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NASA's Cassini Spacecraft Begins Its Final Mission Before Plunging Into Saturn (popsci.com)
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.
... to cry a little during a NASA promotional video?
(I admit I cried a bit during some of the "Farewell to Rosetta" videos, too)
will not give any more information and saturn is a very long ways away. i do not think i would cry but it is a loss non the less and hopfully we cn get another out there.
Prime Directive and all....
WTF are these guys in their nice, air-conditioned office buildings doing that's so daring?
"I don't know, therefore Aliens" Wafflebox1
Life with a potentially separate origin to life on earth is of interest to science. Therefore you don't destroy it. The idea is that you don't destroy something you want to study, because once it is destroyed you won't be able to study it.
I hope that breaks it down for you.
I do not want your cheap brainburning drugs. They are useless for work. And I am a working man today.
They're anthropomorphising the plucky little space probe. Let them have their fun.
I do not want your cheap brainburning drugs. They are useless for work. And I am a working man today.
So, let's deliberately put water bears on Saturn to limit the risk to Titan and Enceladus? How can they be so sure that there isn't a layer of Saturn with composition, pressure, and temperature favorable to life?
So, let's deliberately put water bears on Saturn to limit the risk to Titan and Enceladus? How can they be so sure that there isn't a layer of Saturn with composition, pressure, and temperature favorable to life?
Aside from it being a gas giant, Saturn's huge gravity well will pull Cassini in hard and fast, vaporizing every little bit of it back into elements and simple compounds (like oxides of the metals). No bugs can survive this plunge.
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?
Oh fuck off, troll/retard (pick one).
"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."
Invasion of the Water Bears!
*DUN DUN DUN!*
They came from inner space! Water Bears from the blue marble!
*Eeeeeeeeeeeeeeeek!*
...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?
For all we know water bears could already be there.
Alien life? It's water bears, everywhere.
What follows Cassini. The mission has been a wild success, all the more sweet as is was roundly critized during development as a Battlestar Galactica. I would argue it should be NASA policy to have an active orbiter mission around each of the major planets at all times. Venus and the outer planets, Uranus and Neptune, have been particularly neglected. Titan should also be made the highest priority for investigation after Mars.
I wonder what K'Breel will make of this ? Not only are the devils from the blue planet attacking Mars they're now attackign Saturn !
In fact I wonder who K'Breels equivalent is on Saturn ?
To the core yes - the poster (presumably) meant another, higher, layer may support life (maybe even a mostly solid layer due to pressure).
The ACs are even stupider than usual this morning. If you have to ask why we wouldn't want to contaminate a potential life-bearing body or why entering a gas giant's atmosphere at high speed would prevent any contamination from occurring there, you should be in this thread.
Why don't you let go of the keyboard and do something "daring"?
Those two words caught my eye, too. I was thinking they should save the adjectives for missions where the actually apply.
Life with a potentially separate origin to life on earth is of interest to science. Therefore you don't destroy it. The idea is that you don't destroy something you want to study, because once it is destroyed you won't be able to study it.
I hope that breaks it down for you.
How do we know we're not here because some other race should have been more careful with their probes?
Besides, as far as they know there's nothing there anyway and then we can study how these things do on which ever moon.
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Also might make sense not to irradiate those moons with Cassini's Plutonium 238, no one mentions that ?
where I've already been 21 times before... Not quite Star Trek ;p
tardigrade don't care
Oh great, now the sirens busted AWOOGA AWOOGA abandon ship!
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"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?"
the preceding comment is my own and in no way reflects the opinion of the Joint Chiefs of Staff
What if the nuclear power generator ignites Saturn and creates a new star? Oh, the humanity....
How do we know we're not here because some other race should have been more careful with their probes?
We don't. Hella unlikely though. Given the interconnected biology of life on esrth, it would have had to happen very early on.
Besides, as far as they know there's nothing there anyway and then we can study how these things do on which ever moon.
A colonization experiment would need to be more well thought out than "let's crash this doodad into this possibly life supporting place and see what happens!"
The biggest impediment to that idea is that it is no where near as interesting as finding that there is life on an another body in the universe.
We already know that the little critters named in the article - the tardigrades - are little champions of survival in ridiculous conditions, such as in space http://www.smithsonianmag.com/...
Now, imagine if a properly sterilized probe were to find tardigrades on a non terran body that we could prove did not come from earth.
The shepherds did so well protecting the flock that the sheep no longer believed that wolves existed.
Think of how spacecraft glow white-hot when reentering Earth's atmosphere - that will generally completely vaporize anything not really massive or protected with heat shielding long before it reaches the surface.
That heat is due to friction converting orbital kinetic energy to heat, and anything in orbit that hits Earth's atmosphere will be traveling at at least low-orbit speeds of 7.8km/s so there's a LOT of kinetic energy to shed. 30MJ/kg in fact - compare to the 4MJ/kg of TNT.
Saturn meanwhile is about 95 times more massive than Earth, with 9.5 times the radius (measured at 1 bar). Circular orbital velocity is given by v = sqrt(G * M_planet / r), so low orbit speed will be roughly sqrt(10) times faster than for Earth, or 10x the kinetic energy.
--- Most topics have many sides worth arguing, allow me to take one opposite you.
We don't.
The point though is that there is a lot to be learned from life that arose independently from Earth's, far, *far* more than can be learned from seeing how Earth life might manage to survive in such harsh conditions. At present our understanding of what life is, is based on what evolved from likely a single ancient microbe - all based on DNA and the same basic chemistry. Life that arose completely independently, or even that just spent several billion years evolving in a different direction, would vastly increase our understanding.
Besides, the moons will almost inevitably be contaminated with Earth life eventually - doesn't it make sense to try to put that off until we've done at least some of the science that can only be done before contamination?
And it's not just a matter of trying to avoid wiping out native life, it's a matter of being able to find it in the first place. Native life may well be hidden and/or non-obvious, and we really don't know what we're looking for. We'll have to think up out all sorts of sneaky tricks like detecting unusually complicated chemical products or chirally biased molecules in the environment in order to focus the search into areas of a more manageable size. And none of that will work if Earth life has managed to colonize it - any detection of potential life becomes almost certainly a detection of Earth life, and you're back to square one - an exhaustive search of a massively inhospitable planet.
--- Most topics have many sides worth arguing, allow me to take one opposite you.
By slamming Cassini into Saturn, aren't we going to cheese off the Hydrogues living within Saturn causing them to destroy all life on Earth?
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.
Nope, no sig
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.
Table-ized A.I.
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 so they wouldn't be breeding like crazy. They do go into hibernation without water or oxygen and can last in that state for at least a hundred years
Median lethal doses of for tardigrades was 4400 Gy gamma radiation outside of water over 48 hours, though over 1000 gys made them sterile.
Humans will die despite medical treatment after 8 sv of radiation. I found that solar flares could produce 60 sv to an astronaut in a space suit. But after half an hour of searching, I couldn't find how much radiation a tardigrade would be exposed to over 10 years in whatever shielding is available on the probe.
There were thousands of articles on "how much radiation are you puny humans exposed to in the cushy ISS before NASA makes you come back down a few months later" and even more articles along the lines of "Human astronauts incompetent to undergo cryptobiosis, again in their nice space ships, would get too much radiation on just a little hop to mars." BUT NO FUCKING NUMBERS! Ugh, so unscientific AND anthropocentric!
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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, though, if human explorers visit Saturn in the future to find giant scary water bears, like manatees with teeth. "Damn you, Cassini!"
(Obligotory meme reference)
Table-ized A.I.
20 years before it started, for example.
The directive the trek captains always made excuses around?
"But I have to protect our crew-mate Riker from growing 2 giant green dicks after screwing a Tenticon!"
Table-ized A.I.
"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."
-Styopa
The idea is that you don't destroy something you want to study, because once it is destroyed you won't be able to study it.
I think J. Robert Oppenheimer would strongly disagree with you.
But that's not the whole story...the mass, aerodynamics and thermal characteristics of the entering body also matter.
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.
Is it not also possible that there is already life there that originated from Earth (or Mars, if it ever had non-Earth-based life)? I'm thinking of life-bearing fragments ejected into space as the result of large asteroid impacts in earlier times. It's believed that some number of meteorites found on Earth originated on Mars, While Saturn is much further away from Earth than Mars, I wonder if it would be possible for life-containing rocks from Earth might be ejected by large asteroid strikes and eventually reach the moons of Jupiter or Saturn.
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.
"I don't know, therefore Aliens" Wafflebox1
Well to be fair "kill the little f-ers with fire" is as sterilization strategies go an improvement over what they panned for the Voyager probes which was "try not to hit any planets".
Turns out Saturn also harbors a microbe ecosystem in a layer of its atmosphere..........and here come the water bears!!!!!!
Finding God in a Dog
It's a gamble and big gambles are daring. If I bet my life savings on a football game (stupid), that's bold and daring. It doesn't matter if that game is in my backyard or on the other side of the Earth. It is still a risk. The people working on the mission face real life consequences for its failure. I'd argue they've already done really well and so there isn't much consequences here, but your argument that range plays a roll is clearly silly.
NASA actually considering the ideas behind the prime directive...
True. But we're talking about a satellite here - not a device traditionally known for its gracefully aerodynamic lines or need for reentry style thermal shielding. And we don't have to actually vaporize the whole thing - just get it hot enough to sterilize it.
Also, I think I lied earlier. On further reflection I believe it's the bow-wave compression that actually superheats the air on reentry, not air resistance. Not that it makes a huge difference unless you're studying reentry capsule design.
--- Most topics have many sides worth arguing, allow me to take one opposite you.
That is indeed a possibility. Just as it's a possibility that Earth life actually originated on Mars, which would have cooled faster and become potentially hospitable for life far earlier than Earth. And that wold make it a lot less interesting in a lot of ways, but there would still be many fascinating things learn from potentially hundreds of millions of years of isolation, enough to make the Galapagos islands seem positively pedestrian. And from a genetic engineering perspective the similarities might make what we learn far more valuable on Earth.
--- Most topics have many sides worth arguing, allow me to take one opposite you.
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 the right temperature, its hoppy scents wafting), while a song by Kyuss or Fu Manchu plays in the background and you reflect on how, despite all your problems and uncertainties about the future, life isn't really all that bad. (Sip drink here.) It's not boldly daring to be playing Joust, especially under those conditions, but attacking the Unbeatable(?) Pterodactyl in mid-air is boldly daring within the context of the game.
Similarly, orbits with higher-than-usual collision chances can be boldly daring, within the context of the space probe mission.
[Beer commercial.] Life is hard. Boldy dare to try ours! [/beer commercial]
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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. :/
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.
"I don't know, therefore Aliens" Wafflebox1
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.
"I don't know, therefore Aliens" Wafflebox1
A colonization experiment would need to be more well thought out than "let's crash this doodad into this possibly life supporting place and see what happens!"
Well, it's more of an 'after the events' plan.
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Wouldn't it be great if this then initiated a V***ger-type plotline?
What's that Indian chick that shaved her head doing these days?
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.
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 (thus risking the loss of all the knowledge that we would have obtained). It might even rise to the level of "audaciously bold". But not adventurously courageous. (Although... if the scientist who suggested/designed and programmed this maneuver on a brand new probe would get fired if he botched it up, that would be daring!)
But this craft is going to die anyway. There's just zero risk in this situation.
"I don't know, therefore Aliens" Wafflebox1