1 00:00:00,000 --> 23:59:59,999 >> Hello, and welcome to NASA's Jet Propulsion Laboratory 2 00:00:00,000 --> 23:59:59,999 in Pasadena, California, I'm Preston Dyches. 3 00:00:00,000 --> 23:59:59,999 We are at the end of an era in planetary exploration. 4 00:00:00,000 --> 23:59:59,999 In less than two days, NASA's Cassini spacecraft 5 00:00:00,000 --> 23:59:59,999 will make its fateful, final plunge 6 00:00:00,000 --> 23:59:59,999 into the atmosphere of Saturn 7 00:00:00,000 --> 23:59:59,999 collecting data until the very last moment, 8 00:00:00,000 --> 23:59:59,999 as it ends its 13 year tour of the Saturn system. 9 00:00:00,000 --> 23:59:59,999 The purpose of our briefing today 10 00:00:00,000 --> 23:59:59,999 is to provide background on how we got here with Cassini, 11 00:00:00,000 --> 23:59:59,999 along with preparations for the final plunge, 12 00:00:00,000 --> 23:59:59,999 and some of the science that the Cassini team 13 00:00:00,000 --> 23:59:59,999 hopes to accomplish as Cassini heads into Saturn. 14 00:00:00,000 --> 23:59:59,999 Our participants for the briefing today are, 15 00:00:00,000 --> 23:59:59,999 from NASA headquarters in Washington, 16 00:00:00,000 --> 23:59:59,999 the Director of NASA's Planetary 17 00:00:00,000 --> 23:59:59,999 Science Division, Jim Green. 18 00:00:00,000 --> 23:59:59,999 Up next, we have the Program Manager for Cassini 19 00:00:00,000 --> 23:59:59,999 here at JPL, Earl Maize. 20 00:00:00,000 --> 23:59:59,999 To his left, the Cassini Project Scientist, Linda Spilker. 21 00:00:00,000 --> 23:59:59,999 And finally, Team Lead for Cassini's 22 00:00:00,000 --> 23:59:59,999 ion and neutral mass spectrometer instrument, 23 00:00:00,000 --> 23:59:59,999 or INMS, from Southwest Research Institute 24 00:00:00,000 --> 23:59:59,999 in San Antonio, Hunter Waite. 25 00:00:00,000 --> 23:59:59,999 Alright, a reminder to reporters dialed in on the phones, 26 00:00:00,000 --> 23:59:59,999 please dial star one to get in the queue to ask a question. 27 00:00:00,000 --> 23:59:59,999 And members of the public as well as the media 28 00:00:00,000 --> 23:59:59,999 can ask questions online via Twitter, 29 00:00:00,000 --> 23:59:59,999 using the hashtag #AskNASA. 30 00:00:00,000 --> 23:59:59,999 And with that, let's turn it over to Jim to get started. 31 00:00:00,000 --> 23:59:59,999 >> Thank you very much, Preston. 32 00:00:00,000 --> 23:59:59,999 You know, we're here at a very historic time, 33 00:00:00,000 --> 23:59:59,999 but it really started with the Voyagers, 34 00:00:00,000 --> 23:59:59,999 Voyager One and Two, as we see here in the auditorium, 35 00:00:00,000 --> 23:59:59,999 a full scale Voyager, passing through the Saturn system, 36 00:00:00,000 --> 23:59:59,999 begging us to go back. 37 00:00:00,000 --> 23:59:59,999 And of course, in 2004, Cassini made it 38 00:00:00,000 --> 23:59:59,999 to the Saturn system. 39 00:00:00,000 --> 23:59:59,999 And as you can see, Cassini, this is a smaller scale model, 40 00:00:00,000 --> 23:59:59,999 but if you can imagine the antenna size 41 00:00:00,000 --> 23:59:59,999 on Voyager being the same as Cassini, 42 00:00:00,000 --> 23:59:59,999 this is a very capable, large spacecraft 43 00:00:00,000 --> 23:59:59,999 that has been making fabulous measurements 44 00:00:00,000 --> 23:59:59,999 within the Saturn system. 45 00:00:00,000 --> 23:59:59,999 My first slide, please. 46 00:00:00,000 --> 23:59:59,999 Of course, Saturn, one of the beautiful gas giants 47 00:00:00,000 --> 23:59:59,999 in our solar system, with the beautiful rings. 48 00:00:00,000 --> 23:59:59,999 Studying the planet itself has been incredibly important. 49 00:00:00,000 --> 23:59:59,999 The cloud dynamics and the storms that occur, 50 00:00:00,000 --> 23:59:59,999 and in fact while Cassini was there, a storm that lasted 51 00:00:00,000 --> 23:59:59,999 more than nine months raged in its northern hemisphere. 52 00:00:00,000 --> 23:59:59,999 Next slide, please. 53 00:00:00,000 --> 23:59:59,999 Of course, as we were able to get to higher latitudes, 54 00:00:00,000 --> 23:59:59,999 we were able to look down at the polar region 55 00:00:00,000 --> 23:59:59,999 and see other spectacular things. 56 00:00:00,000 --> 23:59:59,999 The hint of this hexagon pattern on the north pole 57 00:00:00,000 --> 23:59:59,999 was really observed first by the Voyagers, 58 00:00:00,000 --> 23:59:59,999 but we're now back to see that up close and personal. 59 00:00:00,000 --> 23:59:59,999 The size of this whole hexagon, 60 00:00:00,000 --> 23:59:59,999 which is actually a jetstream on the outer rim of it, 61 00:00:00,000 --> 23:59:59,999 is about twice the size of our Earth. 62 00:00:00,000 --> 23:59:59,999 In addition to that, we had opportunities 63 00:00:00,000 --> 23:59:59,999 to begin to look at the moons. 64 00:00:00,000 --> 23:59:59,999 And here, other surprises were well in store for us. 65 00:00:00,000 --> 23:59:59,999 As seen in this image, this is Enceladus. 66 00:00:00,000 --> 23:59:59,999 This is a small moon just outside the rings of Saturn, 67 00:00:00,000 --> 23:59:59,999 and what we thought was an icy ball. 68 00:00:00,000 --> 23:59:59,999 When we observed the Southern Hemisphere, 69 00:00:00,000 --> 23:59:59,999 and geysers of water spewing out into the Saturn system, 70 00:00:00,000 --> 23:59:59,999 it amazed us and began changing the way we view 71 00:00:00,000 --> 23:59:59,999 the habitability or potential habitability of moons 72 00:00:00,000 --> 23:59:59,999 in the outer part of our solar system. 73 00:00:00,000 --> 23:59:59,999 My next image, of course, is the beautiful Titan. 74 00:00:00,000 --> 23:59:59,999 This moon is bigger than the planet Mercury. 75 00:00:00,000 --> 23:59:59,999 It has an atmosphere at twice our atmospheric pressure. 76 00:00:00,000 --> 23:59:59,999 If it was orbiting the Sun and not Saturn, 77 00:00:00,000 --> 23:59:59,999 we would call it a planet. 78 00:00:00,000 --> 23:59:59,999 It's truly a magnificent body. 79 00:00:00,000 --> 23:59:59,999 The Voyagers could only see the haziness 80 00:00:00,000 --> 23:59:59,999 of this beautiful object, but with Cassini, 81 00:00:00,000 --> 23:59:59,999 our ability to penetrate through that haze with our radars, 82 00:00:00,000 --> 23:59:59,999 and seeing what the surface structures and features are, 83 00:00:00,000 --> 23:59:59,999 and the DSA Huygens probe going all the way 84 00:00:00,000 --> 23:59:59,999 down to the surface, revolutionized 85 00:00:00,000 --> 23:59:59,999 our understanding of this spectacular moon. 86 00:00:00,000 --> 23:59:59,999 This is the only other body in the solar system 87 00:00:00,000 --> 23:59:59,999 that has liquid on its surface. 88 00:00:00,000 --> 23:59:59,999 Its seas are about the size of our own Black Sea. 89 00:00:00,000 --> 23:59:59,999 Now, they're not full of water, 90 00:00:00,000 --> 23:59:59,999 but they're full of liquid methane. 91 00:00:00,000 --> 23:59:59,999 This is a spectacular world in its own right. 92 00:00:00,000 --> 23:59:59,999 Next slide, please. 93 00:00:00,000 --> 23:59:59,999 Of course, Saturn has more than 60 moons. 94 00:00:00,000 --> 23:59:59,999 Can't see them all, but we saw approximately 95 00:00:00,000 --> 23:59:59,999 two dozen of them in addition to Enceladus and Titan. 96 00:00:00,000 --> 23:59:59,999 Beautiful moons, with all sorts of structures. 97 00:00:00,000 --> 23:59:59,999 Those that even, in fact, modify the structure of the rings, 98 00:00:00,000 --> 23:59:59,999 creating divisions, or elements that accrete material, 99 00:00:00,000 --> 23:59:59,999 and we begin to see all those 100 00:00:00,000 --> 23:59:59,999 processes up close and personal. 101 00:00:00,000 --> 23:59:59,999 But one of the real stars of the show is Titan. 102 00:00:00,000 --> 23:59:59,999 Our ability to fly by Titan, which is about 20 Saturn radii 103 00:00:00,000 --> 23:59:59,999 away from Saturn, allows us to use the very basic 104 00:00:00,000 --> 23:59:59,999 principle of gravity assists to change 105 00:00:00,000 --> 23:59:59,999 the plane of Cassini's orbit, provide new views, 106 00:00:00,000 --> 23:59:59,999 and therefore observe in beautiful different ways. 107 00:00:00,000 --> 23:59:59,999 The next animation shows you these flybys. 108 00:00:00,000 --> 23:59:59,999 Now what we normally do on flybys 109 00:00:00,000 --> 23:59:59,999 is just get a little idea of what that body is, 110 00:00:00,000 --> 23:59:59,999 but these flybys have revolutionized our opportunity 111 00:00:00,000 --> 23:59:59,999 to use this concept for other missions. 112 00:00:00,000 --> 23:59:59,999 We now know from these flybys how to construct 113 00:00:00,000 --> 23:59:59,999 a global view of this beautiful world, 114 00:00:00,000 --> 23:59:59,999 and we're using it on the clipper mission 115 00:00:00,000 --> 23:59:59,999 that's going to Jupiter and viewing the moon Europa. 116 00:00:00,000 --> 23:59:59,999 Cassini has enabled us to make 117 00:00:00,000 --> 23:59:59,999 those future missions possible. 118 00:00:00,000 --> 23:59:59,999 My next slide, please. 119 00:00:00,000 --> 23:59:59,999 Americans had a wonderful view of an eclipse, 120 00:00:00,000 --> 23:59:59,999 where the moon passed in front of the sun last month. 121 00:00:00,000 --> 23:59:59,999 Millions of people appreciate now 122 00:00:00,000 --> 23:59:59,999 what eclipses are all about. 123 00:00:00,000 --> 23:59:59,999 From our view on Cassini, this is the eclipse, 124 00:00:00,000 --> 23:59:59,999 with Saturn moving in front of the Sun. 125 00:00:00,000 --> 23:59:59,999 This allows in the low light of blocking the Sun, 126 00:00:00,000 --> 23:59:59,999 opportunities to see in greater detail 127 00:00:00,000 --> 23:59:59,999 the ring structure and other elements. 128 00:00:00,000 --> 23:59:59,999 In fact, we were even able to see distant planets, 129 00:00:00,000 --> 23:59:59,999 and the Earth, in a beautiful set of mosaic images 130 00:00:00,000 --> 23:59:59,999 that have been stitched together, as shown here. 131 00:00:00,000 --> 23:59:59,999 That outer ring that you see is called the E ring. 132 00:00:00,000 --> 23:59:59,999 We're able to illuminate it in ways that tells us 133 00:00:00,000 --> 23:59:59,999 that Enceladus' geysers, water being spewed out, 134 00:00:00,000 --> 23:59:59,999 is creating this ring. 135 00:00:00,000 --> 23:59:59,999 Now because of the importance of Enceladus 136 00:00:00,000 --> 23:59:59,999 that Cassini has shown us, and of Titan, 137 00:00:00,000 --> 23:59:59,999 another potential world that could be habitable for life, 138 00:00:00,000 --> 23:59:59,999 perhaps not like we know it, but perhaps 139 00:00:00,000 --> 23:59:59,999 completely different than ours, we had to make 140 00:00:00,000 --> 23:59:59,999 decisions on how to dispose of the spacecraft. 141 00:00:00,000 --> 23:59:59,999 And that led us, inevitably, to the plan 142 00:00:00,000 --> 23:59:59,999 of taking Cassini and plunging it into Saturn. 143 00:00:00,000 --> 23:59:59,999 Because of planetary protection, 144 00:00:00,000 --> 23:59:59,999 and our desire to go back to Enceladus and go back to Titan, 145 00:00:00,000 --> 23:59:59,999 go back to the Saturn system, we must protect 146 00:00:00,000 --> 23:59:59,999 those bodies for future exploration. 147 00:00:00,000 --> 23:59:59,999 Next slide, please. 148 00:00:00,000 --> 23:59:59,999 Well, in the visible camera, 149 00:00:00,000 --> 23:59:59,999 we've seen more than 450,000 images. 150 00:00:00,000 --> 23:59:59,999 Every one of them, in their own way, 151 00:00:00,000 --> 23:59:59,999 are absolutely spectacular. 152 00:00:00,000 --> 23:59:59,999 But we made the decision to go through 153 00:00:00,000 --> 23:59:59,999 and pick the top 100 images, videos, and animations, 154 00:00:00,000 --> 23:59:59,999 and create an ebook, something that allows us 155 00:00:00,000 --> 23:59:59,999 to go back and view what we accomplished, 156 00:00:00,000 --> 23:59:59,999 and the beautiful observations that this mission has done. 157 00:00:00,000 --> 23:59:59,999 You can download this ebook in 158 00:00:00,000 --> 23:59:59,999 several formats at nasa.gov/ebooks. 159 00:00:00,000 --> 23:59:59,999 So with that, let's learn how we plan to plunge Cassini 160 00:00:00,000 --> 23:59:59,999 into Saturn, and what we will learn from that experience. 161 00:00:00,000 --> 23:59:59,999 So let me turn it over to Earl Maize, 162 00:00:00,000 --> 23:59:59,999 the Project Manager for Cassini, Earl? 163 00:00:00,000 --> 23:59:59,999 >> Excuse me, thank you, Jim. 164 00:00:00,000 --> 23:59:59,999 It's been such a unique and incredible privilege 165 00:00:00,000 --> 23:59:59,999 and pleasure to operate this spacecraft, 166 00:00:00,000 --> 23:59:59,999 that before I go into its demise, 167 00:00:00,000 --> 23:59:59,999 I'd like to talk just a little bit about some 168 00:00:00,000 --> 23:59:59,999 of its many accomplishments. 169 00:00:00,000 --> 23:59:59,999 As Jim pointed out, almost half a billion, 170 00:00:00,000 --> 23:59:59,999 I'm sorry, half a million images taken, 171 00:00:00,000 --> 23:59:59,999 4.9 billion miles logged on this spacecraft, 172 00:00:00,000 --> 23:59:59,999 635 gigabytes of data played back. 173 00:00:00,000 --> 23:59:59,999 Now that, by modern standards, is not a whole lot 174 00:00:00,000 --> 23:59:59,999 bigger than a flash drive, but you gotta think 175 00:00:00,000 --> 23:59:59,999 about 80s technology from a billion miles away, 176 00:00:00,000 --> 23:59:59,999 and that all of a sudden becomes pretty amazing. 177 00:00:00,000 --> 23:59:59,999 We had 162 targeted flybys, and as Jim pointed out, 178 00:00:00,000 --> 23:59:59,999 we've been using Titan to great advantage, 179 00:00:00,000 --> 23:59:59,999 and there have been 127 of those. 180 00:00:00,000 --> 23:59:59,999 Could I have the first graphic please? 181 00:00:00,000 --> 23:59:59,999 Just to show you this incredible spacecraft. 182 00:00:00,000 --> 23:59:59,999 Now as it's half, twice again, the size of the model 183 00:00:00,000 --> 23:59:59,999 in this auditorium if you're here, 184 00:00:00,000 --> 23:59:59,999 but it's absolutely splendid, just built for Saturn. 185 00:00:00,000 --> 23:59:59,999 And of course, that's the iconic 186 00:00:00,000 --> 23:59:59,999 north pole of Saturn below it. 187 00:00:00,000 --> 23:59:59,999 Now that is an animation, we did not take 188 00:00:00,000 --> 23:59:59,999 a selfie stick with us, although we could have put one 189 00:00:00,000 --> 23:59:59,999 on the RPWS antenna in hindsight. 190 00:00:00,000 --> 23:59:59,999 That again was something that the 90s didn't know about, 191 00:00:00,000 --> 23:59:59,999 so we'll have to live onward. 192 00:00:00,000 --> 23:59:59,999 But again, it's just been almost flawless operations in both 193 00:00:00,000 --> 23:59:59,999 the instruments and the spacecraft engineering systems, 194 00:00:00,000 --> 23:59:59,999 and then the ground support itself, again, 195 00:00:00,000 --> 23:59:59,999 has just, I think made this mission, 196 00:00:00,000 --> 23:59:59,999 not only do we have an environment 197 00:00:00,000 --> 23:59:59,999 that just is overwhelming with abundance 198 00:00:00,000 --> 23:59:59,999 of scientific mysteries and puzzles, 199 00:00:00,000 --> 23:59:59,999 we've had a spacecraft and a team that could exploit it. 200 00:00:00,000 --> 23:59:59,999 So again, I will probably come back to that point, 201 00:00:00,000 --> 23:59:59,999 but it's just been an amazing, amazing mission. 202 00:00:00,000 --> 23:59:59,999 So what are we gonna do? 203 00:00:00,000 --> 23:59:59,999 Let's get to the last few hours. 204 00:00:00,000 --> 23:59:59,999 Could I have the next animation? 205 00:00:00,000 --> 23:59:59,999 This is the so-called ball of yarn. 206 00:00:00,000 --> 23:59:59,999 What we do, as Jim pointed out, we have a main engine, 207 00:00:00,000 --> 23:59:59,999 and it's a great main engine, but we've got Titan, 208 00:00:00,000 --> 23:59:59,999 and Titan is a phenomenal main engine. 209 00:00:00,000 --> 23:59:59,999 Every time we flyby Titan, every time we flyby Titan, 210 00:00:00,000 --> 23:59:59,999 we get a little bit better view of Titan, 211 00:00:00,000 --> 23:59:59,999 and we get a little bit better view of the Saturn system. 212 00:00:00,000 --> 23:59:59,999 Every one of those course changes, 213 00:00:00,000 --> 23:59:59,999 every orbit change there is, Titan's doing it for us, 214 00:00:00,000 --> 23:59:59,999 and it's done for us for 294 different orbits. 215 00:00:00,000 --> 23:59:59,999 127 times we've made major orbital changes, 216 00:00:00,000 --> 23:59:59,999 and Titan's been at the center of every one of them. 217 00:00:00,000 --> 23:59:59,999 So that's the ball of yarn, 218 00:00:00,000 --> 23:59:59,999 and if I could to go the next one, 219 00:00:00,000 --> 23:59:59,999 let me just show you what Titan did for us. 220 00:00:00,000 --> 23:59:59,999 This is April. 221 00:00:00,000 --> 23:59:59,999 All the time we've been outside the rings, 222 00:00:00,000 --> 23:59:59,999 and being very careful with the rings, and with the dust, 223 00:00:00,000 --> 23:59:59,999 because we really didn't understand the environment well. 224 00:00:00,000 --> 23:59:59,999 But for the grand finale, in order to exploit 225 00:00:00,000 --> 23:59:59,999 every last ounce of our propellant and the science 226 00:00:00,000 --> 23:59:59,999 that Saturn offered inside, we've been what we've 227 00:00:00,000 --> 23:59:59,999 been calling the proximal orbits, or the grand finale. 228 00:00:00,000 --> 23:59:59,999 Titan gave us one last little nudge back in April 229 00:00:00,000 --> 23:59:59,999 and pushed us, the Cassini spacecraft, 230 00:00:00,000 --> 23:59:59,999 between the rings and the planet itself, 231 00:00:00,000 --> 23:59:59,999 and we've been skirting back and forth 232 00:00:00,000 --> 23:59:59,999 in that sense for 22 times since April. 233 00:00:00,000 --> 23:59:59,999 Our last one, unfortunately, was Saturday morning, 234 00:00:00,000 --> 23:59:59,999 or Saturday evening, actually, 235 00:00:00,000 --> 23:59:59,999 we got the callback on Saturday morning. 236 00:00:00,000 --> 23:59:59,999 We don't normally communicate 237 00:00:00,000 --> 23:59:59,999 with the spacecraft during these passages, 238 00:00:00,000 --> 23:59:59,999 because the science is so precious, 239 00:00:00,000 --> 23:59:59,999 we are busy gathering that. 240 00:00:00,000 --> 23:59:59,999 So the call home was Saturn morning, we were here, 241 00:00:00,000 --> 23:59:59,999 got the call home, spacecraft's fine, 242 00:00:00,000 --> 23:59:59,999 it did it again the way it always has. 243 00:00:00,000 --> 23:59:59,999 Monday we got the kiss goodbye from Titan. 244 00:00:00,000 --> 23:59:59,999 119,000 kilometer altitude flyby from Titan took about 245 00:00:00,000 --> 23:59:59,999 39 meters per second of velocity away from the spacecraft, 246 00:00:00,000 --> 23:59:59,999 slowed it down just enough that what's going 247 00:00:00,000 --> 23:59:59,999 to happen on Friday is absolutely inevitable. 248 00:00:00,000 --> 23:59:59,999 So if I could go to that next animation, just to show this. 249 00:00:00,000 --> 23:59:59,999 There is a graphic here, see that Titan flyby? 250 00:00:00,000 --> 23:59:59,999 Now that's behind me, I should be pointing. 251 00:00:00,000 --> 00:00:00,697 That little Titan flyby was enough to put us into Saturn. 252 00:00:00,730 --> 00:00:02,665 It was just distant enough, just close enough, 253 00:00:02,698 --> 00:00:06,636 and just the right orientation to seal Cassini's fate. 254 00:00:06,669 --> 00:00:08,304 So what's gonna happen next? 255 00:00:08,337 --> 00:00:10,506 Could I get the next graphic, please? 256 00:00:10,539 --> 00:00:13,543 We made contact with Cassini for the last time, 257 00:00:13,576 --> 00:00:17,447 for the penultimate time, we ceased 258 00:00:17,480 --> 00:00:19,582 contact about 6:50 this morning. 259 00:00:19,615 --> 00:00:22,285 After the Titan flyby, we got a call home last night, 260 00:00:22,318 --> 00:00:23,653 we were all in the mission support area, 261 00:00:23,686 --> 00:00:24,754 waiting for telemetry. 262 00:00:24,787 --> 00:00:28,291 As it has done over and over again, 263 00:00:28,324 --> 00:00:30,760 Cassini came in on time and in perfect shape. 264 00:00:30,793 --> 00:00:32,628 It got the flyby that it needed, 265 00:00:32,661 --> 00:00:34,397 it got the velocity change it needed, 266 00:00:34,430 --> 00:00:37,400 and it's now on its way into Saturn. 267 00:00:39,635 --> 00:00:43,306 But before it goes, at about 6:50 this morning, 268 00:00:43,339 --> 00:00:47,343 it turned off of Earth back to the job it's been at 269 00:00:47,376 --> 00:00:51,347 for the last 13 years, observing Saturn's system. 270 00:00:51,380 --> 00:00:53,282 It's gonna be taking the last set of pictures 271 00:00:53,315 --> 00:00:56,352 of some of the prime targets that it's visited 272 00:00:56,385 --> 00:00:58,688 over the many years that it's been at Saturn. 273 00:00:58,721 --> 00:00:59,689 And we'll be able to share those 274 00:00:59,722 --> 00:01:02,291 with you sometime on Friday. 275 00:01:02,324 --> 00:01:04,427 They'll be coming back tomorrow, 276 00:01:04,460 --> 00:01:07,530 at about 2:45 tomorrow afternoon, Cassini's gonna turn back, 277 00:01:07,563 --> 00:01:10,500 and play back those final sets of images. 278 00:01:10,533 --> 00:01:12,602 We figure that should take about 11 hours, 279 00:01:12,635 --> 00:01:15,204 so at about one o'clock in the morning 280 00:01:15,237 --> 00:01:17,741 of Friday, September 15th, we will, 281 00:01:20,309 --> 00:01:23,279 the solid state recorders onboard Cassini will be empty, 282 00:01:23,312 --> 00:01:26,349 and we will then reconfigure Cassini 283 00:01:26,382 --> 00:01:29,385 for its very final transmissions. 284 00:01:29,418 --> 00:01:33,322 What we're gonna do is, Cassini is normally a mission 285 00:01:33,355 --> 00:01:36,726 that stores things on data, like it's doing right now, 286 00:01:36,759 --> 00:01:39,595 we're not in contact, we could look all we wanted, 287 00:01:39,628 --> 00:01:42,298 and Cassini's off busy doing its own thing, 288 00:01:42,331 --> 00:01:45,568 stores it on the recorders and plays it back later. 289 00:01:45,601 --> 00:01:47,303 It's doing that right now. 290 00:01:47,336 --> 00:01:49,705 But next Friday morning, we're going to turn Cassini 291 00:01:49,738 --> 00:01:51,474 into what we call, essentially, 292 00:01:51,507 --> 00:01:53,509 a bent pipe transmission system. 293 00:01:53,542 --> 00:01:55,278 Everything that comes from the instruments 294 00:01:55,311 --> 00:01:57,513 is going to go right into the recorder and right back out. 295 00:01:57,546 --> 00:01:59,448 So there'll be a few seconds' delay, 296 00:01:59,481 --> 00:02:02,318 but it's essentially now a real time instrument. 297 00:02:02,351 --> 00:02:05,454 And that's to enable the sampling instruments, 298 00:02:05,487 --> 00:02:09,258 particularly the ion and neutral mass spectrometer, 299 00:02:09,291 --> 00:02:11,427 to get data as deep into the atmosphere 300 00:02:11,460 --> 00:02:13,329 as Cassini will permit it. 301 00:02:13,362 --> 00:02:16,265 We've taken our data rate down to as low as we can handle, 302 00:02:16,298 --> 00:02:18,501 so that no matter what antenna we've got on the ground, 303 00:02:18,534 --> 00:02:19,735 we'll be able to receive it. 304 00:02:19,768 --> 00:02:24,674 So if it's a rainy day in at the, in Canberra, in Australia, 305 00:02:24,707 --> 00:02:26,576 where we'll be tracked, then we'll be able to have 306 00:02:26,609 --> 00:02:28,477 a better chance of getting the data. 307 00:02:28,510 --> 00:02:31,547 We've also got antennas both at the DS End Tracking stations 308 00:02:31,580 --> 00:02:33,649 on the east side of Australia, 309 00:02:33,682 --> 00:02:36,485 but also we've got the New Norcia DSA station 310 00:02:36,518 --> 00:02:38,487 standing at the ready on the west side. 311 00:02:38,520 --> 00:02:40,456 So if we've got a rainy day over the entire continent, 312 00:02:40,489 --> 00:02:41,691 well we're out of luck. 313 00:02:41,724 --> 00:02:45,695 But the best we can do, we've got ourselves covered. 314 00:02:45,728 --> 00:02:48,731 We will turn, at that point also, to make sure 315 00:02:48,764 --> 00:02:53,402 that the high gain antenna, the large dish you see there, 316 00:02:53,435 --> 00:02:54,604 is pointed directly at the Earth, 317 00:02:54,637 --> 00:02:56,439 and that we've rotated the spacecraft 318 00:02:56,472 --> 00:02:59,308 so that the ion neutral mass spectrometer's aperture 319 00:02:59,341 --> 00:03:02,345 is pointing directly into the oncoming atmosphere. 320 00:03:02,378 --> 00:03:03,746 So essentially, it's getting just a full blast 321 00:03:03,779 --> 00:03:06,749 of the atmosphere as it comes in. 322 00:03:06,782 --> 00:03:09,352 So how are we gonna, the last few minutes? 323 00:03:09,385 --> 00:03:12,555 Cassini is not built for atmosphere, as you might imagine. 324 00:03:12,588 --> 00:03:15,458 We're a deep vacuum kind of probe. 325 00:03:16,725 --> 00:03:19,295 That's not to say it hasn't seen atmosphere. 326 00:03:19,328 --> 00:03:20,696 We've flown in the atmosphere of Titan, 327 00:03:20,729 --> 00:03:24,600 we've used the thrusters to battle the torques 328 00:03:24,633 --> 00:03:27,403 and the drag forces that we've had to deal with, 329 00:03:27,436 --> 00:03:29,305 and they've been very effective at it. 330 00:03:29,338 --> 00:03:31,707 So we know how to fly into a little bit of atmosphere, 331 00:03:31,740 --> 00:03:33,476 and we've been doing that for the last five orbits. 332 00:03:33,509 --> 00:03:35,645 We've actually been dipping our toes down 333 00:03:35,678 --> 00:03:37,680 into Saturn's atmosphere for the last five orbits, 334 00:03:37,713 --> 00:03:39,649 and the thrusters have had to fight back, 335 00:03:39,682 --> 00:03:43,319 at what we call a duty cycle, at a 100 percent, 336 00:03:43,352 --> 00:03:45,321 they're working as hard as they possibly can, 337 00:03:45,354 --> 00:03:46,656 they've been up into the 40s. 338 00:03:46,689 --> 00:03:47,723 So we really have been working 339 00:03:47,756 --> 00:03:51,294 the atmospheric effects to some extent. 340 00:03:51,327 --> 00:03:52,461 We have a good sense of these. 341 00:03:52,494 --> 00:03:54,430 But these are really tiny thrusters. 342 00:03:54,463 --> 00:03:56,365 They're built to move a school bus 343 00:03:56,398 --> 00:03:57,700 by just kind of tapping it. 344 00:03:57,733 --> 00:04:01,304 So you know, they're just not gonna be able to do that. 345 00:04:01,337 --> 00:04:03,472 I think, I'm kidding, one eighth pound. 346 00:04:03,505 --> 00:04:06,609 So this is just, you're touching something, 347 00:04:06,642 --> 00:04:08,611 pressing on it a little bit's about an eighth of a pound. 348 00:04:08,644 --> 00:04:11,480 You can imagine what those thrusters have to do 349 00:04:11,513 --> 00:04:13,649 in order to deal with the atmosphere of Cassini. 350 00:04:13,682 --> 00:04:16,218 So before I go on to the next animation, 351 00:04:16,251 --> 00:04:20,423 let me just point out one final moment here. 352 00:04:20,456 --> 00:04:24,527 At 4:55 AM Pacific Daylight Time, loss of signal. 353 00:04:24,560 --> 00:04:26,362 And what's gonna happen is the thrusters 354 00:04:26,395 --> 00:04:28,531 will eventually be overpowered by the atmosphere, 355 00:04:28,564 --> 00:04:31,434 we won't watch Cassini burn up, what we'll watch it do 356 00:04:31,467 --> 00:04:33,436 is slowly turn away from us, and we'll watch 357 00:04:33,469 --> 00:04:35,471 the indicator on the radio science displays 358 00:04:35,504 --> 00:04:39,508 that will go down flat, and essentially loss of signal. 359 00:04:39,541 --> 00:04:42,645 The mission will be over within a minute later. 360 00:04:42,678 --> 00:04:44,447 It's going so fast, and the atmosphere 361 00:04:44,480 --> 00:04:47,750 is thickening so quickly that Cassini will be vaporized 362 00:04:47,783 --> 00:04:52,288 in a few, I think may 100, maybe two minutes, 363 00:04:52,321 --> 00:04:53,522 but I think more like one. 364 00:04:53,555 --> 00:04:55,524 So it's really, it's just inevitable. 365 00:04:55,557 --> 00:04:57,493 It's going in very fast, very steep. 366 00:04:57,526 --> 00:05:01,364 Let's go to the next image, just for fun, to see. 367 00:05:01,397 --> 00:05:06,302 There's the timeline of the last 90 seconds of Cassini. 368 00:05:06,335 --> 00:05:08,404 Every 10 seconds, tick mark there. 369 00:05:08,437 --> 00:05:10,406 And that really, that tick mark, as you can see, 370 00:05:10,439 --> 00:05:14,543 the final one on my right is, or on my left up there, 371 00:05:14,576 --> 00:05:17,480 I believe, is where we lose signal. 372 00:05:17,513 --> 00:05:19,582 So you can see, very very tenuous atmosphere. 373 00:05:19,615 --> 00:05:22,752 Where essentially, the analog of that might be on Earth, 374 00:05:22,785 --> 00:05:25,588 that's about where the International Space Station is, 375 00:05:25,621 --> 00:05:27,556 relative to density. 376 00:05:27,589 --> 00:05:28,758 It's very very thin air. 377 00:05:28,791 --> 00:05:31,360 But Cassini's going so fast, and the thrusters are 378 00:05:31,393 --> 00:05:34,463 so modest for this sort of requirement, 379 00:05:34,496 --> 00:05:36,399 it's just not gonna last much longer. 380 00:05:36,432 --> 00:05:38,634 But you can see that about 70 seconds, 60 seconds in, 381 00:05:38,667 --> 00:05:40,403 the thrusters are gonna start to fight. 382 00:05:40,436 --> 00:05:42,538 For the last minute or so, they will be fighting 383 00:05:42,571 --> 00:05:44,573 the atmosphere increasingly, increasingly, 384 00:05:44,606 --> 00:05:48,277 as it tries to turn Cassini into a more aerodynamically 385 00:05:48,310 --> 00:05:52,381 compatible shape, and eventually they will overcome. 386 00:05:52,414 --> 00:05:54,683 So if I could see the last graphic, please. 387 00:05:54,716 --> 00:05:57,486 This is an animation, so there's Cassini coming in. 388 00:05:57,519 --> 00:05:59,422 This is about that point. 389 00:05:59,455 --> 00:06:00,689 And you can see, we're starting, this is again, 390 00:06:00,722 --> 00:06:04,460 a bit of a artistic license here, but the thrusters, 391 00:06:04,493 --> 00:06:06,662 as you can see down off those extensions on the bottom, 392 00:06:06,695 --> 00:06:08,631 are fighting extremely hard to keep 393 00:06:08,664 --> 00:06:11,667 the antenna pointed directly at the Earth. 394 00:06:11,700 --> 00:06:13,636 And you see, it's gonna start to feel the vibration 395 00:06:13,669 --> 00:06:15,471 of some of the atmospheric torques. 396 00:06:15,504 --> 00:06:17,506 But it will fight, and it will fight, and it will fight. 397 00:06:17,539 --> 00:06:19,575 The mass spectrometer's pointing into the atmosphere, 398 00:06:19,608 --> 00:06:21,544 the antenna is pointing at the Earth, 399 00:06:21,577 --> 00:06:25,481 and it's gonna do that for as it possibly can. 400 00:06:28,750 --> 00:06:30,486 Those of you that have been following this story 401 00:06:30,519 --> 00:06:32,321 for a little while might have noticed 402 00:06:32,354 --> 00:06:34,356 that we've been a little bit ambivalent about 403 00:06:34,389 --> 00:06:37,326 when Cassini's actually going to lose signal. 404 00:06:37,359 --> 00:06:39,628 One of the wonders and mysteries of Saturn 405 00:06:39,661 --> 00:06:42,465 is that we are always surprised. 406 00:06:43,732 --> 00:06:46,302 And we thought we knew what the atmosphere was all about. 407 00:06:46,335 --> 00:06:49,405 We had models that told us, that perhaps we were 408 00:06:49,438 --> 00:06:51,407 not going to get enough atmosphere to even satisfy 409 00:06:51,440 --> 00:06:55,511 the ion and mass requirements during the last five orbits. 410 00:06:56,612 --> 00:06:59,582 We had plans to pop down into the atmosphere, 411 00:06:59,615 --> 00:07:01,383 and if it was too thick, we had plans to pop up, 412 00:07:01,416 --> 00:07:04,353 and pop up again, and pop down, 413 00:07:04,386 --> 00:07:05,621 in order to get this thing fine-tuned. 414 00:07:05,654 --> 00:07:07,423 Well it turned out to be absolutely perfect, 415 00:07:07,456 --> 00:07:09,425 against all of our predictions. 416 00:07:09,458 --> 00:07:11,360 We had all these contingencies planned, 417 00:07:11,393 --> 00:07:12,495 and we threw them away. 418 00:07:12,528 --> 00:07:14,563 But what that tells us, also not only 419 00:07:14,596 --> 00:07:16,298 did we not know the atmosphere, 420 00:07:16,331 --> 00:07:18,467 but the atmosphere affects when you're gonna go in. 421 00:07:18,500 --> 00:07:20,402 Every time you go into the atmosphere and get slowed down, 422 00:07:20,435 --> 00:07:22,638 well you go ina little bit earlier. 423 00:07:22,671 --> 00:07:26,742 So what started at 5:08 is now at 4:55:06 AM Pacific Time. 424 00:07:32,548 --> 00:07:34,517 And that's our story, and we're sticking to it. 425 00:07:34,550 --> 00:07:36,685 [audience laughing] 426 00:07:36,718 --> 00:07:40,589 So with that, I'd like to turn the mic over to Linda Spilker 427 00:07:40,622 --> 00:07:42,725 to tell you about some of the just amazing science 428 00:07:42,758 --> 00:07:45,761 that we're going to get in these last few hours. 429 00:07:45,794 --> 00:07:47,596 >> Well, thank you very much, Earl. 430 00:07:47,629 --> 00:07:50,533 Being part of the Cassini mission for the entire mission 431 00:07:50,566 --> 00:07:52,568 has been an incredible privilege, 432 00:07:52,601 --> 00:07:56,605 both for me and for many of the scientists on board Cassini. 433 00:07:56,638 --> 00:08:00,710 We've had an incredible 13 year journey around Saturn, 434 00:08:02,344 --> 00:08:05,381 returning data like a giant fire hose, 435 00:08:05,414 --> 00:08:07,516 just flooding us with data. 436 00:08:07,549 --> 00:08:09,218 In fact, if you imagine all that data 437 00:08:09,251 --> 00:08:12,354 as a million piece puzzle, Cassini has been slowly 438 00:08:12,387 --> 00:08:15,257 putting together the pieces, we have some of the border, 439 00:08:15,290 --> 00:08:16,659 some of the regions, and we're trying to 440 00:08:16,692 --> 00:08:19,595 put together the picture of the Saturn system, 441 00:08:19,628 --> 00:08:22,765 but we don't have a picture on the cover to guide us, 442 00:08:22,798 --> 00:08:25,401 to tell us what that final set 443 00:08:25,434 --> 00:08:27,469 of data will finally look like. 444 00:08:27,502 --> 00:08:29,338 And what's really great about the grand finale 445 00:08:29,371 --> 00:08:32,608 is it's adding incredible new puzzle pieces 446 00:08:32,641 --> 00:08:35,711 to help us better understand the Saturn system. 447 00:08:35,744 --> 00:08:38,647 And as Earl said, lots of surprises. 448 00:08:38,680 --> 00:08:40,549 Many of the things we thought we knew about Saturn 449 00:08:40,582 --> 00:08:44,386 are more complicated than we originally had imagined. 450 00:08:44,419 --> 00:08:46,455 If we look at the first graphic, 451 00:08:46,488 --> 00:08:50,759 this is an example of looking at Saturn from the outside in. 452 00:08:50,792 --> 00:08:53,495 That's what we're doing with the grand finale orbits. 453 00:08:53,528 --> 00:08:55,731 If you look at that blue figure on your right, 454 00:08:55,764 --> 00:08:57,700 that's the auroral oval at Saturn. 455 00:08:57,733 --> 00:09:00,436 The particles come in, hit the atmosphere, 456 00:09:00,469 --> 00:09:03,372 cause this wonderful aurora. 457 00:09:03,405 --> 00:09:05,608 Just underneath it, you have the hexagon 458 00:09:05,641 --> 00:09:07,710 with the hurricane inside it. 459 00:09:07,743 --> 00:09:10,412 If you look on the bottom right, you can see an image now 460 00:09:10,445 --> 00:09:12,581 in the infrared where you can see the heat energy 461 00:09:12,614 --> 00:09:15,651 coming out from inside of the planet. 462 00:09:15,684 --> 00:09:18,721 And finally, that beautiful image with the hexagon, 463 00:09:18,754 --> 00:09:21,724 so we're looking at different levels from Saturn, 464 00:09:21,757 --> 00:09:23,659 almost like we've taken a magnifying glass 465 00:09:23,692 --> 00:09:26,428 to the planet and the rings. 466 00:09:26,461 --> 00:09:28,731 We've also been looking at the interior, and in a sense, 467 00:09:28,764 --> 00:09:31,500 pulling back the curtain with our gravity 468 00:09:31,533 --> 00:09:34,336 and magnetic field data, to see what Saturn 469 00:09:34,369 --> 00:09:36,639 is like on the inside, as well. 470 00:09:37,773 --> 00:09:39,708 Well as Earl mentioned, we're going to be taking 471 00:09:39,741 --> 00:09:42,544 our last images, we hope about eight o'clock tomorrow night 472 00:09:42,577 --> 00:09:44,713 to have the images up on our raw image site. 473 00:09:44,746 --> 00:09:46,649 If we go to the next graphic. 474 00:09:46,682 --> 00:09:50,452 In that last period of time, looking around Saturn, 475 00:09:50,485 --> 00:09:54,356 what we're doing is we're taking our final picture postcards 476 00:09:54,389 --> 00:09:58,294 of the Saturn system, looking at our favorite targets 477 00:09:58,327 --> 00:10:01,764 to put these images in our Cassini scrapbook. 478 00:10:01,797 --> 00:10:04,667 So we're going to take, if you look at the upper left, 479 00:10:04,700 --> 00:10:08,504 a mosaic of Saturn and the rings in color. 480 00:10:08,537 --> 00:10:11,473 Basically, our last look at the entire system. 481 00:10:11,506 --> 00:10:13,709 Upper right, that's Titan, we're gonna take 482 00:10:13,742 --> 00:10:15,644 some goodbye pictures of Titan, 483 00:10:15,677 --> 00:10:20,416 last look to see if there's any weather or clouds going on. 484 00:10:20,449 --> 00:10:22,551 In the lower left, that's the outer edge of the A ring, 485 00:10:22,584 --> 00:10:25,387 and that bright feature is created by a grouping 486 00:10:25,420 --> 00:10:27,723 of particles that we've nicknamed Peggy. 487 00:10:27,756 --> 00:10:31,393 We've been watching since 2012 to see if Peggy might break 488 00:10:31,426 --> 00:10:34,763 free of the rings and become a moon in her own right, 489 00:10:34,796 --> 00:10:38,334 so we're gonna take a last look, see what Peggy's up to. 490 00:10:38,367 --> 00:10:40,569 In the center, we're gonna watch Enceladus set 491 00:10:40,602 --> 00:10:43,539 behind the northern limn of Saturn, 492 00:10:43,572 --> 00:10:45,674 so very appropriate, Enceladus setting. 493 00:10:45,707 --> 00:10:48,477 Get a look at the propellers, that's on the lower right, 494 00:10:48,510 --> 00:10:49,712 these objects that are trying 495 00:10:49,745 --> 00:10:52,481 to open up gaps in Saturn's rings. 496 00:10:52,514 --> 00:10:54,583 Not quite big enough to do that. 497 00:10:54,616 --> 00:10:58,387 But you can only see those with a spacecraft like Cassini. 498 00:10:58,420 --> 00:11:00,589 And then, in our final moments of data, 499 00:11:00,622 --> 00:11:03,759 we're gonna look on the dark side of Saturn at the point 500 00:11:03,792 --> 00:11:07,496 where Cassini will be plunging into the atmosphere, 501 00:11:07,529 --> 00:11:09,698 looking in the near infrared, the ultraviolet, 502 00:11:09,731 --> 00:11:12,468 trying to get some pictures of Cassini's 503 00:11:12,501 --> 00:11:16,638 final home inside the planet Saturn itself. 504 00:11:16,671 --> 00:11:18,741 Now if we go to the next graphic, 505 00:11:18,774 --> 00:11:21,377 this just came down last night. 506 00:11:21,410 --> 00:11:24,513 This is one of our looks at Titan from the goodbye kiss. 507 00:11:24,546 --> 00:11:27,349 The north pole, you can see the lake region, 508 00:11:27,382 --> 00:11:29,518 we're looking at the north pole of Titan, 509 00:11:29,551 --> 00:11:30,652 looking through the haze. 510 00:11:30,685 --> 00:11:32,621 The haze has cleared remarkably 511 00:11:32,654 --> 00:11:35,524 as summer solstice has approached. 512 00:11:35,557 --> 00:11:37,726 And then if we go to the final graphic, 513 00:11:37,759 --> 00:11:41,296 these are the instruments that will be on and sending back 514 00:11:41,329 --> 00:11:45,300 data during those final moments with Cassini. 515 00:11:45,333 --> 00:11:46,602 And we have eight of them, including 516 00:11:46,635 --> 00:11:50,339 the gas ion and neutral mass spectrometer, 517 00:11:51,473 --> 00:11:53,542 the magnetospheric imaging experiment, 518 00:11:53,575 --> 00:11:55,644 the radio science system will be 519 00:11:55,677 --> 00:11:58,313 sending back its last gravity measurements. 520 00:11:58,346 --> 00:12:00,449 The radio and plasma wave antennas, 521 00:12:00,482 --> 00:12:03,619 and then the ultraviolet and infrared spectrometers 522 00:12:03,652 --> 00:12:06,355 will also be taking data in that time period. 523 00:12:06,388 --> 00:12:10,626 The magnetometer and the dust analyzer, as well. 524 00:12:10,659 --> 00:12:12,694 Now in these very final seconds, 525 00:12:12,727 --> 00:12:15,264 we'll be plunging deeper into the atmosphere 526 00:12:15,297 --> 00:12:18,367 of Saturn than we've ever gone before. 527 00:12:18,400 --> 00:12:19,768 In fact, you can think of Cassini 528 00:12:19,801 --> 00:12:23,305 as becoming the first Saturn probe. 529 00:12:23,338 --> 00:12:25,574 And to tell you more about sniffing the atmosphere 530 00:12:25,607 --> 00:12:28,410 of Saturn, I turn it over to Hunter Waite, 531 00:12:28,443 --> 00:12:30,345 and he's the principal investigator 532 00:12:30,378 --> 00:12:33,415 for the ion and neutral mass spectrometer, Hunter? 533 00:12:33,448 --> 00:12:34,750 >> Thanks, thanks Linda. 534 00:12:34,783 --> 00:12:36,485 The ion neutral mass spectrometer 535 00:12:36,518 --> 00:12:40,622 is actually the sensitive nose of the spacecraft. 536 00:12:40,655 --> 00:12:44,727 If we go to the next graphic, and zoom in on INMS, 537 00:12:48,330 --> 00:12:49,731 you can also see it here. 538 00:12:49,764 --> 00:12:54,403 Gas enters into this front portion of the instrument, 539 00:12:54,436 --> 00:12:58,540 and inside, the molecular composition is determined. 540 00:12:58,573 --> 00:13:00,442 And that's, so we have to be pointed 541 00:13:00,475 --> 00:13:02,711 in the forward direction, in the direction motion 542 00:13:02,744 --> 00:13:06,482 of the spacecraft, as Earl's already indicated. 543 00:13:06,515 --> 00:13:08,383 We've done this on many occasions, 544 00:13:08,416 --> 00:13:12,454 we explored the atmosphere of Titan in the same manner, 545 00:13:12,487 --> 00:13:14,690 we've explored the plumes of Enceladus 546 00:13:14,723 --> 00:13:18,594 with the ion neutral mass spectrometer as well, 547 00:13:18,627 --> 00:13:20,696 and found out about the composition there, 548 00:13:20,729 --> 00:13:24,633 and made some inferences about the internal ocean. 549 00:13:24,666 --> 00:13:26,435 And now, we get a chance to actually look 550 00:13:26,468 --> 00:13:30,472 at the atmosphere that's created in the rings itself, 551 00:13:30,505 --> 00:13:32,341 and the atmosphere of Saturn. 552 00:13:32,374 --> 00:13:35,377 So we're sampling both in this last stage. 553 00:13:35,410 --> 00:13:38,514 If you go to the next graphic, there's some idea 554 00:13:38,547 --> 00:13:41,383 of the sampling that we're doing. 555 00:13:42,651 --> 00:13:47,322 So the five dots indicate the five previous orbits, 556 00:13:47,355 --> 00:13:48,624 where we were at the lowest point, 557 00:13:48,657 --> 00:13:51,693 or closest to the atmosphere so far. 558 00:13:51,726 --> 00:13:55,664 Earlier, we were closer to the rings, and we were, 559 00:13:55,697 --> 00:13:58,600 well we were close to the rings, there's kinda like 560 00:13:58,633 --> 00:14:01,570 three bands that we actually sample. 561 00:14:01,603 --> 00:14:05,340 So we've had a chance to look more at the ring atmosphere, 562 00:14:05,373 --> 00:14:09,444 and to look and progressively see more and more 563 00:14:09,477 --> 00:14:12,447 of the atmosphere of Saturn itself. 564 00:14:12,480 --> 00:14:14,216 And you can see that line on the graphic, 565 00:14:14,249 --> 00:14:15,517 it's called well-mixed atmosphere. 566 00:14:15,550 --> 00:14:17,419 That's where the atmosphere becomes kinda 567 00:14:17,452 --> 00:14:19,521 homogenous in terms of composition. 568 00:14:19,554 --> 00:14:21,623 And we're not gonna quite make it there, 569 00:14:21,656 --> 00:14:25,427 but we'll make it close, and in that period of time, 570 00:14:25,460 --> 00:14:27,629 we'll be able to make our cleanest sample 571 00:14:27,662 --> 00:14:30,766 of the atmosphere of Saturn itself. 572 00:14:30,799 --> 00:14:34,670 So if we go to the final graphic, this is a very pretty 573 00:14:34,703 --> 00:14:37,573 picture of the rings, and of the atmosphere. 574 00:14:37,606 --> 00:14:41,543 You can see kind of a haze, which is the atmosphere, 575 00:14:41,576 --> 00:14:44,613 just above the edge of the planet. 576 00:14:44,646 --> 00:14:48,317 And one of the most important scientific things that we're 577 00:14:48,350 --> 00:14:52,554 trying to figure out is a concept called ring rain. 578 00:14:52,587 --> 00:14:56,358 And this concept was introduced in the early 80s 579 00:14:56,391 --> 00:14:58,594 to actually explain some observations 580 00:14:58,627 --> 00:15:02,731 that we made by both Pioneer and Voyager as they flew by. 581 00:15:02,764 --> 00:15:07,336 And this particular ring rain was actually water vapor 582 00:15:11,339 --> 00:15:14,309 and ice grains from the rings falling into the atmosphere, 583 00:15:14,342 --> 00:15:18,347 and making modifications to the atmosphere and ionosphere. 584 00:15:18,380 --> 00:15:21,483 Well, as Cassini has always delivered, 585 00:15:21,516 --> 00:15:24,319 ring rain is much more extensive than that, 586 00:15:24,352 --> 00:15:26,688 it's much more complicated, we're getting great new data, 587 00:15:26,721 --> 00:15:29,658 we're trying to find out exactly what is coming 588 00:15:29,691 --> 00:15:32,327 from the rings and what is due to the atmosphere. 589 00:15:32,360 --> 00:15:35,297 And that final plunge will allow us to do that. 590 00:15:35,330 --> 00:15:37,466 The other thing that we'll do during that period of time 591 00:15:37,499 --> 00:15:40,469 as we move closer to the mixed atmosphere, 592 00:15:40,502 --> 00:15:43,772 we'll be able to look at some important constituents 593 00:15:43,805 --> 00:15:46,742 that we know are there, and we've been measuring them, 594 00:15:46,775 --> 00:15:50,646 but we'll get a better idea of the hydrogen to helium ratio. 595 00:15:50,679 --> 00:15:53,615 And this is important in terms of the formation 596 00:15:53,648 --> 00:15:56,284 and evolution of Saturn itself. 597 00:15:56,317 --> 00:15:58,620 So we have an extensive set of science objectives 598 00:15:58,653 --> 00:16:02,290 that we're going to execute on this final plunge, 599 00:16:02,323 --> 00:16:04,393 and we're looking forward to getting 600 00:16:04,426 --> 00:16:06,762 the data in near real time. 601 00:16:06,795 --> 00:16:09,531 Thanks, I'll pass it back to Earl. 602 00:16:09,564 --> 00:16:11,466 >> Thanks, Hunter. 603 00:16:11,499 --> 00:16:15,470 After nearly four decades of planning, execution, 604 00:16:15,503 --> 00:16:19,708 implementation, and execution, we are now within 48 hours 605 00:16:19,741 --> 00:16:23,512 of the end of the Cassini mission. 606 00:16:23,545 --> 00:16:27,382 The work of three space agencies, 17 member nations, 607 00:16:27,415 --> 00:16:30,585 hundreds of suppliers, thousands of engineers, 608 00:16:30,618 --> 00:16:33,555 scientists, and support staff are about to come 609 00:16:33,588 --> 00:16:37,526 to a fiery end high above the clouds of Saturn. 610 00:16:38,760 --> 00:16:43,398 The current Cassini team, or family as it has become, 611 00:16:43,431 --> 00:16:45,701 comprised of hundreds of engineers, scientists, 612 00:16:45,734 --> 00:16:47,636 and support staff, has worked for many years 613 00:16:47,669 --> 00:16:51,506 to bring us to this point, and has done a phenomenal job. 614 00:16:51,539 --> 00:16:53,341 As I emphasized at the beginning, 615 00:16:53,374 --> 00:16:56,378 this is about a spacecraft and a team 616 00:16:57,479 --> 00:17:00,315 that has just been absolutely the best one 617 00:17:00,348 --> 00:17:01,717 you could ever ask for in both cases, 618 00:17:01,750 --> 00:17:04,519 and it's coming to an end, unfortunately. 619 00:17:04,552 --> 00:17:07,456 We'll be saddened, there's no doubt about it, 620 00:17:07,489 --> 00:17:09,558 at the loss of such an incredible machine. 621 00:17:09,591 --> 00:17:13,228 But I think all of us, we're going to have a great sense 622 00:17:13,261 --> 00:17:16,398 of pride in, a little bit corny perhaps, 623 00:17:16,431 --> 00:17:18,300 a mission accomplished. 624 00:17:18,333 --> 00:17:20,402 We set out to do something at Saturn, we did it, 625 00:17:20,435 --> 00:17:23,705 we did it extremely well, and we delivered more and more, 626 00:17:23,738 --> 00:17:28,343 and we've left the world informed, but still wondering. 627 00:17:28,376 --> 00:17:30,278 And that, I couldn't ask for me. 628 00:17:30,311 --> 00:17:32,447 We gotta go back, we know it. 629 00:17:32,480 --> 00:17:33,715 We've been gathering all week. 630 00:17:33,748 --> 00:17:36,585 We'll be staffing up the mission control center tomorrow, 631 00:17:36,618 --> 00:17:38,386 standing vigil through the night as we 632 00:17:38,419 --> 00:17:40,355 prepare to say goodbye, both from here, 633 00:17:40,388 --> 00:17:44,626 and a large crowd of our team members at Cal Tech, 634 00:17:44,659 --> 00:17:49,397 as our faithful traveler from Earth makes its final goodbye. 635 00:17:49,430 --> 00:17:52,401 So thank you, Cassini, and farewell. 636 00:17:54,569 --> 00:17:56,338 >> Alright, well thank you very much 637 00:17:56,371 --> 00:17:57,639 to our speakers, just phenomenal. 638 00:17:57,672 --> 00:18:00,475 We're gonna go ahead and open it up for questions, 639 00:18:00,508 --> 00:18:04,279 first of all to reporters here in the auditorium. 640 00:18:04,312 --> 00:18:05,413 Please wait for the mic, 641 00:18:05,446 --> 00:18:08,517 and give us your name and affiliation. 642 00:18:08,550 --> 00:18:12,287 Any questions here? We'll start down front. 643 00:18:14,455 --> 00:18:16,558 >> Hi, Irene Klotz with Aviation Week. 644 00:18:16,591 --> 00:18:20,729 The last image that's gonna be taken from Titan, is it, 645 00:18:22,497 --> 00:18:26,601 from Cassini, is it the image of where it's going to impact? 646 00:18:26,634 --> 00:18:30,338 And what is the speed that Cassini will be traveling 647 00:18:30,371 --> 00:18:33,509 relative to Saturn in the final descent? 648 00:18:35,376 --> 00:18:37,679 >> I think the answer is yes to the first question. 649 00:18:37,712 --> 00:18:40,348 >> Yes, the final image is the place 650 00:18:40,381 --> 00:18:41,449 where Cassini will plunge. 651 00:18:41,482 --> 00:18:43,385 It'll be dark, but that'll be, 652 00:18:43,418 --> 00:18:44,586 we'll take an image there, yes. 653 00:18:44,619 --> 00:18:45,654 >> And in miles per hour, we're going 654 00:18:45,687 --> 00:18:48,323 about 76,000 miles per hour. 655 00:18:49,691 --> 00:18:51,459 >> We'll actually have an image with our visual 656 00:18:51,492 --> 00:18:53,495 and infrared mapping spectrometer, 657 00:18:53,528 --> 00:18:56,565 and that image can sense the heat of Saturn as well. 658 00:18:56,598 --> 00:18:58,466 So we may see some details 659 00:18:58,499 --> 00:19:01,536 of the atmosphere in the near infrared. 660 00:19:01,569 --> 00:19:05,641 >> Thanks, and the 4:55:06, that's Pacific Daylight Time, 661 00:19:06,774 --> 00:19:09,444 what is the actual time on with the 662 00:19:10,545 --> 00:19:12,414 >> It's about an hour and 21 minutes. 663 00:19:12,447 --> 00:19:14,316 It takes the signal an hour and 20, 664 00:19:14,349 --> 00:19:18,320 sorry 23 minutes, to get from Saturn to Earth. 665 00:19:19,420 --> 00:19:22,558 But as far as we're concerned, what we see 666 00:19:23,791 --> 00:19:28,296 and what we live with is the signal from Cassini. 667 00:19:28,329 --> 00:19:29,631 So in that last signal comes down, 668 00:19:29,664 --> 00:19:32,634 that's when things'll happen for us. 669 00:19:32,667 --> 00:19:34,669 >> Okay, another question here in the audience, down front. 670 00:19:34,702 --> 00:19:37,472 >> Frederick Castel, journalist. 671 00:19:37,505 --> 00:19:40,675 Two questions, when you look at the ephemeris 672 00:19:40,708 --> 00:19:44,679 of the different moons, do we see some kind 673 00:19:44,712 --> 00:19:48,317 of Pioneer effect on the Saturn system? 674 00:19:50,485 --> 00:19:52,587 And the other question is, on the long term, 675 00:19:52,620 --> 00:19:56,291 for next mission, future mission, 676 00:19:56,324 --> 00:19:59,294 what's the strategy about plutonium? 677 00:20:00,395 --> 00:20:02,697 >> I'll start with the Pioneer effect, 678 00:20:02,730 --> 00:20:05,533 but I'm going to let Jim handle the next one. 679 00:20:05,566 --> 00:20:06,701 No, we have not. 680 00:20:06,734 --> 00:20:10,205 Because we have so many different perturbations 681 00:20:10,238 --> 00:20:13,208 in the system from the moons, from our own thrusting, 682 00:20:13,241 --> 00:20:17,412 from the thermal pressures of the RTG, even more subtle, 683 00:20:17,445 --> 00:20:20,348 we're just too busy perturbing that trajectory to actually 684 00:20:20,381 --> 00:20:23,718 be able to see something as subtle as the Pioneer effect. 685 00:20:23,751 --> 00:20:28,290 It's just too much going on in the Saturn system. 686 00:20:28,323 --> 00:20:30,558 >> Several years ago, we were able to work 687 00:20:30,591 --> 00:20:33,461 with the administration and Congress to get the approval 688 00:20:33,494 --> 00:20:36,732 to restart the production of plutonium-238. 689 00:20:38,499 --> 00:20:42,737 We've already done a number of tasks, and in 2019 we'll get 690 00:20:42,770 --> 00:20:45,740 back into the production on a regular basis. 691 00:20:45,773 --> 00:20:49,578 We also have approximately 30 kilograms plus 692 00:20:51,546 --> 00:20:56,384 of plutonium available to us for future missions. 693 00:20:56,417 --> 00:20:59,387 The next plutonium mission that we've planned 694 00:20:59,420 --> 00:21:02,657 is a Mars mission, it's Mars 2020. 695 00:21:02,690 --> 00:21:05,660 But I think we're in really good stead 696 00:21:05,693 --> 00:21:08,430 for the next several decades. 697 00:21:08,463 --> 00:21:11,633 Our plan is to keep a stock of plutonium 698 00:21:11,666 --> 00:21:15,570 and not let that be a mission limiting factor. 699 00:21:17,271 --> 00:21:20,608 >> Okay, other questions here in the audience? 700 00:21:20,641 --> 00:21:24,479 Right here, we'll go inside and then outside. 701 00:21:26,814 --> 00:21:29,584 >> Hi, thank you for doing this. 702 00:21:29,617 --> 00:21:32,654 Will we be able to tell anything from the livestream data 703 00:21:32,687 --> 00:21:35,323 on the way into the atmosphere right away? 704 00:21:35,356 --> 00:21:39,327 And if not, how long will it be before we know 705 00:21:39,360 --> 00:21:42,597 a vague idea of what it's telling us? 706 00:21:42,630 --> 00:21:46,401 >> Well, the data the operations team lead 707 00:21:46,434 --> 00:21:48,770 for the INMS tells me that she will display it 708 00:21:48,803 --> 00:21:52,640 20 minutes after the time we take it. 709 00:21:52,673 --> 00:21:56,745 So we're going to get it streamed to us from, 710 00:21:56,778 --> 00:21:59,781 down link to JPL, be transferred to 711 00:21:59,814 --> 00:22:02,317 Southwest Research Institute, and then we'll 712 00:22:02,350 --> 00:22:05,687 have it on a computer down at Cal Tech. 713 00:22:05,720 --> 00:22:08,690 >> Understanding it might take a little bit longer. 714 00:22:08,723 --> 00:22:11,526 >> It could, but that's our plan. 715 00:22:13,628 --> 00:22:15,597 >> Lee Hokes, Wall Street Journal. 716 00:22:15,630 --> 00:22:18,433 You mentioned that Cassini has, 717 00:22:18,466 --> 00:22:19,734 among its many accomplishments, 718 00:22:19,767 --> 00:22:22,704 enabled a series of missions to come. 719 00:22:22,737 --> 00:22:25,774 I wonder if you'd expand on that for a moment. 720 00:22:25,807 --> 00:22:27,742 >> Well, as I mentioned earlier, the concept 721 00:22:27,775 --> 00:22:31,312 of the gravity assists that we were able to get 722 00:22:31,345 --> 00:22:34,716 with Titan allowed our instruments to get 723 00:22:34,749 --> 00:22:37,753 a global view of that beautiful moon. 724 00:22:39,454 --> 00:22:41,689 That's really spectacular, because that means, 725 00:22:41,722 --> 00:22:44,659 when we take it to the Jupiter environment 726 00:22:44,692 --> 00:22:47,662 where the radiation belt is really harsh 727 00:22:47,695 --> 00:22:50,598 all through the area where the Galilean moons are, 728 00:22:50,631 --> 00:22:53,334 we want to be able to get in and get out. 729 00:22:53,367 --> 00:22:55,637 And so then, if we orbit Jupiter, 730 00:22:55,670 --> 00:22:58,740 we can do multiple flybys of the moons, 731 00:22:58,773 --> 00:23:02,444 and the one we're planning to do is Europa, 732 00:23:02,477 --> 00:23:04,679 and from those multiple flybys, 733 00:23:04,712 --> 00:23:08,249 actually create a global view 734 00:23:08,282 --> 00:23:11,219 of that moon as if we were in orbit. 735 00:23:12,453 --> 00:23:14,622 And so Cassini has really pioneered that whole concept, 736 00:23:14,655 --> 00:23:17,425 and that will be our first next attempt 737 00:23:17,458 --> 00:23:19,761 in using that to great effect. 738 00:23:22,563 --> 00:23:24,466 >> Alright, actually we're gonna go to the phones now for a 739 00:23:24,499 --> 00:23:26,568 couple of questions, but we'll come back to the auditorium. 740 00:23:26,601 --> 00:23:30,338 I think we have Marsha Dunn, from the AP, Marsha? 741 00:23:30,371 --> 00:23:31,473 >> Marsha: Yes, can you hear me? 742 00:23:31,506 --> 00:23:32,674 >> Sure. 743 00:23:32,707 --> 00:23:36,377 >> Marsha: Yes, for either Jim or Earl or both, 744 00:23:36,410 --> 00:23:39,614 there seems to be a, the outpouring of love for 745 00:23:39,647 --> 00:23:43,751 Cassini seems to be growing in these last hours and days. 746 00:23:43,784 --> 00:23:46,287 I'm wondering if you had a chance to hear 747 00:23:46,320 --> 00:23:48,656 the Cassini opera from the Planetary Society. 748 00:23:48,689 --> 00:23:50,658 What did you think about that? 749 00:23:50,691 --> 00:23:53,528 And how do you feel hearing from the public, 750 00:23:53,561 --> 00:23:56,398 who's so sorry to see Cassini go? 751 00:23:57,698 --> 00:23:59,634 >> I have heard the opera tribute 752 00:23:59,667 --> 00:24:02,470 from the Planetary Society, and I loved it. 753 00:24:02,503 --> 00:24:04,539 It's very heartwarming to us. 754 00:24:04,572 --> 00:24:06,741 As a matter of fact, we've recently posted 755 00:24:06,774 --> 00:24:09,410 a letter from a six year old boy who invited us 756 00:24:09,443 --> 00:24:12,647 to his Cassini party in Florida on the 15th. 757 00:24:12,680 --> 00:24:16,284 Feeling the love, if I can be so corny, 758 00:24:17,552 --> 00:24:19,588 is just very heartening. 759 00:24:22,323 --> 00:24:24,559 Because it's part of what we try to do, 760 00:24:24,592 --> 00:24:27,662 is to extend everybody out to Saturn. 761 00:24:27,695 --> 00:24:31,466 It's not science for, you know, in the ivory tower, 762 00:24:31,499 --> 00:24:34,769 it's for humanity, and it's for everybody to get on, 763 00:24:34,802 --> 00:24:38,306 ride, come with us, is just phenomenal. 764 00:24:38,339 --> 00:24:40,408 So I'm very heartened by that. 765 00:24:40,441 --> 00:24:43,444 I wish, well never mind, I don't even 766 00:24:43,477 --> 00:24:46,348 want to go there, one more orbit. 767 00:24:47,682 --> 00:24:51,452 So it is where it is, we've gotten this, 768 00:24:51,485 --> 00:24:54,355 and again I couldn't be more heartened 769 00:24:54,388 --> 00:24:57,325 by the outpouring we've had. 770 00:24:57,358 --> 00:24:59,394 >> Absolutely, you know the Cassini family, 771 00:24:59,427 --> 00:25:01,362 as Earl mentioned, is those people 772 00:25:01,395 --> 00:25:05,467 that have worked many years, decades, to get to this point, 773 00:25:07,301 --> 00:25:09,637 and we are absolutely delighted to have 774 00:25:09,670 --> 00:25:14,275 an extended family to share the experiences 775 00:25:14,308 --> 00:25:18,413 that have really enabled enormous science to be done. 776 00:25:20,514 --> 00:25:23,718 In fact, you know, really the science 777 00:25:23,751 --> 00:25:25,720 is not done until we share it. 778 00:25:25,753 --> 00:25:28,323 This is really just the beginning of a number 779 00:25:28,356 --> 00:25:31,492 of discoveries that the data will reveal, 780 00:25:31,525 --> 00:25:33,695 as we try to figure out what the physical phenomena 781 00:25:33,728 --> 00:25:37,765 are that are being described in those observations. 782 00:25:37,798 --> 00:25:41,636 Those will live on for many decades afterwards, 783 00:25:41,669 --> 00:25:46,374 and already they're beckoning us to go back. 784 00:25:46,407 --> 00:25:49,611 You know, between Voyager and Cassini was 30 years. 785 00:25:49,644 --> 00:25:51,680 And I believe that will be 786 00:25:53,314 --> 00:25:55,750 much shorter the next time around. 787 00:25:55,783 --> 00:25:56,751 >> Okay, we're gonna take a couple 788 00:25:56,784 --> 00:25:58,620 of questions from social media. 789 00:25:58,653 --> 00:26:00,455 We've got Jason Townsend from NASA headquarters. 790 00:26:00,488 --> 00:26:01,689 Jason, what's going on? 791 00:26:01,722 --> 00:26:04,325 >> Indeed, there's a lot of interest online here. 792 00:26:04,358 --> 00:26:08,396 Our first question here comes from Salma on Twitter, 793 00:26:08,429 --> 00:26:10,498 who asks, "Will Cassini completely evaporate 794 00:26:10,531 --> 00:26:12,400 "in the atmosphere of Saturn, or will it 795 00:26:12,433 --> 00:26:14,669 "crash into the surface of the planet?" 796 00:26:14,702 --> 00:26:16,771 >> It will be completely vaporized, 797 00:26:16,804 --> 00:26:19,307 like many meteorites hit Earth. 798 00:26:19,340 --> 00:26:21,442 If there's a surface at Saturn, 799 00:26:21,475 --> 00:26:24,679 it's at a hellishly hot pressure and temperature, 800 00:26:24,712 --> 00:26:28,683 and anything from Cassini will vaporize long before. 801 00:26:28,716 --> 00:26:30,518 >> Wonderful, lots of other questions here, 802 00:26:30,551 --> 00:26:32,420 asking about images here. 803 00:26:32,453 --> 00:26:34,389 So Evelyn on Twitter asks, "Will Cassini be able 804 00:26:34,422 --> 00:26:38,426 "to take a close-up image of Saturn as it plunges?" 805 00:26:38,459 --> 00:26:40,428 >> No, we don't have the data rate 806 00:26:40,461 --> 00:26:43,464 to support sending back images in real time. 807 00:26:43,497 --> 00:26:46,267 So the instruments that I showed you did not include 808 00:26:46,300 --> 00:26:49,737 the cameras for those final few moments for the plunge. 809 00:26:49,770 --> 00:26:51,572 So we'll be getting those images back, 810 00:26:51,605 --> 00:26:54,676 the final image will be of the place where Cassini will go, 811 00:26:54,709 --> 00:26:59,280 but it'll be from about 14 hours earlier. 812 00:26:59,313 --> 00:27:00,481 >> Alright, next question here comes 813 00:27:00,514 --> 00:27:02,650 from Twitter user Bilemon, who asks, 814 00:27:02,683 --> 00:27:05,653 "Would it be possible to use a low gain antenna 815 00:27:05,686 --> 00:27:07,422 "at a very low bit rate to monitor 816 00:27:07,455 --> 00:27:10,258 "a heartbeat from Cassini just a little longer?" 817 00:27:10,291 --> 00:27:13,261 [audience laughing] 818 00:27:15,563 --> 00:27:18,633 >> I'll repeat that for the audience. 819 00:27:18,666 --> 00:27:21,536 The spacecraft engineer is in the second row, 820 00:27:21,569 --> 00:27:24,472 and the answer is a resounding no. 821 00:27:24,505 --> 00:27:26,641 If we had done that, we would have 822 00:27:26,674 --> 00:27:28,643 given up some science data. 823 00:27:28,676 --> 00:27:33,381 And really, for a few seconds' more to get those last 824 00:27:33,414 --> 00:27:38,319 packets of spectrometer data was much more important. 825 00:27:38,352 --> 00:27:39,520 >> Okay, we're gonna go back to the phones. 826 00:27:39,553 --> 00:27:41,556 I think we've got Leo Enwright from Irish Television. 827 00:27:41,589 --> 00:27:43,658 Leo, can you hear us? 828 00:27:43,691 --> 00:27:44,759 >> Leo: Yeah, thanks very much. 829 00:27:44,792 --> 00:27:47,462 In fact, my question isn't entirely unrelated 830 00:27:47,495 --> 00:27:49,731 to the last one, because I'm wondering, 831 00:27:49,764 --> 00:27:53,368 there has been some speculation that a good telescope 832 00:27:53,401 --> 00:27:55,303 on Earth, and I presume a league 833 00:27:55,336 --> 00:27:57,472 with one would be able to see this happen. 834 00:27:57,505 --> 00:27:59,407 Is that the case? 835 00:27:59,440 --> 00:28:01,776 >> Well, we're going to try and look with telescopes 836 00:28:01,809 --> 00:28:04,312 from the Earth, we're just not sure. 837 00:28:04,345 --> 00:28:06,748 This flash will be occurring on the day side of Saturn, 838 00:28:06,781 --> 00:28:09,684 and we've done some calculations about brightness. 839 00:28:09,717 --> 00:28:12,253 We think it's not very likely, 840 00:28:12,286 --> 00:28:14,622 but we're sure gonna look anyway. 841 00:28:16,624 --> 00:28:18,226 >> Okay, one more question on the phones. 842 00:28:18,259 --> 00:28:21,396 I'm gonna, I think we've got Dave Mosher 843 00:28:21,429 --> 00:28:23,331 from Business Insider. 844 00:28:25,366 --> 00:28:26,300 >> Dave: Can you guys hear me? 845 00:28:26,333 --> 00:28:28,269 >> Yeah, we sure can. 846 00:28:28,302 --> 00:28:29,670 >> Dave: Alright great, I actually had a follow up 847 00:28:29,703 --> 00:28:32,640 to the previous question, and one more new one. 848 00:28:32,673 --> 00:28:34,742 Do we know which observatories 849 00:28:34,775 --> 00:28:37,478 in the Southern Hemisphere or wherever 850 00:28:37,511 --> 00:28:39,680 on Earth are gonna be trying to see this thing? 851 00:28:39,713 --> 00:28:43,384 That's my first question, for whoever can best answer it. 852 00:28:43,417 --> 00:28:45,353 And then, sorta related to that, 853 00:28:45,386 --> 00:28:47,655 but about the data that's coming back. 854 00:28:47,688 --> 00:28:50,758 I just checked the forecast for Australia, 855 00:28:50,791 --> 00:28:52,527 and it does look like there's a little clouds 856 00:28:52,560 --> 00:28:56,531 and rain in the forecast for the next few days. 857 00:28:56,564 --> 00:28:59,500 I'm curious if you guys are worried about that at all, 858 00:28:59,533 --> 00:29:03,571 or if you're confident that you're gonna get this data back. 859 00:29:04,738 --> 00:29:06,307 >> Well the observatories we're gonna 860 00:29:06,340 --> 00:29:08,643 be using are mostly in Australia. 861 00:29:08,676 --> 00:29:12,313 Australia, of course, Canberra has a great view of Cassini. 862 00:29:12,346 --> 00:29:14,649 Also, we're gonna be using some smaller telescopes, 863 00:29:14,682 --> 00:29:16,350 we're gonna try and look from India, 864 00:29:16,383 --> 00:29:19,387 from China, possibly from Taiwan. 865 00:29:19,420 --> 00:29:21,556 We're really encouraging our amateurs, too, 866 00:29:21,589 --> 00:29:24,325 to get out there and look with their telescopes. 867 00:29:24,358 --> 00:29:25,760 We don't have any giant telescopes 868 00:29:25,793 --> 00:29:28,629 in that region where we can see Cassini. 869 00:29:28,662 --> 00:29:30,398 So we're just saying hey everybody, 870 00:29:30,431 --> 00:29:34,602 go out and take a look, and we'll see what we see. 871 00:29:34,635 --> 00:29:37,371 >> We have every confidence 872 00:29:37,404 --> 00:29:38,673 that we're gonna get the data back. 873 00:29:38,706 --> 00:29:40,541 It's gonna take a pretty hellacious 874 00:29:40,574 --> 00:29:43,377 rainstorm to take out the data. 875 00:29:43,410 --> 00:29:45,580 We've got our data rates down at a very low level. 876 00:29:45,613 --> 00:29:48,549 If we can maintain the 70 meter antenna, 877 00:29:48,582 --> 00:29:50,418 we have a lot of margin. 878 00:29:50,451 --> 00:29:52,320 If we do lose the 70 meter dish, 879 00:29:52,353 --> 00:29:53,721 then our margin is a little bit lower, 880 00:29:53,754 --> 00:29:56,424 but we're still, I believe, comfortable. 881 00:29:56,457 --> 00:30:01,395 Worst case, we still have the New Norcia complex over 882 00:30:01,428 --> 00:30:03,364 on the other side of the continent 883 00:30:03,397 --> 00:30:06,300 that is not really prepared to decommutate 884 00:30:06,333 --> 00:30:08,536 our telemetry immediately, but all the data 885 00:30:08,569 --> 00:30:10,304 will be on the ground, and we can build 886 00:30:10,337 --> 00:30:11,672 the right system to take it back apart. 887 00:30:11,705 --> 00:30:16,277 So we'll get the data, it's just a question of how soon. 888 00:30:16,310 --> 00:30:17,378 >> Okay, thanks guys. 889 00:30:17,411 --> 00:30:18,479 We're gonna go back to social for 890 00:30:18,512 --> 00:30:21,382 a couple more questions, Jason? 891 00:30:21,415 --> 00:30:24,352 >> Alright, Twitter user Jason asks, 892 00:30:24,385 --> 00:30:27,689 "When will a spacecraft visit Saturn again?" 893 00:30:29,657 --> 00:30:31,759 >> So that's for me. 894 00:30:31,792 --> 00:30:33,628 [audience laughing] 895 00:30:33,661 --> 00:30:36,531 I sorta begged for that question. 896 00:30:37,631 --> 00:30:39,567 The observations by Cassini have been 897 00:30:39,600 --> 00:30:43,671 so remarkable for Enceladus and Titan that indeed, 898 00:30:45,372 --> 00:30:48,543 last year we announced the inclusion of those two objects 899 00:30:48,576 --> 00:30:52,613 in our focused science program called New Frontiers. 900 00:30:52,646 --> 00:30:55,616 Those proposals are in, and currently under evaluation, 901 00:30:55,649 --> 00:30:59,487 and they do indeed include proposals 902 00:30:59,520 --> 00:31:02,390 to go back to Titan and Enceladus. 903 00:31:03,724 --> 00:31:07,428 So we'll look through this competition and see what happens. 904 00:31:08,629 --> 00:31:10,498 >> Okay, you've got another question there, Jason? 905 00:31:10,531 --> 00:31:13,601 >> Sure, this one comes from Pietro, who asks, 906 00:31:13,634 --> 00:31:16,237 "If you could go back and change something in Cassini, 907 00:31:16,270 --> 00:31:19,440 "an instrument or skill, what would it be?" 908 00:31:19,473 --> 00:31:21,509 >> Hunter, you wanna take that? 909 00:31:21,542 --> 00:31:23,778 [audience laughing] 910 00:31:23,811 --> 00:31:26,280 Okay, if I could go back and change 911 00:31:26,313 --> 00:31:29,417 some instruments on Cassini, I think I'd select 912 00:31:29,450 --> 00:31:32,587 flying some more capable mass spectrometers. 913 00:31:32,620 --> 00:31:35,590 You know, if we had known about the geysers 914 00:31:35,623 --> 00:31:38,526 on Enceladus ahead of time, that would have perhaps 915 00:31:38,559 --> 00:31:42,363 guided us, something to go back and perhaps look for, 916 00:31:42,396 --> 00:31:45,766 amino acids, fatty acids, possible evidence of life. 917 00:31:45,799 --> 00:31:47,468 So if I could change one thing, 918 00:31:47,501 --> 00:31:49,403 it'd be to carry some spectrometers 919 00:31:49,436 --> 00:31:53,374 that could do some work for looking for life. 920 00:31:53,407 --> 00:31:54,709 >> I wouldn't have touched a damn thing. 921 00:31:54,742 --> 00:31:57,712 [audience laughing] 922 00:31:59,446 --> 00:32:01,782 You know, we went in with everything we possibly could. 923 00:32:01,815 --> 00:32:05,519 We had the Swiss Army knife, and now we know so much more, 924 00:32:05,552 --> 00:32:07,588 now we can fine tune it. 925 00:32:07,621 --> 00:32:11,592 But this spacecraft, like I said, I couldn't have asked 926 00:32:11,625 --> 00:32:15,262 for anything, I couldn't have asked for anything more. 927 00:32:15,295 --> 00:32:19,400 >> Alright, we're gonna come back to the room, I think Emily. 928 00:32:21,635 --> 00:32:24,271 >> Hi, I'm Emily Loctawalla from the Planetary Society, 929 00:32:24,304 --> 00:32:26,340 with a couple of science questions. 930 00:32:26,373 --> 00:32:27,575 Hunter, I'm wondering if you could tell us 931 00:32:27,608 --> 00:32:29,410 a little bit more about that ring rain 932 00:32:29,443 --> 00:32:31,512 concept that you're trying to test, 933 00:32:31,545 --> 00:32:33,514 and what you're learning about it. 934 00:32:33,547 --> 00:32:35,449 And Linda, I know that there's a science team 935 00:32:35,482 --> 00:32:37,518 meeting going on this week, I'm wondering if you can 936 00:32:37,551 --> 00:32:39,453 share any of the early exciting 937 00:32:39,486 --> 00:32:42,623 results from the proximal mission. 938 00:32:42,656 --> 00:32:45,660 >> Well, the ring rain concept, as I mentioned, 939 00:32:45,693 --> 00:32:48,696 was first introduced in the 1980s, 940 00:32:48,729 --> 00:32:53,300 and it was a concept of material from the rings, 941 00:32:53,333 --> 00:32:55,670 mainly water vapor and ice grains, 942 00:32:55,703 --> 00:32:57,605 descending into the atmosphere 943 00:32:57,638 --> 00:33:00,441 and causing changes in the atmosphere. 944 00:33:00,474 --> 00:33:03,511 And we have measured that, and we do see the water. 945 00:33:03,544 --> 00:33:06,647 But we see other constituents as well. 946 00:33:06,680 --> 00:33:10,451 So it's much more complex than we imagined before. 947 00:33:10,484 --> 00:33:13,688 And we'll be, you know, we're trying to, 948 00:33:13,721 --> 00:33:16,490 we're traveling at 31 kilometers per second, 949 00:33:16,523 --> 00:33:19,527 and gas is coming into our instrument very fast, 950 00:33:19,560 --> 00:33:21,562 and with a lot of energy. 951 00:33:22,663 --> 00:33:25,299 And so there's potential to break it apart. 952 00:33:25,332 --> 00:33:29,270 So we're working very carefully to understand 953 00:33:29,303 --> 00:33:33,374 that before we go out and tell the public what we're seeing. 954 00:33:34,475 --> 00:33:35,509 >> Yes Emily, we're having one of our 955 00:33:35,542 --> 00:33:36,744 project science group meetings, 956 00:33:36,777 --> 00:33:39,513 in fact it's the 73rd meeting we are having 957 00:33:39,546 --> 00:33:42,283 of this group since we first got started. 958 00:33:42,316 --> 00:33:45,486 And there have just been some tremendous presentations 959 00:33:45,519 --> 00:33:49,523 about the grand finale science, some of it only days old. 960 00:33:49,556 --> 00:33:52,626 And what I can tell you is that many of our models, 961 00:33:52,659 --> 00:33:54,662 we're finding out, are too simple, 962 00:33:54,695 --> 00:33:56,464 or just out and out wrong. 963 00:33:56,497 --> 00:33:58,365 And so the scientists are carefully looking at 964 00:33:58,398 --> 00:34:01,268 and calibrating their data, and comparing notes, 965 00:34:01,301 --> 00:34:03,604 and discussing it, and there's nothing to make 966 00:34:03,637 --> 00:34:07,608 a scientist happier than finding out hey, my model is wrong, 967 00:34:07,641 --> 00:34:10,411 I have to sorta start over and work it through. 968 00:34:10,444 --> 00:34:12,480 So we have a lot of very very happy scientists. 969 00:34:12,513 --> 00:34:15,516 We're meeting down at Cal Tech, and so hopefully 970 00:34:15,549 --> 00:34:17,651 in the coming months we'll have some answers. 971 00:34:17,684 --> 00:34:20,287 But in particular, the interior of the planet 972 00:34:20,320 --> 00:34:22,423 is very different than we expected, 973 00:34:22,456 --> 00:34:23,624 its gravity field is not at all 974 00:34:23,657 --> 00:34:25,693 what we expected from our models. 975 00:34:25,726 --> 00:34:27,561 Also, the magnetic field, we're finding 976 00:34:27,594 --> 00:34:30,331 that the rotation axis of Saturn 977 00:34:30,364 --> 00:34:34,368 and the magnetic field axis are almost perfectly aligned. 978 00:34:34,401 --> 00:34:36,337 Everything we think we know tells us 979 00:34:36,370 --> 00:34:38,405 that if you don't have at least a small tilt, 980 00:34:38,438 --> 00:34:40,341 you can't maintain those currents 981 00:34:40,374 --> 00:34:42,510 that sustain a magnetic field. 982 00:34:42,543 --> 00:34:46,647 So we have some more thinking and some more work to do. 983 00:34:46,680 --> 00:34:47,782 >> Okay, questions here? 984 00:34:47,815 --> 00:34:50,718 I think there's one in the third row. 985 00:34:52,719 --> 00:34:55,422 >> Hi, Robert Perlman Collect Space. 986 00:34:55,455 --> 00:34:57,558 Not that there'd be any way of verifying this, 987 00:34:57,591 --> 00:35:01,295 but has there been any modeling or any even best guesses 988 00:35:01,328 --> 00:35:03,397 of how Cassini's going to come apart? 989 00:35:03,430 --> 00:35:07,368 And what might be the last piece to survive? 990 00:35:07,401 --> 00:35:10,504 >> Yes, there's been very thorough analysis, 991 00:35:10,537 --> 00:35:15,442 a piece by piece deconstruction, if you will, of Cassini. 992 00:35:15,475 --> 00:35:18,445 And we believe that the final components 993 00:35:18,478 --> 00:35:23,317 to be destroyed will be the aero shell components 994 00:35:23,350 --> 00:35:26,353 that are wrapped around, Cassini has 995 00:35:26,386 --> 00:35:28,656 these radioactive power supplies. 996 00:35:28,689 --> 00:35:32,526 And each little slug of plutonium is wrapped around, 997 00:35:32,559 --> 00:35:34,628 is wrapped with iridium, and then they're 998 00:35:34,661 --> 00:35:37,731 put inside an aero shell, in order to avoid 999 00:35:37,764 --> 00:35:41,635 any possible release during a launch accident or reentry. 1000 00:35:41,668 --> 00:35:44,672 And the iridium has a very high melting point, 1001 00:35:44,705 --> 00:35:47,474 and the material around them is even higher. 1002 00:35:47,507 --> 00:35:48,742 So those will be the last pieces. 1003 00:35:48,775 --> 00:35:52,479 Other than that, taking those, the parts of the spacecraft 1004 00:35:52,512 --> 00:35:55,649 that will be shielded away will last a little bit longer. 1005 00:35:55,682 --> 00:35:57,585 But, you know, a lot of the spacecraft is aluminum, 1006 00:35:57,618 --> 00:35:59,353 it's going to melt very quickly. 1007 00:35:59,386 --> 00:36:03,490 A lot of it's carbon fiber and Mylar and things like that, 1008 00:36:03,523 --> 00:36:06,627 and they're gonna go very quickly. 1009 00:36:06,660 --> 00:36:10,297 >> Okay, how about some more social media questions? 1010 00:36:10,330 --> 00:36:11,465 >> Sure, here's two good ones here. 1011 00:36:11,498 --> 00:36:14,368 The first one comes from user Anshell, who asks 1012 00:36:14,401 --> 00:36:15,636 "What is the last bit of data 1013 00:36:15,669 --> 00:36:19,406 "that we will receive from Cassini?" 1014 00:36:19,439 --> 00:36:22,343 >> The very last bit of data will include 1015 00:36:22,376 --> 00:36:24,445 the ion and neutral mass spectrometer data, 1016 00:36:24,478 --> 00:36:26,714 but they come down in packets, so we don't know 1017 00:36:26,747 --> 00:36:28,682 if the INMS packet will be the last one, 1018 00:36:28,715 --> 00:36:31,318 or a magnetometer packet, or whatever. 1019 00:36:31,351 --> 00:36:32,753 But they'll be coming back as quickly 1020 00:36:32,786 --> 00:36:34,521 as we can send them back. 1021 00:36:34,554 --> 00:36:37,424 So we'll find out with that final bit. 1022 00:36:37,457 --> 00:36:41,495 >> Well actually, and we'll see the radio signal dissipate. 1023 00:36:42,596 --> 00:36:44,665 So our very last bit of science data, 1024 00:36:44,698 --> 00:36:46,433 if we don't get a complete packet, 1025 00:36:46,466 --> 00:36:49,470 could very well be the radio science. 1026 00:36:49,503 --> 00:36:52,439 >> Alright, lots of folks are asking about what happens next. 1027 00:36:52,472 --> 00:36:54,708 So Lisa here says, "What happens to the team working 1028 00:36:54,741 --> 00:36:56,744 "with Cassini Saturn after the mission's end? 1029 00:36:56,777 --> 00:36:58,579 "Are they just reassigned to new projects 1030 00:36:58,612 --> 00:37:01,415 "or missions at NASA, or are they off job hunting?" 1031 00:37:01,448 --> 00:37:02,783 [audience laughing] 1032 00:37:02,816 --> 00:37:05,619 >> Well most of the engineers, 1033 00:37:05,652 --> 00:37:09,390 there is an active planetary program here at JPL, 1034 00:37:09,423 --> 00:37:11,425 and a lot of our engineers have already kind 1035 00:37:11,458 --> 00:37:15,496 of half semi migrated over to these other opportunities. 1036 00:37:15,529 --> 00:37:19,566 We're not having big layoffs or anything like that. 1037 00:37:19,599 --> 00:37:21,502 There's lots of work for everyone. 1038 00:37:21,535 --> 00:37:23,671 Some of us have some paperwork to do. 1039 00:37:23,704 --> 00:37:25,706 [audience laughing] 1040 00:37:25,739 --> 00:37:27,375 And not just me. 1041 00:37:28,375 --> 00:37:30,477 [audience laughing] 1042 00:37:30,510 --> 00:37:32,613 So there's a lot of documentation, and of course, 1043 00:37:32,646 --> 00:37:36,517 the science data, to the extent that it can be funded 1044 00:37:36,550 --> 00:37:40,487 by research grants will continue for decades. 1045 00:37:40,520 --> 00:37:43,524 So those opportunities for both our current 1046 00:37:43,557 --> 00:37:45,726 and young scientists will be at least 1047 00:37:45,759 --> 00:37:47,594 for another couple of decades, gotta be. 1048 00:37:47,627 --> 00:37:49,363 >> Right, and the Cassini scientists are funded 1049 00:37:49,396 --> 00:37:52,466 for the next year, basically to make sure 1050 00:37:52,499 --> 00:37:54,735 they carefully calibrate and understand all 1051 00:37:54,768 --> 00:37:56,670 of this grand finale data, to put it 1052 00:37:56,703 --> 00:37:58,472 in the planetary data system. 1053 00:37:58,505 --> 00:38:00,374 And from there, it'll be accessible 1054 00:38:00,407 --> 00:38:01,642 to future scientists, you know. 1055 00:38:01,675 --> 00:38:05,312 Who knows how many PhD theses will be written 1056 00:38:05,345 --> 00:38:08,582 in the coming decades with Cassini data? 1057 00:38:08,615 --> 00:38:11,251 >> Indeed, you know, Cassini's really given everyone 1058 00:38:11,284 --> 00:38:15,356 on the job training on operating spacecraft 1059 00:38:15,389 --> 00:38:18,692 and keeping our instruments healthy and analyzing the data, 1060 00:38:18,725 --> 00:38:23,331 and so we have a cadre of highly capable scientists, 1061 00:38:25,632 --> 00:38:29,637 engineers, that we'll keep busy for many decades. 1062 00:38:32,739 --> 00:38:36,343 You know, planetary program is doing well. 1063 00:38:36,376 --> 00:38:38,412 We have tremendous support by the administration 1064 00:38:38,445 --> 00:38:41,715 and Congress, we have missions that we're planning now. 1065 00:38:41,748 --> 00:38:45,753 And we really have a very bright future. 1066 00:38:45,786 --> 00:38:48,355 >> Alright, we've got time for another quick followup 1067 00:38:48,388 --> 00:38:51,726 from Leo Enwright from Irish Television, Leo? 1068 00:38:54,528 --> 00:38:57,765 >> Leo: I've a question for Earl and Linda about Enceladus, 1069 00:38:57,798 --> 00:39:01,335 which is a tiny moon not much bigger 1070 00:39:01,368 --> 00:39:04,304 than Ireland, I have to point out. 1071 00:39:04,337 --> 00:39:08,442 And it's just astonishing that it's so active. 1072 00:39:08,475 --> 00:39:11,545 Earl, do you know, do you have any idea 1073 00:39:11,578 --> 00:39:14,481 of the chances that Cassini would 1074 00:39:14,514 --> 00:39:18,485 have actually collided with this tiny moon? 1075 00:39:18,518 --> 00:39:20,487 And for Linda, really, if you wouldn't mind 1076 00:39:20,520 --> 00:39:23,424 just telling us on the scale of things 1077 00:39:23,457 --> 00:39:27,494 that you've seen in your extraordinary career, 1078 00:39:27,527 --> 00:39:29,630 I mean where does Enceladus fit in 1079 00:39:29,663 --> 00:39:32,633 as the amazing surprise, as it were? 1080 00:39:36,570 --> 00:39:41,375 >> Well, we didn't do the math, actually I take that back, 1081 00:39:41,408 --> 00:39:43,744 we did do the math several times for Enceladus, 1082 00:39:43,777 --> 00:39:47,381 and as long as we could control the spacecraft, no problems. 1083 00:39:47,414 --> 00:39:51,285 But we had a big challenge in an uncontrolled spacecraft 1084 00:39:51,318 --> 00:39:53,287 not hitting within a chance 1085 00:39:53,320 --> 00:39:56,590 of one in a million Enceladus in the next 50 years. 1086 00:39:56,623 --> 00:39:58,759 The issues are, of course, that once it's uncontrolled, 1087 00:39:58,792 --> 00:40:00,727 you've got Titan out there pushing it around, 1088 00:40:00,760 --> 00:40:03,564 it could push it just about, as you saw in those graphics, 1089 00:40:03,597 --> 00:40:05,399 just about anywhere you'd want it to go, 1090 00:40:05,432 --> 00:40:08,436 and Enceladus was a good sized target. 1091 00:40:09,569 --> 00:40:12,239 So we didn't do the actual math for any 1092 00:40:12,272 --> 00:40:14,641 of those others to convince ourselves 1093 00:40:14,674 --> 00:40:17,578 that an uncontrolled spacecraft either had to be well 1094 00:40:17,611 --> 00:40:21,749 outside of Saturn, I mean way way outside, or inside. 1095 00:40:24,651 --> 00:40:26,687 >> Well let me answer the second part. 1096 00:40:26,720 --> 00:40:30,390 For Enceladus, I would say Enceladus' discoveries 1097 00:40:30,423 --> 00:40:32,459 made by Cassini are certainly one 1098 00:40:32,492 --> 00:40:33,627 of the most astonishing set 1099 00:40:33,660 --> 00:40:36,430 of discoveries for planetary science. 1100 00:40:36,463 --> 00:40:40,334 To find that there's an ocean world so tiny, 1101 00:40:40,367 --> 00:40:43,370 with the possibility of life, so far from the Sun, 1102 00:40:43,403 --> 00:40:45,405 10 times further from the Sun than the Earth, 1103 00:40:45,438 --> 00:40:49,276 has opened up our paradigm of where you might look for life, 1104 00:40:49,309 --> 00:40:50,744 both within our own solar system 1105 00:40:50,777 --> 00:40:53,747 and in the exoplanet systems beyond. 1106 00:40:53,780 --> 00:40:55,782 So these ocean worlds, Enceladus, 1107 00:40:55,815 --> 00:40:58,752 Titan also has a liquid ocean, has really changed 1108 00:40:58,785 --> 00:41:02,523 our thinking about where to look for life. 1109 00:41:03,623 --> 00:41:05,626 >> Okay, well actually I think that's about 1110 00:41:05,659 --> 00:41:08,495 all the time we have for today for our briefing. 1111 00:41:08,528 --> 00:41:10,230 Thanks again to our speakers, and to all 1112 00:41:10,263 --> 00:41:11,698 of you for your questions. 1113 00:41:11,731 --> 00:41:15,335 Here's how you can watch Cassini coverage 1114 00:41:15,368 --> 00:41:16,570 that NASA television has to offer 1115 00:41:16,603 --> 00:41:18,405 over the next couple of days. 1116 00:41:18,438 --> 00:41:21,275 Tomorrow, September 14th, we'll have a speaker program 1117 00:41:21,308 --> 00:41:24,478 as part of our NASA social event on Cassini, 1118 00:41:24,511 --> 00:41:26,547 from one to two PM Pacific time, 1119 00:41:26,580 --> 00:41:29,416 that's four to five PM Eastern. 1120 00:41:29,449 --> 00:41:30,717 Then on Friday, we'll have live commentary 1121 00:41:30,750 --> 00:41:34,354 from Mission Control from four to five-thirty AM Pacific, 1122 00:41:34,387 --> 00:41:36,623 that's seven to eight-thirty Eastern. 1123 00:41:36,656 --> 00:41:38,392 And following loss of signal, we'll have 1124 00:41:38,425 --> 00:41:39,760 a post-mission briefing right here, 1125 00:41:39,793 --> 00:41:42,496 starting at six-thirty AM Pacific. 1126 00:41:42,529 --> 00:41:47,334 You can watch live at NASA.gov/live. 1127 00:41:47,367 --> 00:41:50,571 More info about Cassini is available at NASA.gov, 1128 00:41:50,604 --> 00:41:52,472 and you'll find a detailed online toolkit 1129 00:41:52,505 --> 00:41:55,542 about Cassini's grand finale and end of mission on the 1130 00:41:55,575 --> 00:41:59,647 mission website at saturn.jpl.NASA.gov/grandfinale. 1131 00:42:01,815 --> 00:42:04,451 And I think we've got a couple more minutes 1132 00:42:04,484 --> 00:42:06,687 before the end of the hour, we'll end now with a replay 1133 00:42:06,720 --> 00:42:09,223 of some of the images and video 1134 00:42:09,256 --> 00:42:10,490 we've shared during our presentation today.