it and you can see it's come here in this this Green Line is its full shape you can see the inflatable Tauruses and the straps and then it reorients itself toward the atmosphere of Earth so that as that earth gravity well is now accelerating us from pulling us back down into the atmosphere there are sensors on the front here to indicate you know how high the heating gets and things like that because we're testing this material system and then we also have a new way of creating a lift vector this instead of dropping mass off we just shift our payload mass within this does the same thing of sort of unbalancing this so that when we fly into the atmosphere we can get a lift vector and so here we go into the atmosphere at Mach 10 the seller eating and heating and look at this I mean it's flying very steadily it's hard to even tell that's what's happening over here it experienced 20 G's of deceleration because we were trying to really push the system and get as much heating as we could in a real mission that would never see actually 20 G's but it was a very successful test and it qualified this particular material system which we call the Gen 1 material system to 30 to 40 watts per centimeter squared and what that means is it would be relevant to the the MSL class missions that we send that we're working on right now but we want this type of system to be able to work for human class missions and that's kind of that's the next step that we're working on we have not done this test yet but we've started working on it's called Thor the terrestrial high ed orbital re-entry test so we're gonna launch on a much bigger rocket and go up higher and faster we're actually catching a ride with Orbital Sciences Antares rocket and so as they get up into orbit will drop off and they'll continue on to the International Space Station but what they've done for us in the partnership is they've gotten our system up to really high velocities and really high energy and so then we fire our deorbit motors inflate our new material system this is now called gen 2 and we're going to come in with five times the heat rate and 50 times the heat load that we did in our previous test testing our new material systems if these proved out then we're talking about 60 to 80 watts per centimeter squared is what we're what we think this material system can do now that starts to become applicable to the human class missions and that's what we're working for here the one thing this test doesn't get us is the scale right so we're flying a 3.7 meter diameter and that that you know that because that would be effective for the msl class missions but for human class missions they're gonna need to be 18 to 23 meters in diameter but we will have proven out the load capability as well as the heat rate capability for this system so I also mentioned supersonic retropropulsion it's being one of the key technologies so in this case we're coming in at supersonic speeds and we need to continue slowing down and so we're gonna fire rockets into that flow and continue slowing slowing down the vehicle now we're partnering with SpaceX on this and so we have some describe data minute we have a computational fluid dynamics to understand how these these Jets are going to interact with this oncoming flow we've done Windtunnel tests and now we're partnering with SpaceX who is one to use supersonic retropropulsion to return its first stage of its rocket as part of their business plan and so we've partnered with them to get the data from those tests and we actually have at this point and so we're able to where we're starting to use that data understand what the real next steps should be for for developing this technology is one of the keys is the the particular configuration is very important for supersonic retropropulsion to understand how how you're gonna fire these Jets to keep your vehicle stable and to slow it down but again this is something that is being demonstrated with SpaceX and the NASA will move it forward on how we need to develop that for human class missions at Mars sir so I'm going to try to repeat make sure I understand so you're wondering within the launch fairing of our rocket if we can't stack a greater number of smaller loads within that but using the smaller smaller diameters okay so the what we've done is studies based on you know look at the different sizes of vehicles that that we need and doing multiple launches or multiple vehicles looked at in space assembly of of different vehicle systems and the trades always come back that we it's more advantageous to be able to have that larger diameter Aero shell right so that's why the high head in this case the hypersonic inflatable decelerator gives us so much of an advantage and did I answer your question oh so okay so it's a reliability yes your reliability issue so yeah that's what the the systems are being designed to be highly reliable but then I think what you might be getting at is like with the Viking missions we sent two Landers even with the Mars exploration Rovers we sent two of those and really in case one failed you know we had another one that was that was there and ready and so I can't say for certain that we'll do that with the the human missions but we're gonna make sure with the human missions we make sure the systems are reliable most of the landings are without humans they're going to be pre positioning resources and getting things and everything is there and turned on and ready before those humans ever leave Earth and so if there is a failure then we wouldn't be something humans we'd be sending another mission to pre position yes so the question is for the inflatable heat shield structures what type of gas do we use to inflate so in the tests that we've done to date we've done nitrogen it's in there and now we're for this last test I mentioned Thor we're actually going to use freon because we're limited in our in our sinner body and freon is going to be a denser give us more performance out of our inflation system so we're going to use the freon gas there it's that is correct it's it's but it's a pretty it's a relatively small amount and we're using it exo-atmospheric Lee but we do but we do it is it is what's inflating the structure and it will come back in yeah yes yes exactly and I'm gonna get to that in about a slide or two I think exactly so yeah so the question was that we or the statement was that we need to take extra payload to Mars to be able to get them back home and that that's absolutely correct the last thing I want to mention on the EDL technology challenges is that being able to precisely land we mentioned that but also being able to avoid hazards that we may not have mapped or didn't know about as it's landing so the first part is precision landing and that has to do with knowing very accurately where you are and the vehicle being able to know where it is on a map and accurately navigate to a point and so our current yeah this is just representative our current knowledge of where we are so that's our error ellipse but if we like a certain technology like what's called terrain relative navigation so a map in the vehicle actually knows the area very well and it's taking pictures of the surface and can find itself on that map and redirect itself to an accurate point you then get this tiny little circle of knowledge error of your location so that's a potential way of getting our landings more accurate we also have hazard avoidance so this is using special sensors such as wide arse and other other instruments and cameras during the descent to understand hey there may be hazards right where I'm trying to land and having the ability to divert to a safe site but still within the requirements of your mission so now we get to your question about what do we need to take along right so if we're looking at the 40 metric tonne missions this would be two Landers going there for 40 metric tonne mission to Mars and so the first Lander has the very first thing is the Mars ascent vehicle so this is how the astronauts would get back off of Mars also has the multi-mission surface exploration vehicle it has a fission surface power unit has to go fetch Rovers it has a drill and then an ISR your Institute resource utilization so a unit that can actually process the atmosphere and/or the ice and water at Mars into useable elements for the mission and then of course there would be a science instrument package as well and the second Lander bringing the astronauts would also bring the inflatable habitat as well as the second surface fission power unit and the second Mars surface exploration unit so figuring out how to package that and put that all together right and get it to Mars and so here's the current concept or a current concept how we would package that into a lander and on the bottom and the base of this Landers you would have packed away the inflatable aeroshell that we talked about right and so the current studies are looking at 40 metric ton missions as well as 70 I mean 27 metric ton missions and 18 metric ton missions and that gets to the trades for how many launches you'd want to make if you could do it with smaller launch vehicles and a but a larger number of launches is that better or what so those are the trades that are going on now yes well so it would but it's it's not immediate right and we would be storing the water inside of container so it wouldn't sublimate from there but if we just brought liquid water to the surface yeah exactly right all right so so this light includes the high ed system and then if we're looking at what an entry at Mars might look like with the human class system we have the inflatable aeroshell with our Lander system being protected inside of that and this this inflatable aeroshell would be 18 to 23 metres across so what much wider than the barn here so it's a very large air shell so point is you've seen what we're doing the exploration and so you've heard about SLS and we're working with our commercial partners to have access to the ISS as well as to low-earth orbit and creating that supply line whereas the SLS that NASA is going to concentrate on is about getting beyond Earth orbits or beyond the earth gravity well and we're developing that from our initial 70 metric ton capability to the 130 metric ton capability that will carry the spacecraft the crew the cargo of equipment to deep space destinations such as Mars and really this is going to be the platform to continue you know America's tradition of human spaceflight now my mind I believe that we humans can and will you know get to the surface of Mars and in fact remember the picture I showed you in the beginning I showed what Mars looks like from Earth here's what earth looks like from Mars taken by one of the Rovers that tiny little speck right there I blew it up for you all right so you're here so that is everything everybody that we know every road every building every city on that tiny little speck it just it for me it really puts things into perspective and so you know these these are some of the challenges that that we're working on today and trying to get humans to the surface of Mars and I like to think about what's going to be real tomorrow and so I have a quick little video for you be happy to take any questions you might have yeah good so the question has to do with on Mars or the moon because it's like Mars yes so the question has to do with how long astronauts can stay on the surface of Mars versus being able to send robots that can stay there longer so actually with the the architectures for human exploration of Mars they can stay there for quite a long time and in the initial missions range we're looking at short duration first if to show that we can get to the surface and get back off successfully but with the Institute resource utilization they can actually potentially stay there quite long as long as we resupply them with a couple main things but they'll be able to produce their own oxygen and serve other the key things that they would need so we could have long-term stays on Mars right most likely but yeah that we're actually trading those things right now we actually don't know exactly what how and when we're going to put humans on Mars and how long we'll have them stay and part of it does have to do with the orbital mechanics right so where and Mars are in relation to each other if we put them on the surface and then what it takes to get them back to earth so essentially when we when we go there and we're gonna stay more than just a few days they're gonna be there for almost two years they can be there for two years yeah well it won't be that we don't do that the first try will actually do it most likely pretty quickly bring them back the first time yeah one second oh there yeah so the question is is whether we actually need lift with the inflatable heat shields for control so it's this is one of the ways that were that we are looking at controlling it so we we do one lift in some form we can generate it different ways but we do want lift so that we can guide these vehicle systems to get them to more accurate landing locations that's the main reason so we get a lift vector that we can control sure so the question is if Langley is the lead Center for EDL and what is our part in it right I get that right ok so there are really four NASA centers that work an entry descent and landing and that's Langley and JPL and Ames Research Center and the Johnson Space Flight Center now we all have different parts Langley would I would think it's easy to say we lead the technology development of it so these these new technologies and developing how we are going to put people in the surface of Mars I think Langley is significantly involved in all the activities that are going on with new ETL technologies now there are some like the deployable the mechanically deployable air shell that's being led at Ames but we're supporting them and helping them with that and so it really is it's a team effort around the agency so the question was costs for making this this dream a reality and actually I cannot answer that for for the entire human mission right and so we're looking at you know just the technology demonstrations and being able to get there and then we're working with the architecture folks which you saw I think the very first week here about the evolvable mars campaign and how it leverages activities from across the agency and so I don't know Steve D do you have a better answer for that for what what it'll cost so yeah we've looked at that a lot and just so you know I think today NASA gets about 17 to 18 billion dollars a year and the human exploration part of that is eight with the eight we do International Space Station all the work on the station and we're developing the rocket and Orion as well as doing some technology work and of course you know we work for the president at NASA the president says we're getting enough however depending on when you want to get humans to Mars I think it's safe to say that we we may need to spend more at maybe we're getting about 75 cents on the dollar we need so we need we need a marginal increase if we want to actually meet that schedule goal of getting there in the 30s yeah so there's certainly or certainly thought given to it so we yeah we have been littering the surface of Mars since the 70s right but each vehicle system that we sin there goes through these planetary protection and we make sure that we are not sending you know bugs from earth and germs from Earth and things like that but yes the the some of the vehicle system parts and pieces and the systems that are no longer functional are just sitting there on the surface of Mars now usable well in the sense maybe some maybe some future human mission absolutely could use some of the material but that's not in our plans at this point we would we wouldn't count on that so the question is are the people who are gonna walk on the surface of Mars alive today so we can get people to Mars by the end of the 2030s right but given the way government works and how it's most likely gonna be the 2040s so yes I would say they are yes so yeah that's one of the technology areas that's being worked on different types of Lacombe you know propulsion to get us to Mars faster and that you I don't know if they'll talk about that next week but that's with radiation protection and the exposure during that cruise stage one of the ways we can mitigate that is actually getting to Mars faster not taking the the six to eight months to get there and so there's there's direct propulsive there's some technology called VASIMR drive and some other things like this that could potentially decrease that time to Mars and that's really a key potentially key for the humans it's not so much of an issue for the pre positioning of the cargo missions and things like that so we can use more efficient and slower methods like solar electric propulsion that would allow us to get there over a longer period of time but we can also use that to slow ourselves down as much as we can getting close to Mars and therefore the landing systems could be more capable when we get there yes absolutely it is yeah so so is the rotational direction of Mars factor factored into the landing so yes well you can't go either way so retrograde or pro-grade but there we go we go with the rotation normal yes right sorry yeah okay so the question is exactly so the question is why aren't we using laser communication instead of just radio communication to get information back from Mars from our vehicles to up to now yeah we have been using the radio communication we actually have experiments that are planned to go to Mars to do laser comm main thing is though to use it during entry descent and landing we have this variable atmosphere to deal with and so if it's real dusty and issues like that we don't know that we'd be able to get a good laser signal and in those critical times right so we still want to have strong radio signal to a satellite that could then relay it through a laser comment so that's why we're looking at laser comm in our orbital assets and another benefit of the laser communication is it can send a lot more information I mean right now we have a few assets there that communicate through radios and there think of them as pipes relatively narrow pipes that we're sending data through and there's this big backlog of data and images waiting to go through these pipes whereas if we get laser communication working we'll be able to get a lot more data back if the question was about the radio blackout or whether it was about the time delay if it's about the time delay though the laser and the radio wave travel at the same speed so there's still even with laser communication 14 minutes right it still could still be the same time - exactly thank you all very much for the last lecture on the radiation protection problem you

Channel: DEEP SPACE TV

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Keywords: langley research center, space exploration, space exploration nasa, space exploration 2018, human spaceflight, human spaceflight missions, nasa lecture, nasa lecture series, space documentary, deep space tv, deep space tv show, deep space tv series, HUMAN MARS MISSION, mars, nasa, space, human mars mission nasa, mars human mission 2024, human mars mission date, HUMANS ON MARS, planet mars, planet mars 2018

Id: sjUE5nuJWhk

Length: 74min 31sec (4471 seconds)

Published: Sun Jul 01 2018