Gadgetory

after 20 years in space NASA's Cassini spacecraft is running out of fuel and so to protect moons of Saturn that could have conditions suitable for life the spectacular end has been planned for this long-lived traveler from Earth guys the seven your journey ends as Cassini becomes part of the planet my name is Linda Stoker I am the Cassini project scientist I have worked on Cassini for almost 30 years and that's the time it takes Saturn to go around the Sun a single time as Cassini project scientist my role is to work with the team about 300 scientists from around the world to plan the best possible science for Cassini to plan those science observations to look at Saturn or the Rings or the icy moons the magnetosphere Titan those kinds of objects and to try and balance between the different science disciplines and find the best science possible right now the Cassini spacecraft is in a set of orbits called the grand finale what we did is use a Titan flyby to propel us all the way across Saturn's rings right now we're diving in between the gap between the Rings and the planet flying in a place that no spacecraft has flown before getting back measurements in particular about the planet itself revealing Saturn from the inside out incredibly detailed pictures of Saturn's rings and then sampling that region between the Rings and the planet before Cassini's final plunge and on the final plunge what we'll be doing is getting a nudge from Titan we call it Titans goodbye kiss it's a distant flyby about 120 thousand kilometers and that pushes us such that we can actually go into Saturn's atmosphere our thrusters will be fighting against the atmosphere as we go in we'll be sending back data until the very last second from our iron and neutral mass spectrometer sampling measuring the composition of Saturn's atmosphere directly and once those tiny thrusters can no longer hold against the atmosphere Cassini will begin to tumble and very shortly thereafter traveling it like 75 thousand miles an hour will burn up in the atmosphere of Saturn be vaporized basically in Saturn's atmosphere probably some of the legacy science of Cassini involves two of its nose and Sela despite all much to our surprise this tiny moon Enceladus only 300 miles across bright white and I see you expecting to be frozen solid instead we found fractures of the South Pole none of these four fractures that we nicknamed tiger stripes there were jets of material going out into space water vapor and ice particles and these contain the whole host of constituents and Cassini could fly through that jet and taste what's coming out from those they told us a lot about the subsurface ocean that's underneath Enceladus this icy crust we found out it was salty I've had a pH very similar to the earth and also we found evidence of excess hydrogen and these tiny nano silica grains that could only grow in very hot water leaving us to conclude that there's hydrothermal vents on the seafloor on the rocky core of Enceladus and we know on earth that around these hydrothermal vents you can get different kinds of life deep in the ocean in the earth where no sunlight penetrates so we wonder could there be life on this tiny ocean world and solidus then there's giant Titan 10 times larger than Enceladus thick atmosphere thick nitrogen atmosphere very similar to the earth we actually landed a European belt Huygens probe parachuted down through the thick atmosphere and landed on the surface of Titan sent back pictures as it was landing information about the atmosphere and about the surface as well and what a supplies was in store because before all we could see was this hazy ball of Titan and to penetrate through that haze now we could see lakes and seas of liquid methane river channels methane plays the role on titan that water plays on the earth we could have methane rain nothing's going through the river channels filling the lakes and seas but methane breaks apart in the upper atmosphere of Titan forms these grains that fall to the surface and possibly form the giant sand dunes that are around the equatorial region of Titan itself so what an amazing place to explore so I think one of my very favorite images is this montage of pictures well that's the backlit Saturn basically Saturn is covering up the Sun and the sunlight is shining through all around the disk of Saturn and all of the Rings the e-ring the G ring the main rings themselves are all glowing in this particular image what's really special about it is that in this image as well is the earth the earth is there and if you look carefully you can see the earth in the moon Mars and Venus are also part of this giant montage and it sort of captures our place in the solar system - you'll be looking back at the earth and Saturn a billion miles away I'll see essentially this pale blue dot as Carl Sagan was saying where everyone you ever knew and everyone who has ever lived and what ever died is on this pale blue dot that picture is really like on it oh I think that'll be a very sad day you know I've worked on the mission for almost three decades and to say goodbye to this wonderful little spacecraft that's returned so much information about the Saturn system basically really written the textbooks about Saturn I think more importantly for me is going to be saying goodbye to my Cassini family I've worked with so many of these people we've gotten to know each other our kids have grown up together please take advance together and so kind of as we all go our separate ways that will be a sad goodbye as well but in a certain sense Cassini is growth and ending and a beginning maybe kind of like a high school graduation everyone's have been together focused on the same goal we've gotten there and now may profound like seeds we're all going to go out work on other missions take our knowledge whether it's in science or engineering and use it to for missions like to rope a clipper or Juno or Mars 2020 for missions that haven't even been started yet to go forward and take those experiences and that knowledge on to the next generation