1 00:00:02,899 --> 00:00:01,370 one way or another you're gonna be on 2 00:00:07,099 --> 00:00:02,909 the ground in seven minutes we want it 3 00:00:08,600 --> 00:00:07,109 to be there safely I'm al Chen and I 4 00:00:10,310 --> 00:00:08,610 lead the landing team for Mars 2020 5 00:00:11,780 --> 00:00:10,320 actually said landing is all about 6 00:00:13,190 --> 00:00:11,790 getting the good club from the top of 7 00:00:15,049 --> 00:00:13,200 the atmosphere down to the bottom of 8 00:00:17,359 --> 00:00:15,059 safely hit the atmosphere going you know 9 00:00:18,740 --> 00:00:17,369 12 13,000 miles per hour we have to 10 00:00:20,060 --> 00:00:18,750 deploy supersonic parachute I mean 11 00:00:21,560 --> 00:00:20,070 that's all before we get down into power 12 00:00:23,390 --> 00:00:21,570 play see we have a new system that'll 13 00:00:24,830 --> 00:00:23,400 take over at this point it'll start 14 00:00:26,929 --> 00:00:24,840 taking images in the ground that'll let 15 00:00:28,759 --> 00:00:26,939 us figure out where we are in latitude 16 00:00:30,169 --> 00:00:28,769 and longitude jezero crater the site 17 00:00:32,269 --> 00:00:30,179 we're going to with Mars my 20 was 18 00:00:34,069 --> 00:00:32,279 actually rejected for curiosity because 19 00:00:35,810 --> 00:00:34,079 the site was considered too unsafe and 20 00:00:37,400 --> 00:00:35,820 really the train was way too rough but 21 00:00:39,110 --> 00:00:37,410 now we have the ability to land at these 22 00:00:40,729 --> 00:00:39,120 places that we never really could go to 23 00:00:42,290 --> 00:00:40,739 before the genzaburo crater site if you 24 00:00:44,090 --> 00:00:42,300 look at the space is pretty obviously a 25 00:00:46,040 --> 00:00:44,100 delta we think that Mars was habitable 26 00:00:48,229 --> 00:00:46,050 four billion years ago so the question 27 00:00:50,330 --> 00:00:48,239 is not just where was that life but also 28 00:00:52,310 --> 00:00:50,340 where could it be preserved for one more 29 00:00:54,200 --> 00:00:52,320 billion years for us to find it later I 30 00:00:56,029 --> 00:00:54,210 worked on curiosity for 10 years so this 31 00:00:57,410 --> 00:00:56,039 is a very familiar feeling I think I was 32 00:01:00,049 --> 00:00:57,420 too young the first time to really 33 00:01:03,139 --> 00:01:00,059 realize what was at stake big G's on the 34 00:01:04,640 --> 00:01:03,149 order of 11 12 14 we are in hard flight 35 00:01:06,350 --> 00:01:04,650 I've been on the other side of this - my 36 00:01:07,670 --> 00:01:06,360 wife was front and center on inside this 37 00:01:09,109 --> 00:01:07,680 is actually the same seat that my wife 38 00:01:11,260 --> 00:01:09,119 was sitting in for the inside landing 39 00:01:14,859 --> 00:01:11,270 the same seat that I was in actually 40 00:01:16,899 --> 00:01:14,869 back in 2012 for the Curiosity as well 41 00:01:20,440 --> 00:01:16,909 a lot of history for us in this room I 42 00:01:22,630 --> 00:01:20,450 shouted for mercy we would be uniquely 43 00:01:23,709 --> 00:01:22,640 positioned as two folks who were married 44 00:01:32,929 --> 00:01:23,719 to each other to know what it's like to 45 00:01:37,999 --> 00:01:34,789 with NASA's Jet Propulsion Laboratory 46 00:01:40,219 --> 00:01:38,009 JPL is where the Mars 2020 mission and 47 00:01:42,289 --> 00:01:40,229 perseverance rover are managed here in 48 00:01:45,109 --> 00:01:42,299 Southern California now getting to Mars 49 00:01:46,849 --> 00:01:45,119 is a test of perseverance in itself as 50 00:01:49,279 --> 00:01:46,859 we have been highlighting over the past 51 00:01:51,230 --> 00:01:49,289 couple of weeks it takes thousands of 52 00:01:53,569 --> 00:01:51,240 people working together to make this 53 00:01:55,969 --> 00:01:53,579 mission a success today we are with one 54 00:01:58,459 --> 00:01:55,979 of the many faces behind the spacecraft 55 00:02:01,429 --> 00:01:58,469 as the lead for the Mars 2020 missions 56 00:02:03,190 --> 00:02:01,439 entry descent and landing al chen has 57 00:02:05,899 --> 00:02:03,200 the important job of making sure 58 00:02:08,300 --> 00:02:05,909 perseverance touches down safely on Mars 59 00:02:09,050 --> 00:02:08,310 next year he joins us live to answer 60 00:02:11,029 --> 00:02:09,060 some questions 61 00:02:13,970 --> 00:02:11,039 now if you have any questions you can 62 00:02:16,009 --> 00:02:13,980 use the hashtag ask NASA or leave them 63 00:02:18,110 --> 00:02:16,019 right here in the YouTube chat now if 64 00:02:20,059 --> 00:02:18,120 you're not seeing the chat box just make 65 00:02:22,190 --> 00:02:20,069 sure that you refresh your page because 66 00:02:24,080 --> 00:02:22,200 we definitely want to hear from you in 67 00:02:26,150 --> 00:02:24,090 light of the times I'm talking to all in 68 00:02:29,270 --> 00:02:26,160 our homes as we are social distancing 69 00:02:33,349 --> 00:02:29,280 welcome out thank you very much for 70 00:02:36,650 --> 00:02:33,359 having me so out what does your title 71 00:02:38,809 --> 00:02:36,660 EDL or entry descent and landing phase 72 00:02:40,699 --> 00:02:38,819 lead mean and what are you doing to help 73 00:02:44,059 --> 00:02:40,709 the spacecraft land on the red planet 74 00:02:45,199 --> 00:02:44,069 safely the intranet sentient landing 75 00:02:47,030 --> 00:02:45,209 team is responsible for getting 76 00:02:48,589 --> 00:02:47,040 perseverance safely from the top of the 77 00:02:50,990 --> 00:02:48,599 atmosphere to wheels down in jezero 78 00:02:52,490 --> 00:02:51,000 crater that means dealing with a lot of 79 00:02:55,039 --> 00:02:52,500 the challenges that Mars can throw at 80 00:02:57,319 --> 00:02:55,049 you we get the atmosphere going 5.4 81 00:02:59,270 --> 00:02:57,329 kilometers per second 12 or 13,000 miles 82 00:03:00,620 --> 00:02:59,280 an hour and we have to deal with the 83 00:03:02,150 --> 00:03:00,630 heating right the spacecraft scripts got 84 00:03:03,680 --> 00:03:02,160 to survive the atmospheric heating the 85 00:03:05,569 --> 00:03:03,690 earth and I am exceeding that occurs 86 00:03:08,000 --> 00:03:05,579 with that when we get the heat shield 87 00:03:09,800 --> 00:03:08,010 going like the Sun while still doing 88 00:03:11,900 --> 00:03:09,810 that while traveling hypersonically the 89 00:03:13,129 --> 00:03:11,910 spacecraft's got to target the landing 90 00:03:15,199 --> 00:03:13,139 site we got to actually steer the 91 00:03:17,059 --> 00:03:15,209 vehicle propulsively to fly where we 92 00:03:20,990 --> 00:03:17,069 want to go and that just gets us down to 93 00:03:22,400 --> 00:03:21,000 were slow to you know about Mach 2 a 94 00:03:24,500 --> 00:03:22,410 little under 2 times the speed of sound 95 00:03:26,509 --> 00:03:24,510 where we deploy a massive supersonic 96 00:03:27,080 --> 00:03:26,519 parachute at that point we got to figure 97 00:03:28,640 --> 00:03:27,090 out where we are 98 00:03:30,050 --> 00:03:28,650 that means popping off the heat shield 99 00:03:32,150 --> 00:03:30,060 take a look at the ground with the radar 100 00:03:34,069 --> 00:03:32,160 and our new terrain relative navigation 101 00:03:36,140 --> 00:03:34,079 system and then trying to figure out 102 00:03:38,089 --> 00:03:36,150 when the best time is to to start 103 00:03:39,999 --> 00:03:38,099 powered flight that's usually when we 104 00:03:42,499 --> 00:03:40,009 get down to about 2 kilometers altitude 105 00:03:44,539 --> 00:03:42,509 so there will right low light up our 106 00:03:45,890 --> 00:03:44,549 rocket engines and fly down to about 20 107 00:03:48,319 --> 00:03:45,900 meters above the ground 108 00:03:49,729 --> 00:03:48,329 and slow down to about one and a half 109 00:03:51,920 --> 00:03:49,739 miles an hour point seven five meters 110 00:03:53,420 --> 00:03:51,930 per second and land the same way that 111 00:03:55,699 --> 00:03:53,430 curiosity did with the sky crane 112 00:03:57,280 --> 00:03:55,709 maneuver putting the perseverance Rover 113 00:03:59,300 --> 00:03:57,290 right on its wheels on the ground and 114 00:04:00,890 --> 00:03:59,310 the face crafts got to do that all 115 00:04:02,750 --> 00:04:00,900 autonomously right this we can't 116 00:04:04,429 --> 00:04:02,760 joystick it on the way in the 117 00:04:07,130 --> 00:04:04,439 spacecrafts on its own and has to it has 118 00:04:09,170 --> 00:04:07,140 to do that entire set of events on its 119 00:04:11,569 --> 00:04:09,180 own to help deal with those challenges 120 00:04:12,710 --> 00:04:11,579 we've spent over seven years my team's 121 00:04:14,569 --> 00:04:12,720 been working on this for over seven 122 00:04:16,640 --> 00:04:14,579 years to get those seven minutes of ETL 123 00:04:18,020 --> 00:04:16,650 to go right we needed to come up with a 124 00:04:19,340 --> 00:04:18,030 design that could get us to the places 125 00:04:21,580 --> 00:04:19,350 that we wanted to go the sites that 126 00:04:24,320 --> 00:04:21,590 folks wanted to go take this mission to 127 00:04:26,480 --> 00:04:24,330 for the the types of objectives we have 128 00:04:28,550 --> 00:04:26,490 once we're on the ground we also had to 129 00:04:29,980 --> 00:04:28,560 be sure that we could see we could take 130 00:04:32,480 --> 00:04:29,990 whatever Mars could throw at it 131 00:04:34,219 --> 00:04:32,490 different places have on Mars just like 132 00:04:35,540 --> 00:04:34,229 here on earth have different terrains we 133 00:04:38,420 --> 00:04:35,550 have to land on that means different 134 00:04:39,920 --> 00:04:38,430 sets of rocks and slopes and craters to 135 00:04:41,360 --> 00:04:39,930 deal with it also means that the weather 136 00:04:42,800 --> 00:04:41,370 is different different places so we have 137 00:04:44,839 --> 00:04:42,810 to deal with different types of 138 00:04:46,610 --> 00:04:44,849 atmospheres and structures that could 139 00:04:48,499 --> 00:04:46,620 occur at different places we've also 140 00:04:50,270 --> 00:04:48,509 done in that in their time a lot of 141 00:04:52,430 --> 00:04:50,280 testing we've been testing supersonic 142 00:04:53,870 --> 00:04:52,440 parachutes testing heat shields testing 143 00:04:56,000 --> 00:04:53,880 the materials that go on heat shields 144 00:04:57,260 --> 00:04:56,010 testing sensors all the sensors we need 145 00:04:59,659 --> 00:04:57,270 for the spacecraft to figure out what's 146 00:05:01,490 --> 00:04:59,669 going on testing our computers and the 147 00:05:03,379 --> 00:05:01,500 flight software but we can't test 148 00:05:05,779 --> 00:05:03,389 everything we can't test the whole thing 149 00:05:07,100 --> 00:05:05,789 and and like it would work on Mars 150 00:05:08,330 --> 00:05:07,110 because Earth is different it's just 151 00:05:09,890 --> 00:05:08,340 different in gravity different in 152 00:05:12,500 --> 00:05:09,900 atmosphere and the places are different 153 00:05:15,290 --> 00:05:12,510 too so we also have to fold in a lot of 154 00:05:16,520 --> 00:05:15,300 simulation work to help us understand if 155 00:05:19,159 --> 00:05:16,530 we're gonna make it successfully to the 156 00:05:21,649 --> 00:05:19,169 ground at jezero someone once told me 157 00:05:23,330 --> 00:05:21,659 right that a wise man once told me that 158 00:05:25,850 --> 00:05:23,340 you never stop testing or simulating in 159 00:05:27,589 --> 00:05:25,860 this case - you just run out of time so 160 00:05:27,890 --> 00:05:27,599 even though spacecrafts almost ready to 161 00:05:30,080 --> 00:05:27,900 launch 162 00:05:32,210 --> 00:05:30,090 you know we're bummed up and getting - 163 00:05:34,640 --> 00:05:32,220 getting to go to the pad next next month 164 00:05:36,529 --> 00:05:34,650 or so in the next month and a half we 165 00:05:38,540 --> 00:05:36,539 are still going to test and simulate 166 00:05:42,680 --> 00:05:38,550 until we run out of time in February 167 00:05:44,570 --> 00:05:42,690 about 280 days from now that's amazing 168 00:05:46,580 --> 00:05:44,580 out and I know that when we were talking 169 00:05:48,790 --> 00:05:46,590 earlier you said it's almost lessened 170 00:05:51,800 --> 00:05:48,800 doll you just keep shedding those pieces 171 00:05:53,870 --> 00:05:51,810 until you come prize of course the rover 172 00:05:55,550 --> 00:05:53,880 being in the middle of it all so it's 173 00:05:58,190 --> 00:05:55,560 very well choreographed but you said 174 00:06:00,410 --> 00:05:58,200 that the new EDL and treat descent 175 00:06:03,710 --> 00:06:00,420 landing camera system is really gonna 176 00:06:05,270 --> 00:06:03,720 help you guys out yeah we have an 177 00:06:07,730 --> 00:06:05,280 interest in landing camera system to 178 00:06:08,990 --> 00:06:07,740 help us do a couple things well with the 179 00:06:10,580 --> 00:06:09,000 system itself we'll show you what it's 180 00:06:11,750 --> 00:06:10,590 like to actually land on Mars we have 181 00:06:13,310 --> 00:06:11,760 cameras that will look up with the 182 00:06:14,780 --> 00:06:13,320 parachute we've never seen a supersonic 183 00:06:16,580 --> 00:06:14,790 parachute inflate on another planet 184 00:06:18,530 --> 00:06:16,590 before so we have three cameras looking 185 00:06:21,080 --> 00:06:18,540 up there and then we have the camera 186 00:06:22,850 --> 00:06:21,090 looking down from the descent stage at 187 00:06:23,900 --> 00:06:22,860 the rover and then one from the rover 188 00:06:26,630 --> 00:06:23,910 looking up the descent stage we can 189 00:06:28,730 --> 00:06:26,640 actually see us pay off the rover during 190 00:06:29,930 --> 00:06:28,740 sky crane I also have a camera on the 191 00:06:32,480 --> 00:06:29,940 bottom of the rover looking down at the 192 00:06:33,740 --> 00:06:32,490 ground rushing up to us so once we land 193 00:06:36,410 --> 00:06:33,750 we'll be able to get all that data back 194 00:06:39,250 --> 00:06:36,420 and use that to see exactly what what 195 00:06:42,100 --> 00:06:39,260 EDL looks like when you're on board and 196 00:06:44,090 --> 00:06:42,110 the rover was a recently named 197 00:06:47,540 --> 00:06:44,100 perseverance and what does that name 198 00:06:49,400 --> 00:06:47,550 mean to you personally well to me 199 00:06:50,960 --> 00:06:49,410 perseverance is all about sticking with 200 00:06:52,610 --> 00:06:50,970 it and you know if when you get knocked 201 00:06:54,170 --> 00:06:52,620 down getting back up again you know 202 00:06:56,270 --> 00:06:54,180 you've got to have a lot of focus here 203 00:06:58,100 --> 00:06:56,280 to work on these kind of things I worked 204 00:06:59,450 --> 00:06:58,110 on curiosity for 10 years to get that 205 00:07:01,700 --> 00:06:59,460 entry descent landing that's seven 206 00:07:03,260 --> 00:07:01,710 minutes of ETL to go right and it'll be 207 00:07:05,540 --> 00:07:03,270 over eight years for a lot of my team by 208 00:07:07,220 --> 00:07:05,550 time we land for this mission to get 209 00:07:08,480 --> 00:07:07,230 those seven minutes to go right and 210 00:07:10,100 --> 00:07:08,490 throughout that time right you have good 211 00:07:11,780 --> 00:07:10,110 days and you have bad days right and the 212 00:07:14,090 --> 00:07:11,790 the bad days make make you want to stop 213 00:07:15,830 --> 00:07:14,100 but you just got to pick yourself up and 214 00:07:16,820 --> 00:07:15,840 know that there's gonna be there's going 215 00:07:19,190 --> 00:07:16,830 to be challenges that you have to deal 216 00:07:23,540 --> 00:07:19,200 with push through those and yearly 217 00:07:25,550 --> 00:07:23,550 weight the next one that's awesome so 218 00:07:27,650 --> 00:07:25,560 now Mars 2020 is landing as you 219 00:07:29,720 --> 00:07:27,660 mentioned in your first answer in jezero 220 00:07:32,660 --> 00:07:29,730 crater now that site was actually deemed 221 00:07:35,060 --> 00:07:32,670 unsafe for previous Mars missions and 222 00:07:37,310 --> 00:07:35,070 MSL so tell me a little bit of what has 223 00:07:39,140 --> 00:07:37,320 changed for this mission now that you're 224 00:07:40,640 --> 00:07:39,150 landing at it it's not a parking lot you 225 00:07:41,990 --> 00:07:40,650 always say it's a little bit scarier 226 00:07:44,960 --> 00:07:42,000 when you're landing in a place like 227 00:07:46,850 --> 00:07:44,970 jezero crater yeah it's definitely a lot 228 00:07:48,590 --> 00:07:46,860 scarier in fact I was on the team right 229 00:07:50,390 --> 00:07:48,600 that assessed jezero is being unsafe for 230 00:07:52,250 --> 00:07:50,400 curiosity and even though our entry 231 00:07:54,560 --> 00:07:52,260 descent landing system looks the same 232 00:07:56,120 --> 00:07:54,570 from the outside we have a couple of 233 00:07:57,530 --> 00:07:56,130 capabilities that we've added that are 234 00:07:59,570 --> 00:07:57,540 pretty important under the hood things 235 00:08:02,180 --> 00:07:59,580 that you might not see when you watch 236 00:08:03,470 --> 00:08:02,190 the sequence of events but are important 237 00:08:05,720 --> 00:08:03,480 for letting us go to a place like des 238 00:08:07,320 --> 00:08:05,730 Rosiers safely it's the the only reason 239 00:08:09,540 --> 00:08:07,330 why I'm willing to go there now actually 240 00:08:11,450 --> 00:08:09,550 and these two capabilities are arranged 241 00:08:13,710 --> 00:08:11,460 Trigger and Turan relative navigation 242 00:08:15,450 --> 00:08:13,720 brain trigger is the ability to deploy 243 00:08:17,909 --> 00:08:15,460 the parachute based on navigated 244 00:08:19,260 --> 00:08:17,919 position back on curiosity we deployed 245 00:08:20,580 --> 00:08:19,270 the parachute just on reaching a 246 00:08:23,309 --> 00:08:20,590 velocity when you get to a certain 247 00:08:25,589 --> 00:08:23,319 velocity about Mach 1.75 deploy the 248 00:08:28,110 --> 00:08:25,599 parachute this time with perseverance 249 00:08:29,550 --> 00:08:28,120 will ask the spacecraft to figure out 250 00:08:31,409 --> 00:08:29,560 where it is as it's going throughout 251 00:08:33,509 --> 00:08:31,419 entry and when it not only gets to the 252 00:08:35,519 --> 00:08:33,519 right velocity but the right place will 253 00:08:36,810 --> 00:08:35,529 deploy the parachute in fact curiosity 254 00:08:39,509 --> 00:08:36,820 actually knew that it was a little bit 255 00:08:41,130 --> 00:08:39,519 past the parachute deploy target when it 256 00:08:42,959 --> 00:08:41,140 deployed its parachute but didn't really 257 00:08:44,759 --> 00:08:42,969 have any anything to do we couldn't do 258 00:08:46,769 --> 00:08:44,769 anything about it this time perseverance 259 00:08:48,509 --> 00:08:46,779 cat it'll use that information about 260 00:08:51,150 --> 00:08:48,519 where it is and deploy that parachute 261 00:08:52,500 --> 00:08:51,160 even more precisely that's allowing us 262 00:08:54,180 --> 00:08:52,510 to shrink our landing uncertainty 263 00:08:56,400 --> 00:08:54,190 ellipse where we could end up to about 264 00:08:58,530 --> 00:08:56,410 an 8 kilometer circle so we can land 265 00:09:00,960 --> 00:08:58,540 within 4 kilometers of a given target on 266 00:09:03,960 --> 00:09:00,970 Mars as that helps us fit into tight 267 00:09:05,639 --> 00:09:03,970 places like like jezero crater the 268 00:09:07,650 --> 00:09:05,649 second capability trained relative 269 00:09:09,540 --> 00:09:07,660 navigation is something that we've added 270 00:09:11,160 --> 00:09:09,550 to the system that happens while we're 271 00:09:12,180 --> 00:09:11,170 coming down on parachute after the 272 00:09:14,730 --> 00:09:12,190 parachute is deployed and the heat 273 00:09:16,380 --> 00:09:14,740 shells off and also in the beginning 274 00:09:19,019 --> 00:09:16,390 part of powered flight when we use those 275 00:09:20,670 --> 00:09:19,029 engines what's going on here is that on 276 00:09:22,170 --> 00:09:20,680 curiosity for example we deployed the 277 00:09:24,150 --> 00:09:22,180 parrot that deployed the heat shield and 278 00:09:26,310 --> 00:09:24,160 had a camera that took pictures of the 279 00:09:27,389 --> 00:09:26,320 ground rushing up at us but we didn't 280 00:09:29,040 --> 00:09:27,399 really use those pictures for anything 281 00:09:31,800 --> 00:09:29,050 we just kind of took that took that 282 00:09:33,689 --> 00:09:31,810 video and looked at it after landing but 283 00:09:37,139 --> 00:09:33,699 it was pretty cool but we didn't try to 284 00:09:38,730 --> 00:09:37,149 use it to help us land safely here with 285 00:09:40,740 --> 00:09:38,740 perseverance we'll take pictures on the 286 00:09:42,720 --> 00:09:40,750 way down just like just like curiosity 287 00:09:45,150 --> 00:09:42,730 did but we use those pictures to match 288 00:09:47,069 --> 00:09:45,160 up with an onboard map just like you or 289 00:09:48,960 --> 00:09:47,079 I can drive around town and kind of you 290 00:09:50,189 --> 00:09:48,970 know hold out a map or you know look for 291 00:09:51,630 --> 00:09:50,199 landmarks as you look outside the window 292 00:09:52,920 --> 00:09:51,640 and match them up with your map and 293 00:09:54,540 --> 00:09:52,930 figure out where you are 294 00:09:57,329 --> 00:09:54,550 that's what perseverance is going to do 295 00:09:58,740 --> 00:09:57,339 - so on the parachute we can we can take 296 00:10:00,660 --> 00:09:58,750 those pictures figure out where we are 297 00:10:02,550 --> 00:10:00,670 and then once we get off the parachute 298 00:10:06,000 --> 00:10:02,560 and use those rocket engines we can fly 299 00:10:07,170 --> 00:10:06,010 to the nearest safe place so that's a 300 00:10:09,120 --> 00:10:07,180 that's pretty important because in the 301 00:10:11,069 --> 00:10:09,130 past we had to ensure that anywhere we 302 00:10:13,680 --> 00:10:11,079 could land anywhere where the rover 303 00:10:16,710 --> 00:10:13,690 could come down was as parking-lot as 304 00:10:18,809 --> 00:10:16,720 possible as flat as boring as free of 305 00:10:20,519 --> 00:10:18,819 rocks or slopes or anything else things 306 00:10:22,769 --> 00:10:20,529 that would kill our Rover 307 00:10:24,449 --> 00:10:22,779 as possible but now with the ability to 308 00:10:26,189 --> 00:10:24,459 figure out exactly where we are and the 309 00:10:27,959 --> 00:10:26,199 ability to fly to places nearby and 310 00:10:30,059 --> 00:10:27,969 select the nearest reachable safe spot I 311 00:10:31,829 --> 00:10:30,069 no longer need the entire place to be a 312 00:10:34,229 --> 00:10:31,839 parking lot I can have lots of little 313 00:10:36,239 --> 00:10:34,239 tiny parking lots amongst all the big 314 00:10:37,859 --> 00:10:36,249 things that people want to see and in 315 00:10:40,019 --> 00:10:37,869 fact if you look to J's row and you see 316 00:10:41,839 --> 00:10:40,029 that that big Delta in the middle that's 317 00:10:43,979 --> 00:10:41,849 so interesting to our science books 318 00:10:45,419 --> 00:10:43,989 we're targeting right on the edge of 319 00:10:47,359 --> 00:10:45,429 that Delta and I can tell you that the 320 00:10:50,309 --> 00:10:47,369 edge of that Delta is a 60 to 80 meter 321 00:10:51,749 --> 00:10:50,319 tall cliff face but we have the ability 322 00:10:53,639 --> 00:10:51,759 because if we're coming right down there 323 00:10:55,019 --> 00:10:53,649 to divert one way or the other 324 00:10:57,239 --> 00:10:55,029 once we figured out where we are and 325 00:10:58,619 --> 00:10:57,249 land safely in the safe spots that are 326 00:11:02,549 --> 00:10:58,629 nearby like the landing strip that's 327 00:11:04,259 --> 00:11:02,559 right at the bottom the Delta well we're 328 00:11:06,479 --> 00:11:04,269 getting a lot of great questions on 329 00:11:08,069 --> 00:11:06,489 social media and one actually pertains 330 00:11:10,649 --> 00:11:08,079 to what you're just talking about right 331 00:11:13,169 --> 00:11:10,659 now a land manish on twitter asks are 332 00:11:15,509 --> 00:11:13,179 there any aspects of this mission or in 333 00:11:20,279 --> 00:11:15,519 the EDL system that you're particularly 334 00:11:22,259 --> 00:11:20,289 nervous about yeah it's a that's a tough 335 00:11:24,209 --> 00:11:22,269 question because so much has to go right 336 00:11:25,169 --> 00:11:24,219 in entry descent landing and you know 337 00:11:28,469 --> 00:11:25,179 you don't get partial credit really 338 00:11:29,939 --> 00:11:28,479 there's really very little that can that 339 00:11:30,749 --> 00:11:29,949 can go wrong and then you'll still make 340 00:11:35,609 --> 00:11:30,759 it 341 00:11:36,689 --> 00:11:35,619 test you know the the things that make 342 00:11:38,969 --> 00:11:36,699 us nervous about every mission I think 343 00:11:40,439 --> 00:11:38,979 are still true here we have the our 344 00:11:42,239 --> 00:11:40,449 supersonic parachute deploying in less 345 00:11:44,099 --> 00:11:42,249 than a second I'm inflating in less than 346 00:11:46,859 --> 00:11:44,109 a second under tremendous loads 347 00:11:48,239 --> 00:11:46,869 that's certainly nerve-wracking but it's 348 00:11:50,189 --> 00:11:48,249 hard to point to anything I mean and 349 00:11:51,419 --> 00:11:50,199 everything is is dangerous that you have 350 00:11:53,729 --> 00:11:51,429 to be careful about when Mars can throw 351 00:11:55,949 --> 00:11:53,739 at you too certainly while we understand 352 00:11:57,539 --> 00:11:55,959 the train very well at jezero there are 353 00:11:59,429 --> 00:11:57,549 many hazards there and we got to make 354 00:12:04,049 --> 00:11:59,439 sure that we land in those safe tiny 355 00:12:06,359 --> 00:12:04,059 parking lots that we can find Alliston 356 00:12:11,239 --> 00:12:06,369 zero on twitter also asks what are the 357 00:12:13,139 --> 00:12:11,249 self repairing abilities of the system 358 00:12:14,639 --> 00:12:13,149 so it's all for pairing I guess 359 00:12:16,229 --> 00:12:14,649 signatory descent landing there's not a 360 00:12:18,299 --> 00:12:16,239 whole lot that we have that self 361 00:12:20,969 --> 00:12:18,309 repairing we do have a system that's 362 00:12:22,649 --> 00:12:20,979 called a second chance that we because 363 00:12:24,419 --> 00:12:22,659 as some of you may know we actually have 364 00:12:27,479 --> 00:12:24,429 two sets of avionics on the on the 365 00:12:29,099 --> 00:12:27,489 spacecraft that we can switch between in 366 00:12:31,229 --> 00:12:29,109 the event of something going really bad 367 00:12:32,969 --> 00:12:31,239 during at recent landing we have the 368 00:12:34,680 --> 00:12:32,979 ability to switch to that backup string 369 00:12:37,499 --> 00:12:34,690 and that'll executing 370 00:12:39,689 --> 00:12:37,509 a much stripped down version of entry 371 00:12:41,040 --> 00:12:39,699 descent and landing that kind of removed 372 00:12:42,509 --> 00:12:41,050 some of the some of the other 373 00:12:45,900 --> 00:12:42,519 capabilities make sure that we try to 374 00:12:47,509 --> 00:12:45,910 land so that's basically about it we 375 00:12:50,519 --> 00:12:47,519 have the ability to deal with some 376 00:12:52,259 --> 00:12:50,529 faults that in the avionics system but 377 00:12:54,360 --> 00:12:52,269 there's really not much right we can't 378 00:12:55,980 --> 00:12:54,370 put the spacecraft in safe mode there's 379 00:12:58,710 --> 00:12:55,990 no going backwards we can't you know 380 00:13:01,199 --> 00:12:58,720 give up halfway through and go back to 381 00:13:02,670 --> 00:13:01,209 before entry we pretty much have to 382 00:13:05,210 --> 00:13:02,680 power through so there's not a lot of 383 00:13:08,370 --> 00:13:05,220 self repair that's possible during ETL 384 00:13:09,870 --> 00:13:08,380 well that's why you guys test a lot and 385 00:13:11,550 --> 00:13:09,880 I'm sure range trigger and terrain 386 00:13:13,410 --> 00:13:11,560 relative navigation as you explained 387 00:13:16,499 --> 00:13:13,420 earlier is really gonna help out now 388 00:13:18,900 --> 00:13:16,509 odds gun on YouTube asks what kind of 389 00:13:22,769 --> 00:13:18,910 materials do you use for the heat shield 390 00:13:25,139 --> 00:13:22,779 which of course is very protective the 391 00:13:26,670 --> 00:13:25,149 heat shield is has the same basic design 392 00:13:28,829 --> 00:13:26,680 the same thermal protection system 393 00:13:30,240 --> 00:13:28,839 material that curiosity did which is 394 00:13:32,400 --> 00:13:30,250 something called pica which is a 395 00:13:35,309 --> 00:13:32,410 phenolic impregnated carbon ablator 396 00:13:38,009 --> 00:13:35,319 so it's an ablative material that's put 397 00:13:39,749 --> 00:13:38,019 on the heat shield and tiles very much 398 00:13:45,720 --> 00:13:39,759 like what we've done on curiosity in the 399 00:13:47,819 --> 00:13:45,730 past and John on YouTube asks since EDL 400 00:13:50,639 --> 00:13:47,829 for perseverance is based on the 401 00:13:53,040 --> 00:13:50,649 strategy for curiosity can you highlight 402 00:13:56,449 --> 00:13:53,050 what the changes and upgrades have been 403 00:13:59,280 --> 00:13:56,459 that you've made in the last eight years 404 00:14:00,980 --> 00:13:59,290 one of the fun things about about 405 00:14:03,449 --> 00:14:00,990 perseverance actually is that you 406 00:14:05,100 --> 00:14:03,459 because it has so much commonality to 407 00:14:06,540 --> 00:14:05,110 curiosity you actually get a chance to 408 00:14:08,249 --> 00:14:06,550 make to fix some of the mistakes you 409 00:14:10,170 --> 00:14:08,259 make last time and we actually made a 410 00:14:11,850 --> 00:14:10,180 couple mistakes on on MSL and got away 411 00:14:13,980 --> 00:14:11,860 with it and have managed to fix them for 412 00:14:15,240 --> 00:14:13,990 Mars 2020 so in addition to the new 413 00:14:17,670 --> 00:14:15,250 capabilities like terrain relative 414 00:14:19,410 --> 00:14:17,680 navigation and range trigger we've 415 00:14:21,389 --> 00:14:19,420 managed to go back and take a look at 416 00:14:23,160 --> 00:14:21,399 some of the issues we had on curiosity 417 00:14:24,420 --> 00:14:23,170 noting which there was so super 418 00:14:27,030 --> 00:14:24,430 significant right we still made it 419 00:14:29,550 --> 00:14:27,040 safely without much problems but we had 420 00:14:32,040 --> 00:14:29,560 a chance to to really dig deep again and 421 00:14:33,689 --> 00:14:32,050 look at our design you know because just 422 00:14:35,939 --> 00:14:33,699 landing safely once isn't enough to 423 00:14:37,769 --> 00:14:35,949 prove that your system works so we spent 424 00:14:39,840 --> 00:14:37,779 a lot of time over the past years poring 425 00:14:41,939 --> 00:14:39,850 over the data from curiosity so we've 426 00:14:43,410 --> 00:14:41,949 made some changes the one of the things 427 00:14:45,030 --> 00:14:43,420 we noticed on curiosity is that we 428 00:14:47,250 --> 00:14:45,040 actually touched down a little slower 429 00:14:48,450 --> 00:14:47,260 than we had intended because we didn't 430 00:14:51,240 --> 00:14:48,460 get the local grab 431 00:14:52,470 --> 00:14:51,250 at Gale Crater correct Gale Crater is 432 00:14:54,120 --> 00:14:52,480 actually a pretty challenging site from 433 00:14:56,550 --> 00:14:54,130 a gravity modeling perspective it's a 434 00:14:57,600 --> 00:14:56,560 pretty deep hole with a pretty big 435 00:14:59,100 --> 00:14:57,610 mountain in the middle of it and we 436 00:15:00,510 --> 00:14:59,110 didn't get the local grabby right and as 437 00:15:00,840 --> 00:15:00,520 a result we actually touch down a little 438 00:15:02,760 --> 00:15:00,850 slower 439 00:15:04,500 --> 00:15:02,770 which is fine right that's not actually 440 00:15:06,360 --> 00:15:04,510 much of an issue it consumes a little 441 00:15:09,540 --> 00:15:06,370 bit more fuel but we've corrected that 442 00:15:12,300 --> 00:15:09,550 issue for for Mars 2020 so that we have 443 00:15:15,240 --> 00:15:12,310 a we think a much better higher fidelity 444 00:15:17,460 --> 00:15:15,250 model of Jezreel so we won't experience 445 00:15:18,660 --> 00:15:17,470 that problem again so that's just an 446 00:15:21,350 --> 00:15:18,670 example of the type of thing we've been 447 00:15:25,470 --> 00:15:21,360 we've been working on since curiosity 448 00:15:27,630 --> 00:15:25,480 and you've also been testing landing in 449 00:15:29,639 --> 00:15:27,640 the Mars atmosphere we talked earlier 450 00:15:31,350 --> 00:15:29,649 about surface pressure readings and 451 00:15:32,910 --> 00:15:31,360 you've protected the wind sensors a 452 00:15:35,850 --> 00:15:32,920 little bit more on the weather center 453 00:15:38,250 --> 00:15:35,860 that is actually on perserverence 454 00:15:42,840 --> 00:15:38,260 and Sonya on you to know what kind of 455 00:15:44,100 --> 00:15:42,850 atmosphere does Mars have Mars 456 00:15:45,449 --> 00:15:44,110 atmosphere is much thinner than that of 457 00:15:48,540 --> 00:15:45,459 Earth's it's about one percent the 458 00:15:50,639 --> 00:15:48,550 density of Earth and it's about 95 459 00:15:52,920 --> 00:15:50,649 percent carbon dioxide and five percent 460 00:15:54,720 --> 00:15:52,930 who cares it's mostly carbon dioxide 461 00:15:57,269 --> 00:15:54,730 it's very little other stuff that 462 00:16:00,000 --> 00:15:57,279 matters from a entry descent landing 463 00:16:01,560 --> 00:16:00,010 perspective so it's actually you know in 464 00:16:02,880 --> 00:16:01,570 some sense carbon dioxide from an 465 00:16:04,560 --> 00:16:02,890 aerodynamics perspective behave 466 00:16:07,170 --> 00:16:04,570 similarly it's the most of the density 467 00:16:10,410 --> 00:16:07,180 that's an issue for us and that's the 468 00:16:11,940 --> 00:16:10,420 that's the big difference for us and you 469 00:16:12,780 --> 00:16:11,950 had mentioned before for entry descent 470 00:16:16,050 --> 00:16:12,790 and landing 471 00:16:18,810 --> 00:16:16,060 how do winds play a variation when it 472 00:16:20,070 --> 00:16:18,820 comes to your landing techniques sure 473 00:16:21,360 --> 00:16:20,080 winds are definitely something that 474 00:16:23,310 --> 00:16:21,370 we're paying attention to and if you 475 00:16:24,990 --> 00:16:23,320 think getting the weather right is hard 476 00:16:27,360 --> 00:16:25,000 here on earth with our weather forecasts 477 00:16:28,829 --> 00:16:27,370 try forecasting the the weather at a 478 00:16:31,079 --> 00:16:28,839 place you've never been to with no 479 00:16:33,569 --> 00:16:31,089 weather satellites and all that in a 480 00:16:35,699 --> 00:16:33,579 season in the future so that's what our 481 00:16:37,530 --> 00:16:35,709 job is to win definitely pushes us 482 00:16:40,890 --> 00:16:37,540 around both literally and and 483 00:16:43,560 --> 00:16:40,900 figuratively we have a lot of events on 484 00:16:45,030 --> 00:16:43,570 the vehicle that are Mach sensitive so 485 00:16:46,230 --> 00:16:45,040 their their wind speed sensitive things 486 00:16:48,150 --> 00:16:46,240 like parachute deploy and heat shield 487 00:16:49,829 --> 00:16:48,160 separation so the wind certainly plays 488 00:16:52,139 --> 00:16:49,839 into a factor there but the biggest 489 00:16:54,360 --> 00:16:52,149 effect really for us in in entry descent 490 00:16:55,889 --> 00:16:54,370 landing is when we're on parachute we're 491 00:16:57,420 --> 00:16:55,899 kind of at the mercy of the wind when 492 00:16:59,100 --> 00:16:57,430 we're on were coming down on parachute 493 00:17:01,470 --> 00:16:59,110 we don't have the ability to steer the 494 00:17:02,280 --> 00:17:01,480 vehicle at that point so the wind 495 00:17:04,230 --> 00:17:02,290 uncertainty that we 496 00:17:05,970 --> 00:17:04,240 is a big contributor is perhaps the 497 00:17:07,590 --> 00:17:05,980 biggest contributor really to our 498 00:17:10,259 --> 00:17:07,600 uncertainty and where we touch down 499 00:17:13,350 --> 00:17:10,269 because that pushes us around so that a 500 00:17:15,449 --> 00:17:13,360 kilometer long or they kilometer circle 501 00:17:19,679 --> 00:17:15,459 of ellipse that we have is dominated by 502 00:17:21,419 --> 00:17:19,689 that by atmospheric uncertainty this is 503 00:17:23,909 --> 00:17:21,429 an interesting question from Trina on 504 00:17:27,750 --> 00:17:23,919 YouTube she wants to know what material 505 00:17:29,220 --> 00:17:27,760 is a supersonic parachute made of it's 506 00:17:31,980 --> 00:17:29,230 perhaps not that surprising but 507 00:17:34,590 --> 00:17:31,990 parachute materials mostly nylon there's 508 00:17:36,899 --> 00:17:34,600 also other other other materials in the 509 00:17:38,370 --> 00:17:36,909 background and others in the skeleton of 510 00:17:40,500 --> 00:17:38,380 the parachute for the broad cuddle is 511 00:17:43,710 --> 00:17:40,510 not we actually strengthen that 512 00:17:44,970 --> 00:17:43,720 parachute since MSL not because of 513 00:17:47,340 --> 00:17:44,980 anything that we saw on curiosity 514 00:17:49,230 --> 00:17:47,350 apologize curiosity was the Mars Science 515 00:17:51,389 --> 00:17:49,240 Laboratory mission so I drop into that 516 00:17:53,159 --> 00:17:51,399 every now and then but since curiosity 517 00:17:55,200 --> 00:17:53,169 we have done some additional parachute 518 00:17:57,330 --> 00:17:55,210 development work in the low density 519 00:17:59,399 --> 00:17:57,340 supersonic decelerator project and then 520 00:18:01,799 --> 00:17:59,409 made us think that perhaps we don't have 521 00:18:03,570 --> 00:18:01,809 we didn't have quite as much margin in 522 00:18:04,049 --> 00:18:03,580 what the parachutes could handle as we 523 00:18:07,950 --> 00:18:04,059 thought 524 00:18:09,659 --> 00:18:07,960 I'm so in the Mars 2020 had a program 525 00:18:12,720 --> 00:18:09,669 that tested our parachutes 526 00:18:14,310 --> 00:18:12,730 supersonically with launches on sounding 527 00:18:16,740 --> 00:18:14,320 rockets out of the Wallops Flight 528 00:18:21,149 --> 00:18:16,750 Facility over and over in the Virginia 529 00:18:22,590 --> 00:18:21,159 and Maryland area Connor on YouTube asks 530 00:18:26,430 --> 00:18:22,600 does perseverance have a backup 531 00:18:27,899 --> 00:18:26,440 parachute yeah it's just like if you 532 00:18:30,090 --> 00:18:27,909 skydive if you would have backup 533 00:18:31,919 --> 00:18:30,100 parachute but we do not 534 00:18:33,330 --> 00:18:31,929 pretty much everything has to work the 535 00:18:36,149 --> 00:18:33,340 first time for us and that includes only 536 00:18:39,570 --> 00:18:36,159 one parachute so yeah it's got to work 537 00:18:40,950 --> 00:18:39,580 perhaps why it jumped to mind when with 538 00:18:45,629 --> 00:18:40,960 that other question about one my nervous 539 00:18:47,730 --> 00:18:45,639 about precisely and that's why you do so 540 00:18:49,980 --> 00:18:47,740 much testing and that's why a maiya on 541 00:18:53,129 --> 00:18:49,990 youtube asks how do you actually test 542 00:18:54,570 --> 00:18:53,139 the EDL systems I know that it is a 543 00:18:56,899 --> 00:18:54,580 process and like you said you'll be 544 00:19:00,000 --> 00:18:56,909 testing up until the very last moment 545 00:19:02,009 --> 00:19:00,010 yeah they there's a there's a mantra JPL 546 00:19:04,409 --> 00:19:02,019 they like to say test as you fly and fly 547 00:19:05,850 --> 00:19:04,419 as you text but what happens when you 548 00:19:07,320 --> 00:19:05,860 can't test is you flying right you can't 549 00:19:08,789 --> 00:19:07,330 do an end-to-end test of the entry 550 00:19:10,710 --> 00:19:08,799 descent landing system even if you 551 00:19:12,720 --> 00:19:10,720 wanted to here on earth even if we you 552 00:19:14,369 --> 00:19:12,730 know had the resources to do it so much 553 00:19:16,049 --> 00:19:14,379 is different about earth between the 554 00:19:16,300 --> 00:19:16,059 atmosphere and the gravity and and all 555 00:19:24,640 --> 00:19:16,310 that 556 00:19:27,040 --> 00:19:24,650 entry descent and landing world to to 557 00:19:28,930 --> 00:19:27,050 say simulate as he fly and fly as you 558 00:19:30,250 --> 00:19:28,940 simulate that's not saying that we don't 559 00:19:31,930 --> 00:19:30,260 do a lot of testing we're doing a lot of 560 00:19:34,030 --> 00:19:31,940 testing at the component level we've 561 00:19:36,070 --> 00:19:34,040 hired engines so actually flown 562 00:19:38,170 --> 00:19:36,080 propellant through them and seeing how 563 00:19:39,760 --> 00:19:38,180 they behave we've tested the parachute 564 00:19:42,040 --> 00:19:39,770 individually we certainly tested parts 565 00:19:44,740 --> 00:19:42,050 of the heat shield material individually 566 00:19:46,480 --> 00:19:44,750 and the radar certainly we radar and 567 00:19:47,680 --> 00:19:46,490 lander vision system right the part of 568 00:19:49,870 --> 00:19:47,690 the training relative navigation system 569 00:19:51,730 --> 00:19:49,880 we were actually able to take out to the 570 00:19:53,230 --> 00:19:51,740 desert under a helicopter and fly over 571 00:19:54,850 --> 00:19:53,240 Mars like terrain and even more 572 00:19:58,060 --> 00:19:54,860 challenging conditions to show that it 573 00:19:59,920 --> 00:19:58,070 works um so we take those pieces and 574 00:20:01,930 --> 00:19:59,930 then model the tests in some sense to 575 00:20:03,340 --> 00:20:01,940 improve our models and then use them and 576 00:20:05,950 --> 00:20:03,350 put those models together into a 577 00:20:07,810 --> 00:20:05,960 simulation to do the end end testing so 578 00:20:09,580 --> 00:20:07,820 the answer really is we try to test as 579 00:20:10,630 --> 00:20:09,590 much as we can up to the level you know 580 00:20:12,460 --> 00:20:10,640 the highest level we can try to 581 00:20:15,810 --> 00:20:12,470 integrate as much as we can and then put 582 00:20:20,290 --> 00:20:15,820 the rest of it together in simulation 583 00:20:22,810 --> 00:20:20,300 and Yaroslav from YouTube wants to know 584 00:20:26,140 --> 00:20:22,820 will perseverance land on Mars at night 585 00:20:28,660 --> 00:20:26,150 or day or does it really matter okay 586 00:20:31,000 --> 00:20:28,670 we're gonna land about 3:30 p.m. local 587 00:20:32,410 --> 00:20:31,010 time on Mars I like to joke that it's 588 00:20:35,680 --> 00:20:32,420 always three o'clock on Mars to me 589 00:20:38,050 --> 00:20:35,690 because we like to land underneath our 590 00:20:39,910 --> 00:20:38,060 orbiters and our orders typically are 591 00:20:42,280 --> 00:20:39,920 going overhead every at the local time 592 00:20:43,540 --> 00:20:42,290 about 3 p.m. every day and for 593 00:20:46,060 --> 00:20:43,550 communication reasons we want to make 594 00:20:48,360 --> 00:20:46,070 sure that we are able to send data from 595 00:20:50,800 --> 00:20:48,370 entry descent landing and relay at home 596 00:20:52,660 --> 00:20:50,810 through missions like the Mars 597 00:20:54,730 --> 00:20:52,670 Reconnaissance Orbiter so typically 598 00:20:56,650 --> 00:20:54,740 we've tried to land at that local time 599 00:21:01,060 --> 00:20:56,660 to make sure that we can send that data 600 00:21:02,950 --> 00:21:01,070 home Isaiah has a great question from 601 00:21:05,760 --> 00:21:02,960 YouTube can you talk about how you use 602 00:21:08,440 --> 00:21:05,770 radar to help land is it similar to 603 00:21:11,980 --> 00:21:08,450 ultrasonic sensors for determining 604 00:21:14,200 --> 00:21:11,990 altitude yes so we definitely are using 605 00:21:16,090 --> 00:21:14,210 a radar just like curiosity did after 606 00:21:18,700 --> 00:21:16,100 that heat shield comes off we've the 607 00:21:20,590 --> 00:21:18,710 first thing we turn on is that radar to 608 00:21:23,410 --> 00:21:20,600 make sure that we get precise position 609 00:21:25,750 --> 00:21:23,420 and velocity that means that we get we 610 00:21:27,760 --> 00:21:25,760 get that we get our position our 611 00:21:28,990 --> 00:21:27,770 altitude from all the six beams that we 612 00:21:29,890 --> 00:21:29,000 have at the front of the descent stage 613 00:21:31,660 --> 00:21:29,900 point 614 00:21:34,300 --> 00:21:31,670 the ground that'll also give us velocity 615 00:21:37,450 --> 00:21:34,310 once we're down low to accuracies of 616 00:21:39,760 --> 00:21:37,460 about 0.1 meter per second or so so we 617 00:21:41,590 --> 00:21:39,770 get both velocity and altitude from that 618 00:21:46,060 --> 00:21:41,600 ka-band radar it's at the front of the 619 00:21:48,130 --> 00:21:46,070 descent stage and going back to when we 620 00:21:50,860 --> 00:21:48,140 talked about how it's like Russian dolls 621 00:21:53,110 --> 00:21:50,870 because you keep having to shed pieces 622 00:21:55,390 --> 00:21:53,120 of the vehicle as you go along like you 623 00:21:58,060 --> 00:21:55,400 said from 12,000 miles per hour to 2 624 00:22:02,560 --> 00:21:58,070 miles per hour in those 7 minutes can 625 00:22:05,020 --> 00:22:02,570 you talk about how the parachute doesn't 626 00:22:06,460 --> 00:22:05,030 come down on the landed Rover that's 627 00:22:08,050 --> 00:22:06,470 what Jim would like to know on youtube 628 00:22:10,080 --> 00:22:08,060 but there's many pieces that you want to 629 00:22:12,400 --> 00:22:10,090 make sure don't land on that Rover 630 00:22:13,630 --> 00:22:12,410 absolutely we're certainly from even 631 00:22:15,640 --> 00:22:13,640 before the start of entry descent 632 00:22:17,590 --> 00:22:15,650 landing casting off pieces that we don't 633 00:22:19,870 --> 00:22:17,600 need of the spacecraft anymore first 634 00:22:22,090 --> 00:22:19,880 with the crew stage which we actually 635 00:22:23,500 --> 00:22:22,100 steer away from a little bit with in the 636 00:22:25,390 --> 00:22:23,510 atmosphere we're flying away from the 637 00:22:27,940 --> 00:22:25,400 crew stage and the crews down smashes 638 00:22:29,860 --> 00:22:27,950 that come off before entry once we get 639 00:22:31,060 --> 00:22:29,870 down low of course once we deploy the 640 00:22:33,070 --> 00:22:31,070 parachute we have to drop that heat 641 00:22:35,920 --> 00:22:33,080 shield that heat shield typically goes a 642 00:22:37,900 --> 00:22:35,930 bit further down from where from where 643 00:22:39,490 --> 00:22:37,910 we're at and then I think specifically 644 00:22:41,410 --> 00:22:39,500 to the question there's the back schlump 645 00:22:43,150 --> 00:22:41,420 air chute which is a concern the 646 00:22:44,710 --> 00:22:43,160 backshell parachute we have a couple of 647 00:22:46,660 --> 00:22:44,720 things that we need to worry about first 648 00:22:48,280 --> 00:22:46,670 as we drop out and then start lighting 649 00:22:49,990 --> 00:22:48,290 up those engines is slowing down we 650 00:22:51,460 --> 00:22:50,000 don't want that back chill in parachute 651 00:22:53,380 --> 00:22:51,470 to hit us in the back of the head so 652 00:22:55,510 --> 00:22:53,390 that's kind of the the near-term problem 653 00:22:57,010 --> 00:22:55,520 so we actually do a different maneuver 654 00:22:58,690 --> 00:22:57,020 so while we're selecting a safe landing 655 00:23:00,220 --> 00:22:58,700 target we're usually flying a bit 656 00:23:01,810 --> 00:23:00,230 sideways of the direction we're flying 657 00:23:03,970 --> 00:23:01,820 to get out of the way of where the 658 00:23:05,710 --> 00:23:03,980 parachute and actual aren't going so 659 00:23:07,990 --> 00:23:05,720 that's part of the near-term avoidance 660 00:23:09,820 --> 00:23:08,000 is we select the landing target that's 661 00:23:11,710 --> 00:23:09,830 that's good from a landing safety 662 00:23:12,790 --> 00:23:11,720 perspective but we're also are dodging 663 00:23:14,860 --> 00:23:12,800 the back shell and parachute in that 664 00:23:16,420 --> 00:23:14,870 near-term and then in the long term this 665 00:23:18,190 --> 00:23:16,430 is back where the atmospheric 666 00:23:19,810 --> 00:23:18,200 uncertainty comes into play that back 667 00:23:21,760 --> 00:23:19,820 shell and parachute are floating around 668 00:23:22,930 --> 00:23:21,770 being pushed around by the wind so they 669 00:23:25,270 --> 00:23:22,940 can end up in a lot of different places 670 00:23:27,460 --> 00:23:25,280 so we also fly a minimum amount of 671 00:23:28,930 --> 00:23:27,470 distance to the side to make sure that 672 00:23:30,760 --> 00:23:28,940 we get far enough away from the back 673 00:23:32,290 --> 00:23:30,770 shell and parachute that they don't come 674 00:23:37,030 --> 00:23:32,300 down on us or we don't land on it 675 00:23:39,430 --> 00:23:37,040 depending on which one lands first as we 676 00:23:41,470 --> 00:23:39,440 said so well choreograph that's for sure 677 00:23:42,760 --> 00:23:41,480 now Robinson of Owen on Twitter asks 678 00:23:45,130 --> 00:23:42,770 what would you do if there was a 679 00:23:48,250 --> 00:23:45,140 massive dust storm raging on Mars when 680 00:23:49,330 --> 00:23:48,260 you want to land perseverance yeah 681 00:23:50,620 --> 00:23:49,340 that's a great question it's something 682 00:23:52,540 --> 00:23:50,630 we ask ourselves all the time and it's 683 00:23:54,610 --> 00:23:52,550 something that came up with the insight 684 00:23:56,740 --> 00:23:54,620 landing not that long ago since they 685 00:23:58,690 --> 00:23:56,750 actually had a dust storm in there and 686 00:24:00,850 --> 00:23:58,700 their opportunity the good news for us 687 00:24:03,100 --> 00:24:00,860 actually in in the 2020 opportunity 688 00:24:04,630 --> 00:24:03,110 watching in July and landing in February 689 00:24:06,940 --> 00:24:04,640 is that we get there in a good time of 690 00:24:09,220 --> 00:24:06,950 year we are not in global dust storm 691 00:24:11,770 --> 00:24:09,230 season or planned encircling dust storm 692 00:24:13,780 --> 00:24:11,780 season Network during that time so we've 693 00:24:16,570 --> 00:24:13,790 looked at the the history of dust storms 694 00:24:17,980 --> 00:24:16,580 at our landing site overall the record 695 00:24:19,990 --> 00:24:17,990 history really at Mars and there's never 696 00:24:22,480 --> 00:24:20,000 been a planet circling dust storm at 697 00:24:24,160 --> 00:24:22,490 that time that being said our vehicle is 698 00:24:26,500 --> 00:24:24,170 actually very capable of handling it if 699 00:24:29,830 --> 00:24:26,510 we needed to the biggest concern for us 700 00:24:31,330 --> 00:24:29,840 with with a dust storm is really about 701 00:24:32,560 --> 00:24:31,340 what it does to our atmospheric and 702 00:24:34,990 --> 00:24:32,570 certainty I told you about how that 703 00:24:36,340 --> 00:24:35,000 pushes around the dust in the atmosphere 704 00:24:37,660 --> 00:24:36,350 will push around our winds rain and 705 00:24:40,150 --> 00:24:37,670 winds is something we cook we care about 706 00:24:41,710 --> 00:24:40,160 it also affects the density but because 707 00:24:43,270 --> 00:24:41,720 we have a guided entry system a system 708 00:24:45,580 --> 00:24:43,280 that actually is adjusting to what 709 00:24:46,810 --> 00:24:45,590 atmosphere it sees as it goes in we're 710 00:24:48,790 --> 00:24:46,820 pretty confident that we can handle 711 00:24:50,650 --> 00:24:48,800 pretty big dust storms as long as we 712 00:24:53,980 --> 00:24:50,660 don't hit kind of the the storm front if 713 00:24:55,330 --> 00:24:53,990 you will of a dust storm if it's a you 714 00:24:57,100 --> 00:24:55,340 know as long as we're not so lucky that 715 00:24:59,080 --> 00:24:57,110 we manage to not just be there at the 716 00:25:00,790 --> 00:24:59,090 right time and right place to hit the 717 00:25:02,650 --> 00:25:00,800 front of a storm we feel pretty 718 00:25:04,540 --> 00:25:02,660 confident that we'd be okay but that 719 00:25:06,940 --> 00:25:04,550 being said we don't really expect a dust 720 00:25:09,280 --> 00:25:06,950 storm global dust storm anyway in our 721 00:25:14,080 --> 00:25:09,290 season at our site it just doesn't 722 00:25:15,610 --> 00:25:14,090 happen hasn't happened at Mars now 723 00:25:17,740 --> 00:25:15,620 cheryl has almost like a follow-up 724 00:25:19,420 --> 00:25:17,750 question to that on twitter and she says 725 00:25:22,090 --> 00:25:19,430 has the team done anything differently 726 00:25:25,990 --> 00:25:22,100 this time to protect perseverance from 727 00:25:28,900 --> 00:25:26,000 that Martian dust we haven't done a 728 00:25:30,190 --> 00:25:28,910 whole lot differently this time out you 729 00:25:31,960 --> 00:25:30,200 could also be thinking about the fact 730 00:25:34,570 --> 00:25:31,970 that on curiosity we blew around some 731 00:25:37,090 --> 00:25:34,580 pebbles and some ended up on the on the 732 00:25:39,220 --> 00:25:37,100 top the rover and maybe maybe it was 733 00:25:40,570 --> 00:25:39,230 related some damage certainly what we 734 00:25:42,340 --> 00:25:40,580 did was characterize what we saw in 735 00:25:43,810 --> 00:25:42,350 curiosity this isn't necessarily dust 736 00:25:45,370 --> 00:25:43,820 that's floating around the atmosphere 737 00:25:47,290 --> 00:25:45,380 the stuff that's kicked up around 738 00:25:49,180 --> 00:25:47,300 skycrane even though the sense Dage is 739 00:25:51,280 --> 00:25:49,190 pretty high and high enough that that 740 00:25:54,430 --> 00:25:51,290 we're not causing a ton of things lying 741 00:25:56,080 --> 00:25:54,440 around some some do so we made sure this 742 00:25:58,840 --> 00:25:56,090 time to make sure that the rover was 743 00:26:00,400 --> 00:25:58,850 design such that there shouldn't be too 744 00:26:01,870 --> 00:26:00,410 many vulnerabilities associated with 745 00:26:03,430 --> 00:26:01,880 those particles that we could be lifting 746 00:26:07,630 --> 00:26:03,440 through our engines being thrown around 747 00:26:09,400 --> 00:26:07,640 at the rover during sky crane and like 748 00:26:11,920 --> 00:26:09,410 we've mentioned before it seems very 749 00:26:13,990 --> 00:26:11,930 similar looking at MSL looking at 750 00:26:15,040 --> 00:26:14,000 curiosity and at perseverance but 751 00:26:16,870 --> 00:26:15,050 there's been some really great 752 00:26:19,600 --> 00:26:16,880 modifications to the wheels that'll be 753 00:26:21,910 --> 00:26:19,610 helpful absolutely those wheels are 754 00:26:23,260 --> 00:26:21,920 there's definitely little thicker I like 755 00:26:25,120 --> 00:26:23,270 to think of them as our landing gear and 756 00:26:29,320 --> 00:26:25,130 not so much as wheels but they were 757 00:26:31,900 --> 00:26:29,330 craters on our landing gear all right 758 00:26:35,380 --> 00:26:31,910 now we've also got a great question from 759 00:26:37,840 --> 00:26:35,390 Ross onic on YouTube asking in the 760 00:26:39,850 --> 00:26:37,850 unfortunate event of a failed landing is 761 00:26:42,340 --> 00:26:39,860 the video of the entry descent and 762 00:26:44,530 --> 00:26:42,350 landing being uploaded in real time to 763 00:26:47,670 --> 00:26:44,540 an orbiter so we can still see it or 764 00:26:50,110 --> 00:26:47,680 does it require a successful landing 765 00:26:52,180 --> 00:26:50,120 that's a great question unfortunately 766 00:26:54,820 --> 00:26:52,190 the the bandwidth that we have to send 767 00:26:56,350 --> 00:26:54,830 back from the vehicle during during 768 00:26:59,260 --> 00:26:56,360 entry descent landing the stream that we 769 00:27:00,250 --> 00:26:59,270 have is about 8 kilobits per second if 770 00:27:02,140 --> 00:27:00,260 you're old enough like me to remember 771 00:27:04,450 --> 00:27:02,150 dial-up that's even slower than a lot of 772 00:27:06,010 --> 00:27:04,460 people's dial-up back in the day so we 773 00:27:07,480 --> 00:27:06,020 don't have the ability to send back 774 00:27:09,520 --> 00:27:07,490 those pictures from the EDL camera 775 00:27:11,920 --> 00:27:09,530 system during entry descent landing we 776 00:27:13,120 --> 00:27:11,930 do have to land successfully that 8 777 00:27:14,890 --> 00:27:13,130 kilobits stream though is full 778 00:27:16,240 --> 00:27:14,900 chock-full of data that will help us 779 00:27:18,190 --> 00:27:16,250 figure out what's wrong that's the 780 00:27:20,410 --> 00:27:18,200 purpose really of the entry descent and 781 00:27:21,730 --> 00:27:20,420 landing comm is to make sure that if 782 00:27:23,050 --> 00:27:21,740 something goes wrong we know what 783 00:27:26,830 --> 00:27:23,060 happens so that we can fix it to the 784 00:27:30,360 --> 00:27:26,840 future now this isn't your first rodeo 785 00:27:33,210 --> 00:27:30,370 this will be your settle landing and 786 00:27:36,070 --> 00:27:33,220 Nicolas wants to know are there any 787 00:27:39,910 --> 00:27:36,080 communications involved with your entry 788 00:27:42,370 --> 00:27:39,920 system in terms of whether those 789 00:27:43,780 --> 00:27:42,380 communications involved during EDL the 790 00:27:45,580 --> 00:27:43,790 the one thing we should all keep in mind 791 00:27:47,770 --> 00:27:45,590 of course is that at least for our 792 00:27:49,600 --> 00:27:47,780 opportunity when we get there the 793 00:27:51,430 --> 00:27:49,610 one-way light time the time it takes for 794 00:27:52,930 --> 00:27:51,440 the radio waves to get from Mars is 795 00:27:55,870 --> 00:27:52,940 going to be about 10 and a half minutes 796 00:27:58,240 --> 00:27:55,880 so by the time that we find out that the 797 00:27:59,860 --> 00:27:58,250 spacecraft has hit the entry point it's 798 00:28:02,290 --> 00:27:59,870 gonna have been on the ground for about 799 00:28:04,090 --> 00:28:02,300 three and a half minutes given that ten 800 00:28:06,040 --> 00:28:04,100 and a half minute ten and a half minute 801 00:28:08,630 --> 00:28:06,050 delay so there is no choice ticking I 802 00:28:11,210 --> 00:28:08,640 mean try to imagine driving your 803 00:28:14,120 --> 00:28:11,220 your RC car with a ten minute delay 804 00:28:16,430 --> 00:28:14,130 between what you see and your commands 805 00:28:18,170 --> 00:28:16,440 back to it no spit you no perseverance 806 00:28:20,120 --> 00:28:18,180 is gonna have to do this on our own we 807 00:28:24,800 --> 00:28:20,130 have no ability to control it at that 808 00:28:27,380 --> 00:28:24,810 point we can get it ready before yes I'm 809 00:28:30,140 --> 00:28:27,390 sorry about that oh no that's okay 810 00:28:32,290 --> 00:28:30,150 yeah and now my on YouTube asks how much 811 00:28:34,940 --> 00:28:32,300 of the entire ADL system is 812 00:28:36,530 --> 00:28:34,950 pre-programmed and how much is changed 813 00:28:39,050 --> 00:28:36,540 on the fly which I guess is a nice 814 00:28:40,760 --> 00:28:39,060 follow up yeah that's a good pop I mean 815 00:28:43,310 --> 00:28:40,770 again the the entry descent landing 816 00:28:45,260 --> 00:28:43,320 sequence itself is pre-programmed and 817 00:28:47,300 --> 00:28:45,270 the spacecraft has to handle ID that 818 00:28:50,330 --> 00:28:47,310 being said it is pretty adjustable we 819 00:28:51,830 --> 00:28:50,340 can change things prior to entry if we 820 00:28:53,600 --> 00:28:51,840 need to we can adjust things like 821 00:28:56,930 --> 00:28:53,610 actually the landing target if we want 822 00:28:59,030 --> 00:28:56,940 to we can adjust we can adjust the 823 00:29:00,140 --> 00:28:59,040 parachute deploy conditions there's a 824 00:29:02,360 --> 00:29:00,150 lot of things that we can adjust with 825 00:29:04,700 --> 00:29:02,370 the vehicle and in fact that connects 826 00:29:06,680 --> 00:29:04,710 back to the activities before landing in 827 00:29:09,290 --> 00:29:06,690 that week before landing pretty much 828 00:29:10,730 --> 00:29:09,300 everything that we're doing is getting 829 00:29:12,800 --> 00:29:10,740 the spacecraft ready to land 830 00:29:14,780 --> 00:29:12,810 that means monitoring the spacecraft 831 00:29:16,040 --> 00:29:14,790 making sure that it's doing the things 832 00:29:17,660 --> 00:29:16,050 that need to do like heating up 833 00:29:19,880 --> 00:29:17,670 different elements of it warming them up 834 00:29:21,380 --> 00:29:19,890 for ETL it also means doing small 835 00:29:22,670 --> 00:29:21,390 maneuvers with the crew stage to make 836 00:29:25,010 --> 00:29:22,680 sure that were the right place to start 837 00:29:27,440 --> 00:29:25,020 ETL and it also means telling the 838 00:29:29,660 --> 00:29:27,450 spacecraft exactly where it is we kind 839 00:29:31,760 --> 00:29:29,670 of navigate during during cruise during 840 00:29:33,650 --> 00:29:31,770 that portion between launch and and 841 00:29:34,880 --> 00:29:33,660 hitting the top of the atmosphere by 842 00:29:36,890 --> 00:29:34,890 staring in the rear view mirror using 843 00:29:39,290 --> 00:29:36,900 the deep space network to do radiometric 844 00:29:41,120 --> 00:29:39,300 navigation using radio signals to 845 00:29:43,370 --> 00:29:41,130 understand where we are and we want to 846 00:29:44,930 --> 00:29:43,380 give the spacecraft the its best 847 00:29:46,610 --> 00:29:44,940 information about where it is at the 848 00:29:48,380 --> 00:29:46,620 start of EDL because it's going to use 849 00:29:53,420 --> 00:29:48,390 that to fly to the target in the 850 00:29:55,850 --> 00:29:53,430 atmosphere MTF see video channel on 851 00:29:58,220 --> 00:29:55,860 youtube asks how nervous will you be 852 00:30:00,200 --> 00:29:58,230 waiting for that signal to finally come 853 00:30:02,480 --> 00:30:00,210 back from perseverance excited to I'm 854 00:30:04,550 --> 00:30:02,490 sure yeah no it's definitely 855 00:30:06,020 --> 00:30:04,560 nerve-wracking right it's it's an open 856 00:30:07,760 --> 00:30:06,030 book it's a test that everyone gets to 857 00:30:09,830 --> 00:30:07,770 see the answer to and no one cares more 858 00:30:11,300 --> 00:30:09,840 than you I think at the time right it's 859 00:30:12,560 --> 00:30:11,310 nerve-wracking because you know you just 860 00:30:15,100 --> 00:30:12,570 go over all the things that could go 861 00:30:16,790 --> 00:30:15,110 wrong you know every minute right it's 862 00:30:18,890 --> 00:30:16,800 you know it's one of those situations 863 00:30:20,750 --> 00:30:18,900 where you want to believe that you've 864 00:30:22,040 --> 00:30:20,760 you know you can you can be there and be 865 00:30:22,440 --> 00:30:22,050 calm because you've done everything you 866 00:30:24,299 --> 00:30:22,450 can 867 00:30:25,590 --> 00:30:24,309 to make sure that you have a good day 868 00:30:27,840 --> 00:30:25,600 but you know there are things that are 869 00:30:29,609 --> 00:30:27,850 beyond your control you know things like 870 00:30:32,369 --> 00:30:29,619 the atmosphere at mars and another 871 00:30:34,889 --> 00:30:32,379 challenges that might be out there so 872 00:30:39,119 --> 00:30:34,899 you know you never can never feel really 873 00:30:41,220 --> 00:30:39,129 good until you're down safely yes I'm 874 00:30:43,259 --> 00:30:41,230 sure it's gonna feel very good now Jimin 875 00:30:45,539 --> 00:30:43,269 who's a six year old asks what is your 876 00:30:47,970 --> 00:30:45,549 favorite discovery or picture from 877 00:30:52,049 --> 00:30:47,980 curiosity and what are you looking 878 00:30:53,729 --> 00:30:52,059 forward to on perseverance I'm gonna 879 00:30:56,249 --> 00:30:53,739 cheat and actually say that my favorite 880 00:30:57,720 --> 00:30:56,259 picture is actually of curiosity from 881 00:31:00,149 --> 00:30:57,730 curiosity from the Mars Reconnaissance 882 00:31:02,789 --> 00:31:00,159 Orbiter there's a picture that people 883 00:31:04,169 --> 00:31:02,799 may have seen of Marshall concert 884 00:31:06,869 --> 00:31:04,179 orbiter which was providing us entry 885 00:31:08,609 --> 00:31:06,879 descent and communications but also took 886 00:31:10,259 --> 00:31:08,619 a picture of us on our way down with 887 00:31:12,330 --> 00:31:10,269 with curiosity you see that parachute 888 00:31:13,470 --> 00:31:12,340 deployed as we're descending so I think 889 00:31:15,419 --> 00:31:13,480 that's a that's certainly one of my 890 00:31:17,729 --> 00:31:15,429 favorite pictures but from the surface I 891 00:31:19,560 --> 00:31:17,739 loved seeing all the all the places that 892 00:31:21,419 --> 00:31:19,570 we've gone to in the years since right 893 00:31:22,440 --> 00:31:21,429 it's it's interesting to work on 894 00:31:25,080 --> 00:31:22,450 something for ten years 895 00:31:26,849 --> 00:31:25,090 land it and then kind of walk away but 896 00:31:29,399 --> 00:31:26,859 with the knowledge though that it's 897 00:31:31,169 --> 00:31:29,409 still going even even now we can still 898 00:31:33,330 --> 00:31:31,179 see pictures from curiosity every day so 899 00:31:34,769 --> 00:31:33,340 that's that's what I'm excited about but 900 00:31:36,299 --> 00:31:34,779 for perseverance I'm excited to get all 901 00:31:38,460 --> 00:31:36,309 that data that we're gonna get from the 902 00:31:40,320 --> 00:31:38,470 EDL camera system I really want to know 903 00:31:43,619 --> 00:31:40,330 what it looks like to to land on Mars 904 00:31:45,570 --> 00:31:43,629 while you're doing it that's pretty 905 00:31:47,580 --> 00:31:45,580 amazing it's gonna be great to see the 906 00:31:48,960 --> 00:31:47,590 first pictures ever of that well thank 907 00:31:50,820 --> 00:31:48,970 you so much for all of these who tuned 908 00:31:53,190 --> 00:31:50,830 in on social media your questions were 909 00:31:56,879 --> 00:31:53,200 awesome and thank you for joining us 910 00:31:57,979 --> 00:31:56,889 today al and good February thank you 911 00:32:01,259 --> 00:31:57,989 very much 912 00:32:03,690 --> 00:32:01,269 the launch period for Mars 2020 opens on 913 00:32:07,049 --> 00:32:03,700 July 17th and the rover is slated to 914 00:32:09,539 --> 00:32:07,059 land on the Red Planet February 18 20 21 915 00:32:11,849 --> 00:32:09,549 now for the latest on the mission follow 916 00:32:13,649 --> 00:32:11,859 us here at NASA persevere on both 917 00:32:15,720 --> 00:32:13,659 Twitter and Facebook and you can watch 918 00:32:19,229 --> 00:32:15,730 all of the behind the spacecraft video 919 00:32:20,909 --> 00:32:19,239 profiles they are on NASA 360s YouTube 920 00:32:23,820 --> 00:32:20,919 channel we're going to be doing these 921 00:32:26,700 --> 00:32:23,830 question and answers with Mars 2020 each 922 00:32:29,310 --> 00:32:26,710 Thursday at 1 p.m. Pacific 4 p.m. 923 00:32:31,440 --> 00:32:29,320 Eastern for the next few weeks as we are 924 00:32:33,149 --> 00:32:31,450 awaiting launch coming up in a couple of 925 00:32:33,779 --> 00:32:33,159 months if you want to explore the 926 00:32:35,639 --> 00:32:33,789 universe 927 00:32:38,070 --> 00:32:35,649 the comfort of your home check out our 928 00:32:41,009 --> 00:32:38,080 NASA at home activities for families and 929 00:32:44,489 --> 00:32:41,019 kids of all ages you can find them on 930 00:32:46,830 --> 00:32:44,499 the nasa.gov home page until then thank