GRAIL Mission Science Briefing

hello I’m DC a goal of NASA’s Jet Propulsion lab we’re here to talk about the science of the grill mission to the moon here to talk about grill we have with us today Bobby Fogle grail program scientist NASA headquarters Washington Maria Zuber grill principal investigator Massachusetts Institute of Technology Cambridge Sammy asthma grill deputy project scientist NASA’s Jet Propulsion Laboratory and Lisa Hubbard t-turn residents Sally Ride science San Diego and we’ll open it up with Bobby Fogle Thank You DC you know they say that you can’t judge a book by it’s cover but you know virtually every planetary mission to one of the inner planets the rocky bodies of the solar system mercury venus the Moon and Mars has done just that they’ve gone to investigate the planetary cover or the planetary surface / atmosphere it’s not that scientists aren’t interested in the planetary interiors on the contrary we’ve known for some time that the interior of planets holds a secret to their formation evolution and internal processes the problem is that investigating the interior is one of the hardest things to do in space science consequently we go to places where we can actually access which is the planetary surface and we look there for clues as to what’s going on in the planetary interior can have the animation please case in point the moon this little animation shows you a little comic of the various different missions that NASA and other space agencies have sent to the moon over the last 50 years every single one of them without exception has focused as its main goal to understand the surface of the Moon or some property at the lunar surface such as radiation not one of them has really had as its focus the internal composition or structure of the moon imagine for a second what the state of medical science would be without the MRI the cat scan the x-ray or the scalpel everything you know about the internal workings of human being would have to come from observing their skin their eyes their hair you have to use those observations to try to figure out what’s going on inside a person pretty primitive a well by analogy this is the state of our understanding of a lunar interior and the interiors of the rocky bodies at this moment in time so you can imagine our delight at NASA headquarters when we selected in 2007 for the discovery mission the Grail mission which is a mission to the planetary interior of the moon now why do we care about the lunar interior well four and a half billion years ago after the moon formed it started heating up due to planetary impacts by asteroids meteorites and comets the heating also came from the breakdown of radioactive elements inside the moon and eventually the melting point of the moon was exceeded and a giant ocean of magma magma was formed this magma ocean was lunar wide and extended down to depths at least as great as 400 kilometers maybe more now out of this magma ocean eventually as it started cooling crystals or mineral started forming those minerals that were denser than the surrounding liquid sank and those that were lighter than surrounding liquid floated you know you see a manifestation of this every time you look up at the moon the face of the moon that shows itself to us you see white areas and dark areas the white areas are composed predominantly of a rock type called an ortho site and anorthosite is dominated by a mineral called an earth ight now an earth ight was lighter than the surrounding magma ocean so it floated and created the lunar Highlands with a lunar crust now eventually the magma ocean fully cooled and tectonic forces took over and shape the moon and its interior even further and eventually there were basin forming impacts and they were flood basalts going into some of the lamare so the moon has a lot of structure structure and this is where Grail will make history grell will be the first mission to actually go to the moon with its primary focus of determining the structure and composition of the internal parts of the moon now to be sure we’ve used gravity science before to try to gain some insight as to what’s

going on inside the moon however these have been very primitive attempts compared to what grill will be able to accomplish if those previous attempts could be likened to a magnifying glass Grail by contrast would be a high-powered microscope so we’re delighted that we’re here and we’re one day away from launch Grail is ready it’s on time and on budget now if the weather would cooperate we’ll have a great mission Maria thank you very much I’m thrilled to be here thrilled to be at this state one day before launch and let me tell you a little bit about the science of the Grail mission I could have the first graphic please that’s a picture of the near side of the moon as we view it from Earth nearly every human in history has looked up and seen that site aside from the sheer beauty of seeing the moon in the night sky that moon surface holds the record of the whole history of the evolution of the moon a great deal of what you see on the lunar surface however has been controlled by processes that have occurred inside the moon the next slide so we’ve learned a lot about the surface of the moon from orbital reconnaissance and we’ve had the fortunate situation of having 12 humans who’ve walked on the surface of the Moon who’ve returned samples these samples have been analyzed for the past 40 years they are still being analyzed today using the newest techniques and they are still providing us with information so we have orbital reconnaissance the surface we have lunar samples which we can analyze in earth labs the piece of the puzzle that has been missing in trying to reconstruct lunar evolution has been a good understanding of the Interior and that’s what Grail hopes to provide so in the next chart I’d like to talk a little bit about what are some basic things about the moon that we don’t understand okay this is a beautiful wide angle camera images of the near Side of the Moon on the left that’s the side that we see from Earth and on the right-hand side that’s the the far side of the moon so as Bobby mentioned we have on the near side of the moon bright areas lunar Highlands which are areas that have melted and light crystals that have floated to the top as these cooled off large impacts battered the surface of the Moon is the material that was left over from accretion and then basaltic magma lavas flooded these large impact basins if you look at the right side you don’t see these Magma’s and we used to think that there was melting underneath the near Side of the Moon and that flooded the impact basins but on the far side we didn’t have these basins so the back side of the Moon melted in the interior but the material was never able to rise to the surface because of the lack of large basins but if you look at the next hand slide this is an elevation map of the moon that was collected from observations from the laser altimeter on the lunar reconnaissance orbiter which is mapping the moon right now in this map white and red correspond to high elevations and blue and purple correspond to low elevations so if you look at the left hand side the dark blue areas you can see that these are actually low areas that were flooded by magmas but now if you look at the vantage point of the third dimension on the right hand side you see that that the the backside of the moon has the largest and deepest impact crater on the planet but yet this never got filled by magma so what that tells us is that what happened on the near side of the moon in the interior was quite different that what happened in the far side of the Moon the back side obviously didn’t melt and and so that’s a fundamental question which has shaped the surface of the Moon which has eluded our understanding now if you also if we could go back to the graphic of the elevation map that bright white area there near the equator very recently an idea has come out where we might not have had one moon but that originally two moons formed around the earth that a small lunar companion formed in orbit around the earth in the same orbit as the moon but ahead of it are behind it and that very slowly over early time this moon the second moon would have collided with the first moon but it would have done so at such a low velocity that it would have added more

material to the moon than it ejected and this would actually have caused a mountain to form rather than a crater this is a very new idea and it made specific hypotheses for what the inside of the moon should be like if this occurred and these ideas can be tested with the Grail mission if we could have the next slide please this is a cross-section of our state of knowledge of the deep interior of the moon on the left hand side is the near side as we view from Earth the the right-hand side is the far side that we never see the purple areas correspond to zones on the front side of the moon where Apollo astronauts left seismometers which probed the interior you can see in the dots there there are some shallow moonquake locations and you can see that there are some deeper moonquake locations shown by the white dots that are deeper there these deeper moonquakes they tend to be triggered by tides we don’t know why the moon quakes occur at those depths and not shallower depths we don’t know why whether there are shallower moonquakes that we’re not detecting we suspect there are we don’t know anything about seismicity on the far side of the moon that would tell us perhaps the structure of the near side versus the far side and why they’re different the next slide please okay here’s a cross-section of what we think the deep interior of the moon might look like information from the Apollo seismometers that is still being analyzed today and from lunar laser ranging where laser station on the earth shoot lasers up to retroreflectors at the Apollo astronauts left every month and tell us about wobbles that give us information about the subtle structure of the interior of the moon the suggestion is that the moon has a very small solid iron core that’s surrounded by a liquid iron core but we don’t actually know for sure that that’s the case it’s actually quite possible that deep inside the moon the core could be titanium oxide which is a material that would have fallen out or condensed out of the crystallized out of the magma ocean and sunk to the deep interior of the moon and we certainly don’t have a good idea about the thermal state we think liquid iron could be melted for the outer core it’s not out of the question that the parts of the deep lunar mantle are actually molten and of course if we want to try to reconstruct the evolution of the moon over time we certainly need to be able to reconstruct the temperature structure of the moon right now so if we can go to the last graphic so in summary what we’re trying to do is with the Grail mission we’re essentially getting a picture into the interior of the moon which we intend to combine with the plethora of orbital observations that have been taken up the surface and are being taken of the surface today and to combine those with the treasure of the lunar samples that we continue to analyze and from those collective observations we intend to provide a holistic view of the origin and the evolution of the moon and by extension how other rocky planets in the inner solar system formed and with that I’ll turn it over to Sammy asmar to tell us how we’re going to execute this mission thank you the team of scientists and engineers that all the institutions affiliated with with the Grail mission have worked hard to ensure that the technique we’ve selected to conduct the science investigation and the design of the flight system ground system and mission operation systems meet the size requirements in some cases would put plenty of margin I’m going to talk briefly about the technique and the design after hearing about the science scenarios so if I can have the first animation slide please once at the moon the two Grail spacecraft will orbit at a very low altitude and we detect the gravity field by precisely measuring the changes in the distance between the two spacecraft so as the two spacecraft orbit and this shows that we were going to the result in gravity map of the MU of the moon as the two spacecraft orbit and this simple scenario they approach a gravity loads such as a mountain that pulls on the first base craft such and increasing the distance and the second spacecraft will sense the same gravity and the distance will decrease and then

as they move forward the trailing spacecraft will sends the same gravity and the distance will increase again so there is a dance going on between the two spacecraft as they orbit every little features of mountains and craters now at the end the resulting gravity field is really resolved from after putting all this data in one big blender and a lot of processing and we get a high resolution gravity field of the moon next slide please the slide shows that we actually can tune our instrument to different targets such as the local and regional features of the moon small craters and mountains all the way to the big global picture in which we look for core and tidal effects the way we too and our instrument is by changing the separation distance between the two spacecraft so we start low altitude and close distance and then we increase the distance and raise the altitude and that will automatically make us more sensitive optimizer sensitivity to the global features the next slide please this shows the mission design from launch to orbit insertion we have several months actually which we use very effectively in addition to navigational aspects on the science side we benefit from the long cruise period by having the spacecraft out gas in the vacuum of space and having our clock drift stabilize the next slide please this shows the radio complexity of the mission so the two spacecraft have two types of radio signals going back and forth between them ka-band or 32 gigahertz and that measures the changes in the distance very precisely and spen which is a time synchronization synchronization exchange of information when the two spacecraft are then in view of ground stations they dump or telemeter the information to the ground next slide please this graphic I’m using to impress upon you how sensitive we are to non-gravitational forces even stuff we can take for granted such as solar radiation pressure sunlight so we had to design the surface properties of the spacecraft to account for solar radiation pressure we are gravity mission so every force acting on the spacecraft is a big factor so we don’t want to we don’t want a mistake non-gravitational forces for actual features from the moon we’re investigating and then the next slide we show to other actually features just reflection of sunlight from the surface of the moon and when the moon is in the shade the ir infrared radiation from the moon these also constitute non-gravitational forces that we care about measuring and calibrating the last slide please doctor I’d weiler of Hecker’s called grail of physics mission and this slide really shows that it is indeed an intersection of two branches of physics mechanics or dynamics and electromagnetism this graphic shows if a spacecraft is orbiting a body a planet moon the moon Mars and we fly over a gravity feature the spacecraft will literally get pulled towards the feature and that effect gets manifested as a Doppler shift in the electromagnetic signal if it flies over a valley or absence of material it will most likely get repelled so this shows the beauty of gravity science or radio science where we actually investigate mechanical forces acting on the spacecraft via electromagnetic effects and then I’ll pass it to me listen great good morning it’s an exciting time to be here at the cape and you can feel the the buzz of the excitement start to increase today as we’re narrowing down the time to launch and hopefully this time tomorrow we’ll be on our way to the moon I’m here to explain to you about the education and public outreach component of Grail which is called grail moon cam it is led by dr. Sally Ride America’s first woman in space and her full team at Sally Ride Science in San Diego one of the unique things about this mission is its NASA’s first planetary mission to include instruments that are fully dedicated to education and public outreach and we intend to tap into that excitement of science and technology using the context of lunar exploration while Grail is in orbit and it’s doing its gravitational experiments moon cam will serve as eyes on the moon

for students next slide please we will do this using cameras there will be four cameras on each spacecraft there are two that are pointing forward and aft at a 60-degree angle and there are two that are pointing directly to the surface and those will be different powered lenses this program is available at absolutely no cost to schools or to students and students will have the opportunity to use those cameras to take their very own photographs of the moon once the spacecraft are in orbit the cameras will be activated and this portion of the mission will last approximately 80 days our mission operations center which would be similar to Mission Control in Houston is located at the University of California San Diego and there we have undergraduate students that have taken part in the planning and operations of this mission and during the actual mission the moon cam phase we will they will serve as a link to students worldwide students will determine what photographs they want to take by accessing the website slide please and there are various ways that they can choose their location just like we learn in different ways there are different ways that they can approach it this slide shows the latitude and longitude which spacecraft will be orbiting at point x next slide and it’s also very interactive students will be able to zoom in on the moon they’ll be able to rotate it they’ll be able to look at both of the ground tracks of the orbiters and they can simply click on the ground track and decide you know it will it will give the information like latitude and longitude and let them decide where they want to take their photographs once they have made that decision they’ll send their request into our mission operation center there at University of California San Diego and there are our undergrad students will help facilitate that and then the images will be available in a gallery on the website students will be able to go back later and identify exactly which picture that they took they’ll be able to annotate the their images they’ll be able to use them for further investigation they will have access matter of fact the general public will have access to all these images they’ll be able to access other student photographs as well to further their investigations both before during and after the mission Sally Ride science is providing support and training for educators we are linking them up with lunar scientists we’re helping them with hands-on activities that address the standards that educators have to meet in their classrooms but more than meeting those standards this is something that’s going to be a lot of fun for the students and engaging in real-world science is going to help not just to help us develop scientifically literate citizens but hopefully to encourage students to enter careers that have to do with science technology engineering and mathematics and you never know what the wow factor is going to be for a student and besides the areas of science and technology you never know what an image might evoke out of a student as far as maybe art or poetry or maybe even music which are things that we often tend to forget about combining with with science it’s difficult for us to to measure the impact of inspiration but NASA does have that inspiration factor and our students certainly need that and it’s something they can get excited about and it’s going to give them their own ownership of these images which it’s been my experience that the kids get really jazzed about I would encourage you next slide to go to our web site at wwm on cam UCSD edu and we would like educators to go there and register we would like the general public to go there and read up and become more informed and get involved it’s also very timely to let you know that we now also have an app for Grail moon cam it is free on iTunes you can go there and you can download it and once images start

coming in from moon cam you’ll be able to view the images there through that app you’ll also be able to track the spacecraft during the mission and we’re also Grail moon cam is available on Facebook so we hope you go and check that out and on Twitter so I hope you’ll come along with us on this journey thank you thank you Lisa we’ll open it up to questions here from the media at the Kennedy Space Center press site please state your name and media affiliation Marcia Marcia Dunn Associated Press the 82 days science face when exactly does it begin m via calendar and might it move up sooner if you get your orbits precise enough quick enough hey march eight i believe is the day ok so the 82 day science phase is the beginning of that is based on both how long it takes the spacecraft to get into their lower circular mapping orbit and then line themselves up so that they start to arrange to each other but it is also based on when the sun angle to the solar panels provides enough sunlight to power them so if all goes well it’s possible but that could be somewhat earlier however you know of course we’re taking the conservative approach of making sure that it that it operates well the chart with all the moon missions over the decades i I believe you said it a previous briefing that was 109 but I can’t remember the number and that includes Apollo landings as well how many of those 109 missions actually study the far side of the Moon I’m just wondering how much still is to be learned about the far side okay so let me think about that okay so he on the early I don’t know the exact numbers but I can call it out to what happened so the early the early reconnaissance missions to the moon went into an equatorial orbit around the moon because they were interested in doing reconnaissance of the far side equator which was the easiest place to get to the astronauts too energetically okay from an energetic standpoint so so information was gained about the equatorial area of the far side and there was very little information on in polar orbit where you would be getting the whole far side so there was I know there was one lunar orbiter that did that early on but and actually there was a Soviet Zond orbiter that also but but very little and then the more recent missions to the moon however you know lunar prospector and lunar reconnaissance orbiter they of course are in a global so so so there has been some information but in terms of studying the interior there is a vast amount to learn because other missions have studied lunar gravity but because of the moon being in the unusual position where it’s in synchronous rotation where we only see one side the way that we typically measure planetary gravity is to track the radio signal of a spacecraft in orbit while the while the planet rotates under the spacecraft but if you never see the far side of the Moon you can never track it directly and so the truth spacecraft actually f2 you use that so that they can track each other I’m hi Irene Klotz with Reuters um for dr. zero you mentioned that one of the scenarios for the core of the moon is that it might have titanium oxide and I was just wondering how once you get these measurements from Grail you’re going to be able to distinguish between the different the different materials and how much of each might be and just how precisely you anticipate being able to definitively know what’s inside the moon okay so so first of all gravity is a potential field measurement so so so you you can come up with many different compositions that could satisfy the gravitational field that you measure which is why you never want to analyze gravity or magnetics or any other potential in isolation so so the actual the value of analyzing the the gravity data is that we have a great deal of compositional data of from the surface which is which allows us to zero in on the bulk composition and what we will be

able to do about the deep interior is greatly reduce the error bars and what the radial distribution of masses and combine that with models of the bulk composition and and from that we expect to be able to distinguish iron versus not iron something like titanium oxide over to Bill harwood CBS I would I have three questions one is just for the sheer precision of your experiment can you guys give me some sense of like your graphics show you know a little dips and little rises over what’s what’s actually happening to the spacecraft in terms of the real dimensions is it drop in a meter is it drop in a few inches and can you tell me a little bit about the accuracy of the distance measurement required in other words at one hundred kilometers how much is it actually what’s actually happening so if over the distances between the two spacecraft would train between 65 to 225 kilometers we are sensitive to changes down to one micron so that’s really on the order of a size of a red blood cell that’s how i create the measurement of the distances mountains or whatever well that was that was just an abstract alistor exactly okay and for dr different the heat of the core of the moon after this much time is that radioactive it keep it hot it would keep a liquid core I mean what’s keeping it looking it’s well there’s several contributions to the heat part of the contribution is is the potential energy of the infalling material as it accreted the moon so there would be some accretion all heat that would be left over and and the rest of the residual heat would be due to the decay of radioactive elements so so Bobby actually talked about the fact that the exterior of the moon we think it largely melted and and the big heavy elements like uranium thorium potassium that are the heat producing radioactive elements those are actually the heaviest and so the idea is that they could have they may have sunk partway into the moon they may have conceivably sunk all the way to the core where they would be providing this this residual heat and actually one of the one of the interesting conundrums is that we think that the moon is some is molten in the deep interior today due to these heat sources yet despite the fact that the moon early in its history we believe was molten on the exterior it looks like the surface cooled off extremely fast because of the large size of the gravity anomalies that we see over those nearside basins so there was a we used to think so the nearside basins have lava flows that are more dense than the surroundings and we thought that if we could subtract away the gravitational attraction of those lava flows that we would see no gravity anomalies but in fact we’ve had near side gravity before and we’ve done that and they’re still whopping an and what that means is that the at least on the near side the moon on the outside pulled off fast enough so it was able to maintain strengths and and so we have this odd situation where the deep interior of the moon still looks like it’s hot but the outside that we know was molten cooled off apparently much more rapidly than the models would indicate so it’s a it’s a fascinating topic of fascinating question in planetary evolution one more quick one for me I’m sorry the second moon theory that you were mentioning to us I’m assuming or I don’t know what I’m assuming but it was this a small body that then accreted on the far side and that made the highlands or is this a larger body that deposited material and then somehow left the same the simulations show so the authors ran a range of simulations and the simulation that they that they interpreted that worked so to speak to produce the far side Highlands is one where you have a moon that’s about a third of the size of the new moon slowly drifted and stuck okay and so there may be there may be other scenarios for making this happen and it’s such an exciting idea I i I’m guessing the modelers are hard at work right now trying to find whether there are different scenarios that might explain that and all in our alternative way i’m todd halvorson afford it today probably for sammy is is there a planetary window associated with this launch in other words how many days do you have to get this launch off the ground and what happens if you don’t fly

in that window geometrically speaking we have about 42 days to launch but i think from a practical point of view it’s down to 30 32 days having to do with fueling the market for a limited period if we miss the entire opportunity then we would have to wait on the order of six months so that when we are wide we avoid solar eclipses at the spacecraft on the moon thanks and this one’s probably for you to I was wondering if you could discuss the low-energy trajectory that you’re taking to the moon why it was selected and whether your arrival date at the moon would change if the launch was pushed back a week or 30 days or whatever so the low-energy trajectory was selected basically to save on costs so you do not you do not have to use a bigger market to get you to the moon faster but also even if you do that you would need once you arrive at the money you would need to break to reduce that velocity and that would require a carrying additional fuel onboard the spacecraft so this avoids that entire problem and also gives us this flexibility so we arrived at the moon on new year’s eve then new year’s day regardless of the launch date so that’s a very nice flexibility in the mission design and as I mentioned earlier turns out there are additional benefits to having a relatively long cruise period on the order of weeks to allow for how gassing of the spacecraft clocks to stabilize the operations team to learn how to fly the mission right over here hi ken kremer for Space Flight magazine from Riyadh to follow up on this idea of the second moon proposal I wonder if you could explain a little bit more about how Grail could help confirm this theory and I’m also wondering at these spots do we know is the composition different is that why we think the second moon okay so I yeah I’d be happy to address that okay so so because this second moon this lunar companion would have accreted from the same material that our moon formed from it should have the same composition okay however because it’s a smaller body it should have cooled off more quickly than our Moon did alright so so one way to test this is to look at the crystallization age of minerals of material in the lunar Highlands there compared to the crystal is a crystallization age of lunar Highlands away from that however there are no plans the books right now to send a lander to the moon to bring back samples from those far side Highlands to earth because you can’t make that measurement in syd you that has to be done in a lab on earth so we need we need to actually bring samples back however what you what you can test okay with Grail is is I told you that the idea was that the Boone had a magma ocean and and it was light crystals of a mineral called plagioclase that rose to the top and then heavy minerals such as the uranium thorium potassium they would have sunk and as this companion accreted to the moon the simulations show that these heavy materials would have been pushed to the near Side of the Moon and this should have formed left a residual on the near side of the Moon which because they’re heavier they would be detectable with gravity so and we have some idea of what the thickness of the magma ocean is so we have some idea of the depth of where this residual density anomaly should be so this is something that we can test very precisely so it’s a it’s a very it’s very good hypothesis testing because it made a prediction that can be tested with with a mission that’s upcoming just I want to follow up if you survive the lunar eclipse I was talking yesterday with some of your colleagues what’s what’s the possibility to extend this mission then okay well I’ll address that true okay okay so that every about every six months there is a solar eclipse that causes the spacecraft to to be in lunar shadow for several hours okay and the the spacecraft were not designed to make it through those eclipses because the they we were designed to do the mission during that period however spacecraft well designed spacecraft often exceed the performance they design them so if if the the two spacecraft made it through the lunar

eclipse in June and both of them would have to make it through then what would have to happen is actually because of the solar geometry you’d have to move the back spacecraft to the front 44 ranging purposes and you’d need to line them up again and and that would take well we think it would take less time than it took the first time because the the Mission Operations team would have a better idea how to analyze or how to operate the spacecraft then they could conceivably begin to range again and there’s another lunar eclipse or another solar eclipse excuse me in in December that one relatively speaking is rather benign compared to the one in June and and so so they could conceivably keep going but but if we were going to do that we would we fully expect to achieve the mission objectives during the primary mission and so we’ve been focused on achieving the primary objectives which is the job of the team right now and after we get get the spacecraft on the way to the moon we can begin to think about whether new science would be possible that would you know enhance our understanding of the moon for for a very small investment and and were were sufficiently under budget that we probably wouldn’t even have to ask for extra funds to do this if I do the money to then do that okay you shouldn’t have to that’s it you understand we have a call on line hi thanks Tunisia with today’s calm question for either dr Fogel or dr. Zuber could you explain in more detail about how having lunar gravity maps could help with some planning future either robotic or manned missions to the moon well if you have a very high precision gravity map then it’s a benefit to both none of two most human exploration as well as robotic exploration you can get to your your point better and more accurately and faster and then just as a follow-up yesterday’s release of the LRO pictures of the three Apollo landing sites and then also this upcoming Grail mission do you feel that these events will perhaps inject new public interest in the room I hope I hope so the moon the moon is a fantastic body in terms of its studying in terms of learning about early planets it’s a it’s nearby it’s accessible and and it preserves the record of what early planets were like so the you know the surface of the Moon four billion years ago other planets in the inner part of the solar system have gone through the same processes that the moon has gone through and and because we’ve studied the moon so significantly and we’re studying it I actually actually think in the next five years we’re really going to rewrite the book in our understanding of of the early planets also remember the moon is your backyard if you had a house the moon would be the house next door and the other closest planets like Mars would be miles away so it pays to understand your nearest neighbor and the moon is affected life on this earth in many different ways and I think the continuing studying of Moon is always going to be a profitable thing great and back here at KCC miss Hubbard well your camera’s be providing like streaming down live pictures images of the moon I didn’t know if that was going to be possible to click on and see live views of the moon and will the children or will it be the team in San Diego be actually taking the pictures I did wasn’t who snaps the picture I believe that the actual the students send the request to Mission Operations Center and then the Mission Operations Center what actually takes yes the photograph and what was the first part of your question again I’m survived streaming from the moon pictures images I I not sure that we know that for sure yet doing so the the way that we were able to get this experiment on the mission was to make it entirely best efforts okay so so the science mission must take place and must take priority and then whatever data rate is left so so it’s it’s conceivable that we can string together some images and bring them down they wouldn’t be quite live because

we’re not going to take the extraordinary efforts that would be required to do live streaming video but we could get conceivably some you know enough images taken that we could make short videos somewhat recent correctly okay thanks did you um and if you haven’t updated weather forecasts for the morning I haven’t had time to look at my email this morning so also just to follow on a little bit what you were saying earlier to Bill about the micron measurements is it is it correct to say that a mountain would move it would move the one of the Grail spacecraft or both over time just a micron or would it be several microns for mountain and can you give us any way to kind of to say like match up a certain size feature with how much of an impact you think it would have on the spacecraft altitude in fact the amount of change in the range or the distance between the two spacecraft will depend on the this load the gravity feature so if it’s a small feature and we’ll move it a little bit if it’s a bigger feature will move it a lot but the interesting part is that sometimes you’ll see a big mountain and you would expect a high gravity signal and then in reality you get no gravity signal and that’s where it gets interesting from the geophysics point of view because the planet has compensated for the wait of this load and for a net zero effect or you fly over a flat region and obviously you look at the topography and images and it’s flat you expect no gravity signal but then our instrument will measure a gravity high again another puzzle then we turns out there are mass cons or subsurface varied features or higher density material that can only be probed through gravity so it’s a very complex and exciting science that way and to bill for follow-up it surely a follow-up to Denise’s question earlier from about the value of this data for future missions i mean you’re talking about subtle effects from these changes and gravity is a vehicle orbits it’s hard for the non engineer to imagine how that would have any impact on landing an unmanned spacecraft ER or whatever on the moon they seem to be the effects seem to be too subtle to to make that a valid selling point as it were so I’m obviously missing something yes oh I should so I should say that this mission was selected completely on the basis of scientific merit so this this mission was not an exploration mission it was the highest-rated science proposal of the two dozen or so that was received but that said look at what we’ve gone through in recent landings on Mars where the error ellipses have gone you know from being quite substantial to being to being very small to the point where with the Mars Science Lab we’re going to be able to put that Lander down very close to the central peak of a crater that preserves the stratigraphy of early history of water okay so so on the moon after Grail you know we we now have imaging of the surface where where we can resolve you know outcrop scale features and if you want to land right next to a particular outcrop you’re going to be able to do it okay so there there will be no reason to do another gravity to the moon in any of our lifetimes if there’s a particular sample return that we want to do a particular reconnaissance in a particular of the Moon you will be able to go exactly there and get it done great any more questions here at can you Space Center all right well thank you very much for joining us this morning Grail launch day coverage which is tomorrow of course whether willing will begin at six a.m eastern on NASA TV as well as you stream for more information about grill please visit us on the web at WWDC gov / grill or grill nasa gov have a good day