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NASA's Cassini Spacecraft Begins Its Final Mission Before Plunging Into Saturn (popsci.com) 86

NASA has announced that their Cassini spacecraft will begin its final mission before slamming into Saturn on April 23rd. The "final mission" consists of a series of dives through a 1,500-mile-wide gap between Saturn and its rings. "No spacecraft has ever gone through the unique region that we'll attempt to boldly cross 22 times," said Thomas Zurbuchen, associate administrator for the Science Mission Directorate at NASA Headquarters in Washington. "What we learn from Cassini's daring final orbits will further our understanding of how giant planets, and planetary systems everywhere, form and evolve. This is truly discovery in action to the very end." The spacecraft will then dive into the gas giant's atmosphere, where it will "break apart, melt, vaporize, and become a part of the very planet it left Earth 20 years ago to explore," Cassini project manager Earl Maize said. Popular Science explains in its report why Cassini has to die: Some space probes are allowed to keep orbiting their targets in perpetuity after their mission ends -- like the Dawn spacecraft at the dwarf planet Ceres. But things are a lot more complicated around Saturn. Whereas Ceres is essentially just a really big rock with no moons, Saturn has 62 satellites, at last count. The gravitational push and pull from those moons -- especially the largest, Titan -- wreak havoc on Cassini's trajectory, which it normally corrects by burning fuel. But the spacecraft's fuel is running out, and ultimately its fate is sealed by its own discoveries; scientists don't want to risk the spacecraft crashing into Titan and Enceladus, which may be capable of supporting life. Although Cassini launched 20 years ago, experiments on the Space Station have suggested microbes can survive for years in the extreme temperatures, radiation, and airless vacuum of space. If NASA were to accidentally put water bears on Enceladus, the tiny Earthlings could potentially wipe out any native lifeforms that the moon may harbor, and/or complicate the search for those alien organisms later. This is why Cassini must die now, while NASA can still control its last swan dive.
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NASA's Cassini Spacecraft Begins Its Final Mission Before Plunging Into Saturn

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  • WTF are these guys in their nice, air-conditioned office buildings doing that's so daring?

    • by Maritz ( 1829006 ) on Thursday April 06, 2017 @04:59AM (#54184001)
      They're anthropomorphising the plucky little space probe. Let them have their fun.
    • Oh, maybe remotely piloting a very expensive probe, with hours long time lag, in orbit around a very cluttered planet and very complex math and projections to assist with what needs to be where.

      Imarine playing a driving sim, where you had to plan the entire race from before it started and had no real time control to move away from something coming at you and 0 options of a do over

      So, plenty to be daring about.

      • by Nutria ( 679911 )

        Nothing you do -- even if it's important and the craft is really expensive -- is bold or daring when you are more than 746,000,000 miles from the action.

        Nothing.

        • Daring: adventurous or audaciously bold // adventurous courage

          Adventurous: willing to take risks or to try out new methods, ideas, or experiences.

          Bold: showing an ability to take risks; confident and courageous.

          So..... flying a very expensive craft, billions of miles away, on hours long time lag, with limited fuel, in a crowded orbit that no human eye has ever seen directly, some how isn't bold or daring?

          Yeah. Sure thing. :/

          • by Nutria ( 679911 )

            They've been controlling interplanetary probes using 335 year old formulae for 35 years.

            Nothing about sitting in a comfy, air-conditioned shirt-sleeve room and programming maneuvers for a 20 year old craft which you've been flying around Saturn for 12 years is risky, audaciously bold, or adventurously courageous.

            Now... if this were a manned expedition, that would be bold and daring!!! Why? Because that's actual risk.

            • You don't understand what the word risk means.. Nor do you seem to understand much more outside your very limited little thoughts.

              Just because a human life isn't hanging in the balance here doesn't mean it's not bold, daring or risky.

              • by Nutria ( 679911 )

                Sure, human life isn't all that hangs in the balance, if for nothing else than since the dawn of humanity, girls have been crushing the souls of ardent admirers who've tried to do something more than yearn from afar.

                And we risk our own money all the time by investing in new ventures. But... we risk our own money: failure means dropping down the socio-economic ladder, with all that entails.

                It would also be a risky move if Cassini were just arriving at Saturn and hadn't done any of it's planned science yet (

    • by Tablizer ( 95088 )

      WTF are these guys in their nice, air-conditioned office buildings doing that's so daring?

      I challenged the boss's bonehead idea and thus might get fired. Like Cassini, I'll also have to say goodbye to my rings and be plunged into the scenery.

    • by Sloppy ( 14984 )

      You know how when you're playing Joust, you sometimes attack the Unbeatable(?) Pterodactyl in mid-air? (Not taking advantage of the conditions where it sometimes flies at a conveniently-placed level where you can stand on a platform and automatically kill it, but where you actually have to hover carefully.)

      This can be a boldly daring act, even if you're playing in an air-conditioned bar at 4:30pm on a hot spring day, with a pint of your favorite American IPA on a little table next to the machine (at just t

      • by Nutria ( 679911 )

        This can be a boldly daring act.

        What's the consequence of failure of failing to defeat the Pterodactyl? Nothing. Your avatar dies and instantly regenerates.

        Thus, not a boldly daring act.

        attacking the Unbeatable(?) Pterodactyl in mid-air is boldly daring within the context of the game.

        That makes it a pseudo-boldly daring act, not an actual boldly daring act.

        Now... if you were strapped to electrodes which gave you a long painful jolt every time you "died" in a video game, then attacking the Unbeatable Pterodactyl in mid-air would actually be boldly daring.

  • scientists don't want to risk the spacecraft crashing into Titan and Enceladus, which may be capable of supporting life...if NASA were to accidentally put water bears on Enceladus, the tiny Earthlings could potentially wipe out any native lifeforms that the moon may harbor...This is why Cassini must die now, while NASA can still control its last swan dive.

    Man. Whoever created those dialogs must be a movie director.

    We are getting a new awesome space movie soon, right?

    • by Tablizer ( 95088 )

      Whoever created those dialogs must be a movie director.

      You mean wants to be. There's a reason they are not.

    • by necro81 ( 917438 )

      We are getting a new awesome space movie soon, right?

      Not anytime soon, no. Cassini was the last of the real flagship, multi-billion dollar planetary exploration programs. The Jovian Icy Moons / Europa mission may or may not proceed. An orbiter mission to Neptune or Uranus isn't scientifically sexy enough to warrant the funding. There was a lot of scraping to get the relatively low-cost Pluto Express launched; a redux of Voyager is astromechanically impractical. We have Juno in orbit around Jupiter, b

  • by muecksteiner ( 102093 ) on Thursday April 06, 2017 @07:35AM (#54184333)

    ...but would it not also have been an option to slingshot Cassini out of the local system of Saturn altogether? (say, via a close fly-by of Titan, or something) To set it on some really long-shot trajectory across the solar system, from which it could conceivably be collected in a few decades once we get the hang of proper space propulsion?

    That way, a truly historic artefact could have been preserved, without risking contamination of Saturn's moons?

    • by dreamchaser ( 49529 ) on Thursday April 06, 2017 @08:26AM (#54184455) Homepage Journal

      There isn't enough fuel left to do that. They are using just about every last drop to do science.

    • FTFA. They're pretty much out of fuel. They cant.

    • by athmanb ( 100367 )

      Also there's no way of tracking an object of that size in a solar orbit so you'd never be able to find it again to collect. Parts of Apollo 10 are still orbiting the sun but there's no way of finding it either.

    • by xession ( 4241115 ) on Thursday April 06, 2017 @12:13PM (#54185693)
      You are absolutely right that it definitely could have gotten enough delta-v to get to any of the outer planets by doing several maneuvers while doing a slingshot orbit around Titan and Saturn. They explored this option pretty extensively with all of the outer planets, including Pluto.

      The problem came down two-fold. One, they would have had to propose a somewhat costly extension to a spacecraft already on borrowed time. And Two, they would have had to leave the Saturn system a while ago, cutting out the last year to year and a half worth of observations to send it off onto another mission that it may not make it to.

      Ultimately they decided, the maximum benefit from the spacecraft would be gained from keeping it in the Saturn system and destroying the spacecraft at the end to protect Titan and Enceledus.
  • If NASA were to accidentally put water bears on Enceladus, the tiny Earthlings could potentially wipe out any native lifeforms that the moon may harbor, and/or complicate the search for those alien organisms later.

    For all we know water bears could already be there.
    Alien life? It's water bears, everywhere.

    • Maybe, but if Cassini crashes on Enceladus and later probes find water bears, there will be doubt if they were there before Cassini crashed. If Cassini smashes into Saturn and later probes find water bears on Enceladus, then that will be historic news.

      • If Cassini smashes into Saturn and later probes find water bears on Enceladus, then that will be historic news

        Why? Because they were smart enough to use the escape pods? Or that NASA built water bear escape pods into Cassini in the first place?

        • by Tablizer ( 95088 )

          Cassini actually flew through the higher parts of Enceladus's water jets to sample them. It's possible residual life on the probe could have been blown off and drifted down to the moon's surface. Thus, if we later find earth-like life on that moon, we cannot rule out probe-related contamination. It was deemed highly unlikely, but ya never know.

          If the jets spew dust-sized particles also, and a spore ends up attaching itself to one, it could gain some radiation protection, and if it relatively quickly falls b

  • "It means," said Marvin, "that the ship is going to dive into Saturn. Saturn... Dive. It's very simple to understand. What do you expect if you steal Hotblack Desiato's stunt ship?"
  • What if the nuclear power generator ignites Saturn and creates a new star? Oh, the humanity....

  • The gaps between the rings are very, very empty. Even the rings are mostly empty. People think it's like they've seen in movies when someone "hides in the asteroid field", ducking and dodging all those big rocks. It's really quite empty.

    I mean, you wouldn't just drive through like there's nothing there, because there's no such thing as a minor encounter at those closing speeds. But going through the gaps in the rings should go pretty much as planned.

  • Tardigrades are incredibly durable, and it's good not to just go shitting all over other planetary bodies, but I was wondering how overly cautious they're being. So I decided to try to figure it out, but I'm missing how much gamma radiation they'd be exposed to in ten years.

    For anyone else curious:

    Tardigrades don't thrive in extreme environments [wikipedia.org] so they wouldn't be breeding like crazy. They do go into hibernation without water or oxygen [wikipedia.org] and can last in that state for at least a hundred years [carleton.edu]

    Median [nih.gov]
    • I wonder why they only mentioned Tardigrades ("water bears")? There's plenty of bacteria that's even more durable in space, and there's probably far more of their spores on the probe than Tardigrades.

      Tardigrades get attention because they are durable multi-cellular animals rather than single cells, and thus a bit "more like us". But single-celled organisms like bacteria still hold the durability records because they have fewer parts to "break" from radiation and temperature extremes.

      It would be a hoot, thou

  • by argStyopa ( 232550 ) on Thursday April 06, 2017 @12:11PM (#54185675) Journal

    "While we feared a resumption of direct attacks since the missile strike least year (their code name for the mission was "Schiaparelli"), the 3rd planet merely continues their siege of Mother Mars: their land-attack rovers plowing implacably above our heads on the Martian surface, continue to drill/probe to find an entrance to our homes. Their reconnaissance orbiters taking constant pictures forcing our defense forces to remain camouflaged. All Martian citizens are ordered to remain on alert! Do not go outside! Do not approach these murderous killing machines!

    However, Martian Military Intelligence has also reported a pending assault on our peace-loving allies of the Ringed Planet. The Water Planet has sent a massive Death-Star which has heretofore patrolled above the Skies of Saturn, seeking any opportunity to slaughter any innocent transport vehicle it would come across, compelling a complete cessation of Qrgrzantik shipments and triggering the Qrgrzantik shortage which we continue to suffer. New information gained by our brave operatives in place on the 3rd planet suggests that in frustration at their inability to engage the Saturnian Space Navy, this death-ship (code name: Cassini) is now intending a suicidal death strike into the Saturnian home-cloud. This is the exact sort of attack such frustrated barbarians would finally attempt.

    We offer our brethren-in-arms in Saturn our hopes and prayers that all will be safe.
    We now return you to regularly scheduled programming.
    MSN out."

  • The first sentence of this article says "NASA has announced that their Cassini spacecraft will begin its final mission before slamming into Saturn on April 23rd". This makes it sound like Cassini will slam into Saturn on April 23rd, which is not true. They will begin their final mission on April 23rd causing Cassini to slam into Saturn sometime in September.

  • Turns out Saturn also harbors a microbe ecosystem in a layer of its atmosphere..........and here come the water bears!!!!!!

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