NASA's Mission to Europa: Exploring a Potentially Habitable World

well good evening thank you all for coming to this second of our exploring space lectures for this year my name is Bruce Campbell I'm the chair of the Center for Earth and Planetary Studies here at the National Air and Space Museum and it's my pleasure first of all to acknowledge the generous support of our sponsors for this series Aerojet Rocketdyne and the United Launch Alliance these two companies have been instrumental yes these two companies have been instrumental in launching and propelling many of the spacecraft that you've seen explore the solar system over the last many years I think we'd also like to acknowledge congressman Culberson as well as Bob did and tonight we are fortunate to have with us dr. Bob Pappalardo who as you've seen is the Europa mission project scientist at the Jet Propulsion Laboratory in California Bob received his PhD in geology from Arizona State University prior to that while at Brown University he'll planned the Galileo spacecraft observations of Jupiter's icy satellites and after Brown he became an assistant professor at the University of Colorado in Boulder he joined the Jet Propulsion lab in 2006 where his research focuses on the processes that shape the icy satellites of the outer solar system now join me please in welcoming Bob Pappalardo thank you very much Bruce this is a pleasure to be here an honor to be here to talk about Europa one of the most spectacular objects in the solar system not just because it has really cool geology but also because there is the possibility that there could be life in a global scale ocean beneath it's icy shell this is our spacecraft the current best representation of the spacecraft that we hope can visit Europa as soon as the mid-2020s as I mentioned in the QA we've been working for nearly 20 years to get going a dedicated mission to Europa since the discoveries from the Galileo mission showed that Europa most likely has this global ocean so we're going to talk a little about why we think there's global ocean what that implies in terms of the possibilities for life we'll look at the cool geology and we'll talk about this spacecraft mission and what it can do toward plumbing Europa's ice shell telling us where there's water what the characteristics of Europa might be like essentially whether it may be a habitable environment and then the next steps beyond that here's the star of our show it doesn't look like it's about size versus mean but it sure doesn't look like Earth's moon it's not covered with impact craters instead we see these bright Plains criss-crossed by these weird lines and some darker kind of modeled areas but very few impact craters visible in this image in fact from the number of the paucity of large impacts here's one that's not one that's something else we can get an idea of the age of Europa's surface Europe was formed with the rest of the solar system about four and a half billion years ago but the surface has been repaved from the few craters we we know one twenty ten to twenty kilometre crater should form about every four million years so you count them all up and say well that surface must be only about 60 million years old something has repaved Europa since the time dinosaurs roamed the earth it's these ingredients for life that I want you to kind of see interwoven here as we go forward when and this is the case in when we think about exploring Mars or Europa or another planetary world does it have a solvent like liquid water is the best one for the kinds of chemical reactions that could allow for life does it have the right elements from which organic molecules could be built a tough one is whether there is the right chemical energy for reactions that could power life because at Europa we don't we're not going to life at the surface you'll see why but maybe there could be life in the interior ocean and are these ingredients around for a while if they're if they just show up for a few years or even a few million years that might not be enough the moons of Jupiter were discovered in 1610 by Galileo and so collectively they bear his name the Galilean moons so that was this is the discovery photo and this is what we know today based on the Galileo mission the mission that was named for Galileo Galilei that orbited Jupiter from 1995 to 2003 and every time every couple of months it would do an orbit and every every orbit it would fly by one of these large moons and about a dozen times it flew by Europa and we know some from telescopic observations we know some from previous observations from the Voyager spacecraft that flew past the two Voyager spacecraft that flew through the Jupiter system but most of what we know is from the Galileo mission so let's take a closer look at Europa itself mention the bright Plains the dark model terrain there's another crater here that spewed ejecta across the surface of Europa let's look close up at ridged Plains it's criss crossed by these bizarre ridges and grooves and associated kind of dark material the heck's going on there it's really like nothing we see on earth and then there are these chaotic regions these regions where the surface is broken up kind of like cooking hamburger on a grill or something they're the pre-existing train is just crumbled away we'll take a look more closely at both of those this is what we think we know about Europa's interior we know this from gravity data and from magnetometry data and from putting the pieces together what we know about how planets work and the compositions out in the outer solar system so we can use gravity data to tell us how centrally concentrated Europa is so as the Galileo spacecraft flew by Europa it would put your OPA would perturb the orbit of the spacecraft just a little bit and from that we can actually say Oh Europa must be denser down in its center than it is elsewhere and if we take the assumption that what makes up moons out there is things like iron and things like rock and things like water ice then you get a model something like this about a hundred kilometres of h2o what's that about sixty miles of h2o some of which may be liquid as we'll talk about the best model is that the water ice shell may be about 20 kilometers about 13 miles that can we'll talk about that a little bit as well but that there's that leaves about 80 kilometers of liquid water above a rocky sea floor that makes for about twice the volume of all the Earth's oceans combined at little Europa the size of Earth's moon so the gravity data tells us that Europa central concentrated we actually know from telescopic and Voyager observations that there's ice on the surface why do we think there's liquid water ocean well some of that evidence comes from geology but the best evidence actually comes from magnetic data from understanding the magnetic field in the vicinity of Europa so the Galileo spacecraft had magnetometer and as spacecraft sailed by Europa there was a signal that looked like Europa has a magnetic field okay maybe it has a magnetic field of its own Ganymede its neighbor has a magnetic field of its own so not completely crazy but then the Galileo spacecraft flew by again and the magnetic field had shifted like completely turned around so magnetic fields don't just flip on really short timescales so what was realized because actually Callisto seemed to be doing the same thing is that Europa is behaving as a conductor there's something inside Europa in the shallow subsurface that's essentially conducting electricity it's kind of like Europa set off the metal detector let me explain what I mean Jupiter has a gigantic magnetic field if you could see it in the sky the angular size of Jupiter's magnetic field as viewed from Earth would be about the size of the full moon in the sky incredibly powerful magnet and Europa is orbiting within that well Europa feels a changing magnetic field of Jupiter because of the geometry the tilt of Jupiter's magnetic field as it rotates around so Europa's just minding its own business orbiting Jupiter but it feels a changing magnetic field from Jupiter and Europa seems to be creating a magnetic field of its own to counter Jupiter's so so back to the metal detector idea if I if I take my iphone through a metal detector it sets it off because metal detector is like big magnet and if I take something if I move something metal through a magnet it creates another little magnetic field to counter that and sets off the metal detector so it's kind of what Europa did to the Galileo spacecraft so something's something's weird here so that tells us there's a conductor in the shallow subsurface of Europa well what conducts electricity in the shallow subsurface of an icy moon salty water would and so that's the best evidence that there's an ocean within Europa comes from that magnetic field data we don't know how thick that ocean is or how salty that's something we want to do with this mission but we're pretty sure this notion up in there we'd like to confirm it we'd like to confirm it with other data of course this is kind of the interior picture of Europa scales are exaggerated a little bit and why would you oppa have a liquid water ocean within it today if it's only the size of Earth's moon we know where its moon is pretty cold and dead today so shouldn't Europa have lost all of its internal heat by now after four and a half billion years just like our Moon has lost most of its internal heat there's another source of heating out there that doesn't apply at least doesn't apply anymore to our Moon and that's called tidal heating coming from tidal flexing Europa as it orbits Jupiter gets a little closer and a little farther again not to scale but the orbits little egg-shaped little a bit eccentric when Europa is closest to Jupiter it is stretched out more and when it's farthest from Jupiter it contracts a bit and kind of like bending a paperclip back and forth that generates heat its frictional heat as Europa is flexed again not to scale but Europa every time it orbits Jupiter every eighty five hours every three-and-a-half Earth days it's ice shell is flexing by about thirty meters that's the prediction for how much it would flex as it goes around that'll generate a lot of heat some of you may know IO Europa's neighbor is the most volcanically active body in the solar system that's the moon one in the Galilean moon one in from Europa it flexes something like 100 meters it's crazy it to generate all that heat at IO well a little farther out at Europa it's not enough to make a super volcanic reactive body but it's enough we think to maintain a liquid water ocean and you do the math and you say okay it makes sense for the ice shell to be something like twenty or thirty kilometers thick above above an ocean intern above the rock we don't know how much of that title heat is in the rocky part of Europa if the title heat is just in the ice shell that's enough to maintain an ocean but it could be that there's a bunch of heat put into the mantle as well to keep it warm and for there to be volcanoes down on the sea floor of Europa we don't know yet so something else we want to do with a mission is we want to test for this flexing we want to fly by Europa when it's at different places in its orbit and measure the gravitational field very precisely by doing that we'll be able to infer how much it's flexing and to nail in another way the idea that Europa has an ocean down there all this tidal flexing kind of breaks the surface too and so when we look at pictures like this of Europa were zooming into some of the highest resolution Galileo data here that may help explain these ridges and cracks that crisscross the surface although just what the heck is making something like this the most common feature on your rope are these ridges and they come in pairs these double ridges what's going up and then into the center and then up again and down lights coming from from this way from the right I think the best model for this is kind of like a tree root growing beneath an asphalt sidewalk and pushing it upward to make a double Ridge and break the cold brittle ice on Europa and it may be because that stretching creates cracks and then those cracks there's movement back and forth and that back and forth movement creates heat and that warm ice wants to rise up like a tree root beneath the sidewalk that's I think a good way to explain these ridges but there's no scientific consensus actually as to how these form they're they may relate to water welling up from the interior they relate to to compression pushing together the surface so there are a lot of different ways scientists have thought of to explain these ridges and really going there and understanding the geological relationships close up and even understanding the 3d nature of the subsurface is going to tell us how these form and we'll talk a little bit about how to do that well one of the things like say here is that the Galileo mission was very limited its antennae didn't open it sent back its data at 40 bits per second through a secondary intent of the size of a coffee can lid the older folks in the Calvin a coffee can with and and and so we don't have a lot of the surface covered with the upcoming mission we're going to get all of the surface covered at 50 to 100 meters per pixel imaging resolution there are also these things that are called bands this one's a sickle shaped one across the surface of Europa and if you look at the older structures the things that cuts you can imagine there's this thing up here that's kind of funny-looking and then this down here is kind of funny-looking and this Ridge and this Ridge they fit back together if in Photoshop you cut this thing out and put push the edges back together and well we've done that Photoshop is our friend and planetary science there it is so here that that's what that used to look like and that and that and a crack came and split the surface and the surface pulled apart somehow to form these bands here at colleague Illustrated this version this probably took 10 million years to happen but this is an idea of how these bands opened up so something is pulling apart the crust and allowing warmer material to use out some have argued it's water I think it's more likely that warm glacial flowing ice moved out over something like 10 million years so it's kind of like plate tectonics that we have on the earth where there are areas where the surface is pulled apart and just recently there is a paper that describes some evidence of a place where the surface seems to have pushed together and there might be something like subduction subduction zones where like on earth one plate dives beneath another very cool geology what we need to understand more and what are the implications for water and where is their water what's the role of water and creating these features there are some impacts this is that one with the bright rays it's a Welsh name will we know it by but I can't really pronounce my Welsh its what it's named for and but still doesn't look like a crater on the moon because it's very shallow it formed into something relatively warm like like poking a warm cake it rebounded back up that's about 20 kilometers across and then you go to bigger structures there are only two of these and they kind of look like bull's-eyes so this is a place where you'd expect a big crater but instead there are these rings and what probably happened is that the impact was large enough to punch through the crater that formed punched through the entire icy shell and water raced in and the crater filled in with ice and slush and pulled into the center to break the the surface in these concentric rings so again only two of these and it suggests that these impacts penetrated through an ice shell about 20 kilometers thick 13 miles thick so but that stuff in the center probably came from down in that ocean we saw a lot of reddish looking things wherever the surface of Europa has been breached in some way there seems to be this reddish stuff what I suspect is going on is that the bright icy stuff surrounding it is probably just a thin coating and if you went to your open dusted it off you'd probably see this dark stuff so what is this dark reddish stuff well we're not so sure we can look at the spectral fingerprints the fingerprints of light reflected off of Europa's surface people do this from Earth using earth-based telescopes or Hubble telescope and with the Galileo mission we to do it from flybys and with the upcoming mission we'll do it even better with flybys and other other techniques the idea here is where we're looking at reflection off the surface in near-infrared wavelengths right beyond the color red where our eyes can't see longer wavelengths and we can look at at the at the how much light is reflected off the surface versus the wavelength we can see down in here but not out here so this blue curve is what ice looks like if there are these very characteristic dips I don't do this for a living but good friends and colleagues who do oh yeah that's water ice alright because they know there's this dip right here at one point five microns micrometer is micrometers and another at two and then I look at this and say oh well there's water in there but that's not water ice because they're not as deep and there's somewhat asymmetric they're just displaced for for compare the shapes not not the vertical offset and and so what can make it that subtly different shape well the the best fits are magnesium sulfate hydrate that's Epsom salt if this stuff came from the ocean that could be a pretty good place to take about but the other good fit is a sulfuric acid hydrate that's battery acid which is not a good place to take about so and the truth is probably somewhere in between there probably both of these things what's probably going on is that there's stuff that's come from the interior and welled up to the surface and even float on the surface that contains epsom salts but once it gets to the surface then Jupiter's radiation takes over so have that illustration of Jupiter's magnetic field Jupiter is a giant particle accelerator when there are charged particles out there as there are lots of them because IO is a litter bug and then things get with its volcanoes and then things get charged ionized and then they get accelerated by Jupiter and they're whipping around Jupiter is rotating every 10 hours and these things are going around every 10 hours even though they're really far from Jupiter they're going in incredibly high velocities and they're slamming into Europa and that'll break apart h2o water into H floats away and O which hangs around on the surface and if is magnesium sulfate hydrate well they'll be magnesium hanging around and sulphur because all these things get broken up and can recombine and some of it recombines probably to form battery acid so that's a simple story but it's probably not the real story in other words we need to understand better these little Wiggles because we could tell pretty precisely what's on the surface what other salts are on the surface and whether they're organic materials on the surface in this dark stuff if we could see the finer wick Wiggles in these curves and and if we had a more sensitive instrument with higher resolution and that's what we'll have with the upcoming mission the upcoming mission we'll also be able to catch tiny dust particles that are knocked off of Europa's surface and analyze them and and right there at the spacecraft and say oh look there's organics in here right send us back the data we'll say look they're organics in here and there's also on board there will be a mass spectrometer that will sniff the atmosphere it's a very thin atmosphere around Europa is 10 to the minus 12 of Europe of Earth's atmosphere and and look for the gases and that includes volatile organics that might be out there until very precisely what chemicals are down what's the chemistry of this dark stuff on the surface by the way neither magnesium sulfate nor battery acid is read a recent idea is that might be table salt NaCl when you irradiated in the lab turns this kind of brownish color so that's an interesting idea and there is some evidence for sodium at Europa so we need to understand the chemistry to really get at the habitability of the ocean what is the interior of the ocean like what's its composition like and to understand what part of it is from external factors and keep in mind that oxygen that I mentioned breaking apart because that's going to be a key part of the story coming up if we look at the surface we see these spots and pits littering the surface that called lenticular Latin for freckles I kind of have to give them a fancy name there's something like five ten kilometers across there they're sort of rounded they something they commonly occur together and as a geologist I knew when these pictures first came back we've seen that somewhere before and the somewhere is places like well I haven't seen I've seen in books but places like the Gulf of Mexico where there is salt that moves up from below sediment and then comes and pops its way up through the sediments well that's probably not exactly what's happening in Europa but something close to it it's probably ice warm ice rising up from the base of the ice shell like a lava lamp again I'm showing my age so older ones in the crowd no no lava lamps the the tidal heat we talked about is is best that there's a most title heat down near the base of the ice shell where the ice is warmest and so this warm ice wants to rise up through colder ice and so you get these blobs moving up here's a simulation done by Amy bar back when she was a grad student with me Colorado many years ago and in her model the the base of this is is the roughly the temperature of the ocean of salt salty ocean and the surface is frigid so Europa's surface is a hundred degrees Kelvin that's minus 280 Fahrenheit or if you like Celsius minus 170 Celsius so very cold and stiff ice but the ice down here is is kind of you know it it's warm enough to flow like glaciers flow ice flows over long timescales this is way sped up it'll be something like a hundred thousand years for ice down here to rise up toward to near the surface but it probably happens over long timescales and then the colder ice will sink down to replace it so this is a way that Europa's ice shell may circulate stuff from the bottom including any organisms if they are down there in the ocean can get up to the surface and stuff near the surface can get down into the ocean again this this is going to play a role as we talk about chemical energy here in just a few minutes oh sorry I didn't mention that right the how do you get this stuff to the surface so this warm ice isn't getting all the way up because it's so cold and so stiff so if the surface is fractured it might be able to make its way all the way up to the surface there's one more major type of feature on Europa and this one probably directly relates to liquid water and that's the aptly named chaos terrain where blocks big iceberg like blocks have moved around wrote translated in this more hamburger like stuff kind of like to showed early on so something has caused the surface to break up some heat source from below has probably caused the surface to break up for features to move around right like this probably fit back together with that these guys fit back together real well this looks like it's tilted a bit something has disrupted the surface here let's take a look at this area connemara chaos as its called from all the way out let's zoom in so that chaos region is here I was in my office at brown when we were planning the Galileo images for my friend Jeff called and said Bob we have to take pictures of the red rabbit Jeff what are you talking about the bunny here it is the upside-down bunny and we did we ended up retargeting images that were going to be taken somewhere else to this area which even from a distance look like it was going to be fascinating and so we're going to zoom into various levels of Galileo data taken at different times during the mission to see this region revealed so now you see these kind of plates that we were looking at earlier that broke apart these bright areas are actually stuff that was tossed out of the crater pull put a thousand kilometers away zooming down now into images at about 55 meters per pixel show these rotated twisted blocks this is about the size of a small city we used to compare it to Providence this is about the size of an interstate highway and then we'll zoom into some of the highest resolution images of the tour we're gonna mark chaos starts to become like a place something like Monument Valley with plateaus and cliffs and stuff that has down off these cliffs about ten meters per pixel now whose get rid of that little bar and then we go out into the surroundings and see some of these iceberg like regions there's a ridge that's seen better days that's about a kilometer across if I remember the Titanic would be about that big for scale but this doesn't look like a smooth skating pond like it was liquid water but certainly liquid water is needed to allow these blocks to move around as much as they have here so is this literally an exposure of the ocean or maybe some of these blobs of warm ice have risen up and kind of like on a mosh pit that moved the surface around crowd surfing I always get that wrong that's sort of this well one of the best models was a relatively recent one that kind of combines the idea that there's melting and that there's this convection this warm ice that's bubbled up from below that if there's these blobs of warm ice are places where tidal heating will concentrate because they're warm and they're rising up that ice is squishier than the colder ice surrounding so that squishy ice can heat up more to the point that there's melting right within the ice shell creating a pocket of melt and if there's a pocket of melt the surface above could just collapse into it and then it refreezes again later so that's a nice model for how these chaos regions might form it's pretty tough to get liquid water exposed to space at Europa with a hundred Kelvin at the surface but for short amounts of time it is possible that there could be bubbling and frothing remember there's a vacuum it will go right to a solid which leads into a relatively recent funding from the Hubble Space Telescope the tantalizing evidence for plumes at Europa those familiar with Saturn and Enceladus Enceladus is a very active moon orbiting Saturn and it has plumes of water vapor that are spewing out of it well the Hubble Space Telescope in the ultraviolet found some bright regions on the limb of Europa from a few years ago and its oxygen and its hydrogen that's glowing there at the limb of Europa and so that could mean that there was some sort of outburst and then you know that radiation comes along and breaks it up into o and H and maybe that's what we were seeing but then NASA was intrigued by this idea and gave lots of Hubble telescope time to the group that found this and they looked for months and months and never saw it again so was this a big outburst and could only be seen once was the result not really right because it's a really hard observation to make we're not sure so as we plan our mission we're planning for the possibility there might be plumes we want to look and see if we can spot them and then if they're there we want to fly through them because if we're measuring the composition of the dust and the gas around Europa and fly through one of these we could directly sample what's in the subsurface of Europa by flying through a plume which would be just fantastic so we have an ultraviolet instrument on the mission our plume hunter to go after whether there are plumes at Europa so to sum up the ingredients for life water much more than all of the Earth's oceans combined essential elements well we saw this dark reddish stuff we don't know if they're organics there we don't really know the composition yet we have to find out really we we know number one number two well we've ideas we don't know we need to keep exploring and get there and find out but one would think that from Europa's formation and from later impacts bringing the right materials to Europa that it should probably be there the right elements to build organic molecules carbon hydrogen oxygen phosphorus nitrogen sulfur chemical energy is a hard one so what we're talking about again is is could there be enough energy for life down here in the ocean because you're not going to get sunlight you're not going to get photosynthesis going on down beneath 20 kilometers rice for that matter light penetrates you know not too far into into ice well on earth there are lots of organisms that don't care about sunlight they live off other chemical reactions these guys don't care about sunlight they live off the chemical energy from these black smokers on the Earth's ocean floors places where water has seeped through cracks and pores in the rock and hit places in the rocky interior not too far down where warm rock is welling up and that water gets charged with chemical nutrients comes back out into the cold water and those chemical nutrients just condense out and these critters live very close to such things so could there be the chemical energy for life at Europa well Europa's seafloor there might be very similar chemical energy pouring out of the subsurface and we've got another source - the h2o here getting bombarded by radiation breaking up into H and O leaving the oxygen behind if all the oxygen and other oxidants on Europa's surface could be dumped into Europa's ocean Europa's ocean would have more will be more oxygenated than Earth's oceans are so there's the potential for lots of fuel for life at Europa surface that could get if it can get into the ocean so the circulation of Europa's ice shell like that convection we talked about or like melting to form these chaos regions is really critical understanding what's going on inside the ice shell to the idea of whether there could be life at Europa can we get those oxidants the fuel for life into Europa's ocean because if we just have the other part of the reaction the reductant not good enough we need both sides of the battery so the mission we're talking about carries and ice-penetrating radar at long wavelengths and bruce campbell is part of that radar team at long wavelengths ice is pretty transparent to radar signal and go right through cold clean ice and if it hits liquid water it's going to bounce back through that ice and back up to the spacecraft so we're going to carry a radar that will broadcast at Europa and then listen to what comes back and we're going to be plumbing the ice shell trying to understand where there is liquid water within that radar I'll penetrate at least a few kilometers the hope is it could penetrate all the way through the ice shell as well as for stable environment Europe has probably been simmering tightly heated for billions of years we don't know that for sure further understanding of the evolution of the Galilean satellites as a whole will hopefully tell us that so this leads into the goals and objectives for the Europa mission we're going to have to speed through a little bit have some cool graphics so give me the hook point immune - overall we want to understand the ocean the ice shell its composition its geology we also want to understand what the surface looks like close up because someday after this mission maybe soon after this mission we want to send a lander to the surface because if you want to go beyond habitability beyond understanding could Europa have life you want to go touch the surface sample that stuff get beneath the layer where radiation has messed stuff up and scoop some of that stuff up from tens of centimeters below the surface and look for signs of life so before we can do that we need to understand the surface where we want to go scientifically and how rough is it are there places we could land that are smooth this is the best Galileo picture of Europa six meters per pixel somewhat oblique like you're looking at an airplane window and boy that looks like a tough place to land but that's what the JPL engineers are studying right now whether we could send a lander to a place like this or how we know we could do it this is our labeled version of our spacecraft here are well first of all it's it's solar here are the solar panels each of these eight panels is about two by four meters in size let's see radio antenna for communicating with earth magnetometer boom these are the radar antennas there are high frequency antennas two of them each 16 meters long and VHF antennas four of them each about two meters long that we to attach to the solar panels the solar panels are essentially going to be part of the radar system the instruments like the cameras and the spectrometers are looking down at the surface of Europa while the the instruments like the dust detector and and the mass spectrometer is looking for gases are pointing in the direction we're moving so it's like they're here and looking down and we're flying through this stuff that those instruments want to sense while looking down at what the cameras want to see so that way all the instruments can work at the same time any of you familiar with the Cassini spacecraft the instruments are kind of bolted all over and only a couple can work during any flyby of say Titan at Saturn we want all the instruments to work at the same time both for the scientific synergy that brings and because this is a nasty radiation environment we don't want our spacecraft bathing and radiation while two instruments look we want them all looking at the same time I mentioned most of the instruments so I won't dwell here but I'll just I'll just name them quickly I mentioned mass spectrometer sniffs the gases dust analyzer for the dust magnetometer a plasma instrument helps out the magnetometer in doing its job of understanding how salty and thick that ocean is ultraviolet search for plumes camera system can get up to 1/2 meter per pixel images of the surface of Europa for reconnaissance and for understanding the surface close-up infrared spectrometer ice-penetrating radar whoops I forgot one the thermal imager is going to look for hot spots are there places that are warm enough at Europa that they're essentially glowing hot and we can detect that heat it's the telecommunication system the radio of the spacecraft that does the gravity science that I mentioned there are a couple of ways to get to Europa we can take an evita trajectory Earth Venus Earth earth gravity cyst that's a lot of time spent in the inner solar system getting up enough energy to get out to Jupiter with the mass of this spacecraft in fact it would take seven and a half years the launch period that we're shooting for if budgets allow and if nASA says to go in that direction is May 20-22 so when the launch period would open so that's the earliest we would be launching so that's a conventional rocket like an Atlas at Delta for maybe the Falcon heavy but NASA is developing the SLS the Space Launch System a big big rocket that we could take on a direct trajectory to Jupiter and if it's ready in time we the time of flight to Jupiter's about 2.7 years less than three years that would be nice as as our project manager says kind of my engineering a peer equivalent at JPL he hoped so because he wants to get there before he retires so once we get there then what happens I've been talking about these tours and the petals of the flybys but what does that really mean here's a depiction of the spacecraft coming in here's the orbit of Europa Jupiter's down the center there and it's showing when we get first captured by Jupiter a long orbit or petal and the beginning of the second well let's look at this animated here you once we make all these flybys we're going to envelop Europa in a web of flybys that here I'll skip to my that one there it is from the side where we're going to develop Europa with something like 45 flybys this isn't an orbiter around Europa itself but it's an orbiter around Jupiter but every time it makes a flyby of Europa and after 45 my Star Trek reference we get kind of like a tholian web formed around Europa enveloping it encasing it and allowing us to sample all latitudes and longitudes around Europa you and see if I can get that to work one last piece of the puzzle is that we are beginning studies as I mentioned of a possible Lander not to join the Clipper mission the Europa mission that we've been talking about but to follow up soon after and the idea is to try to get a few tens of kilograms of scientific instruments simple similar to spirit and opportunities payload mass down to Europa's surface and we're looking at trying to land something like this guy and in doing so use something like a mini sky crane like was used at Mars to help to send this little guide to the surface that would be designed to be able to withstand a range of possible surface features right Europa might be very lumpy and hard to land on or maybe we'll find some really nice smooth spots but the goal is to to get to the surface the kinds of instruments that could detect organic materials directly with big samples that are scooped out from the subsurface so we'll see the results of these studies in the coming year or so so to wrap up Europa first seen over 400 years ago has the potential exploration of Europa has the potential to really revolutionize science in the coming decades we have lots of examples of chemical reactions and we have lots of examples of rocks and repots of examples of of other natural phenomena we only have one real example of life to study biology is pretty much the same on earth all things are related in that there are 20 amino acids everything uses ATP to store energy if we could find an example of life of different life of life of an independent origin of Europa it would revolutionize our understanding of biology so that's a practical implication of finding life there but beyond that the question of are we alone is one that's been with us for a long time it's one that sometimes we just assume it in science fiction but we really don't know how common is life out there in the universe if we could find another example of life right here in our solar system that would say that life is very common and if it's not there maybe it would say hey life is that much more rare than we thought and the same place that revolutionized science 400 years ago when following Galileo's observations we realized there are other planets out there we're not the center of the universe that place Europa one of those moons the Galileo first saw and realized we're not the center of the universe has the potential to revolutionize science again so with that thank you and we'll take some questions please see our website for more information so I'll take those in turn so the ice-penetrating radar patsies to the ice it's never going to make it all the way down to the to the ocean floor it's going to be a challenge making it through 20 kilometers 10 or 20 kilometers of ice if it's there because it's difficult for ice-penetrating radar to get through cold oh sorry warm dirty ice we think your rope is ice it might be warm and dirty it's easier for it to get your cold clean ice so what we're hoping for is regions areas where it's cold and clean enough that it'll get all the way through the ice but it's not going to it's that signal won't make it beyond as for Lander yes there's definitely thought of well after an initial lander then might we be able to someday get into the liquid water whether it be a lake or all the way down into the ocean of Europa so but the lander would certainly want to at least dig beneath the depth that radiation has processed the surface an attempt to restart as we're going here so it is title heating the same or does it always increase so very complex question in other words very complex well maybe it's simple we don't know but where the ice is warmest is where we think the title heating will concentrate and so the where it's warmest may move around you might have a big upwelling and then the heat concentrates there to the point it melts melted water doesn't tightly heat and so now it cools off and maybe somewhere else it's heating up more now that said we think there may be a cycle on the order of a hundred million years where Europa as a whole gets warmer and then cooler again and this is because IO is thought to be in a cycle where its eccentricity how how oval that orbit is changes over time and IO pulls Europa along with it it's an amazingly complex and an interesting system and so it's probably true that Europa has hundred million year cycles of being warmer and colder as related to IO getting warmer and colder in its orbit it because of its orbit changing the evidence seems to me to point to an entire geologist seems to point to we may be in a waning phase right now we might have to wait around another 50 hundred million years before Europa really gets going again so yeah yeah yeah absolutely right there it's there's not a lot of solar energy out there but we're using solar panels June the Juno mission is paving the way it's on the way to Jupiter it's using solar panels what we did is we looked at the instruments that we thought NASA would select and we said yeah we can power those with solar and then NASA in picking the instruments that were proposed said to us okay can you accommodate these instruments if we pick something kinda like this and we looked at it carefully and we said yes as we're learning more of course we're learning that oh oh this is room oh yeah we forgot to tell you we want to run for more of the orbit oh yeah well it's going to be harder to do the radar than we thought or harder to do the mass spectrometer than we thought so it's starting to push the system but unlike a nuclear mission where you have where you're you're quanta you have to add another entire RTG or a unit to power the spacecraft we can add more panels and so originally we were thinking three panels on each side we're up to four panels on each side going into the the NASA selection we might need a fifth and so but we can grow incrementally that way in cost and in mass rather than adding another giant radio thermal unit nuclear-powered unit wait so does the radio does the the radiation environment and your open make it impossible to send people there again I want to instill the use of crude mission although sells crude to use that term but we don't have a good term for people the mission it is plausible remember about a meter of ice will stop the radiation so someday people I think will visit Europa ultimately and make ice caves essentially right if we want to explore Europa we do it by finding or by building an ice cave or by landing something on the surface massive enough that has enough shielding to be safe now are people able to wander around on the surface of Europa there would need to be either lots of shielding or some sort of magnetic shielding all right and so then we get back into the science-fiction realm but it is plausible to have some sort of magnetic field in enveloping astronauts in the distant future that would deflect the radiation particles so essentially why doesn't Europa have an atmosphere today it may have had one in the past it's a small moon not a lot of gravity so like our like Earth's moon molecules are lost to space over time just because the gravity is low and so the particles will drift away but also in this radiation environment the stuff gets just gets stripped off very quickly so if there are plumes at Europa bill bill those particles will be dissociated when I think my computer's died this is really sad I was trying to show the movie and now it's really unhappy so the particles will get stripped away oh man I'm going to be on the phone with JPL tomorrow morning I see we stopped there if there are plumes today some of that stuff will just freeze to the ground and some of it yeah will be dissociated and stripped away rings around Jupiter resulting from some of these quote flown a good point it R is there evidence for rings or related phenomenon at Jupiter associated with plumes not really so at at Saturn and Enceladus is orbit yeah there's the e-ring and that's made from stuff that's being off and solidus now Enceladus has much much less gravity than even Europa so lots more can escape right so lots of stuff will fall to the ground that the particles will fall to the ground at Europa at the same time people have done calculations to say based on what we don't see we don't see a lot of stuff there you could limit how much plume activity there could really be so I think it was something like only 10% of what Enceladus spews out is it plausible to have at Europa say you can use Aurora I don't think will be associated with plumes Ganymede has a its own internal magnetic field and there are Aurora Academy it associated with that there might be faint gloves at Europa but we have you know when we get there we'll look for them yes yeah there are some but it would Aurora employing concentrated at the poles but there there may be just glow associated with Europe with very thin atmosphere and any pollutants if they're there right is there Europa science coming from the Juno mission which is going to Jupiter it's it's really concentrating at Jupiter I think there might be some very distant observations of Europa and the ultraviolet but but not a lot coming in terms of Europa science that's really concentrated on the big guy right why Europa instead of Enceladus or Mars well it fortunately hasn't been a choice of Europa or Mars if it were they'll be tired Europa might well girl was losing right and I mentioned congressman Culberson who's insured that we're going to explore Europa and continue to do Mars as for Enceladus and and tighten that Saturn those are really important places to explore as well and sell it as maybe spewing its ocean water out into space if there's light there we might be able to sample it directly though there are challenges in doing so it's not easy and and Titan probably has an internal ocean and it has lakes of ethane and methane on the surface how cool is that that maybe there's some sort of weird life there so we want to do that too and NASA is investigating an ocean worlds program that would allow for such a thing so I mean I I would advocate if I had to choose I would advocate for Europa because of the potential for the ingredients for life so even though radiation is deadly to life on the surface you die in something like eight minutes to eight hours I think I did the math once at Europa um if you didn't have soup well it's cold too but but that allows for those oxidants those radiation products right that's actually good thing for life that might exist within and some of this doesn't have that and Enceladus might be going through a burst of activity now and it's not clear there's been enough time for life to get going in its ocean we're still learning at Enceladus so yeah I hate having to choose between among the children you know I I think I think John Culberson would like to add to that the oceans they're shielded by ice an ocean that has been oxygenated for millions of years that ocean that has been shielded from radiation from asteroid impact a there is almost certainly black smokers on the bottom if I Ballard points out that the ocean chemistry on earth was finally explained by black smokers on the bottom of our ocean you couldn't figure out the chemistry of the ocean did not match what was coming out of the rivers until a Ballard discovered black smokers and also the kids tree lined up perfectly if Bob Ballard tells me that the oak the entire volume of Earth's oceans circulates the mid-ocean ridges every four to six million years let's sink in for a minute that's happening on your elbow so you've got an absolutely perfect environment oxygenated ocean shielded from radiation asteroids that has all the chemical elements for life the most likely place in our environment in our neighborhood where to find life NASA kept cancelling it so I mean I wrote it in a little I'm chairman of the subcommittee to make sure we take care of NASA the FBI I make sure I'm chair of this committee and I tell you it is fit this is the only mission it is illegal for NASA not yeah did I tell your congressman Culberson is an advocate okay we have time for one more question right away oh where did the water come from in the first place it's cold out there there was lots of h2o lots of water in the nebula from which the Sun and the planets formed and here in the inner solar system that only some of it only a little bit was able to stay around out there in the outer solar system lots of it was able to stay around in the form of ice and it wasn't burned off essentially in law so I was able to condense out there at Europa and Ganymede and Callisto or about half ice and a half Rock farther from Jupiter it was warm Jupiter it was colder out there and then you go further out in the solar system Saturn Uranus etc lots of ice ice is like rock out there and condensed out and stayed here in the inner solar system lots of it was lost didn't condense how jessica's who was too warm thank you all right well first off let me thank everyone for coming out tonight we'd also like to once again acknowledge the sponsorship of Aerojet Rocketdyne and United Launch Alliance will be having the next talk in this series on june 1st when Pamela Conrad from the NASA Goddard Space Flight Center will come out and talk about the topic of life in extreme environments so that should be a great talk as well it's been a great series so far and please join me again in thanking Bob for a fantastic talk you

Channel: Smithsonian National Air and Space Museum

Views: 98,904

Rating: 4.7856207 out of 5

Keywords: Jupiter, Europa, NASA

Id: SmJE93gxuPw

Length: 69min 49sec (4189 seconds)

Published: Thu Jul 07 2016

Reddit Comments

[u/alllie]

Jupiter's moon Europa may have an internal ocean of liquid water, plus the chemistry and energy life needs to exist. Robert Pappalardo, Europa Mission project scientist at the Jet Propulsion Laboratory, will discuss NASA’s plans to send a robotic mission to evaluate Europa’s potential for life and address one of humanity’s most fundamental questions: Are we alone in the universe?

Edit: I've been watching NASA lectures so YouTube keeps showing me more. Sorry if you don't like them. :(

[u/aykontakt]

I thought that was no longer a possibility because they discovered massive amounts of radiation from Jupiter like a year ago.