NASA's Cassini probe is on a collision course with Saturn

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, a spectacular end has been planned. Traveller from Earth. [MUSIC] In the skies of Saturn, the journey ends [MUSIC]. As Cassini becomes part of the planet itself. [MUSIC] My name is Linda Spilker. I am the Cassini project scientist. I've 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 a team of 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 try and balance between the different science disciplines and find the best science possible. [MUSIC] [MUSIC] Right now the Cassini spacecraft is in a set of orbits called the grand finale. What we did is use a tightened flyby to propel us all the way across Saturn's rings and right now we're diving between the gap between the rings and the planet. Flying in a place that no space craft has flown before, giving back measurements back 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 Kissimmee's final plunge. And on the final plan for what we're doing is getting a nudge from Titan, we call it Titan's Goodbye Kiss. It's a distant fly by about 120,000 km and that pushes us such that we could actually go into Saturn's atmosphere. Our thrusters will be fighting against the atmosphere as we go in. Will be sending back data until the very last second from our eye in a 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 at Like 75,000 miles an hour, will burn up in the atmosphere of Saturn, be vaporized basically in Saturn's atmosphere. [MUSIC] Probably some of the legacy signs of Cassini involves two of its moons, Enceladus and Titan Much to our surprise this tiny [UNKNOWN] some 300 miles across bright white and icy, we expected it to be frozen solid. Instead we found fractures at the South Pole, out of these four fractures that we nicknamed tiger stripes were jettison material going out into space. Water vapor and ice particles and these contained a whole host of constituents and Cassini could fly through that jet and taste what's coming out from those. It told us a lot about the sub-circus ocean that's underneath and Callidus' icy crust. We found out it was salty, had a ph very similar to the Earth. Also, we found evidence of excess hydrogen, there was tiny nano silica grains that could only grow in hot water, leading us to conclude that there's hydrothermal vents in the sea floor, in the rocky core of [UNKNOWN]. And we know on earth, around these hydrothermic vents, we can get different forms of life, deep in the ocean No sunlight penetrates. So we wonder, could there be life on this tiny ocean world in Enceladus. Then there's giant Titan, ten times larger than Enceladus, thick atmosphere, thick nitrogen atmosphere very similar to the Earth. We actually landed a European built Huygens probe, parachuted down through the thick atmosphere, 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 surprise was in store because before all we could see was this hazy ball of Titan. And to penetrate through that haze, now could see lakes and seas of liquid methane, river channels. Methane plays the role on Titan, but water plays on the Earth. You can have methane rain Methane flowing to the river channels, filling the lights of seas. Methane breaks apart and we have the atmosphere of Titan. Forms these grains that crawl down 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. I think one of my very favorite images is this montage of pictures that's the backlit Saturn basically Saturn is covering up the sun, and the sunlight is shinning through all 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. Earth is there, and if you look carefully, you can see the Earth and the Moon. Mars and Venus are also part of this giant montage, and it sort of Captures our place in the solar system to be looking back at the Earth from Saturn a billion miles away and see essentially this pale blue dot. As Carl Sagan once said, where everyone you ever knew and everyone who has ever lived and ever died is on this pale blue dot, and that picture is really iconic. [MUSIC] I think that'll be a very sad day. 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. [MUSIC] Basically rewritten the textbook to that status. I think more importantly, for me, it's going to be saying goodbye to my [UNKNOWN] family. I've worked with so many of these people, we've gotten to know each other, our kids have grown up together, we've taken vacations 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 both an ending and a beginning. Maybe kind of like a high school graduation. Everyone has been together focused on the same goal or have gotten there and people are kind of like seeds. We're all going to go out work on other missions, take on knowledge whether it's in science or engineering, And use it for missions like Europa Clipper or Juno or Mars 2020 or missions that haven't even been started yet to go forward and take those experiences and that knowledge onto the next generation.