so the orbit of the earth here in the orbit of the moon, dawn was far way from the sun in 2010. this year it's four times as far with as far with the sun, more than 1500 times as far from earth as the moon, well in excess of a million times farther away than the international space station. and that to me is what is really cool. .. >> this is the same sun that so

dominated in art, literature literature, culture, mythology and religion, throughout all of human history. this is the same sun that is the gravitational master of our solar sister. it is the third of 1,000,000 times times the mass of our planet. it's her signpost in the milky way galaxy yet we can send spacecraft to the other side of the sun. when i say say we i don't mean the don team, i don't mean everybody here at nassau or the entire engineering and science community. i mean everybody. i think everybody participates in missions like this. to me, everyone who has ever looked up at the night sky and wondered, anyone who has curiosity at all about earth and how it fits in, anybody who feels the longing to know the cosmos or who wants to understand the nature of nature.

for that matter anybody who has ever felt that drive for a bold adventure, and noble undertaking to go beyond the next horizon and see what is there. everybody participates in a mission like this. that to me is what is most exciting about this kind of thing. i think of dawn and the other spacecraft around here as humankind's' robotic investors to the cosmos. i think we all share not. that is what what i think is rewarding about this. so that raises a question, how do we do this? we start by setting the spacecraft on top of a huge bob and hoping that it blows up in a controlled fashion, it usually does. we got dawn got dawn off to a beautiful launch. in fact dawn launched at dog, the sun is rising in the

background so we left cape canaveral at dawn in september september 2007. when we got into the space, it's a conventional view of the sun and the center, here's the orbits of earth and the orbits of other bodies. as as we follow the trajectory for dawn along if one it is this nice camellia blue color is where we are thrusting with the engine and where stark is where we are coasting. we launched in september 2007 when earth was here. we coasted a little bit and then thrust and had some coasting and thrusting when we are checking out the engines and other systems getting the spacecraft ready for its interplanetary journey. we got into a pattern of ion thrusting most of the time and as a subtle technical detail the duration of the coast. here are exaggerated because the software used to generate this

trajectory samples just once a day. we're actually thrusting more than it looks like. you can see thrusting most of the time. the long coast. where we flew by mars to speed up the spacecraft and the week continued spiraling farther and farther from the sun until july of 2011. we went into orbit around best and accompanied it for 14 months making a comprehensive set of measurements and maneuvering from one orbit to another. one of the benefits of ion propulsion system is once we are in orbit we can fly to different orbits to optimize our scientific investigations. we'll use the ion system to

break out of orbit, undertake a two and half your client through the main asteroid belt until we got the series just a little bit more of a year ago. when into orbit in the spacecraft to stay there and will stay there essentially forever. in fact, where the line turns from bold to light represents the end of don's prime mission which was june thirtieth. so we successfully completed this a .8 year, three, three and half a billion mile journey a few weeks ago but were very grateful that nasa decided to extend the mission because it's going so well and there's still more neat things that we can do. we are continuing our exploration there. resume and now and see where don is today and you can see we have progressed beyond the primary mission and on the scale you can't see the difference between where don is aware series are basically in the same place on the solar system but we can zoom in and see where best is today. one thing that is interesting is we depart from here and that was a little more than one vesta a

year ago. don is actually farther from vesta than the earth is from the sun. again, this is cool, it's a reminder that this is an interplanetary spaceship. we go to distant bodies in orbit them that we can travel from their huge distances to go elsewhere to explore. since i mentioned earth we can zoom in and see where earth is today and that's where it is right now. those that came here drove in through the guard facility, parked up. and were here right now. unfortunately i can see that gentleman back there you left your lights on. you might want to go take care that. so that's the overview of the true deck trajectory. when you look at a picture it's flat and static. it's easy to forget the solar is in motion.

i think of it as the solar system with a big, beautiful complex choreography. choreography. let's look at an animation of what's going on. i want to get oriented first so as the animation progresses you can follow it. so the standard view, the sun is in the center, blue is the orbit of earth, red is the orbit of mars, this is the orbit of vesta and this is the orbit of series. starting out by showing you the locations of these things where they were in march of 2007 see you can synchronize your watching of it in preparation of the september 2007 launch. what you'll see is the vesta will go all the way around the sun before we get to it and series will go around almost two full times before we get to it. it's much more complicated than just going out a certain distance to the sun. you have to

get to the right place at the right time. so here it leaves earth and lights up, we are now aiming to fly by mars, that, that occurred when we are coasting. we have flown by mars, were aiming for vesta that won't get there until here and series is going to go all the way around the sun for another full revolution before we get there. finally as as we get into 2011 don gets to vesta and goes into orbit and spends 14 months they're making extensive measurements. in september 2012 it has received a has for series and looks like it's not that far away but that's a long arduous climb through the asteroid belt. two two and half years to get there. as we get into early 2015 it to go into orbit that's where the spacecraft is right now. once again that is where it will be effectively forever, orbiting the sun with the largest body between mars and jupiter.

it is continuing now it's exploration of this strange alien world. so, that's a broad overview of the mission. i can tell you that we have lots of things going on. were very busy, lots of of things going on all of the time. i will not bore you with the details of what is happening. instead i will thank you for your attention. i appreciate you letting me tell you about the don mission. thank you very much. [applause] >> i'm happy to take questions for a while. if you you'd like to ask a question please come to the microphone and model people are doing that i will let you know if you're interested in the don mission you can go to our website, you can see all kinds

of cool things about the mission, we release a new new picture every day, sometimes more we release a new picture of series, lots of educational activities there for students and teachers and we are all students so a lot of neat things to learn. if you enjoy the way i talk about it i have a blog called the bay to journal i write about the mission. plus we have more frequent status reports. so questions. >> thank you very much, the lecture was fascinating. you spoke about the formation of jupiter and how that stopped the formation of these proto-planets. i was wondering if you could say a little a little bit more about how that happened. >> so first, can someone say that the microphone works so everybody can hear. >> i will not repeat the question for you. >> when jupiter formed did several things, it's gravity

tugged and pulled on all of the other material that was orbiting the sun. it started up. the consequence of that is when things hit they wouldn't necessarily come together with these gentle approaches and stick together. rather they would tend to hit a higher velocity and not stick together but break apart. in addition, it eject it a lot of the material from that region and scattered it elsewhere in the solar system. so not only were collisions occurred less effective in building larger bodies but fewer collisions and less material to work with. so what was there did not get the opportunity to continue growing. did that answer your question? >> you stated one of the main mission points was to measure the gravitational field.

what kind of tolerance is there between the field and when it actually arrives. how do you account for fluctuations in fuel consumption. >> so how do we account for the fact that we didn't know it won't got there. >> that's insightful question. it is another one of the unique aspects of the dawn mission is that this is the only mission ever that has gone to a massive solar system body to orbited which had not previously been visited by a flyby spacecraft. so mercury, venus, the venus, the earth, mars, jupiter, saturn, these massive bodies that spacecraft have orbited have been visited based flyby, dawn did not. so there were a number of ways be accounted for. but thanks to the ion propulsion system essentially what we would do it would measure the

gravitational pull with the extraordinary accuracy that it is able to achieve, measure that gravitational pull and then update our flight plan, our thrust profile that is, the aiming of the engine, and updated to account for improving accuracy in the gravitational field as we got closer. essentially you fly in a little, measure the field, flying closer and measured more accurately and then continue that process does that make sense? >> hello. and congratulations on this extraordinary accomplishment. i was wondering as i was looking at the amazing photographs that

it is the surface of series is like a record of every piece of whatever from space that slammed into it. i was just wondering, is there, do you think any of the surface of an object like series is the result of any kind of internal forces. is there any way to know that? >> that's a good question. i give wordy answers. i'll start with the short answer, yes. there is good reason to believe, in fact excellent reason to believe that there are internal geological processes operating on series which directly affect the surface. we can see that in several ways. one is a shoji the crater then a a moment you'll see it rotating into view in this picture, it it will be the bright thing. as i said, that is measured to

be only about 80 million years old. and the bright material there has to be even younger than that. so, there are current processes but more to the point you started with a reasonable comment that it is recorded everything that it hit throughout the more than four and half 1,000,000,000 a billion years of the solar system. in fact, there are number of areas on series, you can't see it will in this picture which actually are relatively smooth and don't show many craters. we have mathematical methods, i could describe if you are interested for predicting how many craters of certain sizes should occur on series, partly based on some of the craters we see on vesta. there are not as many large craters there as it seems there

should be. so the suggestion that perhaps there are geological processes that over time erase those craters. one of the things that planetary geologists are working on is understanding the nature of these processes. there other geological evidence as well of the effect of series internal activity much more recently, occurring much more recently than the foreign have billing your sense of forms. does that make sense? >> yes good evening, two questions on the design of the spacecraft. first of all you mentioned that it had another ion engine which i seem is to. >> we had three. >> the star war type fighters

only have two we have three. >> our lasers are not as powerful as theirs but you can have everything. >> those were goldplated it's a military project. is that strictly for redundancy or do you actually use those to eliminate the need to turn the craft around? >> before i answer let me explain for other people when he asked about redundancy the ideas do we have more than one in case one fails. >> so it turns out there is a mechanism that we understand very well by which ion engines wear out in space, because of use just like lots of physical devices get consumed by their use. so given the amount of xeon propellant that we had to expended to accomplish the

mission we had to have two ion engines. one would wear out too soon or we didn't have sufficient confidence that we could do it with one. so we carried to in order to have sufficient lifetime. the third is for exactly what you raised. that was an insightful observation. the third is in case one fails. however all three are still healthy. so we did not have problems with ion engine. we don't pick them on the basis of what direction we want to thrust because you can see in this picture and i will turn the pitcher off in a moment because my computer doesn't like staying on one picture for too long or maybe it won't quit for me and embarrass me. but there is 1 inch in here, one here and one on the backside. that's not enough to cover all the directions anyway. if you you want to pointed up in this way.

if we want to point an ion engine in that direction we rotate the spacecraft and pointed in that direction and go there. >> thank you. this is an ambitious size of solar array to have work and unfold perfectly, did you have a trade off between thinking of using like a radioisotope power power supply or what was your thinking? >> well thank you for the answer. >> you might want to wait till after answer but that's your call. once again for other people's benefits there's radioisotope thing that he refer to in fact for the people in the room i don't know if you can see the laser pointer but this black structure sticking out of the side of voyager is what is called the radioisotope, the stale model here has i'm if you going to the museum which i think is open this evening. you can see models on the galileo spacecraft as well.

so these are devices which contain radioactive material and when they decay they produce heat and the heat is used to produce electricity. it's not a nuclear reactor but it uses nuclear energy. we didn't not consider them using on dawn for several reasons. they're very expensive and so you only use them if you have to. they were well worth the investment for the fabulous return of voyager and cassini and other missions. also, they don't produce enough electrical power. devices like that only can produce 100 or a few hundred watts. the ion engine itself to turn on takes well over 500 watts. normally we have never operated

it at that low-power level. when we started we were thrusting with more than 2 kilowatts. so the mass of these devices would completely overwhelm the benefit of the ion propulsion system. we have to propel that mass through the solar system. having the largest solar rays was a better tree. but every mission makes its own thought of where it will be most effective. >> thank you so much. i was wondering how we know the debris on earth came from there and why the north part of it is much more densely created than the cell. >> so the first part, how do we know these meteorites and i forgot to say if you want to come up and take a look look at it afterwards you are welcome

to. how do we know they came from earth? there's a number of evidence but it started with a method i need to explain to called infrared reflected spectrum. infrared, a wavelength of wavelength of light that we can't see but we know is there, just as there is wavelength of sound we can't hear but your dog can confirm for you that there is wavelength of sound that we can hear but it's detectable. reflectance that just means the infrared light in the sun pounces off vesta goes elsewhere just like the visible light does on the spectrum is where you break the light into its constituent colors. so think of using a prism on white light and you see quite literally all of the colors of the rainbow. we can do that with infrared light as well. it turns out when you do that the infrared reflection contains

the fingerprint or signature of the material that reflected it. some infrared wavelengths are reflected strongly so it's bright, some are not reflected well so it is dark. this produces a distinctive pattern for different materials. around 1970 astronomers started using infrared detectors to look at astronomical bodies. they looked at vesta, measured the infrared spectrum and found it was a wonderful match for the large class of minerals that occurred in the media rights for experts, so the meteorites if you want to get them are not very expensive because they're common. i bought this myself before i

heard of the dawn mission because i thought it would be cool to own a piece of vesta. these minerals were a great match for vesta. that's what made the initial connection. other lines of evidence that i can tell you about, giving a, giving a long answer but it wasn't until dawn got there and made more detailed evidence that we were able to clinch the story. the other question is wise the is the northern hemisphere more densely created than the southern. the reason because of the impact that excavated the material happened to occur deep in the southern hemisphere near the south pole. some of that material was thrown out with energy that it left the vicinity of vesta and went elsewhere including here on earth. some of it just like a big impact on earth some would fly up and come down someplace else. so it landed elsewhere in the southern hemisphere and it you

race to the craters that are ready formed there and resurfaced it. you can think of it as the northern hemisphere records for a half 1,000,000,000 years of stuff falling on it whereas the southern hemisphere had its record whites clean. it only only records 1 billion years. >> thank you. >> i apologize for my wordiness. >> hello. i have a good intuition for chemical rocket engine. i've watched watched videos and heard it live the audio, but i don't have the good intuition of what the ion -- is like. >> nobody does. >> he's like darth vader i'm wondering, what would it semi, what would happen if my hand was or what if my wasted 10 feet away from it. so first role the ion engine can

only work in a vacuum chamber. so, in space, somebody can hear me? so in space nobody can hear you, you can hear and ion engine in space, doesn't make a sound. what what it feel like if you put your hand in front of it? there's a lot of energy in these very high velocity xeon ions. kilowatts. it's a highly efficient system. it's not perfectly efficient so not all of the electrical energy goes into that. but it is very high-energy. if putting your hand in the vacuum of space was tolerable you would not appreciate the effect of this high-energy xeon ions impinging on your skins. it would be very damaging.

it's very energetic. what was the third -- what if you stood 10 feet away away from it. that's no problem. we have vacuum change chambers and as long as it is 20 feet of cross were in the safety of the laboratory outside. >> the point is, it produces produces the glow in that picture that i showed you is the benefit of effective topography. if you look with your you can see it but it's not exactly blinding. but it just as this gentle glow as the zions exit with the velocity that is so high you can't detect their motion because of the velocity in their tiny size. >> thank you. >> hello. with the ion engine, how long did it take you to make it? and i have a second question.

>> you mean how long did it take to fabricator manufacturer door how long to make it from earth tour destination. >> fabricate fabricate. >> like most of the components on the spacecraft these things take my don't know exactly how long been around a year or so. most things take six months to a couple of years to make because you have to produce these things to very strict standards. you do not want them, you want them to operate correctly space. they go through extensive testing. so the total time from when you start with raw material until you have the ion engine on the spacecraft ready to go is years

because you test the individual engine then put it on the spacecraft and tested there and then you test the whole spacecraft with the engine on it. so we started building the spacecraft in in 2005 and didn't launch until 2007. >> also, why did you use xeon as a propellant? >> a number of reasons for choosing xenon. early tests of ions did use other propellants, mercury was a common one. but xeon has a number of advantages. i mentioned it's one of the so-called noble gases or a gases. it's not chemically reactive. that means that when technicians are loading it on the spacecraft there's no risk to their health.

they don't have to wear special protective gear in case there is a leak. another benefit is that there is a mechanism that we understand well by which a little bit of the xeon leaks out of the engine at low velocity. so the spacecraft ends up having a cloud of xenon around it. because it xenon is inert it doesn't risk other systems from a chemically reactive compounds that could degrade optical surfaces like damage to the camera for the solar race or interfere with the electronics or affect the temperature of surfaces. everything on the spacecraft is designed with great care. xenon won't interfere with that. you can see your eager to say something else but i've proven i'm wordy so i have to tell you

a few more things. xenon is very easy to store. we launch with 937937 pounds contained in just 71 gallons. a tank about 1 yard across and that tall. we need to be able to store it effectively because space is at a premium in the spacecraft. >> okay, thank you. >> hello. thank you for the talk. i was curious as the end of the mission approach was there any particular last things that you wanted to see there. also about the end-of-life plan lake it will it just float off into space? >> i'm not sure was there any particular things we wanted to see at the end of the mission as we were approaching the end? >> yes. so that's a fun question. as it turns out there weren't.

the reason was because even before the end of the prime mission. i will take you back. dawn, like all mass omissions has a well-defined set of objectives. you personally, you and i and all other taxpayers have made an investment in what nasa does. so we have to make sure the investment is done responsibly. you don't just build the spacecraft, launch until until it to do good things. we agree it's worth this investment to accomplish a certain set of objectives. we had a well-defined set of objectives that we wanted to accomplish in the mission. we surpass, not just met but surpassed all the objectives i think by february or march of this year. the end of the prime mission wasn't until june. by the time the mission ended we were ecstatic with this rich trove of data we were returning.

sure, the cosmos is endlessly fascinating and there will always be interesting things to look at, but we were in a fortunate position of not needing urgently to just see one more thing. certainly things we would like to see and that's why it's wonderful that nassau has chosen to extend the mission but there is nothing that by the time in the end of the prime mission that we felt we are rushing to see. i think the second question you asked is sort of what's going to happen to the spacecraft. it will stay in orbit just as surely as the moon stays in orbit around the earth and the earth stays in orbit around the sun. it it is the moon of series. we will continue operating as song is to an important criteria are met.

besides the spacecraft remains healthy and productive. that in itself is two criteria. and as long as nassau continues to choose to invest its precious and limited funding into dawn. in any case, when the spacecraft completes its operational lifetime and i could explain to people are interested why that will occur, it will become an inert celestial monument to human creativity and ingenuity in orbit around series. it's not going to go anywhere else. it will remain in orbit. >> thank you. >> good evening. thank you very much. that you make our dreams about space true. >> if i can inner property.

it's not just your dreams, thought of our dreams. is so cool. yes it's exciting. >> the question is what are the biggest problems in the spacecraft have happened. and how did you solve this problem. >> did someone tell you test that question? nobody did i know. >> the question was, what's the biggest problem that happened to the spacecraft are in the mission. the nice thing is, if you ask anybody associated with the dawn mission you would get the same answer. we did have a big problem. the mission was successful so it's okay, but the spacecraft has devices called reaction wheels. these are discs discs about the spigot that are electrically spun and they are light gyroscopes there's a

phenomenon that you may remember from high school physics where you take a spinning bicycle bill and hold it on the shaft and the wheel spins looks like nobody went to the same high school i did. he said on the barstool and as you rotate the wheel you spin on the stool. this has has to do with what experts -- the point is these discs as we change the speed at which they spin we can turn, and rotate the spacecraft. in the zero gravity frictionless space there's no other way to turn it. if you have a wheel like this any change the speed this spacecraft will turn. that's how we orient the spacecraft. and many of them are oriented the same way. so we we need three of those because they are three dimension. up, down, left, left, right, or pitch rolling back. you need three for redundancy we

have four. we couldn't and didn't want the mission to fail because of some random failure. however, to have failed. we didn't bill this the spacecraft to be able to tolerate two failures. failures like that could be catastrophic for the mission. one failed in june of 2010, one failed in august of 2012 as we are in the process of breaking out of orbit from vesta to begin the journey to series. there is no good reason why the mission should have been successful following that second failure. but, one of the things that is cool about the missions is that we found a way. one of our mottos is that if it's not impossible to not worth doing. so, that's what makes nasa so

need. so we found ways to control the spacecraft and fly it in ways that we had truly never thought of were considered when the spacecraft was on earth or even in its vicinity. i give you one aspect of that, it's a much longer story because it comes back to an earlier question. we have a very small supply of conventional rocket propellant called hydrazine. we have 12 gallons on board. it was not meant for this purpose but we have thrusters on the spacecraft. if if you squirt some out of this thrusters it makes it turned like this if you squirted out of this thruster it makes it turned like that. we had not intended to fly the spacecraft that way but that is one of the ways we are doing it.

we didn't have enough of this hydrazine, this chemical to fly the mission so we undertook a very ambitious campaign. this was a huge amount of work by very dedicated, creative and capable team of men and women at jpl and with our partners at orbital a tk and came up with ways to use the hydra cheat hydrazine more efficiently than we thought. one year ago it would've occurred to us that would be in the position now been able to undertake an extended mission because the hydrazine was so tight we didn't think it would last until now. but it did. >> it sounds like this problem -- is very common for spacecraft it happened in in international

space station a lot of times. what is the root course for this program? >> so the question as it sounds like these devices like gyroscopes that failures are common is that fair question. >> yes it's a common problem. and why it happened every time. >> that's a good question. but it's a misperception. there many satellites and spacecraft with these devices that operate flawlessly, essentially endlessly for notches years but decades. the ones come i told you that would happen. i will invite the audiovisual people to go to something else or -- thank you.

almost spacecraft and satellites they operate flawlessly for years and years. truly many billions of revolutions. the ones that don't operate are the ones that make the news that you've heard about. but really they do work very well. there happens to be a number of satellites and spacecraft like dawn that used one particular design which we all found out too late wasn't reliable for endless years of operation after the rigors of a launch, the temperature changes, the radiation, the for bidding environment of space and so those have not worked to successfully in a number of spacecraft. on most satellites they do.

so it's just this batch. then here you have a device that spinning. it's not like an electrical circuit where there's no mechanical movement. this constant motion, for years and years without stopping, that's a challenging problem for people to solve to make them so they work reliably. so the truly overwhelming majority do work beautifully. unfortunately some don't. >> thank you very much i would like to make a comment. >> okay on behalf of the organizers here. >> in the spacecraft the venus work for 40 years successfully.

the space station use different than reactors, but say momentum and they work successfully no problem. my question is about the electric propulsion. how much did -- work under the development of the propulsion, being that important as we see here. and how much particularly to use that aircraft and propulsion, i in the mid- 1970s for young came to gpm to work on electric propulsion and after a short time everyone went to do something else. >> is a question what is the

history of the development of i am propulsion? when this term electric propulsion that he is using is one of the other terms for it. so goes well back before that. the first recorded thoughts about i am propulsion were by robert goddard in 19 oh six. the father of american rocketry. they published a paper on it, sterling or, a colleague in the 1960s nonoaud you making the accurate point that engineers at hughes aircraft and elsewhere did, it was worked on by people in nassau and private industry from the 50s up through the present. there's a rich history of many creative and talented people contributing to the development

of it. if i suggested that jpl was the organization that developed under thought of it are the only want to work on it, i didn't mean to suggest that. when i said i raise the question of how can we travel around the solar system more easily and less expensively, it was that we could turn to the i am propulsion, that brilliant people have been working on for nearly one century. >> though it's very important for -- why did it was such importance. >> i'd be happy to talk about this more. you may have some incomplete perception of jpl's role in the development. they are not solely responsible

for the development of i am propulsion. it was a joint nassau development and we have taken advantage of the brilliant work that was done by many people to have the success. i think rather than get into details of the technical history or think there are broader questions that would be of interest. come up afterwards and we'll talk. thank you. >> also is used for -- >> most people don't know about station keeping but you are right. there many space craft that use ir propulsion. dawn is not the only one jpl's deep space one was. that's where we learn to fly i compulsion. i'm glad you're so interested. i would be. i would be delighted to talk to more about it afterwards. you also have some good knowledge in history. >> hello. jupiter and one of the first photos that you showed of the orbits around the sun commit

jupiter showed that it goes through the pockets of -- and i'm wondering why it didn't clear that material? >> or your for referring to the slide with asteroid belt both leading jupiter and following. >> yes of there's three. >> that's a good question. it doesn't go through those because those are going around the sun just as jupiter is. but just so everyone is following, remember the picture of the asteroid belt. he was observant enough to see that there are two groups of asteroids ahead of and behind jupiter. those are called trojan asteroids and they, bodies that

and think that orbit the sun or doesn't have to orbit but when one body is orbiting another they turn out to be places in its orbit that are relatively stable for other bodies to orbit. so both ahead of and behind jupiter are two such places. asteroids that happen to have wandered through this place kind of get trapped. for experts there's a little bit of -- it's not that jupiter's plowing through them but they are orbiting the sun with jupiter and the relatively stable. there are places like that for earth that orbit around the sun and even the moon's orbit around the earth. >> thank you. >> there are people. >> okay. we were going going to

answer questions but there's another one first. >> is there ever going to be a spacecraft that travels into space to refuel dawn? >> so will there be another spacecraft flying into space to refuel it? that's a good question. guess i can answer the question by asking your question. when you grow up, would you be willing to make a spacecraft that will travel into space to refuel dawn? [applause] and i hope the answer is yes. so nasa doesn't plan to do that, but we are waiting for smart, creative, energetic, enthusiastic people like you to come up with great missions like that.

right now dawn is well over 1 million times away than the space station. so that's a long way even for robotic that is spacecraft without astronauts on board to go refuel another one rather than if we're going to send a spacecraft out there instead of carrying fuel it could carry advanced new instruments and stands there's a more sophisticated cameras and things like that that we haven't even thought of. nevertheless, it's a great idea. if you do it and i'm old and retired, send me whatever the future communications method will be and tell me how dawn is doing. thank you. [applause] so we have a couple of questions from people who are watching now in the live stream and thank you for that.

i'm not very good at pronouncing some of these things i will spell it. the kyanite asks, was there any plans for dawn to visit a third body in the asteroid belt such as palace? palace, pal las is another large body comparable in size to vesta. the answer to that is, no. there. there was never such a plan. but i presume the background for the question is for those who read about these things on the internet, i have been reading for years that dawn has actually done studies of going to the other body. i genuinely don't know what the origin of that rumor is but i can tell you, we never looked at it. i've read it many places, we've never looked at it.

our targets were vested in series from the time that we had them. we never had intent to go anywhere else. as you may know from reading in the news recently, just in the last few months we gave nassau the option of sending the spacecraft to another body for an extended mission possibility. so, the extended mission after the completion of the primary mission. so he told nasa that if they would consider extending the mission we could continue to stay in orbit around series or go to a different body. nasa considered the scientific merit of remaining in orbit, continuing to make the detailed observation were flying to a different body, they considered and concluded the best use of this precious resource that we

have funded is to continue at series to make more measurements of this, the only door for the planet in the solar system. i hope that answers your question. the other question and this'll be the last one is from -- who ask, are we able to determine the mass or other properties of the object which collided with vesta? so remember the big crater, the the 300-mile diameter crater near the south pole avesta which is the source of the meteorites crashed into it around 1 billion years ago. it is estimated the body that crashed into a is around 30 or so miles in diameter. that's pretty big. if you imagine that crashing into your backyard that probably

wouldn't be appreciated by you or your neighbors. that's a big thing. it's large compared to the object which crashed into earth and is primarily responsible for the extinction of the dinosaurs and other species 66 million years ago. that was a big impact. a messy estimated size of it. once again, thank, thank you very much for coming to jpl and hearing about the mission. [applause] [inaudible] [inaudible] [inaudible]

>> with donald trump elected as the next u.s. president, milani a trump becomes our second born first lady sense louisa adams. learn more about presidential spouses from the book first ladies. it's a look at to the personal lives and influence into every presidential spouse in american history. it is a companion to the tv series and interviews with 54 of the nations leading first lady historians. biographies of 451st ladies in photos from from each others lives. it's published by public affairs and available wherever you buy books and available in paperback >> c-span's washington journal, live everyday live every day with news and policy issues that impact too.

there's a morning, joining us is about to set, edited chief on the hill on what is next legislatively with the republican-controlled congress and donald trump as president. watch "washington journal" live 7:00 a.m. eastern on thursday morning. >> republican senator kelly ayotte of new hampshire conceded to mackey hash of this evening. they led senator app by just 1 million votes. but she is not pursuing a recount tip in the second seat to democrats after the election. president obama this afternoon call for unity invited president-elect donald trump to the white house. his remarks from the rose garden are about ten minutes. [inaudible] >> good afternoon everybody.

yesterday, before votes were tallied i shot a video that some of you may have seen in which i said to the american people, regardless of what side you are on in the election, regardless of whether your candidate won or lost, the sun would come up in the morning. and that is one bit of prognosticating that is actually true. the sun is up. i know everybody know everybody had a long night. i did as well. i had a chance to talk to president-elect trump last night about 3:30 a.m. to congratulate him on winning the election and i had a chance to invite him to come to the white house tomorrow to talk about making sure there is a successful transition between our presidencies. it is no secret the president-elect and i have some pretty significant differences. but remember, eight years ago

president bush and i had some pretty significant differences. president bush's team could not have been more professional, or more gracious in making sure we had a smooth transition so that we could hit the ground running. one thing you realize quickly missed job is the presidency and vice presidency is bigger than any of us. so i have instructed my team to follow the example that president bush's team set eight years ago and work as hard as we can to make sure this is a successful transition for the president-elect. because we are now rooting for success in uniting and leaving the country. the peaceful transition of power is one of the hallmarks of our democracy. over the next few months we are going to show that to the world. i also had a chance last night

to speak with secretary clinton. i had a chance to hear her remarks. i cannot be prouder. she has lived an extraordinary life of public service. she was a great first lady, she she was an outstanding senator from the state of new york. and she could not have been a better secretary of state. i am proud of her. a lot of americans look up to her. her candidacy and nomination was historic and sends a message to her daughters across the country that they can achieve at the highest level of politics. i'm confident jim president clinton will continue to do great work for people here in the united states and around the world. everybody is sad when their side loses in an election. but the day after we have to remember that we are actually on one team.

this is an intramural scrimmage. we are not democrats first or republicans first. we are americans first. we are patriots first. we all want what is best for this country. that is what i heard in mr. trump's remarks last night. that is what i heard when i spoke to him. and i was heartened by that. that is what the country needs. a sense of unity. a sense of inclusion. a respect for our institutions. our way of life, the rule of law, and a respect for each other. i hope he maintains that spirit throughout this transition and i certainly hope that is how his presidency has a chance to begin.

i also told my team today to keep their heads up. the remarkable work they have done, day in and day out often without fanfare, often without attention, working agencies, work in obscure areas of policy that make government run better and make it more responsive and more efficient and make it more service friendly so that is helping more people, that remarkable work has left the next president with a stronger, better country than the one that existed eight years ago. win or lose in this election, that was always our mission from day one. everyone on my team should be

extraordinarily proud of everything they have done. so should all the americans i've had a chance to meet across this country who do the hard work of building on that progress every single day. teachers and schools, doctors in the er clinic, small businesses putting their all into starting something up making sure they're treating employees well. other important work that is done by moms and dads and families and congregations in every state. the work of perfecting this unit. so this was a long and hard-fought campaign. a lot of our fellow americans are exalted today. a lot of americans are less so but that is the nature of campaigns. that's the nature of democracy. it is hard. sometimes contentious and noisy.

it's not always inspiring. but to the young people who got into politics for the first time and may be disappointed by the results, i want you to know you have to stay encouraged. don't get cynical. don't ever think you cannot make a difference. secretary clinton clinton said this morning, i am for what is fighting for what is right is worth it. sometimes you lose an argument, sometimes you lose an election. the path this country has taken has never been a straight line. we think and say and sometimes we move in ways that some people think is forward and others

think is moving back. that's okay. i have lost elections before, joe has, but, you know. [laughter] that is the way politics works sometimes. we try really hard to persuade people that we are right and then people vote. and then if we lose we learn from our mistakes, we do reflection, we lick our wounds, we brush ourselves off, we get back in the arena. we go go at it. we try even harder the next time. the point is we all go forward. with the presumption of good faith and our fellow citizens. because that presumption of good

faith is essential to a vibrant and functional democracy. that is how the country has moved forward for 240 years. sally pushed boundaries and freedom around the world. it's how we expanded the rights of our founding to reach all of our citizens. it's how we have come this far. as i am confident that the incredible journey we are honest americans will go on. i'm looking forward to doing what i can to make sure the next president is successful in that. i've said before, i think of this job as being a relay runner. you take the baton, you run your best race, and hopefully by the time you handed off you are a little further ahead and have made a little progress. i can say that we have done and i want to make sure that handoff is well executed.

ultimately we are all on the same team. thank you very much everybody. [applause] [inaudible] [inaudible] [inaudible] two a headline in the washington post. trump victory reverses u.s. energy and environmental priorities as he battles to

cancel the international paris climate accord. in the new york times, uncertainty over donald trump's foreign policy risks global instability. today, number four and later swayed in about the election of donald trump as the next u.s. president. including australian prime minister, his tweet says, this trailing government congratulates president-elect trump. with our shared international interest, our relationship our relationship will continue to be strong. next, a discussion from china central television on u.s. asia relations after the election. this is about half an hour. [inaudible] >> hello. donald trump has won the presidency of the united states. what has this surprising election told us about the political process in the united at